0001485003-23-000090 | 10-K | XBRL Viewer

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Cover - USD ($) $ in Millions	12 Months Ended
Cover - USD ($) $ in Millions	Dec. 31, 2022	Feb. 21, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36296
Entity Registrant Name	Sesen Bio, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-2025616
Entity Address, Address Line One	245 First Street
Entity Address, Address Line Two	Suite 1800
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	444-8550
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	SESN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 161.6
Entity Common Stock, Shares Outstanding		203,492,202
Documents Incorporated by Reference	Portions of the registrant’s Definitive Proxy Statement relating to the 2023 Annual Meeting of Stockholders ("2023 Proxy Statement") or an amendment to this Annual Report on Form 10-K are incorporated by reference into Part III of this Annual Report on Form 10-K. The registrant will file the 2023 Proxy Statement or an amendment to this Annual Report on Form 10-K with the Securities and Exchange Commission within 120 days of December 31, 2022.
Entity Central Index Key	0001485003
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2022
Audit Information [Abstract]
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 112,553	$ 162,636
Short term marketable securities	54,366	0
Restricted cash	21,000	0
Accounts receivables	0	21,011
Other receivables	825	3,482
Prepaid expenses and other current assets	400	18,476
Total current assets	189,144	205,605
Non-current assets:
Restricted cash	30	20
Property and equipment, net	0	43
Intangible assets	0	14,700
Goodwill	0	13,064
Long term prepaid expenses	0	7,192
Other assets	0	123
Total non-current assets	30	35,142
Total Assets	189,174	240,747
Current liabilities:
Accounts payable	1,233	2,853
Accrued expenses	29,636	8,255
Other current liabilities	115	460
Total current liabilities	30,984	11,568
Non-current liabilities:
Contingent consideration	0	52,000
Deferred tax liability	0	3,969
Deferred revenue	0	1,500
Total non-current liabilities	0	57,469
Total Liabilities	30,984	69,037
Stockholders’ Equity:
Preferred stock, $0.001 par value per share; 5,000,000 shares authorized at December 31, 2022 and 2021; no shares issued and outstanding at December 31, 2022 and 2021	0	0
Common stock, $0.001 par value per share; 400,000,000 shares authorized at December 31, 2022 and 2021; 202,759,043 and 199,463,645 shares issued and outstanding at December 31, 2022 and 2021, respectively	202	199
Additional paid-in capital	494,675	487,768
Accumulated deficit	(336,141)	(316,257)
Other comprehensive loss	(546)	0
Total Stockholders’ Equity	158,190	171,710
Total Liabilities and Stockholders’ Equity	$ 189,174	$ 240,747

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021	May 03, 2021	May 02, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	400,000,000	400,000,000	400,000,000	200,000,000
Common stock, shares issued (in shares)	202,759,043	199,463,645
Common stock, shares outstanding (in shares)	202,759,043	199,463,645

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement [Abstract]
Total revenue	$ 40,000	$ 26,544	$ 11,236
Operating expenses:
Research and development	38,594	25,312	29,191
General and administrative	39,787	29,393	14,302
Restructuring charge	11,764	5,528	0
Intangibles impairment charge	27,764	31,700	0
Change in fair value of contingent consideration	(52,000)	(56,840)	(11,180)
Total operating expenses	65,909	35,093	32,313
Loss from Operations	(25,909)	(8,549)	(21,077)
Interest income	1,854	17	224
Other income (expense), net	296	(77)	(99)
Loss Before Taxes	(23,759)	(8,609)	(20,952)
Benefit (provision) from income taxes	3,875	8,273	(1,445)
Net Loss After Taxes	(19,884)	(336)	(22,397)
Deemed Dividend	0	0	(147)
Net loss attributable to common stockholders - basic	(19,884)	(336)	(22,544)
Net loss attributable to common stockholders - diluted	$ (19,884)	$ (336)	$ (22,544)
Net loss per common share - basic (in dollars per share)	$ (0.10)	$ 0	$ (0.19)
Net loss per common share - diluted (in dollars per share)	$ (0.10)	$ 0	$ (0.19)
Weighted-average common shares outstanding - basic (in shares)	200,546	182,323	118,221
Weighted-average common shares outstanding for diluted (in shares)	200,546	182,323	118,221
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	License [Member]	License [Member]	License [Member]

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (19,884)	$ (336)	$ (22,397)
Unrealized loss on marketable securities	546	0	0
Total comprehensive loss	$ (20,430)	$ (336)	$ (22,397)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	ATM Facility	Common Stock	Common Stock ATM Facility	Additional Paid-in Capital	Additional Paid-in Capital ATM Facility	Accumulated Other Comprehensive Loss Investments	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2019			106,801,409
Beginning balance at Dec. 31, 2019	$ (26,700)		$ 107		$ 266,717		$ 0	$ (293,524)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(22,397)							(22,397)
Share-based compensation	$ 1,757				1,757
Exercises of stock options (in shares)	12,000		12,000
Exercises of stock options	$ 13				13
Sales of common stock under 2014 ESPP (in shares)			28,186
Sales of common stock under 2014 ESPP	11				11
Exercise of common stock warrants (in shares)			238,110
Exercises of common stock warrants	131				131
Issuance of common stock and common stock warrants, net of issuance costs (in shares)				33,369,942
Issuance of common stock and common stock warrants, net of issuance costs	37,958			$ 33		$ 37,925
Unrealized loss on marketable securities	0
Ending balance (in shares) at Dec. 31, 2020			140,449,647
Ending balance at Dec. 31, 2020	(9,227)		$ 140		306,554		0	(315,921)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(336)							(336)
Share-based compensation	$ 5,143				5,143
Exercises of stock options (in shares)	34,000		33,610
Exercises of stock options	$ 42				42
Exercise of common stock warrants (in shares)			2,048,059
Exercises of common stock warrants	1,126		$ 2		1,124
Issuance of common stock and common stock warrants, net of issuance costs (in shares)				56,932,329
Issuance of common stock and common stock warrants, net of issuance costs		$ 174,962		$ 57		$ 174,905
Unrealized loss on marketable securities	$ 0
Ending balance (in shares) at Dec. 31, 2021	199,463,645		199,463,645
Ending balance at Dec. 31, 2021	$ 171,710		$ 199		487,768		0	(316,257)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(19,884)							(19,884)
Share-based compensation	$ 6,909				6,909
Exercises of stock options (in shares)	2,000		2,031
Exercises of stock options	$ 1				1
Exercise of common stock warrants (in shares)	0
Issuance of common stock for RSU vesting (in shares)			3,293,367
Issuance of common stock for RSU vesting	$ 0		$ 3		(3)
Unrealized loss on marketable securities	$ (546)						(546)
Ending balance (in shares) at Dec. 31, 2022	202,759,043		202,759,043
Ending balance at Dec. 31, 2022	$ 158,190		$ 202		$ 494,675		$ (546)	$ (336,141)

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
ATM Facility
Issuance costs	$ 5.4	$ 1.2

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash Flows from Operating Activities:
Net loss	$ (19,884)	$ (336)	$ (22,397)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	13	85	122
Share-based compensation	6,909	5,143	1,757
Change in fair value of contingent consideration	(52,000)	(56,840)	(11,180)
Intangibles impairment charge	27,764	31,700	0
Net amortization of discounts and premiums on marketable securities	(913)	0	0
Changes in operating assets and liabilities:
Accounts receivable (net)	21,010	(24,493)	0
Other receivables	2,658	0	0
Prepaid expenses and other assets	18,076	(17,964)	(1,304)
Long term prepaid expenses	7,192	0	0
Other assets	123	0	0
Accounts payable	(1,620)	(249)	1,200
Accrued expenses and other liabilities	17,067	(4,424)	(2,035)
Deferred revenue	(1,500)	(1,500)	3,000
Net cash provided by (used in) operating activities	24,895	(68,878)	(30,837)
Cash Flows from Investing Activities:
Purchase of marketable securities	(128,999)	0	0
Proceeds from maturity of marketable securities	75,000	0	0
Disposal of equipment	30
Purchases of equipment		(4)	(8)
Net cash used in investing activities	(53,969)	(4)	(8)
Cash Flows from Financing Activities:
Proceeds from issuance of common stock under ATM Offering, net of issuance costs	0	174,962	37,958
Proceeds from exercises of stock options	1	42	13
Proceeds from exercises of common stock warrants	0	1,126	131
Proceeds from sale of common stock pursuant to ESPP	0	0	11
Net cash provided by financing activities	1	176,129	38,113
Net (decrease) increase in cash, cash equivalents and restricted cash	(29,073)	107,247	7,268
Cash, cash equivalents and restricted cash - beginning of period	162,656	55,409	48,141
Cash, cash equivalents and restricted cash - end of period	133,583	162,656	55,409
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	112,553	162,636	52,389
Short term restricted cash	21,000	0	3,000
Long term restricted cash	30	20	20
Total cash, cash equivalents and restricted cash	133,583	162,656	55,409
Supplemental cash flow disclosure:
Cash paid for amounts included in the measurement of lease liabilities	127	174	154
Supplemental disclosure of non-cash operating activities:
Right-of-use assets obtained in exchange for lease obligations	0	0	290
Supplemental disclosure of non-cash financing activities:
Deemed Dividend on adjustment of exercise price on certain warrants	$ 0	$ 0	$ 147

DESCRIPTION OF BUSINESS	12 Months Ended
DESCRIPTION OF BUSINESS	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS	DESCRIPTION OF BUSINESS Sesen Bio, Inc. ("Sesen Bio" or the “Company”), a Delaware corporation formed in February 2008, is a late-stage clinical company that previously focused on advancing targeted fusion protein therapeutics (“TFPTs”) for the treatment of patients with cancer. The Company’s most advanced product candidate, VicineumTM, also known as VB4-845, is a locally administered targeted fusion protein composed of an anti-epithelial cell adhesion molecule ("EpCAM") antibody fragment tethered to a truncated form of Pseudomonas exotoxin A for the treatment of non-muscle invasive bladder cancer (“NMIBC”). On July 15, 2022, the Company made the strategic decision to voluntarily pause further development of Vicineum in the United States. The decision was based on a thorough reassessment of Vicineum following discussions with the United States Food and Drug Administration ("FDA"), which had implications on the size, timeline and costs of an additional Phase 3 clinical trial, which the FDA previously confirmed would be required for a potential resubmission of a biologics license application ("BLA") for Vicineum for the treatment of NMIBC. As a result of this decision, the Company turned its primary focus to consummating a strategic transaction with the goal of maximizing stockholder value. Following an extensive process of evaluating strategic alternatives, including identifying and reviewing potential candidates for a strategic transaction, on September 20, 2022, the Company, Seahawk Merger Sub, Inc., a Delaware corporation and a wholly-owned subsidiary of the Company (“Merger Sub”), and CARISMA Therapeutics Inc. (“Carisma”), entered into the Agreement and Plan of Merger and Reorganization dated as of September 20, 2022, as amended by the First Amendment thereto dated as of December 29, 2022 and the Second Amendment thereto dated as of February 13, 2023 (the “Merger Agreement”), pursuant to which, among other things, and subject to the satisfaction or waiver of certain conditions set forth in the Merger Agreement, Merger Sub will merge with and into Carisma, with Carisma continuing as a wholly-owned subsidiary of the Company and the surviving corporation of the merger (the “Merger”). The Company’s board of directors unanimously approved the Merger Agreement and resolved to recommend that its stockholders approve the proposals described in the Merger Agreement. If the Merger is completed, the business of Carisma will continue as the business of the combined company. The Company continues to believe that Vicineum has benefits for patients and healthcare providers that can be maximized through a company with a larger infrastructure, and as such, it is seeking a partner that can execute further development to realize the full potential of Vicineum. As a result of such decision and the Company’s subsequent decision to enter into the proposed Merger with Carisma, it no longer plans to pursue regulatory approval of Vicineum for NMIBC in the European Union (the “E.U.”) and has started to wind down certain of its manufacturing operations and business development partnerships. Additionally, the Company is seeking a partner for the further development of Vicineum and has initiated a formal process and engaged a financial advisor for the potential sale of Vicineum. If the proposed Merger is consummated, the combined company does not expect to pursue further development of Vicineum. Anticipated Merger with CARISMA Therapeutics Inc. The Merger is expected to be completed during the first quarter of 2023. In connection with the Merger, the Company is seeking the approval of its stockholders to, among other things, (a) issue the shares of its common stock issuable in connection with the Merger pursuant to the rules of The Nasdaq Stock Market LLC (“Nasdaq”), and (b) amend its amended and restated Certificate of Incorporation (the “Certificate of Incorporation”) to effect a reverse stock split of the outstanding shares of its common stock at a ratio of 1-for-20 (clauses (a) and (b), collectively, the “Sesen Bio Voting Proposals”). The special meeting of stockholders in which the Company’s stockholders will be asked to vote on the Sesen Bio Voting Proposals (the “Special Meeting”) will be held on March 2, 2023 at 10:00 a.m. Eastern Time. Sesen Bio’s future operations are highly dependent on the success of the Merger and there can be no assurances that the Merger will be successfully consummated. In the event that Sesen Bio does not complete the Merger with Carisma, Sesen Bio may continue to review and evaluate strategic alternatives, including, without limitation, a dissolution of Sesen Bio. Viventia Acquisition In September 2016, the Company entered into a Share Purchase Agreement with Viventia Bio, Inc., a corporation incorporated under the laws of the Province of Ontario, Canada ("Viventia"), the shareholders of Viventia named therein (the “Selling Shareholders”) and, solely in its capacity as seller representative, Clairmark Investments Ltd., a corporation incorporated under the laws of the Province of Ontario, Canada (“Clairmark”) (the “Share Purchase Agreement”), pursuant to which the Company agreed to and simultaneously completed the acquisition of all of the outstanding capital stock of Viventia from the Selling Shareholders (the “Viventia Acquisition”). In connection with the closing of the Viventia Acquisition, the Company issued 4.0 million shares of its common stock to the Selling Shareholders, which at that time represented approximately 19.9% of the voting power of the Company as of immediately prior to the issuance of such shares. Clairmark is an affiliate of Leslie L. Dan, a director of the Company until his retirement in July 2019. In addition, under the Share Purchase Agreement, the Company is obligated to pay to the Selling Shareholders certain post-closing contingent cash payments upon the achievement of specified milestones and based upon net sales, in each case subject to the terms and conditions set forth in the Share Purchase Agreement, including: (i) a one-time milestone payment of $12.5 million payable upon the first sale of Vicineum (the “Purchased Product”), in the United States; (ii) a one-time milestone payment of $7.0 million payable upon the first sale of the Purchased Product in any one of certain specified European countries; (iii) a one-time milestone payment of $3.0 million payable upon the first sale of the Purchased Product in Japan; and (iv) quarterly earn-out payments equal to 2% of net sales of the Purchased Product during specified earn-out periods. Such earn-out payments are payable with respect to net sales in a country beginning on the date of the first sale in such country and ending on the earlier of (i) December 31, 2033, and (ii) fifteen years after the date of such sale, subject to early termination in certain circumstances if a biosimilar product is on the market in the applicable country. Under the Share Purchase Agreement, the Company, its affiliates, licensees and subcontractors are required to use commercially reasonable efforts, for the first seven years following the closing of the Viventia Acquisition, to achieve marketing authorizations throughout the world and, during the applicable earn-out period, to commercialize the Purchased Product in the United States, France, Germany, Italy, Spain, United Kingdom, Japan, China and Canada. Certain of these payments are payable to individuals or affiliates of individuals that became employees or members of the Company's board of directors. However, as of December 31, 2022, none of these individuals are active employees or members of the Company's board of directors. Liquidity and Capital Resources As of December 31, 2022, the Company had cash, cash equivalents, and marketable securities of $166.9 million and an accumulated deficit of $336.1 million. The Company incurred positive cash flows from operating activities of $24.9 million for the year ended December 31, 2022. The Company incurred negative cash flows from operating activities $68.9 million and $30.8 million for the years ended December 31, 2021 and 2020, respectively. Since the Company’s inception, it has received no revenue from sales of its products, and the Company anticipates that operating losses will continue for the foreseeable future as it seeks to close the Merger with Carisma. The Company has financed its operations to date primarily through private placements of its common stock, preferred stock, common stock warrants and convertible bridge notes, venture debt borrowings, its initial public offering ("IPO"), follow-on public offerings, sales effected in "at-the-market" ("ATM") offerings, commercialization partnership, out-license agreements and an asset purchase agreement. See “Note 13. Stockholders’ Equity (Deficit)” below for information regarding the Company’s recently completed equity financings. Management believes that the Company’s cash and cash equivalents as of December 31, 2022 will be sufficient to fund the Company's operations for at least the next twelve months from the date these consolidated financial statements were issued. Funding Requirements The Company's future funding requirements will depend on the outcome of the proposed Merger with Carisma. The Company is subject to a number of risks similar to other clinical companies that have determined to focus primarily on pursuing a strategic transaction, including, but not limited to, those which are described under Part I Item 1A. Risk Factors of this Annual Report on Form 10-K. The Company will incur substantial expenses if and as it: •addresses its ongoing litigation related to the Merger; •maintains and protects its intellectual property portfolio; •reduces its personnel and incurs related severance and employee-related costs; •explores, evaluates and pursues any strategic alternatives if the Merger is not completed. The Company's future capital requirements will depend on many factors, including: •the outcome and the timing of the proposed Merger with Carisma; •the outcome and timing of any pending or future litigation involving the Company or its business; •the costs and timing of maintaining and enforcing the Company’s intellectual property rights and defending any intellectual property-related claims; and •its obligation to make milestone, royalty and other payments to third-party licensors under its licensing agreements. Until such time, if ever, as the Company can generate substantial revenues, the Company expects to finance the cash needs through a combination of equity offerings, debt financings, or government or other third-party funding. To the extent that the Company raises additional capital through the sale of equity or convertible debt securities, the ownership interests of existing stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of existing stockholders. Debt financing, if available, may involve agreements that include liens or other restrictive covenants limiting the Company’s ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If the Company is unable to raise additional funds when needed, it may be required to delay, limit, reduce or terminate its assessment of strategic alternatives. If the Company does not successfully consummate the proposed Merger with Carisma, its board of directors may decide to explore other strategic alternatives, including, without limitation, a dissolution of the company.

BASIS OF PRESENTATION	12 Months Ended
BASIS OF PRESENTATION	Dec. 31, 2022
Accounting Policies [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION The accompanying financial statements have been prepared in accordance with United States generally accepted accounting principles ("GAAP"). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the ASC and Accounting Standards Updates ("ASUs"), promulgated by the Financial Accounting Standards Board ("FASB"). Use of Estimates The preparation of financial statements in accordance with GAAP and the rules and regulations of the Securities and Exchange Commission ("SEC") requires the use of estimates and assumptions, based on judgments considered reasonable, which affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and assumptions on historical experience, known trends and events and various other factors that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Although management believes its estimates and assumptions are reasonable when made, they are based upon information available at the time they are made. Management evaluates the estimates and assumptions on an ongoing basis and, if necessary, makes adjustments. Due to the risks and uncertainties involved in the Company’s business and evolving market conditions, and given the subjective element of the estimates and assumptions made, actual results may differ from estimated results. The most significant estimates and judgments impact the fair value of intangible assets, goodwill and contingent consideration; income taxes (including the valuation allowance for deferred tax assets); research and development expenses; and going concern considerations. Principles of Consolidation The Company’s consolidated financial statements include the accounts of the Company, its wholly owned subsidiary Viventia and its indirect subsidiaries, Viventia Bio USA Inc. and Viventia Biotech (EU) Limited. All intercompany transactions and balances have been eliminated in consolidation. Foreign Currency Translation The functional currency of the Company and each of its subsidiaries is the United States dollar.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Dec. 31, 2022
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Cash, Cash Equivalents, Restricted Cash and Concentration of Credit Risk The Company's cash is held on deposit in demand accounts at a large financial institution in amounts in excess of the Federal Deposit Insurance Corporation ("FDIC") insurance coverage limit of $250,000 per depositor, per FDIC-insured bank, per ownership category. Restricted cash represents cash held by the Company's primary commercial bank to collateralize a letter of credit issued related to a license agreement and the credit limit on the Company's corporate credit card, and are classified as short term and long term, respectively. The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Financial instruments that potentially subject the Company to credit risk principally consists of cash equivalents, marketable securities, and accounts receivable. The Company limited its credit risk associated with cash equivalents and marketable securities by investing in highly-rated money market funds, US government securities, and treasury securities. The Company does not believe that it is subject to any significant concentrations of credit risk from these financial institutions. Marketable Securities The Company classifies all of its marketable securities as available-for-sale. The marketable securities consist of holdings in US treasury securities and US government securities, with maturity dates ranging from March 2023 to November 2023, which is consistent with the Company's investment policy. Accordingly, these investments are recorded at fair value which is determined based on quoted market prices. Amortization and accretion of discounts and premiums are recorded as interest income. Realized gains and losses are included in other income (expense), net. Unrealized gains and losses are included in other comprehensive loss as a component of stockholder’s equity (deficit) until realized. Property and Equipment Property and equipment are recorded at cost. Maintenance and repairs are charged to expense as incurred, and costs of improvements and renewals are capitalized. Depreciation is recognized using the straight-line method over the estimated useful lives of the relative assets. The Company uses an estimated useful life of five years for lab equipment, four years for furniture and fixtures, three years for computer equipment and software and the lesser of five years or the remaining lease term for leasehold improvements. Indefinite-Lived Intangible Assets The Company’s intangible assets consisted of indefinite-lived, acquired in-process research and development ("IPR&D") worldwide product rights to Vicineum as a result of the acquisition of Viventia in 2016. IPR&D assets acquired in a business combination are considered indefinite-lived until the completion or abandonment of the associated research and development efforts. Indefinite-lived intangible assets are quantitatively tested for impairment at least annually during the fourth quarter of the fiscal year, or more often if indicators of impairment are present. Impairment testing of indefinite-lived intangible assets requires management to estimate the future discounted cash flows of an asset using assumptions believed to be reasonable, but which are unpredictable and inherently uncertain. Actual future cash flows may differ from the estimates used in impairment testing. The Company recognizes an impairment loss when and to the extent that the estimated fair value of an intangible asset is less than its carrying value. In addition, on a quarterly basis, the Company performs a qualitative review of its business operations to determine whether events or changes in circumstances have occurred which could indicate that the carrying value of its intangible assets was not recoverable. If an impairment indicator is identified, an interim impairment assessment is performed. During the second quarter of 2022, the Company observed an evolution of the current market treatment paradigm in NMIBC, with substantial uptake of intravesical chemotherapy (monotherapy and combination therapy) during the ongoing BCG shortage. The Company has also experienced a sustained decline in share price and a resulting decrease in its market capitalization. On July 15, 2022, the Company made the strategic decision to voluntarily pause further development of Vicineum in the United States. The decision was based on a thorough reassessment of Vicineum following discussions with the FDA, which had implications on the size, timeline, and costs of an additional Phase 3 clinical trial for the treatment of NMIBC. Management updated the discounted cash flow model using the market participant approach and considered preliminary terms of potential partnering deal to conclude the fair value of its intangible asset of Vicineum E.U. rights. The Company concluded that the carrying value of its intangible asset of Vicineum E.U. rights of $14.7 million was fully impaired as of June 30, 2022 and was reduced to zero in the second quarter of 2022. In August 2021, the Company received a Complete Response Letter ("CRL") from the FDA regarding its BLA for Vicineum for the treatment of NMIBC, its lead product candidate. In the CRL, the FDA determined that it could not approve the BLA for Vicineum in its present form and provided recommendations specific to additional clinical/statistical data and analyses in addition to chemistry, manufacturing, and controls ("CMC") issues pertaining to a recent pre-approval inspection and product quality. Given the inherent uncertainty in the development plans for Vicineum (and Vysyneum in the EMA) as a result of the CRL and the withdrawal of the Company's marketing authorization application ("MAA"), an interim impairment analysis was conducted in the third quarter of 2021, which concluded that the carrying value of the Company’s intangible asset of Vicineum United States rights was fully impaired as of September 30, 2021. The $31.7 million of impairment charges were due to delays in the expected start of commercialization and lower probabilities of success, combined with higher operating expenses expected to be incurred prior to commercialization, resulting in lower expected future cash flows estimated in the United States market. Goodwill Goodwill on the Company's consolidated balance sheets is the result of the Company’s acquisition of Viventia in September 2016 and represents the difference between the purchase price and the fair value of the identifiable tangible and intangible net assets acquired under the acquisition method of accounting. Goodwill is not amortized; rather than recording periodic amortization, goodwill is quantitatively tested for impairment at least annually during the fourth quarter of the fiscal year, or more often if indicators of impairment are present. Impairment testing of goodwill requires management to estimate the future discounted cash flows of a reporting unit using assumptions believed to be reasonable, but which are unpredictable and inherently uncertain. Actual future cash flows may differ from the estimates used in impairment testing. If the fair value of the equity of a reporting unit exceeds the reporting unit’s carrying value, including goodwill, then goodwill is considered not to be impaired. The Company recognizes a goodwill impairment when and to the extent that the fair value of the equity of a reporting unit is less than the reporting unit's carrying value, including goodwill. The Company has only one reporting unit. In addition, on a quarterly basis, the Company performs a qualitative review of its business operations to determine whether events or changes in circumstances have occurred which could have a material adverse effect on the estimated fair value of each reporting unit and thus indicate a potential impairment of the goodwill carrying value. If an impairment indicator is identified, an interim impairment assessment is performed. During the second quarter of 2022, the Company observed continued trends in its market capitalization as compared to the carrying value of its single reporting unit as well as changes in certain assumptions in the fair value of the business including market share, size, length and cost of a clinical trial, and time to potential market launch. The Company identified these changes as potential impairment indicators and performed a quantitative impairment analysis in advance of its typical annual assessment date of October 1. The Company reassessed the underlying assumptions used to develop its revenue projections, which were then used as significant inputs to determine the fair value of equity. The Company updated its revenue forecast models based on further expected launch delays in both United States and outside of the United States ("OUS") regions. The Company also recently observed an evolution of the current treatment paradigm in NMIBC, with substantial uptake of intravesical chemotherapy (monotherapy and combination therapy) during the ongoing BCG shortage resulting in lower projected peak market share for Vicineum. The Company also considered other factors including the preliminary valuations of strategic alternatives during the fair value assessment. As a result of the interim impairment test, the Company concluded that the carrying value of its goodwill of $13.1 million was fully impaired as of June 30, 2022. Based on the annual testing and quarterly reviews performed, the Company concluded that there was no goodwill impairment during the year ended December 31, 2021. Contingent Consideration The Company uses a discounted cash flow model to estimate the fair value of the contingent consideration liability each reporting period, which represents the present value of projected future cash flows associated with regulatory approval milestones and royalties on net sales due to the selling shareholders of Viventia Bio Inc. as a result of the Viventia Acquisition in September 2016. See "Note 1. Description of Business" above for additional information. Contingent consideration is measured at its estimated fair value on a recurring basis at each reporting period, with fluctuations in value resulting in a non-cash charge to earnings (or loss) during the period. The estimated fair value measurement is based on significant unobservable inputs (Level 3 within the fair value hierarchy), including internally developed financial forecasts, probabilities of success and timing of certain milestone events and achievements, which are inherently uncertain. Actual future cash flows may differ from the assumptions used to estimate the fair value of contingent consideration. The valuation of contingent consideration requires the use of significant assumptions and judgments, which management believes are consistent with those that would be made by a market participant. Management reviews its assumptions and judgments on an ongoing basis as additional market and other data is obtained, and any future changes in the assumptions and judgments utilized by management may cause the estimated fair value of contingent consideration to fluctuate materially, resulting in earnings volatility. The estimated fair value of its contingent consideration was determined using probabilities of successful achievement of regulatory milestones and commercial sales, the period in which these milestones and sales were expected to be achieved through 2033, the level of commercial sales of Vicineum then-forecasted for the United States, Europe, Japan, China and other potential markets. Earnouts were determined using an earnout rate of 2% on all commercial net sales of Vicineum through December 2033. The discount rate applied to the 2% earnout was derived from the Company's estimated weighted-average cost of capital, which has fluctuated from 9.3% as of December 31, 2021. Milestone payments constitute debt-like obligations, and therefore a high-yield debt index rate was applied to the milestones in order to determine the estimated fair value. This index rate was 8.0% as of December 31, 2021. On July 15, 2022, the Company made the strategic decision to voluntarily pause further development of Vicineum in the United States. The decision was based on a thorough reassessment of Vicineum following discussions with the FDA, which had implications on the size, timeline, and costs of an additional Phase 3 clinical trial for the treatment of NMIBC. The Company continues to believe that Vicineum has benefits for patients and healthcare providers that can be maximized through a company with a larger infrastructure, and as such, it is seeking a partner for the further development of Vicineum. Accordingly, during the second quarter of 2022, the Company concluded that it is no longer expected to pay related milestone and earnout payments to the former shareholders of Viventia, with the exception of the potential 2% earnout payment related to China, Hong Kong, Macau and Taiwan (collectively, “Greater China”) region since those territory rights had been out-licensed. Qilu Pharmaceutical, Co., Ltd. ("Qilu") held the exclusive license to develop Vicineum in the Greater China region, and accordingly, the $1.8 million estimated earnout payment in the Greater China region remained as long-term contingent consideration as of June 30, 2022. During the third quarter of 2022, Qilu informed the Company that it no longer intended to commercialize Vicineum, due to additional effort and costs required to gain regulatory approval in that region without prior US approval. As such, the Company and Qilu were in the process of negotiating a termination of the Qilu License Agreement, which was terminated on December 23, 2022. Accordingly, the Company concluded that it no longer expected to owe any future earnout payments related to the Greater China region and reduced its remaining $1.8 million of contingent consideration liabilities to zero as of September 30, 2022. Leases The Company accounts for operating leases under ASC Topic 842, Leases. The Company’s lease portfolio as of December 31, 2022 includes a property lease for its headquarters in Cambridge, MA. The Company determines if an arrangement is a lease at the inception of the contract and has made a policy election to not separate out non-lease components from lease components, for all classes of underlying assets. The asset components of the Company’s operating leases are recorded as operating lease right-of-use assets and reported within other assets on the Company's consolidated balance sheet. The short-term and long-term liability components are recorded in other current liabilities and other liabilities, respectively, on the Company’s consolidated balance sheet. As of December 31, 2022, the Company did not have any finance leases. Right-of-use assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term at the commencement date. The Company uses an incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments, if an implicit rate of return is not provided with the lease contract. Operating lease right-of-use assets are adjusted for incentives received. Operating lease costs are recognized on a straight-line basis over the lease term, in accordance with ASC 842, and also include variable operating costs incurred during the period. Lease costs also include amounts related to short-term leases. Research and Development Costs Research and development activities are expensed in the period incurred. Research and development expenses consist of both internal and external costs associated with all basic research activities, clinical development activities and technical efforts required to develop a product candidate. Internal research and development consist primarily of personnel costs, including salaries, benefits and share-based compensation, facilities leases, research-related overhead, pre-approval regulatory and clinical trial costs, manufacturing and other contracted services, license fees and other external costs. In certain circumstances, the Company is required to make advance payments to vendors for goods or services that will be received in the future for use in research and development activities. In such circumstances, the advance payments are recorded as prepaid assets and expensed when the activity has been performed or when the goods have been received. Share-Based Compensation The Company recognizes the grant-date fair value of share-based awards granted as compensation as expense on a straight-line basis over the requisite service period, which is generally the vesting period of the award. To date, the Company has not issued awards where vesting is subject to market conditions. From time to time, the Company has granted to its executives' stock option awards which contain both performance-based and service-based vesting criteria. Performance milestone events are specific to the Company’s corporate goals, including certain clinical development objectives related to the new clinical trial, regulatory and financial objectives. Share-based compensation expense associated with performance-based vesting criteria is recognized using the accelerated attribution method if the performance condition is considered probable of achievement in management’s judgment. The fair value of stock options is estimated at the time of grant using the Black-Scholes option pricing model, which requires the use of inputs and assumptions such as the fair value of the underlying stock, exercise price of the option, expected term, risk-free interest rate, expected volatility and dividend yield. The fair value of each grant of options during the years ended December 31, 2022, 2021 and 2020 was determined using the following methods and assumptions: •Expected Term. Given the plain vanilla nature of the options granted by the Company, the expected term is determined using the "simplified" method, as prescribed in SEC Staff Accounting Bulletin ("SAB") No. 107 ("SAB 107"), whereby the expected life equals the arithmetic average of the vesting term (generally four years) and the original contractual term (ten years) of the option, taking into consideration multiple vesting tranches. •Risk-Free Interest Rate. The risk-free rate is based on the interest rate payable on United States Treasury securities in effect at the time of grant for a period that is commensurate with the assumed expected term. •Expected Volatility. The expected volatility is based on historical volatilities of a representative group of publicly traded biopharmaceutical companies, including the Company's own volatility, which were commensurate with the assumed expected term, as prescribed in SAB 107. •Dividend Yield. The dividend yield is 0% because the Company has never declared or paid, and for the foreseeable future does not expect to declare or pay, a dividend on its common stock. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and net operating loss ("NOL") and research and development credit ("R&D credit") carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. A valuation allowance is recorded to the extent it is more likely than not that some portion or all of the deferred tax assets will not be realized. Unrecognized income tax benefits represent income tax positions taken on income tax returns that have not been recognized in the financial statements. The Company recognizes the benefit of an income tax position only if it is more likely than not (greater than 50%) that the tax position will be sustained upon tax examination, based solely on the technical merits of the tax position. Otherwise, no benefit is recognized. The tax benefits recognized are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The Company recognizes accrued interest and penalties related to uncertain tax positions as income tax expense in its consolidated statements of operations. As of December 31, 2022 and 2021, the Company did not have any uncertain tax positions. Revenue Recognition The Company recorded revenue from former out-license agreements and OUS business development partnership agreements, including the former license agreement (the “Roche License Agreement”) with F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc. (collectively, “Roche”) and its former OUS partnerships. Under each of these agreements, the Company granted the counterparty an exclusive license to develop and commercialize the underlying licensed product. These agreements contain up-front license fees, development and regulatory milestone payments, sales-based milestone payments, and sales-based royalty payments. The Company determines whether the out-license agreements and OUS business development partnership agreements are in scope of ASC 606, which it adopted as of January 1, 2018. Under ASC 606, in determining the appropriate amount of revenue to be recognized as the Company fulfills its obligations under these agreements, management performs the following steps: 1) Identification of the contract; 2) Determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; 3) Measurement of the transaction price, including the constraint on variable consideration; 4) Allocation of the transaction price to the performance obligations; and 5) Recognition of revenue when or as the Company satisfies each performance obligation. Development and Regulatory Milestones and Other Payments At the inception of an arrangement that includes development milestone payments, management evaluates whether the development milestones are considered probable of being reached and estimate the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated development milestone value is included in the transaction price. Development milestone payments that are not within the Company's control or the licensee's control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. For payments pursuant to sales milestones and royalty payments, the Company will not recognize revenue until the subsequent sale of a licensed product occurs. For arrangements with one than one performance obligations, the milestones are generally allocated entirely to the license performance obligation, as (1) the terms of milestone and royalty payments relate specifically to the license and (2) allocating milestones and royalties to the license performance obligation is consistent with the overall allocation objective, because management’s estimate of milestones and royalties approximates the standalone selling price of the license. In December 2021, a $20 million milestone was achieved due to Roche initiating a Phase II clinical trial. The Company invoiced Roche $20 million with payment terms of 30 days following the achievement of the corresponding milestone event, pursuant to the Roche License Agreement. Management evaluated the transaction under ASC 606 and determined it is probable that a significant revenue reversal will not occur in future periods, which was not the case in the previous periods. Accordingly, the Company recorded $20 million as license revenue and accounts receivables in the fourth quarter of 2021. In January 2022, the payment of $20 million was received. The Company recognized $40.0 million of license revenue related to the asset purchase agreement with Roche during the year ended December 31, 2022 and $26.5 million of license revenue related to the Roche, Qilu and Hikma License Agreements during the year ended December 31, 2021. Comprehensive Loss Comprehensive loss includes net loss and other comprehensive loss. For the year ended December 31, 2022, other comprehensive loss included changes in unrealized income and loss on marketable securities. For the years ended December 31, 2021 and 2020 comprehensive loss was equal to net loss.

RECENT ACCOUNTING PRONOUNCEMENTS	12 Months Ended
RECENT ACCOUNTING PRONOUNCEMENTS	Dec. 31, 2022
Accounting Standards Update and Change in Accounting Principle [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	RECENT ACCOUNTING PRONOUNCEMENTS Adopted in 2022 In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity ("ASU 2020-06"). ASU 2020-06 simplifies the complexity associated with applying US GAAP for certain financial instruments with characteristics of both liability and equity. More specifically, the amendments focus on the guidance for convertible instruments and derivative scope exception for contracts in an entity’s own equity. The ASU also amends the diluted earnings per share ("EPS") guidance, including the requirement to use the if-converted method for all convertible instruments. ASU 2020-06 is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021, and should be applied on a full or modified retrospective basis. The Company adopted this guidance on a modified retrospective basis effective January 1, 2022 and it did not have an impact on the Company's financial position, results of operations including per-share amounts, or cash flows. In May 2021, the FASB issued ASU No. 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options ("ASU 2021-04"). ASU 2021-04 clarifies and reduces diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options (for example, warrants) that remain equity classified after modification or exchange. ASU 2021-04 is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021, and should be applied on a prospective basis. The Company adopted this guidance effective January 1, 2022 and it did not have an impact on the Company's financial position, results of operations including per-share amounts, or cash flows. Other recent accounting pronouncements issued, but not yet effective, are not expected to be applicable to the Company or have a material effect on the consolidated financial statements upon future adoption.

- Definition

The entire disclosure for change in accounting principle. Includes, but is not limited to, nature, reason, and method of adopting amendment to accounting standards or other change in accounting principle.

+ References

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+ Details

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS

The carrying values of cash and cash equivalents, restricted cash, prepaid expenses and other current assets, and accounts payable on the Company’s consolidated balance sheets approximated their fair values as of December 31, 2022 and 2021 due to their short-term nature.

Certain of the Company’s financial instruments are measured at fair value using a three-level hierarchy that prioritizes the inputs used to measure fair value. This fair value hierarchy prioritizes the use of observable inputs and minimizes the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows:

Level 1: Inputs are quoted prices for identical instruments in active markets,

Level 2: Inputs are quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; or model-derived valuations whose inputs are observable or whose significant value drivers are observable.

Level 3: Inputs are unobservable and reflect the Company’s own assumptions, based on the best information available, including the Company’s own data.

The following tables set forth the carrying amounts and fair values of the Company's financial instruments measured at fair value on a recurring basis as of December 31, 2022 and 2021 (in thousands):


	December 31, 2022
					Fair Value Measurement Based on
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents:
Money market funds	$	76,728	$	76,728	$	76,728	$	—	$	—
Marketable securities:
US government securities	$	49,431	$	49,431	$	—	$	49,431	$	—
US treasury securities	$	4,935	$	4,935	$	—	$	4,935	$	—


	December 31, 2021
					Fair Value Measurement Based on
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Money market funds (cash equivalents)	$	16,382	$	16,382	$	16,382	$	—	$	—
Liabilities:

Contingent consideration - long term	$	52,000	$	52,000	$	—	$	—	$	52,000

The Company evaluates transfers between fair value levels at the end of each reporting period. There were no transfers of assets or liabilities between fair value levels during the year ended December 31, 2022.

The Company considers valuations obtained from third party pricing sources when estimating the fair value of marketable securities.

Contingent Consideration

The estimated fair value of the Company’s contingent consideration was determined using probabilities of successful achievement of regulatory milestones and commercial sales, the period in which these milestones and sales are expected to be achieved ranging from 2025 to 2033, and the level of commercial sales of Vicineum then-forecasted for the United States, Europe, Japan, China, and other potential markets. Earnouts were determined using an earnout rate of 2% on all commercial net sales of Vicineum through December 2033. The discount rate applied to the 2% earnout was derived from its estimated weighted-average cost of capital, which was 9.3% as of December 31, 2021. Milestone payments constitute debt-like obligations, and therefore a high-yield debt index rate was applied to the milestones in order to determine the estimated fair value. This index rate was 8.0% as of December 31, 2021.

The following table sets forth a summary of the change in the fair value of the Company's total contingent consideration liability, measured on a recurring basis at each reporting period, for the year ended December 31, 2022.


Balance at December 31, 2021	$	52,000

Change in fair value of contingent consideration - long term	(52,000)
Balance at December 31, 2022	$	—

The fair value of the Company’s contingent consideration is determined based on the present value of projected future cash flows associated with sales-based milestones and earnouts on net sales and is heavily dependent on discount rates to estimate the fair value at each reporting period. Earnouts are determined using an earnout rate of 2% on all commercial net sales of Vicineum through December 2033. The discount rate applied to the 2% earnout is derived from the Company’s weighted average cost of capital, which was 9.3% as of December 31, 2021. Milestone payments constitute debt-like obligations, and therefore a high-yield debt index rate is applied to the milestones in order to determine the estimated fair value. This index rate was 8.0% as of December 31, 2021.

On July 15, 2022, the Company made the strategic decision to voluntarily pause further development of Vicineum in the United States. The decision was based on a thorough reassessment of Vicineum following discussions with the FDA, which had implications on the size, timeline, and costs of an additional Phase 3 clinical trial for the treatment of NMIBC. The Company continues to believe that Vicineum has benefits for patients and healthcare providers that can be maximized through a company with a larger infrastructure, and as such, it is seeking a partner for the further development of Vicineum. Accordingly, the Company concluded that it is no longer expected to pay related milestone and earnout payments to the former shareholders of Viventia. Therefore, the Company’s contingent consideration liability as of December 31, 2022 was zero.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

RESTRICTED CASH AND MARKETABLE SECURITIES

12 Months Ended

Dec. 31, 2022

Cash and Cash Equivalents [Abstract]

RESTRICTED CASH AND MARKETABLE SECURITIES

The Company's short-term restricted cash balance as of December 31, 2022 was $21.0 million. This represents the settlement amount of the Securities Litigation (as defined below in Note 11. “Commitment and Contingencies”), including the insurance carriers' coverage, which was funded into an escrow account in the fourth quarter of 2022. On January 31, 2023, the court issued an order granting final approval of the settlement of the Securities Litigation. Accordingly, this matter is now resolved.

The following table sets forth the composition of the Company’s marketable securities:


	December 31, 2022
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
US government securities	$	49,939	$	—	$	(508)	$	49,431
US treasury securities	4,973		—		(38)		4,935
Total Marketable Securities	$	54,912	$	—	$	(546)	$	54,366

The Company had no marketable securities as of December 31, 2021

RECEIVABLES	12 Months Ended
RECEIVABLES	Dec. 31, 2022
Receivables [Abstract]
RECEIVABLES	RECEIVABLES The accounts receivable balance as of December 31, 2021 was $21.0 million, comprised primarily of a $20.0 million milestone achieved in December 2021 due to Roche initiating a Phase II clinical trial. The Company invoiced Roche $20.0 million with payment terms of 30 days following the achievement of the corresponding milestone event, pursuant to the Roche License Agreement. In January 2022 the payment of $20.0 million was received. Additionally, in June 2021, the Qilu License Agreement was recognized by Shandong Province, Bureau of Science and Technology as a "Technology Transfer". As such, the Company recorded $0.9 million of revenue and accounts receivable for the additional purchase price resulting from Qilu's obligation to pay Sesen Bio an amount equal to its recovery of VAT. The Company received this payment in the second quarter of 2022. The other receivable balance as of December 31, 2022 was $0.8 million, primarily consisting of German VAT recovery related to drug substance sent to Baxter. The Company expects to collect the remaining balance in 2023. The other receivable balance as of December 31, 2021 was $3.5 million, primarily consisting of German VAT recovery related to drug substance sent to Baxter.

PROPERTY AND EQUIPMENT

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

PROPERTY AND EQUIPMENT

The following table sets forth the composition of property and equipment, net as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
Lab equipment	$	94	$	569
Furniture and fixtures	—		16
Computer equipment	7		99
Software	4		32
Leasehold improvements	—		293
Property and equipment, gross	105		1,009
Less: accumulated depreciation	(105)		(966)
Total Property and Equipment, Net	$	—	$	43

Depreciation expense was de minimis, $0.1 million and $0.1 million for the years ended December 31, 2022, 2021 and 2020, respectively.

INTANGIBLES AND GOODWILL

12 Months Ended

Dec. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

INTANGIBLES AND GOODWILL

Intangibles

Intangible assets on the Company's consolidated balance sheet were the result of the Viventia Acquisition in September 2016. The following table sets forth the composition of intangible assets as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
IPR&D intangible assets:
Vicineum United States rights	$	—	$	—
Vicineum European Union rights	—		14,700
Total Intangibles	$	—	$	14,700

The fair value of the acquired intangible assets for the United States and E.U. rights of Vicineum is determined using a risk-adjusted discounted cash flow approach, which includes probability adjustments for projected revenues and operating expenses based on the success rates assigned to each stage of development for each geographical region; as well as discount rates applied to the projected cash flows.

During the second quarter of 2022, the Company observed an evolution of the current market treatment paradigm in NMIBC, with substantial uptake of intravesical chemotherapy (monotherapy and combination therapy) during the ongoing BCG shortage. The Company has also experienced a sustained decline in share price and a resulting decrease in its market capitalization. On July 15, 2022, the Company made the strategic decision to voluntarily pause further development of Vicineum in the United States. The decision was based on a thorough reassessment of Vicineum following discussions with the FDA, which had implications on the size, timeline, and costs of an additional Phase 3 clinical trial for the treatment of NMIBC. Management updated the discounted cash flow model using the market participant approach and considered preliminary terms of potential partnering deal to conclude the fair value of its intangible asset of Vicineum E.U. rights. The Company concluded that the carrying value of its intangible asset of Vicineum E.U. rights of $14.7 million was fully impaired as of June 30, 2022 and was reduced to zero in the second quarter of 2022.

In August 2021, the Company received a CRL from the FDA regarding its BLA for Vicineum for the treatment of NMIBC, its lead product candidate. In the CRL, the FDA determined that it could not approve the BLA for Vicineum in its present form and provided recommendations specific to additional clinical/statistical data and analyses in addition to CMC issues pertaining to a recent pre-approval inspection and product quality. Given the inherent uncertainty in the development plans for Vicineum (and Vysyneum in the EMA) as a result of the CRL and the withdrawal of the Company's MAA, an interim impairment analysis

was conducted in the third quarter of 2021, which concluded that the carrying value of the Company’s intangible asset of Vicineum United States rights was fully impaired as of September 30, 2021. The $31.7 million of impairment charges were due to delays in the expected start of commercialization and lower probabilities of success, combined with higher operating expenses expected to be incurred prior to commercialization, resulting in lower expected future cash flows estimated in the United States market.

Goodwill

Goodwill on the Company's consolidated balance sheet is the result of the Viventia Acquisition in September 2016. Goodwill had no carrying value as of December 31, 2022 and had a carrying value of $13.1 million as of December 31, 2021.

During the second quarter of 2022, the Company observed continued trends in its market capitalization as compared to the carrying value of its single reporting unit as well as changes in certain assumptions in the fair value of the business including market share, size, length and cost of a clinical trial, and time to potential market launch. The Company identified these changes as potential impairment indicators and performed a quantitative impairment analysis in advance of its typical annual assessment date of October 1. The Company reassessed the underlying assumptions used to develop its revenue projections, which were then used as significant inputs to determine the fair value of equity. The Company updated its revenue forecast models based on further expected launch delays in both United States and OUS regions. The Company also recently observed an evolution of the current treatment paradigm in NMIBC, with substantial uptake of intravesical chemotherapy (monotherapy and combination therapy) during the ongoing BCG shortage resulting in lower projected peak market share for Vicineum. The Company also considered other factors including the preliminary valuations of strategic alternatives during the fair value assessment. As a result of the interim impairment test, the Company concluded that the carrying value of its goodwill of $13.1 million was fully impaired as of June 30, 2022.

Based on the annual testing and quarterly reviews performed, the Company concluded that there was no goodwill impairment during the year ended December 31, 2021.

ACCRUED EXPENSES

12 Months Ended

Dec. 31, 2022

Payables and Accruals [Abstract]

ACCRUED EXPENSES

The following table sets forth the composition of accrued expenses as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
Research and development	$	40	$	1,841
Payroll-related expenses	1,404		2,967
Restructuring charge related	5,733		1,497
Professional fees	301		597
Legal expenses, including the preliminary securities litigation settlement	21,919		1,344
Other	239		9
Total Accrued Expenses	$	29,636	$	8,255

COMMITMENTS AND CONTINGENCIES	12 Months Ended
COMMITMENTS AND CONTINGENCIES	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal Proceedings From time to time, the Company may become subject to legal proceedings, claims, and litigation arising in the ordinary course of business. When the Company becomes aware of a claim or potential claim, it assesses the likelihood of any loss or exposure. In accordance with authoritative guidance, the Company records loss contingencies in its financial statements only for matters in which losses are probable and can be reasonably estimated. Where a range of loss can be reasonably estimated with no best estimate in the range, the Company records the minimum estimated liability. If the loss is not probable or the amount of the loss cannot be reasonably estimated, the Company discloses the nature of the specific claim if the likelihood of a potential loss is reasonably possible, and the amount involved is material. The Company continuously assesses the potential liability related to the Company’s pending litigation and revises its estimates when additional information becomes available. The Company is not currently a party to any material legal proceedings, other than as described below. On August 19, 2021, August 31, 2021, and October 7, 2021, three substantially identical securities class action lawsuits captioned Bibb v. Sesen Bio, Inc., et al., Case No. 1:21-cv-07025, Cizek v. Sesen Bio, Inc., et. al., Case No. 1:21-cv-07309 and Markman v. Sesen Bio, Inc. et al., Case No. 1:21-cv-08308 were filed against the Company and certain of its officers in the United States District Court for the Southern District of New York. The three complaints alleged violations of Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and Rule 10b-5 promulgated thereunder based on statements made by the Company concerning the BLA for Vicineum for the treatment of BCG-unresponsive NMIBC. The three complaints sought compensatory damages and costs and expenses, including attorneys’ fees. On October 29, 2021, the court consolidated the three cases under the caption In re Sesen Bio, Inc. Securities Litigation, Master File No. 1:21-cv-07025-AKH (the “Securities Litigation”), and appointed Ryan Bibb, Rodney Samaan, Lionel Dreshaj and Benjamin Dreshaj (collectively, the “Lead Plaintiffs”) collectively as the lead plaintiffs under the Private Securities Litigation Reform Act. On November 1, 2021, two stockholders filed motions to reconsider asking the court to appoint a different lead plaintiff. On November 24, 2021, defendants filed a motion to transfer venue to the United States District Court for the District of Massachusetts. That motion was fully briefed as of December 13, 2021, but the court has not ruled on that motion. On December 6, 2021, the Lead Plaintiffs filed an amended class action complaint (the “Amended Complaint”). The Amended Complaint alleged the same violations of Sections 10(b) and 20(a) of the Exchange Act and Rule 10b-5 promulgated thereunder on the same theory as the prior complaints. The defendants moved to dismiss the Amended Complaint on March 7, 2022, and that motion was fully briefed on May 6, 2022. On June 3, 2022, before the court ruled on the motion to dismiss, the parties requested that the court hold any decision on the motion to dismiss in abeyance to provide the parties with an opportunity to engage in mediation. On June 30, 2022 and July 6, 2022, the Company and the plaintiffs engaged in mediation sessions in an attempt to resolve the Securities Litigation and continued to discuss a potential settlement over the following weeks. On July 19, 2022, the parties reached an agreement in principle to settle the Securities Litigation. Pursuant to that agreement, the Company and the individual defendants will pay or cause to be paid to members of the class who submit timely and valid proofs of claims. In exchange, the Lead Plaintiffs will dismiss the action and all class members who do not timely and validly opt-out of the settlement will provide broad customary releases to the Company and the individual defendants. On August 3, 2022, the parties entered into a Stipulation and Agreement of Settlement to settle the Securities Litigation, which was filed with the court on August 17, 2022. The Stipulation and Agreement of Settlement related to the Securities Litigation provides for a settlement payment of $21.0 million to the class and the dismissal of all claims against the Company and the other defendants. On September 1, 2022, the United States District Court for the Southern District of New York issued an order denying the motions to appoint a different lead plaintiff. On September 28, 2022, the court issued an order granting preliminary approval of the proposed settlement of the Securities Litigation. The settlement payment of $21.0 million, including the insurance carriers coverage, was funded into an escrow account in the fourth quarter of 2022. Accordingly, $21.0 million remained in restricted cash on the Company's balance sheet as of December 31, 2022. On January 31, 2023, the court issued an order granting final approval of the settlement of the Securities Litigation. Accordingly, this matter is now resolved. On September 20, 2021 and September 24, 2021, two substantially similar derivative lawsuits captioned Myers v. Sesen Bio, Inc., et al., Case No. 1:21-cv-11538 and D’Arcy v. Sesen Bio, Inc., et. al., Case No. 1:21-cv-11577 were filed against the Company’s board of directors and certain of its officers in the United States District Court for the District of Massachusetts, with the Company named as a nominal defendant. On January 12, 2022, a third derivative complaint captioned Tang v. Sesen Bio, Inc., et al., was filed in Superior Court in Massachusetts against the Company’s board of directors and certain of its officers (the “State Derivative Litigation”). The three derivative complaints alleged breach of fiduciary duties, waste of corporate assets, and violations of federal securities laws based on statements made by the Company concerning the BLA for Vicineum for the treatment of BCG-unresponsive NMIBC. The D’Arcy complaint further alleged unjust enrichment, abuse of control, gross mismanagement and aiding and abetting thereof. The three derivative complaints sought unspecified damages, restitution and disgorgement of profits, benefits and compensation obtained by the defendants and costs and expenses, including attorneys’ fees. On October 18, 2021, the court consolidated the two federal court cases under the caption In re Sesen Bio, Inc. Derivative Litigation, Lead Case No. 1:21-cv-11538 (the “Federal Derivative Litigation”). On December 22, 2021, the court entered a joint stipulation among the parties to stay the Federal Derivative Litigation until after a ruling on any motion to dismiss filed by defendants in the Securities Litigation. On May 1, 2022, the plaintiffs filed a verified consolidated shareholder derivative complaint in the Federal Derivative Litigation. On May 18, 2022, the court entered a joint stipulation among the parties to stay the State Derivative Litigation until after a ruling on any motion to dismiss filed by defendants in the Securities Litigation. On July 6, 2022, the Company and the plaintiffs to the Federal Derivative Litigation and the State Derivative Litigation engaged in mediation in an attempt to resolve the litigation, with settlement discussions continuing over the following days. On July 19, 2022, the parties reached an agreement in principle to settle the Federal Derivative Litigation, the State Derivative Litigation and other potential related derivative claims (collectively, the “Derivative Litigation”). Pursuant to that agreement, the individual defendants will cause the Company to adopt certain enhancements to its corporate governance policies and procedures. In exchange, plaintiffs will dismiss the Derivative Litigation and, on behalf of the Company, provide broad customary releases to the individual defendants. On August 22, 2022, the parties entered into a Stipulation of Settlement to settle the Derivative Litigation, which was filed with the court on August 30, 2022. The Stipulation of Settlement related to the Derivative Litigation confirms that the Company previously adopted certain corporate governance enhancements in response to, among other things, the filing of the Derivative Litigation, and that, subject to final court approval, the Company will adopt additional corporate governance enhancements. The Stipulation of Settlement also provides for a $630,000 payment for plaintiffs’ attorneys' fees due to the benefits the corporate governance enhancements are intended to provide to the Company. The payment of plaintiffs’ attorneys' fees is being funded by the Company. On September 2, 2022, the court issued an order granting preliminary approval of the Stipulation of Settlement related to the Derivative Litigation. On November 8, 2022, the court issued an order granting final approval of the Stipulation of Settlement related to the Derivative Litigation. Accordingly, this matter is now resolved. On November 28, 2022, a purported stockholder filed a complaint in the United States District Court for the Southern District of New York against the Company and its board of directors, captioned Keller v. Sesen Bio, Inc., et al., Case No. 1:22-cv-10085 (S.D.N.Y.) (the “Original Keller Complaint”). The Original Keller Complaint asserted claims against the Company and its board of directors under Section 14(a) of the Exchange Act and Rule 14a-9 promulgated thereunder for allegedly false and misleading statements in the proxy statement/prospectus filed as part of the Registration Statement on Form S-4 (File No. 333-267891) (the "Registration Statement") in connection with the Merger and under Section 20(a) of the Exchange Act for alleged “control person” liability with respect to such allegedly false and misleading statements and sought, among other relief, an order enjoining the Merger and an award for plaintiffs’ fees and costs. On December 20, 2022, the purported stockholder voluntarily dismissed the Original Keller Complaint and on December 21, 2022, filed a new complaint as a putative class action in the Court of Chancery for the State of Delaware, captioned Keller v. Sesen Bio, Inc., et al., Case No. 2022-1186 (Del. Ch. Dec. 21, 2022) (the “New Keller Complaint”). Along with the complaint, the purported stockholder filed motions for expedited proceedings and for a preliminary injunction to enjoin the Special Meeting. The New Keller Complaint and associated filings contain substantially the same assertions as the Original Keller Complaint, and seek, among other relief, an order enjoining the Merger and an award for plaintiffs’ fees and costs. On February 3, 2023, a purported stockholder filed a complaint in the United States District Court for the District of Delaware against the Company and its board of directors, captioned Plumley v. Sesen Bio, Inc., et al., Case No. 1:23-cv-00131 (D. Del.) (the “Plumley Complaint”). The Plumley Complaint asserts claims under Section 14(a) of the Exchange Act and Rule 14a-9 promulgated thereunder for allegedly false and misleading statements in the proxy statement/prospectus filed as part of the Registration Statement in connection with the Merger and under Section 20(a) of the Exchange Act for alleged “control person” liability with respect to such allegedly false and misleading statements and seeks, among other relief, an order enjoining the Merger and an award for plaintiffs’ fees and costs. On February 7, 2023, another purported stockholder filed a complaint in the United States District Court for the Southern District of New York against the Company and its board of directors, captioned Franchi v. Sesen Bio, Inc., et al., 1:23-cv-01041 (S.D.N.Y.) (the “Franchi Complaint”). The Franchi Complaint contains substantially similar allegations and claims and seeks substantially similar relief as the Plumley Complaint. Additionally, on February 9, 2023, another purported stockholder filed a complaint in the United States District Court for the Southern District of New York against the Company and its board of directors, captioned Menzer v. Sesen Bio, Inc., et al., 23-cv-01119 (S.D.N.Y.) (the “Menzer Complaint”). The Menzer Complaint contains substantially similar allegations and claims and seeks substantially similar relief as the Plumley Complaint and the Franchi Complaint. On October 21, 2022, November 4, 2022, February 8, 2023, February 13, 2023 (as updated on February 15, 2023) and February 17, 2023, the Company received letters from purported stockholders (collectively, the “Demand Letters”) demanding that the Company amend the Registration Statement to provide additional disclosures that such stockholders allege were improperly omitted from the Registration Statement, including information regarding the financial projections for Carisma, the financial analyses performed by the Company’s financial advisor in support of its fairness opinion, and the background and process leading to the execution of the Merger Agreement. In addition, the Company received a books and records demand, dated November 18, 2022 (the “Section 220 Demand”), on behalf of a purported stockholder of the Company seeking access to certain relevant books and records of the Company’s pursuant to Section 220 of the Delaware General Corporation Law in connection with the Merger and the securities and derivative litigations arising out of the CRL that the Company received from the FDA. The Section 220 Demand states that the purpose of the demand is to, among other things, investigate purported questions of director independence and disinterestedness and the possibility of wrongdoing, mismanagement, and/or material non-disclosure related to the Company board’s approval of the Merger and the other transactions contemplated thereby and to determine whether suit should be brought in connection therewith. The Company believes that the claims asserted in the Demand Letters, the Section 220 Demand, the New Keller Complaint, the Plumley Complaint, the Franchi Complaint and the Menzer Complaint are without merit and intends to vigorously defend against them. At this time, no assessment can be made as to the likely outcome or whether the outcome will be material to the Company. Executive Employment Agreements The Company has entered into employment agreements and offer letters with certain of its key executives, providing for separation payments and benefits in certain circumstances, as defined in the agreements.

LEASES

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

LEASES

The Company accounts for operating leases under ASC Topic 842, Leases. The Company's lease portfolio included an operating lease for its 31,100 square foot facility in Winnipeg, Manitoba which consisted of manufacturing, laboratory, warehouse, and office space. During the third quarter of 2022, the Company entered into a Lease Termination Agreement (the “Lease Termination Agreement”) pursuant to which the Company terminated its operating lease agreement. As part of the execution of the Lease Termination Agreement, the Company paid the landlord the all-inclusive sum of CAD $1.2 million (USD $0.9 million). Operating lease cost under this lease were $0.2 million for the year ended December 31, 2022 and $0.3 million for the year ended December 31, 2021.

The right of use asset total was zero as of December 31, 2022 and $123,300 as of December 31, 2021. As of December 31, 2021, the asset component of the Company’s operating leases was recorded as operating lease right-of-use assets and reported within other assets on the Company's condensed consolidated balance sheets. The short-term lease liability was zero as of December 31, 2022 and $123,300 as of December 31, 2021. As of December 31, 2021, the short-term lease liability was recorded in other current liabilities on the Company’s condensed consolidated balance sheets. There was no long-term operating lease liability as of December 31, 2022 or December 31, 2021. Operating lease cost is recognized on a straight-line basis over the term of the lease.

In addition, the Company has short-term property leases for modular office space for 1) its corporate headquarters in Cambridge, MA and 2) office space in Philadelphia, PA. The minimum monthly rent for these office spaces is $2,500 and $18,000, respectively. The Company terminated the Philadelphia lease on December 31, 2022 and plans to terminate the Cambridge lease in connection with the closing of the anticipated Merger with Carisma. The short-term lease in Cambridge ends in June 2023.

The components of lease cost for the years ended December 31, 2022 and 2021 is as follows (in thousands):


	Year Ended December 31, 2022		Year Ended December 31, 2021
Lease Cost:
Operating lease (including related operating costs)	$	245	$	327
Short term property leases	213		262
Total lease costs	$	458	$	589


Supplemental Information:	Year Ended December 31, 2022		Year Ended December 31, 2021
Weighted-average remaining lease term (years)	0		0.75
Weighted-average discount rate - operating leases	—	%	12	%

STOCKHOLDERS' EQUITY DEFICIT

12 Months Ended

Dec. 31, 2022

Equity [Abstract]

STOCKHOLDERS' EQUITY DEFICIT

STOCKHOLDERS' EQUITY (DEFICIT)

Equity Financings

ATM Offering

In November 2019, the Company entered into an Open Market Sale Agreement SM (the "Sale Agreement") with Jefferies LLC ("Jefferies"), under which the Company may issue and sell shares of its common stock, par value $0.001 per share, from time to time (the “ATM Offering”) for an aggregate sales price of up to $35.0 million through Jefferies. In October 2020 and February 2021, the Company entered into Amendments No. 1 and No. 2 to the Sale Agreement, respectively. Amendments No. 1 and No. 2 modified the Sale Agreement to reflect that the Company may issue and sell shares of its common stock from time to time for an aggregate sales price of up to an additional $50.0 million and $34.5 million, respectively. In June 2021, the Company entered into Amendment No. 3 to the Sale Agreement, which modified the Sale Agreement to remove the maximum dollar amount of shares of common stock that may be sold pursuant to the Sale Agreement. In June and July 2021, the Company filed prospectus supplements with the SEC in connection with the offer and sale of up to an aggregate of $200.0 million of common stock pursuant to the Sale Agreement. Sales are made by any method that is deemed to be an ATM offering as defined in Rule 415(a)(4) of the Securities Act of 1933, as amended, including but not limited to sales made directly on or through the Nasdaq Capital Market or any other existing trading market for the Company's common stock. The Company may sell shares of its common stock efficiently from time to time but has no obligation to sell any of its common stock and may at any time suspend

offers under the Sale Agreement or terminate the Sale Agreement. Subject to the terms and conditions of the Sale Agreement, Jefferies will use its commercially reasonable efforts to sell common stock from time to time, as the sales agent, based upon the Company’s instructions, which include a prohibition on sales below a minimum price set by the Company from time to time. The Company has provided Jefferies with customary indemnification rights, and Jefferies is entitled to a commission at a fixed rate equal to 3.0% of the gross proceeds for each sale of common stock under the Sale Agreement. The Company did not sell any shares of common stock pursuant to the Sale Agreement during the year ended December 31, 2022. The Company raised $175.0 million of net proceeds from the sale of 56.9 million shares of common stock at a weighted-average price of $3.17 per share during the year ended December 31, 2021. Share issuance costs, including sales agent commissions, related to the ATM Offering totaled $5.4 million during the year ended December 31, 2021.

June 2019 Financing

In June 2019, the Company raised $27.8 million of net proceeds from the sale of 20.4 million shares of common stock and accompanying warrants to purchase an additional 20.4 million shares of common stock in an underwritten public offering (the "June 2019 Financing"). The combined purchase price for each share of common stock and accompanying warrant was $1.47. Subject to certain ownership limitations, the warrants issued in the June 2019 Financing were exercisable immediately upon issuance at an exercise price of $1.47 per share, subject to adjustments as provided under the terms of such warrants, and had a one-year term that expired on June 21, 2020.

Preferred Stock

Pursuant to its Certificate of Incorporation, the Company is authorized to issue 5.0 million shares of "blank check" preferred stock, $0.001 par value per share, which enables its board of directors, from time to time, to create one or more series of preferred stock. Each series of preferred stock issued shall have the rights, preferences, privileges and restrictions as designated by the board of directors. The issuance of any series of preferred stock could affect, among other things, the dividend, voting and liquidation rights of the Company's common stock. The Company had no preferred stock issued and outstanding as of December 31, 2022 and 2021.

Common Stock

Following approval by the Company’s stockholders on May 3, 2021, an amendment became effective to the Certificate of Incorporation that increased the number of authorized shares of common stock from 200 million to 400 million, of which 203 million and 199 million shares were issued and outstanding as of December 31, 2022 and 2021, respectively. In addition, the Company had reserved for issuance the following amounts of shares of its common stock for the purposes described below as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022	2021
Shares of common stock issued	202,759	199,464
Shares of common stock reserved for issuance for:
Warrants	187	199
Stock options	15,304	15,703
RSUs	4,695	3,041
Shares available for grant under 2014 Stock Incentive Plan	4,532	8,933
Shares available for sale under 2014 Employee Stock Purchase Plan	2,300	2,300
Total shares of common stock issued and reserved for issuance	229,777	229,640

The voting, dividend and liquidation rights of holders of shares of common stock are subject to and qualified by the rights, powers and preferences of holders of shares of preferred stock. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company's stockholders; provided, however, that, except as otherwise required by law, holders of common stock shall not be entitled to vote on any amendment to the Company’s Certificate of Incorporation that relates solely to the terms of one or more outstanding series of preferred stock if the holders of such affected series are entitled, either separately or together as a class with the holders of one or more such series, to vote thereon. There shall be no cumulative voting.

Dividends may be declared and paid on the common stock from funds lawfully available thereof as and when determined by the board of directors and subject to any preferential dividend or other rights of any then-outstanding preferred stock. The

Company has never declared or paid, and for the foreseeable future does not expect to declare or pay, dividends on its common stock.

Upon the dissolution of the Company, whether voluntary or involuntary, holders of common stock will be entitled to receive all assets of the Company available for distribution to its stockholders, subject to any preferential or other rights of any then-outstanding preferred stock.

Warrants

All of the Company’s outstanding warrants are non-tradeable and equity-classified because they meet the derivative scope exception under ASC Topic 815-40, Derivatives and Hedging - Contracts in Entity’s Own Equity ("ASC 815-40"). The following table sets forth the Company's warrant activity for the year ended December 31, 2022 (in thousands):


Issued	Exercise Price	Expiration	December 31, 2021	Issued	(Exercised)	(Cancelled)	December 31, 2022

Mar-2018	$0.55*	Mar-2023	132	—	—	—	132
Nov-2017	$0.55*	Nov-2022	12	—	—	(12)	—
May-2015	$11.83	Nov-2024	28	—	—	—	28
Nov-2014	$11.04	Nov-2024	27	—	—	—	27
			199	—	—	(12)	187

* Exercise price shown (i) reflects modification described below and (ii) subject to further adjustment based on down round provision added by amendment described below.

Warrant Modifications

In October 2019, the Company entered into transactions with holders of its outstanding 2018 Warrants and 2017 Warrants to purchase the Company's common stock. At such time, the 2018 Warrants and 2017 Warrants utilized the same form of warrant, which contained a prohibition on variable rate transactions (as defined therein). Warrant holders agreed to waive such prohibition in exchange for certain concessions from the Company. Management evaluated the warrants after modifications and determined that they continued to be equity-classified under the derivative scope exception of ASC 815-40. The warrants were revalued immediately before and immediately after the modifications to calculate the $1.1 million incremental value of the modified warrants. The Company considers this incremental value to be akin to an offering cost since the modifications were directly related to enabling the ATM Offering and would not have otherwise been incurred. Therefore, in the fourth quarter of 2019, management initially capitalized the $1.1 million to deferred financing cost asset, with an offsetting credit to additional paid-in capital, and then reclassified the deferred financing cost asset to reduce the ATM Offering proceeds within equity as proceeds were received from sales of common stock under the ATM Offering.

2018 Warrants

In October 2019, the Company entered into transactions with the holders of its outstanding 2018 Warrants pursuant to which such holders either (i) exercised their warrants pursuant to a Warrant Exercise Agreement (the "2018 Warrant Exercise Agreements") or (ii) amended their warrants pursuant to a Warrant Amendment Agreement (the "2018 Warrant Amendment Agreements"). As consideration for those holders executing the 2018 Warrant Exercise Agreements, the Company reduced the exercise price of the warrants from $1.20 to $0.60 per share of the Company's common stock, resulting in proceeds of $2.0 million from the exercise of 3.4 million warrants. Pursuant to the 2018 Warrant Amendment Agreements, the prohibition on certain variable rate transactions included in the 2018 Warrants was amended to exclude ATM offerings and the exercise price of the warrants was reduced from $1.20 to the lesser of (a) $0.95 per share of common stock and (b) the exercise price as determined from time to time pursuant to the anti-dilution provisions in the 2018 Warrant Amendment Agreements. During the second quarter of 2020, the anti-dilution provision was triggered to lower the exercise price of the warrants to $0.55; as such, the Company recognized a deemed dividend of approximately $0.1 million which reduced the income available to common stockholders. As the Company has an accumulated deficit balance, there is no overall impact to additional paid-in capital, as the deemed dividend is recorded as offsetting debit and credit entries to additional paid-in capital. Therefore, the amounts were not presented on the Statement of Stockholders' Equity (Deficit).

In connection with the 2018 Warrant Exercise Agreements and 2018 Warrant Amendment Agreements, the Company entered into an amendment to the Securities Purchase Agreement dated March 21, 2018 related to the March 2018 Financing, by and among the Company and each purchaser identified on the signature pages thereto, with certain holders representing greater than 50.1% of the securities issued based on initial subscription amounts, pursuant to which the prohibition on variable rate transactions, including ATM offerings, was deleted in its entirety.

2017 Warrants

In October 2019, the Company entered into transactions with the holders of its outstanding 2017 Warrants pursuant to which such holders either (i) exercised their warrants pursuant to a Warrant Exercise Agreement (the "2017 Warrant Exercise Agreements") or (ii) amended their warrants pursuant to a Warrant Amendment Agreement (the "2017 Warrant Amendment Agreements"). As consideration for those holders executing the 2017 Warrant Exercise Agreements, the Company reduced the exercise price of the warrants from $0.80 to $0.55 per share of the Company's common stock. Pursuant to the 2017 Warrant Amendment Agreements, the prohibition on certain variable rate transactions, including ATM offerings, included in the 2017 Warrants was deleted in its entirety and the exercise price of the warrants was reduced from $0.80 to the lesser of (a) $0.55 per share of common stock and (b) the exercise price as determined from time to time pursuant to the anti-dilution provisions in the 2017 Warrant Amendment Agreements. As of December 31, 2022, there has been no adjustment to the exercise price of these warrants.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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+ Details

EARNINGS (LOSS) PER SHARE

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Abstract]

EARNINGS (LOSS) PER SHARE

A net loss cannot be diluted. Therefore, when the Company is in a net loss position, basic and diluted loss per common share are the same. If the Company achieves profitability, the denominator of a diluted earnings per common share calculation includes both the weighted-average number of shares outstanding and the number of common stock equivalents, if the inclusion of such common stock equivalents would be dilutive. Dilutive common stock equivalents potentially include warrants, stock options and non-vested restricted stock awards and units using the treasury stock method, along with the effect, if any, from outstanding convertible securities. The majority of the Company’s outstanding warrants to purchase common stock have participation rights to any dividends that may be declared in the future and are therefore considered to be participating securities. Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. During periods of loss, no loss is allocated to the participating securities since the holders have no contractual obligation to share in the losses of the Company.

Additionally, an entity that presents earnings per share shall recognize the value of the effect of an anti-dilution provision in an equity-classified freestanding financial instrument in the period the anti-dilution provision is triggered. That effect shall be treated as a deemed dividend and as a reduction of income available to common stockholders in basic earnings per share. The deemed dividend is added back to income available to common stockholders when applying the treasury stock method for diluted earnings per share.

For periods with net income, diluted net earnings per share is calculated by either (i) adjusting the weighted-average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period as determined using the treasury stock method or (ii) the two-class method considering common stock equivalents, whichever is more dilutive. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to common stockholders.

The two-class method was not applied for the twelve months ended December 31, 2022, 2021 and 2020 as the Company’s participating securities do not have any obligation to absorb net losses.

For purposes of the diluted net loss per share calculation, common stock equivalents are excluded from the calculation if their effect would be anti-dilutive.

The following potentially dilutive securities outstanding as of December 31, 2022, 2021 and 2020 have been excluded from the denominator of the diluted loss per share of common stock outstanding calculation (in thousands):


	December 31,
	2022	2021	2020
Warrants	187	199	2,247
Stock options	15,304	15,703	10,147
RSUs and PSUs	4,695	—	—
Total	20,186	15,902	12,394

SHARE-BASED COMPENSATION

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

SHARE-BASED COMPENSATION

The following table sets forth the amount of share-based compensation expense recognized by the Company by line item on its Consolidated Statements of Operations and Comprehensive Loss for the years ended December 31, 2022, 2021 and 2020 (in thousands):


	Year Ended December 31,
	2022		2021		2020
Research and development	$	1,985	$	973	$	350
General and administrative	4,924		4,170		1,407
Total Share Based Compensation	$	6,909	$	5,143	$	1,757

2014 Stock Incentive Plan

The Company's 2014 Stock Incentive Plan, as amended (the "2014 Plan"), was adopted by its board of directors in December 2013 and subsequently approved by its stockholders in January 2014. The 2014 Plan became effective immediately prior to the closing of the Company's IPO in February 2014 and provides for the grant of incentive and non-qualified stock options, restricted stock awards and restricted stock units, stock appreciation rights and other stock-based awards, with amounts and terms of grants determined by the Company's board of directors at the time of grant, to the Company's employees, officers, directors, consultants and advisors.

At the Annual Meeting of the Company's stockholders in June 2019, the Company's stockholders approved an amendment to the 2014 Plan that (i) increased by 7.9 million the number of shares of common stock reserved for issuance under the 2014 Plan and (ii) eliminated the “evergreen” or automatic replenishment provision of the 2014 Plan, pursuant to which the number of shares of common stock authorized for issuance under the 2014 Plan was automatically increased on an annual basis. At the Annual Meeting of the Company’s stockholders in May 2021, the Company’s stockholders approved an amendment to the 2014 Plan that increased by 12 million the number of shares of common stock reserved for issuance under the 2014 Plan. There were approximately 4.5 million shares of common stock available for issuance under the 2014 Plan as of December 31, 2022.

Stock options outstanding under the 2014 Plan generally vest over a four-year period at the rate of 25% of the grant vesting on the first anniversary of the date of grant and 6.25% of the grant vesting at the end of each successive three-month period thereafter. Stock options granted under the 2014 Plan are exercisable for a period of ten years from the date of grant. There were approximately 12.2 million stock options outstanding under the 2014 Plan as of December 31, 2022.

On September 9, 2021, the Board of Directors and the Compensation Committee of the Company approved a retention program for all current employees, except for the Chief Executive Officer, pursuant to which the Company will provide certain incentives designed to retain such employees (the “Retention Program”). Pursuant to the Retention Program and effective as of October 1, 2021, the Company’s non-executive employees received a combination of a cash bonus award and a one-time restricted stock unit (“RSU”) award which vested in full on September 30, 2022, subject to continued employment through September 30, 2022. Each RSU represents a contingent right to receive one share of the Company’s common stock. The Company recorded an expense of $2.5 million for retention-related RSUs for the year ended December 31, 2022.

Also pursuant to the Retention Program and effective as of October 1, 2021, the Company’s executive officers, except for the Chief Executive Officer, were granted a one-time performance-based restricted stock unit (“PSU”) award equal to the value of approximately fifty percent of current base salary. Each PSU represents a contingent right to receive one share of the Company’s common stock upon the satisfaction of pre-determined performance criteria. Subject to continued employment, such awards vest on September 30, 2023 upon the determination by the Compensation Committee of the level of achievement of certain key milestones consisting of a clinical trial milestone, an employee retention milestone and cash management milestones. As of December 31, 2022, achievement was deemed probable for only the cash management milestone, representing $87,000 (or 20% of the PSU awards). Therefore, $55,000 was expensed during the year ended December 31, 2022, and $32,000 remains measured but unrecognized.

A summary of the status of restricted stock units is presented below:


			Restricted Stock Units (in thousands)
Unvested at December 31, 2021			3,041
Granted RSU			4,160
Granted PSU			1,004
Vested			(3,293)
Canceled or forfeited			(217)
Unvested at December 31, 2022			4,695

The weighted average remaining contractual life of unvested RSUs and PSUs as of December 31, 2022 is 2.67 years. The weighted average remaining contractual life of unvested RSUs and PSUs as of December 31, 2021 is 9.75 years.

2009 Stock Incentive Plan

The Company maintains a 2009 Stock Incentive Plan, as amended and restated (the "2009 Plan"), which provided for the grant of incentive and non-qualified stock options and restricted stock awards and restricted stock units, with amounts and terms of grants determined by the Company's board of directors at the time of grant, to its employees, officers, directors, consultants and advisors. Upon the closing of its IPO in February 2014, the Company ceased granting awards under the 2009 Plan and all shares (i) available for issuance under the 2009 Plan at such time and (ii) subject to outstanding awards under the 2009 Plan that expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased without having been fully exercised or resulting in any common stock being issued were carried over to the 2014 Plan. Stock options granted under the 2009 Plan are exercisable for a period of ten years from the date of grant. There were approximately 0.1 million fully vested stock options outstanding under the 2009 Plan as of December 31, 2022.

Out-of-Plan Inducement Grants

From time to time, the Company has granted equity awards to its newly hired employees, including executives, in accordance with the Nasdaq Stock Market LLC ("Nasdaq") employment inducement grant exemption (Nasdaq Listing Rule 5635(c)(4)). Such grants are made outside of the 2014 Plan and act as an inducement material to the employee's acceptance of employment with the Company. There were approximately 2.9 million stock options outstanding which were granted as employment inducement awards outside of the 2014 Plan as of December 31, 2022.

Stock Options

The following table sets forth a summary of the Company’s total stock option activity, including awards granted under the 2014 Plan and 2009 Plan and inducement grants made outside of stockholder approved plans, for the years ended December 31, 2022, 2021 and 2020:


	Number of Shares under Option (in thousands)	Weighted-Average Exercise Price	Weighted-Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2019	6,236	$1.52	8.83	$	358
Granted	4,044	$0.87
Exercised	(12)	$1.13
Canceled or forfeited	(121)	$1.04
Outstanding at December 31, 2020	10,147	$1.26	8.50	$	3,160
Granted	8,273	$3.32
Exercised	(34)	$1.23
Canceled or forfeited	(2,683)	$3.70
Outstanding at December 31, 2021	15,703	$1.93	8.03	$	82
Granted	1,510	$0.72
Exercised	(2)	$0.32
Canceled or forfeited	(1,907)	$1.90
Outstanding at December 31, 2022	15,304	$1.82	7.19	$	3
Exercisable at December 31, 2022	10,427	$1.72	6.77	DM

The Company recognized share-based compensation expense of $6.9 million, $5.1 million, and $1.8 million for the years ended December 31, 2022, 2021, and 2020, respectively. The stock option related expenses were $4.3 million, $4.6 million and $1.8 million for the years ended December 31, 2022, 2021 and 2020, respectively. The RSU related expense was $2.5 million and $0.5 million for the years ended December 31, 2022 and 2021, respectively. The Company did not record RSU related expenses for the year ended December 31, 2020. As of December 31, 2022, there was $5.5 million of total unrecognized compensation cost related to non-vested stock options which the Company expects to recognize over a weighted-average period of 1.88 years. The weighted-average grant-date fair value of stock options granted during the year ended December 31, 2022, 2021 and 2020 were $0.46, $2.16 and $0.56, respectively. The total intrinsic value of stock options exercised for the years ended December 31, 2022, 2021 and 2020 was de minimis.

For the years ended December 31, 2022, 2021 and 2020, the grant-date fair value of stock options was determined using the following weighted-average inputs and assumptions in the Black-Scholes option pricing model:


	Year Ended December 31,
	2022	2021	2020
Fair market value	$0.72	$3.32	$0.87
Grant exercise price	$0.72	$3.32	$0.87
Expected term (in years)	6.0	6.0	6.1
Risk-free interest rate	2.1%	0.9%	1.3%
Expected volatility	71.8%	74.6%	71.5%
Dividend yield	—%	—%	—%

EMPLOYEE BENEFIT PLANS	12 Months Ended
EMPLOYEE BENEFIT PLANS	Dec. 31, 2022
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS 2014 Employee Stock Purchase Plan The Company's 2014 Employee Stock Purchase Plan ("2014 ESPP") was adopted by its board of directors in December 2013 and subsequently approved by its stockholders in January 2014. The 2014 ESPP became effective immediately prior to the closing of the Company's IPO in February 2014 and established an initial reserve of 0.2 million shares of the Company's common stock for issuance to participating employees. At the Annual Meeting of the Company's stockholders in May 2021, the Company's stockholders approved an amendment to the 2014 ESPP that increased by 2.3 million the number of shares of common stock reserved for issuance under the 2014 ESPP. The purpose of the 2014 ESPP is to enhance employee interest in the success and progress of the Company by encouraging employee ownership of common stock of the Company. The 2014 ESPP provides employees with the opportunity to purchase shares of common stock at a 15% discount to the market price through payroll deductions or lump sum cash investments. The Company estimates the number of shares to be issued at the end of an offering period and recognizes expense over the requisite service period. Shares of the common stock issued and sold pursuant to the 2014 ESPP are shown on the consolidated statements of changes in stockholders' equity (deficit). As of December 31, 2022, there were 2.3 million shares of common stock available for sale under the 2014 ESPP. The Company sold a de minimis number of shares under the ESPP for the years ended December 31, 2022, 2021 and 2020, respectively. Defined Contribution Plans United States - 401(k) Plan The Company maintains a 401(k) defined contribution retirement plan which covers all of its United States employees. Employees are eligible to participate on the first of the month following their date of hire. Under the 401(k) plan, participating employees may defer up to 100% of their pre-tax salary, subject to certain statutory limitations. Employee contributions vest immediately. The plan allows for a discretionary match per participating employee up to a maximum of $4,000 per year. The Company contributed a de minimis amount for each of the three years ended December 31, 2022, 2021 and 2020, respectively. Canada - Defined Contribution Plan The Company maintains a defined contribution plan for its Canadian employees. Participants may contribute a percentage of their annual compensation to this plan, subject to statutory limitations. The Company contributes up to the first 4% of eligible compensation for its Canadian-based employees to the retirement plan. The Company contributed a de minimis amount for each of the three years ended December 31, 2022, 2021 and 2020, respectively.

INCOME TAXES

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

INCOME TAXES

The following table sets forth the components of the Company's loss before income taxes by country (in thousands):


	Year Ended December 31,
	2022		2021		2020
Country
United States	$	(37,289)	$	(32,757)	$	(35,529)
Canada	13,530		24,148		14,577
Total Loss Before Income Taxes	$	(23,759)	$	(8,609)	$	(20,952)

The Company's tax benefit (provision) is comprised of the following components (in thousands):


	Year Ended December 31,
	2022		2021		2020
Current Tax Provision
Federal	$	—	$	—	$	—
State	—		—		—
Foreign	(94)		(286)		(1,445)
Total current (provision)	$	(94)	$	(286)	$	(1,445)
Deferred tax provision
Federal	$	—	$	—	$	—
State	—		—		—
Foreign	3,969		8,559		—
Total deferred benefit (provision)	$	3,969	$	8,559	$	—

Total Tax Benefit (Provision)	$	3,875	$	8,273	$	(1,445)

The following table sets forth a reconciliation of the statutory United States federal income tax rate to the Company’s effective income tax rate:


	Year ended December 31,
	2022		2021		2020
United States federal statutory income tax rate	21.0	%	21.0	%	21.0	%
Impact of foreign rate differential	(3.3)		(15.9)		(4.2)
State taxes, net of federal benefit	0.9		2.3		2.0
Stock option cancellations	—		(1.1)		(0.2)
Contingent consideration	59.1		178.2		14.4
General business credits and other credits	0.5		2.4		6.6
Goodwill write-off	(14.8)	%	—	%	—	%
Permanent differences	(1.9)		(1.4)		0.2
Other	(0.2)		(13.8)		(2.1)
Foreign taxes	—		(3.3)		(6.9)
Change in valuation allowance	(44.6)		(72.3)		(37.7)
Effective Income Tax Rate	16.7	%	96.1	%	(6.9)	%

The following table sets forth the tax effects of temporary differences that gave rise to significant portions of the Company's deferred tax assets and liabilities (in thousands):


	December 31,
	2022		2021		2020
Deferred tax assets:
NOL carryforwards	$	66,374	$	63,381	$	57,935
R&D credit carryforwards	4,489		4,316		3,787
IRC 174 Capitalized R&D	6,214		—		—
Accruals and other	5,326		4,058		3,811
Capitalized start-up costs	34		53		70
Other	16		41		28
Gross deferred tax assets	82,453		71,849		65,631
Deferred tax liabilities:
IPR&D	—		(3,969)		(12,528)

Gross deferred tax liabilities	—		(3,969)		(12,528)
Valuation allowance	(82,453)		(71,849)		(65,631)
Net Deferred Tax Liability	$	—	$	(3,969)	$	(12,528)

In assessing the realizability of the Company's deferred tax assets, management considers all relevant positive and negative evidence in determining whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The realization of deferred tax assets is dependent on several factors, including the generation of sufficient taxable income prior to the expiration of the NOL and R&D credit carryforwards. The Company has generated NOLs since its inception, and management believes that it is more likely than not that the Company's deferred tax assets will not be realized. As a result, valuation allowances of $82.5 million, $71.8 million and $65.6 million have been established as of December 31, 2022, 2021 and 2020, respectively. The $10.6 million increase in the valuation allowance was attributable to the NOL for the year ended December 31, 2022.

The following table summarizes the Company's NOL and R&D and other credit carryforwards in the United States and Canada as of December 31, 2022 (in millions):


	Amount		Expiration Beginning in	Through
United States:
Federal NOL carryforwards - indefinite	$	101.2	None	None
Federal NOL carryforwards	$	117.7	2030	2038
State NOL carryforwards	$	138.4	2030	2041
Federal R&D credit carryforwards	$	2.6	2027	2041
State R&D credit carryforwards	$	0.9	2027	2041
Canada:
Federal non-capital loss carryforwards	$	43.2	2035	2041
Federal scientific research and experimental development expense carryforwards	$	5.1	2032	2041
Federal and provincial investment tax credit carryforwards	$	1.2	2032	2041

Under the Tax Reform Act of 1986 (the "Act'), NOL and R&D credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service, and there are similar provisions in certain state and non-US tax laws. NOL and R&D credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interests of significant shareholders over a three-year period in excess of 50 percent, as defined in Sections 382 and 383 of the Internal Revenue Code, respectively. This could limit the amount of tax attributes that can be utilized to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. Management completed a Section 382 study through March 31, 2016 and determined that it is more likely than not that the Company's NOL carryforwards are subject to a material limitation. Accordingly, the Company reduced its NOL carryforward by $0.8 million. The Company has continued to raise additional equity capital since March 2016 but has not done any additional analysis to determine whether or not ownership changes, as defined in the Act, have occurred, which would result in additional limitations. There could be additional ownership changes in the future that could further limit the amount of NOL carryforwards that the Company can utilize. The Company has not yet conducted a study of its R&D credit carryforwards. Such a study may result in an adjustment to the Company’s R&D credit carryforwards; however, until a study is completed, and any adjustment is known, no amount is being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s R&D credit carryforwards, and, if an adjustment is required, it would be offset by an adjustment to the valuation allowance.

The Company assesses the impact of various tax reform proposals and modifications to existing tax treaties in all jurisdictions where it has operations to determine the potential effect on its business and any assumptions it has made about its future taxable income. The Company cannot predict whether any specific proposals will be enacted, the terms of any such proposals or what effect, if any, such proposals would have on its business if they were to be enacted. Beginning in 2022, the Tax Cuts and Jobs Act of 2017 eliminates the currently available option to deduct research and development expenditures and requires taxpayers to amortize them over five years. The U.S. Congress is considering legislation that would defer the amortization requirement to future periods, however, the Company has no assurance that the provision will be repealed or otherwise modified.

As of December 31, 2022, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts have been recognized in the Company's consolidated statements of operations. Due to NOL and R&D credit carryforwards that remain unutilized, income tax returns filed in the United States, certain states within the United States and Canadian tax jurisdictions from the Company's inception through 2021 remain subject to examination by the taxing jurisdictions. There are currently no audits in process in any of the Company's tax filing jurisdictions.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

LICENSE AGREEMENTS	12 Months Ended
LICENSE AGREEMENTS	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
LICENSE AGREEMENTS	LICENSE AGREEMENTS In-License Agreements License Agreement with Zurich The Company has a license agreement with the University of Zurich ("Zurich") which grants the Company exclusive license rights, with the right to sublicense, to make, have made, use and sell under certain patents primarily directed to the Company's targeting agent, including an EpCAM chimera and related immunoconjugates and methods of use and manufacture of the same (the “Zurich License Agreement”). These patents cover some key aspects of Vicineum. Upon the Company's receipt of the CRL regarding the BLA for Vicineum for the treatment of BCG-unresponsive NMIBC, the Company became obligated to pay $0.5 million in a milestone payment to Zurich. The Company is also obligated to pay up to a 4% royalty on the net product sales for products covered by or manufactured using a method covered by a valid claim in the Zurich patent rights. Royalties owed to Zurich will be reduced if the total royalty rate owed by the Company to Zurich and any other third party is 10% or greater, provided that the royalty rate to Zurich may not be less than 2% of net sales. The obligation to pay royalties in a particular country expires upon the expiration or termination of the last of the Zurich patent rights that covers the manufacture, use or sale of a product. There is no obligation to pay royalties in a country if there is no valid claim that covers the product or a method of manufacturing the product. The Company recorded expenses of $0.3 million and $0.5 million related to meeting a development milestone, the submission of the Company’s BLA with the FDA in December 2020, and a regulatory milestone, the Company’s receipt of the CRL from the FDA in August 2021, respectively. License Agreement with Micromet The Company has a License Agreement with Micromet AG ("Micromet"), now part of Amgen, Inc., which grants it nonexclusive rights, with certain sublicense rights, for know-how and patents allowing exploitation of certain single chain antibody products (the “Micromet License Agreement”). These patents (which are now expired) cover some key aspects of Vicineum. Under the terms of the Micromet License Agreement, as of December 31, 2022, even though the patents have expired, the Company may be obligated to pay up to €2.4 million in milestone payments for the first product candidate that achieves applicable regulatory and sales-based development milestones (approximately $2.6 million at exchange rates in effect on December 31, 2022). The Company is also required to pay up to a 3.5% royalty on the net sales for products covered by the agreement, which includes Vicineum. The royalty rate owed to Micromet in a particular country will be reduced to 1.5% if there are no valid claims covering the product in that country. The obligation to pay royalties in a particular country expires upon the later of the expiration date of the last valid claim covering the product and the tenth anniversary of the first commercial sale of the product in such country. Finally, the Company is required to pay to Micromet an annual license maintenance fee of €50,000, which can be credited towards any royalty payment the Company owes to Micromet. The Company recorded an expense of €0.7 million ($0.9 million) related to achievement of a development milestone in the three months ended December 31, 2020, due to the submission of the Company's BLA for Vicineum with the FDA in December 2020. The Company recorded an expense of €0.5 million ($0.6 million) related to the submission of the MAA to the EMA for Vysyneum™ in the first quarter of 2021. For the year ended December 31, 2022, the Company recorded an expense of €50,000 ($51,770) related to the annual license maintenance fee. Vysyneum is the proprietary brand name conditionally approved by the EMA for oportuzumab monatox in the E.U. License Agreement with XOMA The Company has a license agreement with XOMA Ireland Limited ("XOMA") which grants it non-exclusive rights to certain XOMA patent rights (which are now expired) and know-how related to certain expression technology, including plasmids, expression strains, plasmid maps and production systems (the “XOMA License Agreement”). These patents and related know-how cover some key aspects of Vicineum. Under the terms of the XOMA License Agreement, even though the patents have expired, the Company is required to pay up to $0.25 million in milestone payments for a product candidate that incorporates know-how under the license and achieves applicable clinical development milestones. The Company is also required to pay a 2.5% royalty on the net sales for products incorporating XOMA’s technology, which includes Vicineum. The Company has the right to reduce the amount of royalties owed to XOMA on a country-by-country basis by the amount of royalties paid to other third parties, provided that the royalty rate to XOMA may not be less than 1.75% of net sales. In addition, the foregoing royalty rates are reduced by 50% with respect to products that are not covered by a valid patent claim in the country of sale. The obligation to pay royalties in a particular country expires upon the later of the expiration date of the last valid claim covering the product and the tenth anniversary of the first commercial sale of the product in such country. Out-License Agreements Roche License Agreement In June 2016, the Company entered into the license agreement with Roche (the “Roche License Agreement”), pursuant to which the Company granted Roche an exclusive, worldwide license, including the right to sublicense, to its patent rights and know-how related to the Company’s monoclonal antibody EBI-031 and all other IL-6 anti-IL-6 antagonist monoclonal antibody technology owned by the Company (collectively, the "Roche Licensed Intellectual Property"). Under the Roche License Agreement, Roche is required to continue developing, at its cost, EBI-031 and any other product made from the Roche Licensed Intellectual Property that contains an IL-6 antagonist anti-IL monoclonal antibody (“Roche Licensed Product”) and pursue ongoing patent prosecution, at its cost. On July 15, 2022, the Company entered into an asset purchase agreement with Roche (the “Roche Asset Purchase Agreement”) pursuant to which Roche purchased all patent rights and know-how related to the monoclonal antibody EBI-031 and all other IL-6 antagonist monoclonal antibody technology owned by the Company for up to $70.0 million. As a result of the Roche Asset Purchase Agreement, the Roche License Agreement was terminated resulting in no further diligence, milestone or royalty payment obligations under the Roche License Agreement. Pursuant to the Roche Asset Purchase Agreement, Roche made a $40.0 million payment to the Company upon execution of the Roche Asset Purchase Agreement, which was recorded as license revenue in the third quarter of 2022. The Roche Asset Purchase Agreement also provides that Roche will make an additional $30.0 million payment to the Company upon Roche’s initiation of a Phase 3 clinical trial with EBI-031 for a defined indication if initiated prior to December 31, 2026. Pursuant to ASC 606, the variable consideration of $30.0 million is constrained. Therefore, the amount was not recorded as revenue during the year ended December 31, 2022. At or prior to the effective time of the Merger, the Company will enter into a Contingent Value Rights Agreement (the “CVR Agreement”) with a rights agent (“Rights Agent”) pursuant to which the Company intends to declare a dividend payable to the Company’s stockholders of record as of a date agreed to by the Company and Carisma prior to the effective time of the Merger with respect to the receipt of one contingent value right (each, a “CVR”) for each outstanding share of the Company’s common stock held by such stockholders on such date. Each CVR will represent the contractual right to receive (i) contingent cash payments upon the receipt by the Company of certain proceeds payable by Roche, if any, pursuant to the Roche Asset Purchase Agreement, upon the achievement by Roche of a specified milestone set forth in the Roche Asset Purchase Agreement, as well as (ii) proceeds from any sale of the Company's legacy assets, including Vicineum, subject to certain customary deductions, including for expenses and taxes, in the event any sale occurs prior to March 31, 2027. The contingent payments under the CVR Agreement, if they become due, will be payable to the Rights Agent for subsequent distribution to the holders of the CVRs. In the event that no such proceeds are received, holders of the CVRs will not receive any payment pursuant to the CVR Agreement. There can be no assurance that any cash payment will be made or that any holders of CVRs will receive any amounts with respect thereto. Former OUS Business Development Partnership Agreements Qilu License Agreement On July 30, 2020, the Company and its a wholly-owned subsidiary, Viventia Bio, Inc., entered into an exclusive license agreement with Qilu (the “Qilu License Agreement”) pursuant to which the Company granted Qilu an exclusive, sublicensable, royalty-bearing license, under certain intellectual property owned or exclusively licensed by the Company, to develop, manufacture and commercialize Vicineum (the “Qilu Licensed Product”) for the treatment of NMIBC and other types of cancer (the “Field”) in China, Hong Kong, Macau and Taiwan ("Greater China”). The Company also granted Qilu a non-exclusive, sublicensable, royalty-bearing sublicense, under certain other intellectual property licensed by the Company to develop, manufacture and commercialize the Qilu Licensed Product in Greater China. The Company retains (i) development, and commercialization rights in the rest of the world excluding Greater China, the Middle East and North Africa region ("MENA”) and Turkey and (ii) manufacturing rights with respect to Vicineum in the rest of the world excluding China. In consideration for the rights granted by the Company, Qilu agreed to pay to the Company a one-time upfront cash payment of $12 million, and milestone payments totaling up to $23 million upon the achievement of certain technology transfer, development and regulatory milestones. All payments were to be inclusive of value-added tax ("VAT"), which can be withheld by Qilu upon payment, and for which future recovery of such taxes may be available. Qilu also agreed to pay the Company a 12% royalty based upon annual net sales of Qilu Licensed Products in Greater China. The royalties are payable on a Qilu Licensed Product-by-Licensed Product and region-by-region basis commencing on the first commercial sale of a Licensed Product in a region and continuing until the latest of (i) twelve years after the first commercial sale of such Qilu Licensed Product in such region, (ii) the expiration of the last valid patent claim covering or claiming the composition of matter, method of treatment, or method of manufacture of such Qilu Licensed Product in such region, and (iii) the expiration of regulatory or data exclusivity for such Qilu Licensed Product in such region (collectively, the “Royalty Terms”). The royalty rate is subject to reduction under certain circumstances, including when there is no valid claim of a licensed patent that covers a Qilu Licensed Product in a particular region or no data or regulatory exclusivity of a Qilu Licensed Product in a particular region. On December 23, 2022, the Company terminated the Qilu License Agreement. In connection with the termination of the Qilu License Agreement, the Company agreed to make an aggregate payment to Qilu of $1.4 million, which consists of a $1.2 million termination fee payable upon the termination of the Qilu License Agreement, which was paid in the fourth quarter of 2022, and a $200,000 payment payable upon our receipt of certain clinical data and chemistry, manufacturing, and controls data from Qilu, which such payment was not made as of December 31, 2022. Accordingly, $0.2 million remained on the Company's balance sheet in accrued liabilities as of December 31, 2022. Hikma License Agreement On November 30, 2020, the Company entered into a license agreement with a third party pursuant to which the Company granted an exclusive, sublicensable, royalty-bearing license, under certain intellectual property owned or exclusively licensed by the Company, to commercialize Vicineum in the MENA region (the "Hikma License Agreement"). The Company retained development and commercialization rights in the rest of the world excluding Greater China, Turkey, and MENA. In consideration for the rights granted by the Company, the counterparty to the Hikma License Agreement agreed to pay to the Company an upfront payment of $3 million, which would be subject to certain tax withholdings. In addition, the counterparty agreed to pay to the Company milestone payments upon the achievement of certain sales-based milestones as well as a royalty based upon annual net sales in the MENA region for the term of the Hikma License Agreement. On July 20, 2022, the Company provided notice of termination of the Hikma License Agreement as a result of the Company’s strategic decision to voluntarily pause further development of Vicineum in the United States. In connection with such termination, the Company refunded to Hikma the $3.0 million upfront payment. EIP License Agreement On August 5, 2021, the Company entered into an exclusive license agreement with EİP Eczacıbaşı İlaç Pazarlama A.Ş., (“EIP”) pursuant to which it granted EIP an exclusive license to register and commercialize Vicineum for the treatment of BCG-unresponsive NMIBC in Turkey and Northern Cyprus (the “EIP License Agreement"). Under the terms of the License Agreement, the Company was entitled to receive an upfront payment of $1.5 million. The Company and EIP have subsequently amended the license agreement to defer EIP's payment of the upfront payment to coincide with the potential FDA approval of Vicineum. The Company would have been eligible to receive additional regulatory and commercial milestone payments of $2.0 million and also to receive a 30% royalty on net sales in Turkey and Northern Cyprus. On July 20, 2022, the Company provided notice of termination of the EIP License Agreement as a result of the Company’s strategic decision to voluntarily pause further development of Vicineum in the United States. The EIP License Agreement was terminated on October 20, 2022.

RESTRUCTURING AND RELATED ACTIVITIES

12 Months Ended

Dec. 31, 2022

Restructuring and Related Activities [Abstract]

RESTRUCTURING AND RELATED ACTIVITIES

On July 15, 2022, the Company approved a restructuring plan to reduce operating expenses and better align its workforce with the needs of its business following the decision to voluntarily pause further development of Vicineum in the United States (the “2022 Restructuring Plan”). Execution of the 2022 Restructuring Plan is expected to be substantially completed in connection with the closing of the Merger with Carisma, which is expected to occur in the first quarter of 2023. The 2022 Restructuring Plan includes an incremental reduction in the Company’s workforce as well as additional cost-saving initiatives intended to preserve capital during the pendency of the Merger with Carisma and while the Company seeks a potential partner for the further development of Vicineum.

The Company also incurred one-time cash costs associated with the termination of certain contracts and all other activities under the 2022 Restructuring Plan. The following is a summary of accrued restructuring costs related to the 2022 Restructuring Plan, (in thousands):


	2022 Restructuring Plan
Severance and benefits costs	$	6,976
Contract termination and other associated costs	4,788
Total restructurings costs	11,764
Cash payments	(6,031)
Balance at December 31, 2022	$	5,733

Restructuring costs related to the 2022 Restructuring Plan were recorded in operating expenses in the Company’s Condensed Consolidated Statements of Operations and Comprehensive Loss in the year ended December 31, 2022. The Company expects that substantially all accrued restructuring costs as of December 31, 2022 will be paid in cash in connection with the closing of the Merger with Carisma, which is expected to be completed in the first quarter of 2023.

On August 30, 2021, the Company approved a restructuring plan to reduce operating expenses and better align its workforce with the needs of its business following receipt of the CRL from the FDA regarding the BLA for Vicineum for the treatment of BCG-unresponsive NMIBC (the “2021 Restructuring Plan”).

The 2021 Restructuring Plan included a reduction in the Company’s workforce by 18 positions (or approximately 35% of the Company’s workforce as of the date of the 2021 Restructuring Plan), as well as additional cost-saving initiatives intended to preserve capital while the Company continued development of Vicineum. The following is a summary of accrued restructuring costs related to the 2021 Restructuring Plan:


	2021 Restructuring Plan
Balance as of December 31, 2021	$	1,497
Cash payments	(1,497)
Balance at December 31, 2022	$	—

Restructuring costs related to the 2021 Restructuring Plan were recorded in operating expenses in the Company’s Consolidated Statements of Operations and Comprehensive Loss in the year ended December 31, 2021.

SUBSEQUENT EVENTS	12 Months Ended
SUBSEQUENT EVENTS	Dec. 31, 2022
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS Nasdaq Delisting Notice In connection with the Merger with Carisma, the Company is seeking the approval of its stockholders to, among other things, (a) issue the shares of its common stock issuable in connection with the Merger pursuant to the rules of Nasdaq, and (b) amend its amended and restated Certificate of Incorporation to effect a reverse stock split of the outstanding shares of its common stock at a ratio of 1-for-20 (clauses (a) and (b), collectively, the “Sesen Bio Voting Proposals”). The special meeting of stockholders in which the Company’s stockholders will be asked to vote on the Sesen Bio Voting Proposals will be held on March 2, 2023 at 10:00 a.m. Eastern Time (the "Special Meeting"). On January 25, 2023, the Company was notified by the Listing Qualifications Department (the “Staff”) of Nasdaq that, based upon the Company’s non-compliance with the $1.00 bid price requirement for continued listing on The Nasdaq Capital Market, as set forth in Nasdaq Listing Rule 5550(a)(2) (the “Bid Price Rule”), the Company’s common stock will be delisted from Nasdaq unless it timely requests a hearing before a Nasdaq Hearings Panel (the “Panel”). The Company requested a hearing before the Panel, which stayed any delisting action by the Staff and ensured the Company’s common stock remains listed and eligible for trading on Nasdaq pending a determination by the Panel. The hearing had been scheduled for March 16, 2023. On February 24, 2023, the Company received a determination from the Nasdaq Office of General Counsel that the Panel granted the Company an exception from its non-compliance with the Bid Price Rule to complete the Merger by March 10, 2023. Pursuant to Nasdaq Listing Rule 5110(a), the Company must demonstrate compliance with all initial listing requirements of Nasdaq upon the closing of the Merger. The Company is seeking approval for the Merger and the implementation of a reverse stock split of its common stock at the Special Meeting. In the event the Company fails to establish compliance with the initial listing standards by March 10, 2023, the common stock will be delisted from Nasdaq, unless granted an additional exception by the Panel. As previously disclosed, on January 24, 2022, the Company received written notice from the Staff indicating that, based upon the closing bid price for its common stock for the previous 30 consecutive business days, the Company no longer satisfied the Bid Price Rule and, in accordance with the Nasdaq Listing Rules, was afforded an initial grace period of 180 calendar days, through July 25, 2022, and a second 180-calendar day period, through January 23, 2023, to regain compliance with the Bid Price Rule. The Company did not regain compliance with the Bid Price Rule by January 23, 2023, which resulted in the Staff’s January 25, 2023, determination.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Dec. 31, 2022
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in accordance with GAAP and the rules and regulations of the Securities and Exchange Commission ("SEC") requires the use of estimates and assumptions, based on judgments considered reasonable, which affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and assumptions on historical experience, known trends and events and various other factors that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Although management believes its estimates and assumptions are reasonable when made, they are based upon information available at the time they are made. Management evaluates the estimates and assumptions on an ongoing basis and, if necessary, makes adjustments. Due to the risks and uncertainties involved in the Company’s business and evolving market conditions, and given the subjective element of the estimates and assumptions made, actual results may differ from estimated results. The most significant estimates and judgments impact the fair value of intangible assets, goodwill and contingent consideration; income taxes (including the valuation allowance for deferred tax assets); research and development expenses; and going concern considerations.
Principles of Consolidation	Principles of Consolidation The Company’s consolidated financial statements include the accounts of the Company, its wholly owned subsidiary Viventia and its indirect subsidiaries, Viventia Bio USA Inc. and Viventia Biotech (EU) Limited. All intercompany transactions and balances have been eliminated in consolidation.
Foreign Currency Translation	Foreign Currency Translation The functional currency of the Company and each of its subsidiaries is the United States dollar.
Cash, Cash Equivalents, Restricted Cash and Concentration of Credit Risk	Cash, Cash Equivalents, Restricted Cash and Concentration of Credit RiskThe Company's cash is held on deposit in demand accounts at a large financial institution in amounts in excess of the Federal Deposit Insurance Corporation ("FDIC") insurance coverage limit of $250,000 per depositor, per FDIC-insured bank, per ownership category. Restricted cash represents cash held by the Company's primary commercial bank to collateralize a letter of credit issued related to a license agreement and the credit limit on the Company's corporate credit card, and are classified as short term and long term, respectively. The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Financial instruments that potentially subject the Company to credit risk principally consists of cash equivalents, marketable securities, and accounts receivable. The Company limited its credit risk associated with cash equivalents and marketable securities by investing in highly-rated money market funds, US government securities, and treasury securities. The Company does not believe that it is subject to any significant concentrations of credit risk from these financial institutions.
Marketable Securities	Marketable SecuritiesThe Company classifies all of its marketable securities as available-for-sale. The marketable securities consist of holdings in US treasury securities and US government securities, with maturity dates ranging from March 2023 to November 2023, which is consistent with the Company's investment policy. Accordingly, these investments are recorded at fair value which is determined based on quoted market prices. Amortization and accretion of discounts and premiums are recorded as interest income. Realized gains and losses are included in other income (expense), net. Unrealized gains and losses are included in other comprehensive loss as a component of stockholder’s equity (deficit) until realized.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost. Maintenance and repairs are charged to expense as incurred, and costs of improvements and renewals are capitalized. Depreciation is recognized using the straight-line method over the estimated useful lives of the relative assets. The Company uses an estimated useful life of five years for lab equipment, four years for furniture and fixtures, three years for computer equipment and software and the lesser of five years or the remaining lease term for leasehold improvements.
Indefinite-Lived Intangible Assets	Indefinite-Lived Intangible Assets The Company’s intangible assets consisted of indefinite-lived, acquired in-process research and development ("IPR&D") worldwide product rights to Vicineum as a result of the acquisition of Viventia in 2016. IPR&D assets acquired in a business combination are considered indefinite-lived until the completion or abandonment of the associated research and development efforts. Indefinite-lived intangible assets are quantitatively tested for impairment at least annually during the fourth quarter of the fiscal year, or more often if indicators of impairment are present. Impairment testing of indefinite-lived intangible assets requires management to estimate the future discounted cash flows of an asset using assumptions believed to be reasonable, but which are unpredictable and inherently uncertain. Actual future cash flows may differ from the estimates used in impairment testing. The Company recognizes an impairment loss when and to the extent that the estimated fair value of an intangible asset is less than its carrying value. In addition, on a quarterly basis, the Company performs a qualitative review of its business operations to determine whether events or changes in circumstances have occurred which could indicate that the carrying value of its intangible assets was not recoverable. If an impairment indicator is identified, an interim impairment assessment is performed. During the second quarter of 2022, the Company observed an evolution of the current market treatment paradigm in NMIBC, with substantial uptake of intravesical chemotherapy (monotherapy and combination therapy) during the ongoing BCG shortage. The Company has also experienced a sustained decline in share price and a resulting decrease in its market capitalization. On July 15, 2022, the Company made the strategic decision to voluntarily pause further development of Vicineum in the United States. The decision was based on a thorough reassessment of Vicineum following discussions with the FDA, which had implications on the size, timeline, and costs of an additional Phase 3 clinical trial for the treatment of NMIBC. Management updated the discounted cash flow model using the market participant approach and considered preliminary terms of potential partnering deal to conclude the fair value of its intangible asset of Vicineum E.U. rights. The Company concluded that the carrying value of its intangible asset of Vicineum E.U. rights of $14.7 million was fully impaired as of June 30, 2022 and was reduced to zero in the second quarter of 2022. In August 2021, the Company received a Complete Response Letter ("CRL") from the FDA regarding its BLA for Vicineum for the treatment of NMIBC, its lead product candidate. In the CRL, the FDA determined that it could not approve the BLA for Vicineum in its present form and provided recommendations specific to additional clinical/statistical data and analyses in addition to chemistry, manufacturing, and controls ("CMC") issues pertaining to a recent pre-approval inspection and product quality. Given the inherent uncertainty in the development plans for Vicineum (and Vysyneum in the EMA) as a result of the CRL and the withdrawal of the Company's marketing authorization application ("MAA"), an interim impairment analysis was conducted in the third quarter of 2021, which concluded that the carrying value of the Company’s intangible asset of Vicineum United States rights was fully impaired as of September 30, 2021. The $31.7 million of impairment charges were due to delays in the expected start of commercialization and lower probabilities of success, combined with higher operating expenses expected to be incurred prior to commercialization, resulting in lower expected future cash flows estimated in the United States market.
Goodwill	Goodwill Goodwill on the Company's consolidated balance sheets is the result of the Company’s acquisition of Viventia in September 2016 and represents the difference between the purchase price and the fair value of the identifiable tangible and intangible net assets acquired under the acquisition method of accounting. Goodwill is not amortized; rather than recording periodic amortization, goodwill is quantitatively tested for impairment at least annually during the fourth quarter of the fiscal year, or more often if indicators of impairment are present. Impairment testing of goodwill requires management to estimate the future discounted cash flows of a reporting unit using assumptions believed to be reasonable, but which are unpredictable and inherently uncertain. Actual future cash flows may differ from the estimates used in impairment testing. If the fair value of the equity of a reporting unit exceeds the reporting unit’s carrying value, including goodwill, then goodwill is considered not to be impaired. The Company recognizes a goodwill impairment when and to the extent that the fair value of the equity of a reporting unit is less than the reporting unit's carrying value, including goodwill. The Company has only one reporting unit. In addition, on a quarterly basis, the Company performs a qualitative review of its business operations to determine whether events or changes in circumstances have occurred which could have a material adverse effect on the estimated fair value of each reporting unit and thus indicate a potential impairment of the goodwill carrying value. If an impairment indicator is identified, an interim impairment assessment is performed. During the second quarter of 2022, the Company observed continued trends in its market capitalization as compared to the carrying value of its single reporting unit as well as changes in certain assumptions in the fair value of the business including market share, size, length and cost of a clinical trial, and time to potential market launch. The Company identified these changes as potential impairment indicators and performed a quantitative impairment analysis in advance of its typical annual assessment date of October 1. The Company reassessed the underlying assumptions used to develop its revenue projections, which were then used as significant inputs to determine the fair value of equity. The Company updated its revenue forecast models based on further expected launch delays in both United States and outside of the United States ("OUS") regions. The Company also recently observed an evolution of the current treatment paradigm in NMIBC, with substantial uptake of intravesical chemotherapy (monotherapy and combination therapy) during the ongoing BCG shortage resulting in lower projected peak market share for Vicineum. The Company also considered other factors including the preliminary valuations of strategic alternatives during the fair value assessment. As a result of the interim impairment test, the Company concluded that the carrying value of its goodwill of $13.1 million was fully impaired as of June 30, 2022. Based on the annual testing and quarterly reviews performed, the Company concluded that there was no goodwill impairment during the year ended December 31, 2021.
Contingent Consideration	Contingent Consideration The Company uses a discounted cash flow model to estimate the fair value of the contingent consideration liability each reporting period, which represents the present value of projected future cash flows associated with regulatory approval milestones and royalties on net sales due to the selling shareholders of Viventia Bio Inc. as a result of the Viventia Acquisition in September 2016. See "Note 1. Description of Business" above for additional information. Contingent consideration is measured at its estimated fair value on a recurring basis at each reporting period, with fluctuations in value resulting in a non-cash charge to earnings (or loss) during the period. The estimated fair value measurement is based on significant unobservable inputs (Level 3 within the fair value hierarchy), including internally developed financial forecasts, probabilities of success and timing of certain milestone events and achievements, which are inherently uncertain. Actual future cash flows may differ from the assumptions used to estimate the fair value of contingent consideration. The valuation of contingent consideration requires the use of significant assumptions and judgments, which management believes are consistent with those that would be made by a market participant. Management reviews its assumptions and judgments on an ongoing basis as additional market and other data is obtained, and any future changes in the assumptions and judgments utilized by management may cause the estimated fair value of contingent consideration to fluctuate materially, resulting in earnings volatility. The estimated fair value of its contingent consideration was determined using probabilities of successful achievement of regulatory milestones and commercial sales, the period in which these milestones and sales were expected to be achieved through 2033, the level of commercial sales of Vicineum then-forecasted for the United States, Europe, Japan, China and other potential markets. Earnouts were determined using an earnout rate of 2% on all commercial net sales of Vicineum through December 2033. The discount rate applied to the 2% earnout was derived from the Company's estimated weighted-average cost of capital, which has fluctuated from 9.3% as of December 31, 2021. Milestone payments constitute debt-like obligations, and therefore a high-yield debt index rate was applied to the milestones in order to determine the estimated fair value. This index rate was 8.0% as of December 31, 2021. On July 15, 2022, the Company made the strategic decision to voluntarily pause further development of Vicineum in the United States. The decision was based on a thorough reassessment of Vicineum following discussions with the FDA, which had implications on the size, timeline, and costs of an additional Phase 3 clinical trial for the treatment of NMIBC. The Company continues to believe that Vicineum has benefits for patients and healthcare providers that can be maximized through a company with a larger infrastructure, and as such, it is seeking a partner for the further development of Vicineum. Accordingly, during the second quarter of 2022, the Company concluded that it is no longer expected to pay related milestone and earnout payments to the former shareholders of Viventia, with the exception of the potential 2% earnout payment related to China, Hong Kong, Macau and Taiwan (collectively, “Greater China”) region since those territory rights had been out-licensed. Qilu Pharmaceutical, Co., Ltd. ("Qilu") held the exclusive license to develop Vicineum in the Greater China region, and accordingly, the $1.8 million estimated earnout payment in the Greater China region remained as long-term contingent consideration as of June 30, 2022. During the third quarter of 2022, Qilu informed the Company that it no longer intended to commercialize Vicineum, due to additional effort and costs required to gain regulatory approval in that region without prior US approval. As such, the Company and Qilu were in the process of negotiating a termination of the Qilu License Agreement, which was terminated on December 23, 2022. Accordingly, the Company concluded that it no longer expected to owe any future earnout payments related to the Greater China region and reduced its remaining $1.8 million of contingent consideration liabilities to zero as of September 30, 2022.
Leases	Leases The Company accounts for operating leases under ASC Topic 842, Leases. The Company’s lease portfolio as of December 31, 2022 includes a property lease for its headquarters in Cambridge, MA. The Company determines if an arrangement is a lease at the inception of the contract and has made a policy election to not separate out non-lease components from lease components, for all classes of underlying assets. The asset components of the Company’s operating leases are recorded as operating lease right-of-use assets and reported within other assets on the Company's consolidated balance sheet. The short-term and long-term liability components are recorded in other current liabilities and other liabilities, respectively, on the Company’s consolidated balance sheet. As of December 31, 2022, the Company did not have any finance leases. Right-of-use assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term at the commencement date. The Company uses an incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments, if an implicit rate of return is not provided with the lease contract. Operating lease right-of-use assets are adjusted for incentives received. Operating lease costs are recognized on a straight-line basis over the lease term, in accordance with ASC 842, and also include variable operating costs incurred during the period. Lease costs also include amounts related to short-term leases.
Research and Development Costs	Research and Development Costs Research and development activities are expensed in the period incurred. Research and development expenses consist of both internal and external costs associated with all basic research activities, clinical development activities and technical efforts required to develop a product candidate. Internal research and development consist primarily of personnel costs, including salaries, benefits and share-based compensation, facilities leases, research-related overhead, pre-approval regulatory and clinical trial costs, manufacturing and other contracted services, license fees and other external costs. In certain circumstances, the Company is required to make advance payments to vendors for goods or services that will be received in the future for use in research and development activities. In such circumstances, the advance payments are recorded as prepaid assets and expensed when the activity has been performed or when the goods have been received.
Stock-Based Compensation	Share-Based Compensation The Company recognizes the grant-date fair value of share-based awards granted as compensation as expense on a straight-line basis over the requisite service period, which is generally the vesting period of the award. To date, the Company has not issued awards where vesting is subject to market conditions. From time to time, the Company has granted to its executives' stock option awards which contain both performance-based and service-based vesting criteria. Performance milestone events are specific to the Company’s corporate goals, including certain clinical development objectives related to the new clinical trial, regulatory and financial objectives. Share-based compensation expense associated with performance-based vesting criteria is recognized using the accelerated attribution method if the performance condition is considered probable of achievement in management’s judgment. The fair value of stock options is estimated at the time of grant using the Black-Scholes option pricing model, which requires the use of inputs and assumptions such as the fair value of the underlying stock, exercise price of the option, expected term, risk-free interest rate, expected volatility and dividend yield. The fair value of each grant of options during the years ended December 31, 2022, 2021 and 2020 was determined using the following methods and assumptions: •Expected Term. Given the plain vanilla nature of the options granted by the Company, the expected term is determined using the "simplified" method, as prescribed in SEC Staff Accounting Bulletin ("SAB") No. 107 ("SAB 107"), whereby the expected life equals the arithmetic average of the vesting term (generally four years) and the original contractual term (ten years) of the option, taking into consideration multiple vesting tranches. •Risk-Free Interest Rate. The risk-free rate is based on the interest rate payable on United States Treasury securities in effect at the time of grant for a period that is commensurate with the assumed expected term. •Expected Volatility. The expected volatility is based on historical volatilities of a representative group of publicly traded biopharmaceutical companies, including the Company's own volatility, which were commensurate with the assumed expected term, as prescribed in SAB 107. •Dividend Yield. The dividend yield is 0% because the Company has never declared or paid, and for the foreseeable future does not expect to declare or pay, a dividend on its common stock.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and net operating loss ("NOL") and research and development credit ("R&D credit") carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. A valuation allowance is recorded to the extent it is more likely than not that some portion or all of the deferred tax assets will not be realized. Unrecognized income tax benefits represent income tax positions taken on income tax returns that have not been recognized in the financial statements. The Company recognizes the benefit of an income tax position only if it is more likely than not (greater than 50%) that the tax position will be sustained upon tax examination, based solely on the technical merits of the tax position. Otherwise, no benefit is recognized. The tax benefits recognized are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The Company recognizes accrued interest and penalties related to uncertain tax positions as income tax expense in its consolidated statements of operations. As of December 31, 2022 and 2021, the Company did not have any uncertain tax positions.
Revenue Recognition	Revenue Recognition The Company recorded revenue from former out-license agreements and OUS business development partnership agreements, including the former license agreement (the “Roche License Agreement”) with F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc. (collectively, “Roche”) and its former OUS partnerships. Under each of these agreements, the Company granted the counterparty an exclusive license to develop and commercialize the underlying licensed product. These agreements contain up-front license fees, development and regulatory milestone payments, sales-based milestone payments, and sales-based royalty payments. The Company determines whether the out-license agreements and OUS business development partnership agreements are in scope of ASC 606, which it adopted as of January 1, 2018. Under ASC 606, in determining the appropriate amount of revenue to be recognized as the Company fulfills its obligations under these agreements, management performs the following steps: 1) Identification of the contract; 2) Determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; 3) Measurement of the transaction price, including the constraint on variable consideration; 4) Allocation of the transaction price to the performance obligations; and 5) Recognition of revenue when or as the Company satisfies each performance obligation. Development and Regulatory Milestones and Other Payments At the inception of an arrangement that includes development milestone payments, management evaluates whether the development milestones are considered probable of being reached and estimate the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated development milestone value is included in the transaction price. Development milestone payments that are not within the Company's control or the licensee's control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. For payments pursuant to sales milestones and royalty payments, the Company will not recognize revenue until the subsequent sale of a licensed product occurs. For arrangements with one than one performance obligations, the milestones are generally allocated entirely to the license performance obligation, as (1) the terms of milestone and royalty payments relate specifically to the license and (2) allocating milestones and royalties to the license performance obligation is consistent with the overall allocation objective, because management’s estimate of milestones and royalties approximates the standalone selling price of the license.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss and other comprehensive loss. For the year ended December 31, 2022, other comprehensive loss included changes in unrealized income and loss on marketable securities. For the years ended December 31, 2021 and 2020 comprehensive loss was equal to net loss.
Recent Accounting Pronouncements	Adopted in 2022 In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity ("ASU 2020-06"). ASU 2020-06 simplifies the complexity associated with applying US GAAP for certain financial instruments with characteristics of both liability and equity. More specifically, the amendments focus on the guidance for convertible instruments and derivative scope exception for contracts in an entity’s own equity. The ASU also amends the diluted earnings per share ("EPS") guidance, including the requirement to use the if-converted method for all convertible instruments. ASU 2020-06 is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021, and should be applied on a full or modified retrospective basis. The Company adopted this guidance on a modified retrospective basis effective January 1, 2022 and it did not have an impact on the Company's financial position, results of operations including per-share amounts, or cash flows. In May 2021, the FASB issued ASU No. 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options ("ASU 2021-04"). ASU 2021-04 clarifies and reduces diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options (for example, warrants) that remain equity classified after modification or exchange. ASU 2021-04 is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021, and should be applied on a prospective basis. The Company adopted this guidance effective January 1, 2022 and it did not have an impact on the Company's financial position, results of operations including per-share amounts, or cash flows. Other recent accounting pronouncements issued, but not yet effective, are not expected to be applicable to the Company or have a material effect on the consolidated financial statements upon future adoption.
Fair Value Measurement	The carrying values of cash and cash equivalents, restricted cash, prepaid expenses and other current assets, and accounts payable on the Company’s consolidated balance sheets approximated their fair values as of December 31, 2022 and 2021 due to their short-term nature. Certain of the Company’s financial instruments are measured at fair value using a three-level hierarchy that prioritizes the inputs used to measure fair value. This fair value hierarchy prioritizes the use of observable inputs and minimizes the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: Level 1: Inputs are quoted prices for identical instruments in active markets, Level 2: Inputs are quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; or model-derived valuations whose inputs are observable or whose significant value drivers are observable. Level 3: Inputs are unobservable and reflect the Company’s own assumptions, based on the best information available, including the Company’s own data.

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS (Tables)

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Schedule of Carrying Amounts and Fair Values of Financial Instruments Measured

The following tables set forth the carrying amounts and fair values of the Company's financial instruments measured at fair value on a recurring basis as of December 31, 2022 and 2021 (in thousands):


	December 31, 2022
					Fair Value Measurement Based on
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents:
Money market funds	$	76,728	$	76,728	$	76,728	$	—	$	—
Marketable securities:
US government securities	$	49,431	$	49,431	$	—	$	49,431	$	—
US treasury securities	$	4,935	$	4,935	$	—	$	4,935	$	—


	December 31, 2021
					Fair Value Measurement Based on
	Carrying Amount		Fair Value		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Money market funds (cash equivalents)	$	16,382	$	16,382	$	16,382	$	—	$	—
Liabilities:

Contingent consideration - long term	$	52,000	$	52,000	$	—	$	—	$	52,000

Schedule of Contingent Consideration Liability


Balance at December 31, 2021	$	52,000

Change in fair value of contingent consideration - long term	(52,000)
Balance at December 31, 2022	$	—

RESTRICTED CASH AND MARKETABLE SECURITIES (Tables)

12 Months Ended

Dec. 31, 2022

Cash and Cash Equivalents [Abstract]

Marketable Securities

The following table sets forth the composition of the Company’s marketable securities:


	December 31, 2022
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
US government securities	$	49,939	$	—	$	(508)	$	49,431
US treasury securities	4,973		—		(38)		4,935
Total Marketable Securities	$	54,912	$	—	$	(546)	$	54,366

The Company had no marketable securities as of December 31, 2021

PROPERTY AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

Schedule of Composition of Property and Equipment

The following table sets forth the composition of property and equipment, net as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
Lab equipment	$	94	$	569
Furniture and fixtures	—		16
Computer equipment	7		99
Software	4		32
Leasehold improvements	—		293
Property and equipment, gross	105		1,009
Less: accumulated depreciation	(105)		(966)
Total Property and Equipment, Net	$	—	$	43

INTANGIBLES AND GOODWILL (Tables)

12 Months Ended

Dec. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Composition of Intangible Assets

The following table sets forth the composition of intangible assets as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
IPR&D intangible assets:
Vicineum United States rights	$	—	$	—
Vicineum European Union rights	—		14,700
Total Intangibles	$	—	$	14,700

ACCRUED EXPENSES (Tables)

12 Months Ended

Dec. 31, 2022

Payables and Accruals [Abstract]

Schedule of Components of Accrued Expenses

The following table sets forth the composition of accrued expenses as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
Research and development	$	40	$	1,841
Payroll-related expenses	1,404		2,967
Restructuring charge related	5,733		1,497
Professional fees	301		597
Legal expenses, including the preliminary securities litigation settlement	21,919		1,344
Other	239		9
Total Accrued Expenses	$	29,636	$	8,255

LEASES (Tables)

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

Schedule of Lease Cost

The components of lease cost for the years ended December 31, 2022 and 2021 is as follows (in thousands):


	Year Ended December 31, 2022		Year Ended December 31, 2021
Lease Cost:
Operating lease (including related operating costs)	$	245	$	327
Short term property leases	213		262
Total lease costs	$	458	$	589


Supplemental Information:	Year Ended December 31, 2022		Year Ended December 31, 2021
Weighted-average remaining lease term (years)	0		0.75
Weighted-average discount rate - operating leases	—	%	12	%

STOCKHOLDERS' EQUITY DEFICIT (Tables)

12 Months Ended

Dec. 31, 2022

Equity [Abstract]

Schedule of Common Stock

In addition, the Company had reserved for issuance the following amounts of shares of its common stock for the purposes described below as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022	2021
Shares of common stock issued	202,759	199,464
Shares of common stock reserved for issuance for:
Warrants	187	199
Stock options	15,304	15,703
RSUs	4,695	3,041
Shares available for grant under 2014 Stock Incentive Plan	4,532	8,933
Shares available for sale under 2014 Employee Stock Purchase Plan	2,300	2,300
Total shares of common stock issued and reserved for issuance	229,777	229,640

Schedule of Warrants Outstanding and Warrant Activity

The following table sets forth the Company's warrant activity for the year ended December 31, 2022 (in thousands):


Issued	Exercise Price	Expiration	December 31, 2021	Issued	(Exercised)	(Cancelled)	December 31, 2022

Mar-2018	$0.55*	Mar-2023	132	—	—	—	132
Nov-2017	$0.55*	Nov-2022	12	—	—	(12)	—
May-2015	$11.83	Nov-2024	28	—	—	—	28
Nov-2014	$11.04	Nov-2024	27	—	—	—	27
			199	—	—	(12)	187

* Exercise price shown (i) reflects modification described below and (ii) subject to further adjustment based on down round provision added by amendment described below.

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-URI https://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21475-112644

+ Details

EARNINGS (LOSS) PER SHARE (Tables)

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Abstract]

Schedule of Potentially Dilutive Securities Excluded from Diluted Loss Calculation


	December 31,
	2022	2021	2020
Warrants	187	199	2,247
Stock options	15,304	15,703	10,147
RSUs and PSUs	4,695	—	—
Total	20,186	15,902	12,394

SHARE-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of Share-Based Compensation Expense


	Year Ended December 31,
	2022		2021		2020
Research and development	$	1,985	$	973	$	350
General and administrative	4,924		4,170		1,407
Total Share Based Compensation	$	6,909	$	5,143	$	1,757

Schedule of the Status of Restricted Stock Units

A summary of the status of restricted stock units is presented below:


			Restricted Stock Units (in thousands)
Unvested at December 31, 2021			3,041
Granted RSU			4,160
Granted PSU			1,004
Vested			(3,293)
Canceled or forfeited			(217)
Unvested at December 31, 2022			4,695

Schedule of Stock Option Activity


	Number of Shares under Option (in thousands)	Weighted-Average Exercise Price	Weighted-Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2019	6,236	$1.52	8.83	$	358
Granted	4,044	$0.87
Exercised	(12)	$1.13
Canceled or forfeited	(121)	$1.04
Outstanding at December 31, 2020	10,147	$1.26	8.50	$	3,160
Granted	8,273	$3.32
Exercised	(34)	$1.23
Canceled or forfeited	(2,683)	$3.70
Outstanding at December 31, 2021	15,703	$1.93	8.03	$	82
Granted	1,510	$0.72
Exercised	(2)	$0.32
Canceled or forfeited	(1,907)	$1.90
Outstanding at December 31, 2022	15,304	$1.82	7.19	$	3
Exercisable at December 31, 2022	10,427	$1.72	6.77	DM

Schedule of Weighted-Average Inputs and Assumptions in Black-Scholes Option


	Year Ended December 31,
	2022	2021	2020
Fair market value	$0.72	$3.32	$0.87
Grant exercise price	$0.72	$3.32	$0.87
Expected term (in years)	6.0	6.0	6.1
Risk-free interest rate	2.1%	0.9%	1.3%
Expected volatility	71.8%	74.6%	71.5%
Dividend yield	—%	—%	—%

INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Schedule of Components of Pre-tax Loss

The following table sets forth the components of the Company's loss before income taxes by country (in thousands):


	Year Ended December 31,
	2022		2021		2020
Country
United States	$	(37,289)	$	(32,757)	$	(35,529)
Canada	13,530		24,148		14,577
Total Loss Before Income Taxes	$	(23,759)	$	(8,609)	$	(20,952)

Schedule of Components of Income Tax Benefit (Provision)

The Company's tax benefit (provision) is comprised of the following components (in thousands):


	Year Ended December 31,
	2022		2021		2020
Current Tax Provision
Federal	$	—	$	—	$	—
State	—		—		—
Foreign	(94)		(286)		(1,445)
Total current (provision)	$	(94)	$	(286)	$	(1,445)
Deferred tax provision
Federal	$	—	$	—	$	—
State	—		—		—
Foreign	3,969		8,559		—
Total deferred benefit (provision)	$	3,969	$	8,559	$	—

Total Tax Benefit (Provision)	$	3,875	$	8,273	$	(1,445)

Reconciliation of Expected Income Tax Expense

The following table sets forth a reconciliation of the statutory United States federal income tax rate to the Company’s effective income tax rate:


	Year ended December 31,
	2022		2021		2020
United States federal statutory income tax rate	21.0	%	21.0	%	21.0	%
Impact of foreign rate differential	(3.3)		(15.9)		(4.2)
State taxes, net of federal benefit	0.9		2.3		2.0
Stock option cancellations	—		(1.1)		(0.2)
Contingent consideration	59.1		178.2		14.4
General business credits and other credits	0.5		2.4		6.6
Goodwill write-off	(14.8)	%	—	%	—	%
Permanent differences	(1.9)		(1.4)		0.2
Other	(0.2)		(13.8)		(2.1)
Foreign taxes	—		(3.3)		(6.9)
Change in valuation allowance	(44.6)		(72.3)		(37.7)
Effective Income Tax Rate	16.7	%	96.1	%	(6.9)	%

Schedule Components of Deferred Tax Liabilities

The following table sets forth the tax effects of temporary differences that gave rise to significant portions of the Company's deferred tax assets and liabilities (in thousands):


	December 31,
	2022		2021		2020
Deferred tax assets:
NOL carryforwards	$	66,374	$	63,381	$	57,935
R&D credit carryforwards	4,489		4,316		3,787
IRC 174 Capitalized R&D	6,214		—		—
Accruals and other	5,326		4,058		3,811
Capitalized start-up costs	34		53		70
Other	16		41		28
Gross deferred tax assets	82,453		71,849		65,631
Deferred tax liabilities:
IPR&D	—		(3,969)		(12,528)

Gross deferred tax liabilities	—		(3,969)		(12,528)
Valuation allowance	(82,453)		(71,849)		(65,631)
Net Deferred Tax Liability	$	—	$	(3,969)	$	(12,528)

Schedule of Credit Carryforwards

The following table summarizes the Company's NOL and R&D and other credit carryforwards in the United States and Canada as of December 31, 2022 (in millions):


	Amount		Expiration Beginning in	Through
United States:
Federal NOL carryforwards - indefinite	$	101.2	None	None
Federal NOL carryforwards	$	117.7	2030	2038
State NOL carryforwards	$	138.4	2030	2041
Federal R&D credit carryforwards	$	2.6	2027	2041
State R&D credit carryforwards	$	0.9	2027	2041
Canada:
Federal non-capital loss carryforwards	$	43.2	2035	2041
Federal scientific research and experimental development expense carryforwards	$	5.1	2032	2041
Federal and provincial investment tax credit carryforwards	$	1.2	2032	2041

RESTRUCTURING AND RELATED ACTIVITIES (Tables)

12 Months Ended

Dec. 31, 2022

Restructuring and Related Activities [Abstract]

Schedule of Restructuring Reserve by Type of Cost

The following is a summary of accrued restructuring costs related to the 2022 Restructuring Plan, (in thousands):


	2022 Restructuring Plan
Severance and benefits costs	$	6,976
Contract termination and other associated costs	4,788
Total restructurings costs	11,764
Cash payments	(6,031)
Balance at December 31, 2022	$	5,733

The following is a summary of accrued restructuring costs related to the 2021 Restructuring Plan:


	2021 Restructuring Plan
Balance as of December 31, 2021	$	1,497
Cash payments	(1,497)
Balance at December 31, 2022	$	—

DESCRIPTION OF BUSINESS (Details) - USD ($) $ in Thousands, shares in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Cash, cash equivalents, and marketable securities		$ 166,900
Accumulated deficit		336,141	$ 316,257
Negative cash flows from operating activities incurred		$ (24,895)	$ 68,878	$ 30,837
Viventia Bio Inc.
Variable Interest Entity [Line Items]
Shares of common stock issued to the selling shareholders (in shares)	4.0
Percentage of voting interests acquired	19.90%
Period during which quarterly earn-outs are payable after date of net sales	15 years
Period in which acquiree is to use commercially reasonable efforts to achieve marketing authorizations	7 years
Viventia Bio Inc. \| Vicinium \| Collaborative Arrangement, Revenue based on Specified Milestone
Variable Interest Entity [Line Items]
Percentage of net sales of quarterly earn-out payments during earn-out periods	2.00%
Viventia Bio Inc. \| Vicinium \| Collaborative Arrangement, Revenue based on Specified Milestone \| United States
Variable Interest Entity [Line Items]
One-time milestone payment upon first sale of product	$ 12,500
Viventia Bio Inc. \| Vicinium \| Collaborative Arrangement, Revenue based on Specified Milestone \| Europe
Variable Interest Entity [Line Items]
One-time milestone payment upon first sale of product	7,000
Viventia Bio Inc. \| Vicinium \| Collaborative Arrangement, Revenue based on Specified Milestone \| Japan
Variable Interest Entity [Line Items]
One-time milestone payment upon first sale of product	$ 3,000

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	1 Months Ended		3 Months Ended			12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	Jan. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2022 USD ($) unit	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2022 USD ($)
Property, Plant and Equipment [Line Items]
Insurance coverage limit						$ 250,000
Intangibles impairment charge					$ 31,700,000	$ 27,764,000	$ 31,700,000	$ 0
Number of reporting units \| unit						1
Goodwill		$ 13,064,000	$ 13,100,000	$ 13,064,000		$ 0	13,064,000
Goodwill impairment							$ 0
License agreement, royalty rate			2.00%			2.00%
Contingent consideration liability, measurement input		0.080		0.080			0.080
Business combination, contingent consideration, liability			$ 1,800,000			$ 0			$ 0
Dividend yield						0.00%
License and related revenue						$ 40,000,000	$ 26,544,000	$ 11,236,000
Discount Rate
Property, Plant and Equipment [Line Items]
Weighted-average cost of capital		9.30%		9.30%			9.30%
Roche
Property, Plant and Equipment [Line Items]
Proceeds from milestone achieved	$ 20,000,000
Performance-Based Awards
Property, Plant and Equipment [Line Items]
Award vesting period						4 years
Expected term (in years)						10 years
IPR&D intangible assets:
Property, Plant and Equipment [Line Items]
Total Intangibles		$ 14,700,000		$ 14,700,000		$ 0	$ 14,700,000
Licensing Agreements \| Roche
Property, Plant and Equipment [Line Items]
Milestone payment		$ 20,000,000
Milestone payment term		30 days
Vicinium \| Europe \| IPR&D intangible assets:
Property, Plant and Equipment [Line Items]
Intangibles impairment charge			14,700,000
Total Intangibles		$ 14,700,000	$ 0	14,700,000		$ 0	$ 14,700,000
EBI-031 \| Roche
Property, Plant and Equipment [Line Items]
License and related revenue				$ 20,000,000
Proceeds from milestone achieved	$ 20,000,000
Lab equipment
Property, Plant and Equipment [Line Items]
Estimated useful life						5 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated useful life						4 years
Computer equipment
Property, Plant and Equipment [Line Items]
Estimated useful life						3 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated useful life						5 years

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets:
Fair Value	$ 54,366
Liabilities:
Contingent consideration - long term	0	$ 52,000
US government securities
Assets:
Fair Value	49,431
US treasury securities
Assets:
Fair Value	4,935
Recurring \| Quoted Prices in Active Markets (Level 1)
Assets:
Money market funds	76,728	16,382
Liabilities:
Contingent consideration - long term		0
Recurring \| Quoted Prices in Active Markets (Level 1) \| US government securities
Assets:
Fair Value	0
Recurring \| Quoted Prices in Active Markets (Level 1) \| US treasury securities
Assets:
Fair Value	0
Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Money market funds	0	0
Liabilities:
Contingent consideration - long term		0
Recurring \| Significant Other Observable Inputs (Level 2) \| US government securities
Assets:
Fair Value	49,431
Recurring \| Significant Other Observable Inputs (Level 2) \| US treasury securities
Assets:
Fair Value	4,935
Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Money market funds	0	0
Liabilities:
Contingent consideration - long term		52,000
Recurring \| Significant Unobservable Inputs (Level 3) \| US government securities
Assets:
Fair Value	0
Recurring \| Significant Unobservable Inputs (Level 3) \| US treasury securities
Assets:
Fair Value	0
Carrying Amount \| Recurring
Assets:
Money market funds	76,728	16,382
Liabilities:
Contingent consideration - long term		52,000
Carrying Amount \| Recurring \| US government securities
Assets:
Fair Value	49,431
Carrying Amount \| Recurring \| US treasury securities
Assets:
Fair Value	4,935
Fair Value \| Recurring
Assets:
Money market funds	76,728	16,382
Liabilities:
Contingent consideration - long term		$ 52,000
Fair Value \| Recurring \| US government securities
Assets:
Fair Value	49,431
Fair Value \| Recurring \| US treasury securities
Assets:
Fair Value	$ 4,935

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS - Narrative (Details) - USD ($)	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Option, Quantitative Disclosures [Line Items]
License agreement, royalty rate	2.00%		2.00%
Contingent consideration liability, measurement input				0.080
Business combination, contingent consideration, liability	$ 0	$ 0	$ 1,800,000
Discount Rate
Fair Value, Option, Quantitative Disclosures [Line Items]
Weighted-average cost of capital				9.30%

FAIR VALUE MEASUREMENT AND FINANCIAL INSTRUMENTS - Summary of Changes in Fair Value of Company's Total Contingent Consideration (Details)	12 Months Ended
	Dec. 31, 2022 USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Ending balance	$ 0
Significant Unobservable Inputs (Level 3)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	52,000,000
Change in fair value of contingent consideration - long term	(52,000,000)
Ending balance	$ 0

RESTRICTED CASH AND MARKETABLE SECURITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Short term restricted cash	$ 21,000	$ 0	$ 3,000

RESTRICTED CASH AND MARKETABLE SECURITIES - Schedule of Cash, Cash Equivalents, Restricted Cash And Marketable Securities (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 54,912
Unrealized Gains	0
Unrealized Losses	(546)
Fair Value	54,366
US government securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	49,939
Unrealized Gains	0
Unrealized Losses	(508)
Fair Value	49,431
US treasury securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	4,973
Unrealized Gains	0
Unrealized Losses	(38)
Fair Value	$ 4,935

RECEIVABLES (Details) - USD ($) $ in Thousands	1 Months Ended
RECEIVABLES (Details) - USD ($) $ in Thousands	Jan. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Jun. 30, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivables		$ 21,011	$ 0
Other receivables		3,482	$ 825
Roche
Accounts, Notes, Loans and Financing Receivable [Line Items]
Milestone achieved		$ 20,000
Payment terms		30 days
Proceeds from milestone achieved	$ 20,000
Qilu Pharmaceutical Co., Ltd.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivables				$ 900

PROPERTY AND EQUIPMENT - Property and Equipment and Related Accumulated Depreciation (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 105	$ 1,009
Less: accumulated depreciation	(105)	(966)
Total Property and Equipment, Net	0	43
Lab equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	94	569
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	0	16
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7	99
Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4	32
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 0	$ 293

PROPERTY AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 13	$ 85	$ 122

INTANGIBLES AND GOODWILL - Composition of Intangible Assets (Details) - IPR&D intangible assets: - USD ($) $ in Thousands	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Total Intangibles	$ 0		$ 14,700
United States \| Vicinium
Finite-Lived Intangible Assets [Line Items]
Total Intangibles	0		0
European Union \| Vicinium
Finite-Lived Intangible Assets [Line Items]
Total Intangibles	$ 0	$ 0	$ 14,700

INTANGIBLES AND GOODWILL - Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Jun. 30, 2022	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Intangibles impairment charge		$ 31,700,000	$ 27,764,000	$ 31,700,000	$ 0
Goodwill	$ 13,100,000		0	13,064,000
Goodwill impairment				0
IPR&D intangible assets:
Finite-Lived Intangible Assets [Line Items]
Total Intangibles			0	14,700,000
Vicinium \| Europe \| IPR&D intangible assets:
Finite-Lived Intangible Assets [Line Items]
Intangibles impairment charge	14,700,000
Total Intangibles	$ 0		$ 0	$ 14,700,000

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References + Details

ACCRUED EXPENSES - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Research and development	$ 40	$ 1,841
Payroll-related expenses	1,404	2,967
Restructuring charge related	5,733	1,497
Professional fees	301	597
Legal expenses, including the preliminary securities litigation settlement	21,919	1,344
Other	239	9
Total Accrued Expenses	$ 29,636	$ 8,255

COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	12 Months Ended
COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	Dec. 31, 2022 USD ($) lawsuit	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Loss Contingencies [Line Items]
Restricted cash	$ 21,000	$ 0	$ 3,000
Securities Litigation
Loss Contingencies [Line Items]
Number of lawsuits \| lawsuit	3
Estimated litigation liability	$ 21,000
Restricted cash	$ 21,000
Federal Derivative Litigation
Loss Contingencies [Line Items]
Number of lawsuits \| lawsuit	3
Payment of litigation fees	$ 630

LEASES - Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
LEASES - Narrative (Details) $ in Millions	Sep. 30, 2022 USD ($)	Sep. 30, 2022 CAD ($)	Dec. 31, 2022 USD ($) ft²	Dec. 31, 2021 USD ($)
Lessee, Lease, Description [Line Items]
Short term property leases			$ 213,000	$ 262,000
Operating lease (including related operating costs)			245,000	327,000
Right-of-use asset			$ 0	$ 123,300
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]			Other assets	Other assets
Short term lease liability			$ 0	$ 123,300
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]			Other current liabilities	Other current liabilities
Canada
Lessee, Lease, Description [Line Items]
Office space (in square feet) \| ft²			31,100
Operating lease, termination expense	$ 900,000	$ 1.2
Massachusetts
Lessee, Lease, Description [Line Items]
Monthly rent			$ 2,500
Pennsylvania
Lessee, Lease, Description [Line Items]
Monthly rent			$ 18,000

LEASES - Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
LEASES - Lease Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Lease Cost:
Operating lease (including related operating costs)	$ 245	$ 327
Short term property leases	213	262
Total lease costs	$ 458	$ 589
Supplemental Information:
Weighted-average remaining lease term (years)	0 years	9 months
Weighted-average discount rate - operating leases	0.00%	12.00%

STOCKHOLDERS' EQUITY DEFICIT - Equity Financing (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended				2 Months Ended	12 Months Ended
	Feb. 28, 2021	Oct. 31, 2020	Nov. 30, 2019	Jun. 30, 2019	Jul. 31, 2021	Dec. 31, 2021	Dec. 31, 2022
Class of Stock [Line Items]
Common stock, par value (in dollars per share)						$ 0.001	$ 0.001
Aggregate sales price					$ 200.0
Proceeds from sale of stock				$ 27.8
Sale of stock, number of units issued (in shares)				20.4
Number of warrants (in shares)				20.4
Stock and warrants price per share (in dollars per share)				$ 1.47
Exercise price per warrant (in dollars per share)				$ 1.47
Expected term				1 year
ATM Facility
Class of Stock [Line Items]
Common stock, par value (in dollars per share)			$ 0.001
Additional shares to be issued	$ 34.5	$ 50.0
Aggregate sales price			$ 35.0
Commission fixed rate			3.00%
Proceeds from sale of stock						$ 175.0
Sale of stock, number of units issued (in shares)						56.9
Weighted-average stock price per share (in dollars per share)						$ 3.17
Issuance of common stock, issuance cost						$ 5.4

STOCKHOLDERS' EQUITY DEFICIT - Preferred Stock (Details) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Equity [Abstract]
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

STOCKHOLDERS' EQUITY DEFICIT - Common Stock (Details)	12 Months Ended
STOCKHOLDERS' EQUITY DEFICIT - Common Stock (Details)	Dec. 31, 2022 vote shares	Dec. 31, 2021 shares	May 03, 2021 shares	May 02, 2021 shares	Dec. 31, 2020 shares	Dec. 31, 2019 shares
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	400,000,000	400,000,000	400,000,000	200,000,000
Common stock, shares issued (in shares)	202,759,043	199,463,645
Common stock, shares outstanding (in shares)	202,759,043	199,463,645
Common Stock
Class of Stock [Line Items]
Common stock, shares issued (in shares)	202,759,043	199,463,645			140,449,647	106,801,409
Number of votes \| vote	1

STOCKHOLDERS' EQUITY DEFICIT - Summary of Common Stock Issued and Reserved for Issuance (Details) - shares	Dec. 31, 2022	Dec. 31, 2021
Class of Warrant or Right [Line Items]
Common stock, shares issued (in shares)	202,759,043	199,463,645
Shares of common stock reserved for issuance for:
Total shares of common stock issued and reserved for issuance (in shares)	229,777,000	229,640,000
Warrants
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	187,000	199,000
Stock options
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	15,304,000	15,703,000
RSUs
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	4,695,000	3,041,000
Shares available for grant under 2014 Stock Incentive Plan
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	4,532,000	8,933,000
Shares available for sale under 2014 Employee Stock Purchase Plan
Shares of common stock reserved for issuance for:
Shares of common stock reserved for issuance (in shares)	2,300,000	2,300,000

STOCKHOLDERS' EQUITY DEFICIT - Warrants (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Jun. 30, 2019
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)		$ 1.47
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	199
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	0
Warrants Cancelled (in shares)	(12)
Warrants outstanding, ending balance (in shares)	187
Warrants, Expiring March 2023
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.55
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	132
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	0
Warrants Cancelled (in shares)	0
Warrants outstanding, ending balance (in shares)	132
Warrants, Expiring November 2022
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.55
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	12
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	0
Warrants Cancelled (in shares)	(12)
Warrants outstanding, ending balance (in shares)	0
Warrants, Expiring November 2024, Issued May 2015
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 11.83
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	28
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	0
Warrants Cancelled (in shares)	0
Warrants outstanding, ending balance (in shares)	28
Warrants, Expiring November 2024, Issued November 2014
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 11.04
Warrant Or Right Outstanding [Roll Forward]
Warrants outstanding, beginning balance (in shares)	27
Warrants Issued (in shares)	0
Warrants Exercised (in shares)	0
Warrants Cancelled (in shares)	0
Warrants outstanding, ending balance (in shares)	27

STOCKHOLDERS' EQUITY DEFICIT - Warrants Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Oct. 31, 2019	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2019	Jun. 30, 2019
Class of Warrant or Right [Line Items]
Increase in warrant value	$ 1,100		$ 1,100
Exercise price per warrant (in dollars per share)								$ 1.47
Proceeds from exercises of common stock warrants				$ 0	$ 1,126	$ 131
Exercise of stock warrants (in shares)				0
Deemed dividend		$ 100
Common Stock
Class of Warrant or Right [Line Items]
Exercise of stock warrants (in shares)					2,048,059	238,110
2018 Warrants
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)				$ 0.55
Exercise of stock warrants (in shares)				0
2018 Warrants \| Common Stock
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.60	$ 0.55					$ 1.20
Proceeds from exercises of common stock warrants	$ 2,000
Exercise of stock warrants (in shares)	3,400,000
2017 Warrants
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)				$ 0.55
Exercise of stock warrants (in shares)				0
2017 Warrants \| Common Stock
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.55						0.80
2018 Warrant Amendment, Amendment to Securities Purchase Agreement
Class of Warrant or Right [Line Items]
Minimum percentage of securities issued	50.10%
2018 Warrant Amendment, Amendment to Securities Purchase Agreement \| Common Stock
Class of Warrant or Right [Line Items]
Exercise price per warrant (in dollars per share)	$ 0.95						$ 1.20

EARNINGS (LOSS) PER SHARE - Schedule of Antidilutive Securities (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from calculation of diluted net (loss) income per share (in shares)	20,186	15,902	12,394
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from calculation of diluted net (loss) income per share (in shares)	187	199	2,247
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from calculation of diluted net (loss) income per share (in shares)	15,304	15,703	10,147
RSUs and PSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from calculation of diluted net (loss) income per share (in shares)	4,695	0	0

SHARE-BASED COMPENSATION - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share Based Compensation	$ 6,909	$ 5,143	$ 1,757
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share Based Compensation	1,985	973	350
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share Based Compensation	$ 4,924	$ 4,170	$ 1,407

SHARE-BASED COMPENSATION - Narrative (Details) - USD ($)	1 Months Ended		12 Months Ended
	May 31, 2021	Jun. 30, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Oct. 01, 2021	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)			15,304,000	15,703,000	10,147,000		6,236,000
Share-based compensation expense			$ 6,909,000	$ 5,143,000	$ 1,757,000
Unrecognized compensation cost, non-vested stock options			$ 5,500,000
Weighted average period unvested stock to be recognized			1 year 10 months 17 days
Weighted-average grant-date fair value of stock options granted (in dollars per share)			$ 0.46	$ 2.16	$ 0.56
Share-based Payment Arrangement, Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)			2,900,000
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)			15,304,000	15,703,000
Share-based compensation expense			$ 4,300,000	$ 4,600,000	$ 1,800,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)			4,695,000	3,041,000
Unvested weighted average remaining contractual life			2 years 8 months 1 day	9 years 9 months
Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
Unvested weighted average remaining contractual life			2 years 8 months 1 day	9 years 9 months
2014 Stock Incentive Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance (in shares)	12,000,000	7,900,000
Shares reserved for future issuance (in shares)			4,500,000
Award vesting period			4 years
Expected term			10 years
Options outstanding (in shares)			12,200,000
Retention Program \| RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares received per award (in shares)			1
Share-based compensation expense			$ 2,500,000	$ 500,000	$ 0
Retention Program \| Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares received per award (in shares)						1
Share-based compensation expense			55,000
Percent of base salary						50.00%
Unrecognized compensation expense			32,000
Retention Program, cash management milestone \| Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense			$ 87,000
Achievement deemed probable, percent			20.00%
Stock Incentive Plan 2009 \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term			10 years
Vested stock options outstanding (in shares)			100,000
Vesting on the First Anniversary of Date of Grant \| 2014 Stock Incentive Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of original number of shares subject to the option vesting			25.00%
Vesting at End of Each Successive Three-Month Period Thereafter \| 2014 Stock Incentive Plan \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of original number of shares subject to the option vesting			6.25%

SHARE-BASED COMPENSATION - Summary of Status and Changes of Unvested Restricted Stock (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2022 shares
Number of Shares
Unvested, beginning balance (in shares)	3,041
Vested (in shares)	(3,293)
Canceled or forfeited (in shares)	(217)
Unvested, ending balance (in shares)	4,695
RSUs
Number of Shares
Granted (in shares)	4,160
Performance-Based Awards
Number of Shares
Granted (in shares)	1,004

SHARE-BASED COMPENSATION - Stock Options (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of Shares under Option (in thousands)
Outstanding at beginning of period (in shares)	15,703	10,147	6,236
Granted (in shares)	1,510	8,273	4,044
Exercised (in shares)	(2)	(34)	(12)
Canceled or forfeited (in shares)	(1,907)	(2,683)	(121)
Outstanding at end of period (in shares)	15,304	15,703	10,147	6,236
Exercisable at end of period (in shares)	10,427
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 1.93	$ 1.26	$ 1.52
Granted (in dollars per share)	0.72	3.32	0.87
Exercised (in dollars per share)	0.32	1.23	1.13
Cancelled or forfeited (in dollars per share)	1.90	3.70	1.04
Outstanding at end of period (in dollars per share)	1.82	$ 1.93	$ 1.26	$ 1.52
Exercisable at end of period (in dollars per share)	$ 1.72
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-average Remaining Contractual Life (in years), Outstanding	7 years 2 months 8 days	8 years 10 days	8 years 6 months	8 years 9 months 29 days
Weighted-average Remaining Contractual Life (in years), Exercisable	6 years 9 months 7 days
Aggregate Intrinsic Value, Outstanding	$ 3	$ 82	$ 3,160	$ 358

SHARE-BASED COMPENSATION - Weighted-Average Inputs and Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair market value (in dollars per share)	$ 0.72	$ 3.32	$ 0.87
Grant exercise price (in dollars per share)	$ 0.72	$ 3.32	$ 0.87
Expected term (in years)	6 years	6 years	6 years 1 month 6 days
Risk-free interest rate	2.10%	0.90%	1.30%
Expected volatility	71.80%	74.60%	71.50%
Dividend yield	0.00%	0.00%	0.00%

EMPLOYEE BENEFIT PLANS (Details) - USD ($) shares in Millions	1 Months Ended	12 Months Ended
	May 31, 2021	Dec. 31, 2022	Feb. 28, 2014
United States
Defined Benefit Plan Disclosure [Line Items]
Defined contribution retirement plan, maximum employee contribution deferred		100.00%
Discretionary match per participating employee, maximum		$ 4,000
Canada
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of employees' eligible compensation		4.00%
2014 Employee Stock Purchase Plan
Defined Benefit Plan Disclosure [Line Items]
Shares of common stock reserved for issuance (in shares)			0.2
Number of additional shares authorized (in shares)	2.3
Common stock purchase price, discount rate		15.00%
Common stock available for sale (in shares)		2.3

INCOME TAXES - Components of Pre-tax Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Taxes [Line Items]
Total Loss Before Income Taxes	$ (23,759)	$ (8,609)	$ (20,952)
United States
Income Taxes [Line Items]
Pre-tax income (loss) U.S.	(37,289)	(32,757)	(35,529)
Canada
Income Taxes [Line Items]
Pre-tax income (loss) Canada	$ 13,530	$ 24,148	$ 14,577

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 20
-Section 25
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=126941158&loc=d3e41242-110953

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(8))
-URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-URI https://asc.fasb.org/extlink&oid=120399901&loc=d3e537907-122884

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8924-108599

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

INCOME TAXES - Components of Income Tax Provisions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current Tax Provision
Federal	$ 0	$ 0	$ 0
State	0	0	0
Foreign	(94)	(286)	(1,445)
Total current (provision)	(94)	(286)	(1,445)
Deferred tax provision
Federal	0	0	0
State	0	0	0
Foreign	3,969	8,559	0
Total deferred benefit (provision)	3,969	8,559	0
Benefit (provision) from income taxes	$ 3,875	$ 8,273	$ (1,445)

INCOME TAXES - Reconciliation of Expected Income Tax Expense (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation:
United States federal statutory income tax rate	21.00%	21.00%	21.00%
Impact of foreign rate differential	(3.30%)	(15.90%)	(4.20%)
State taxes, net of federal benefit	0.90%	2.30%	2.00%
Stock option cancellations	0.00%	(1.10%)	(0.20%)
Contingent consideration	59.10%	178.20%	14.40%
General business credits and other credits	0.50%	2.40%	6.60%
Goodwill write-off	(14.80%)	0.00%	0.00%
Permanent differences	(1.90%)	(1.40%)	0.20%
Other	(0.20%)	(13.80%)	(2.10%)
Foreign taxes	0.00%	(3.30%)	(6.90%)
Change in valuation allowance	(44.60%)	(72.30%)	(37.70%)
Effective Income Tax Rate	16.70%	96.10%	(6.90%)

INCOME TAXES - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
NOL carryforwards	$ 66,374	$ 63,381	$ 57,935
R&D credit carryforwards	4,489	4,316	3,787
IRC 174 Capitalized R&D	6,214	0	0
Accruals and other	5,326	4,058	3,811
Capitalized start-up costs	34	53	70
Other	16	41	28
Gross deferred tax assets	82,453	71,849	65,631
Deferred tax liabilities:
IPR&D	0	(3,969)	(12,528)
Gross deferred tax liabilities	0	(3,969)	(12,528)
Valuation allowance	(82,453)	(71,849)	(65,631)
Net Deferred Tax Liability	$ 0	$ (3,969)	$ (12,528)

INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Valuation allowance	$ 82,453	$ 71,849	$ 65,631
Valuation allowance change	10,600
NOL carryforward reduced amount	$ 800

INCOME TAXES - Schedule of Credit Carryforwards (Details) $ in Millions	Dec. 31, 2022 USD ($)
United States: \| Federal
Income Taxes [Line Items]
NOL carryforwards	$ 117.7
United States: \| State
Income Taxes [Line Items]
NOL carryforwards	138.4
Indefinite \| United States: \| Federal
Income Taxes [Line Items]
NOL carryforwards	101.2
R&D credit carryforwards \| United States: \| Federal
Income Taxes [Line Items]
Tax credit carryforwards	2.6
R&D credit carryforwards \| United States: \| State
Income Taxes [Line Items]
Tax credit carryforwards	0.9
R&D credit carryforwards \| Canada
Income Taxes [Line Items]
Tax credit carryforwards	5.1
Non-capital loss carryforwards \| Canada
Income Taxes [Line Items]
Tax credit carryforwards	43.2
Investment tax credit carryforwards \| Canada
Income Taxes [Line Items]
Tax credit carryforwards	$ 1.2

LICENSE AGREEMENTS (Details) € in Thousands					1 Months Ended			3 Months Ended					12 Months Ended
LICENSE AGREEMENTS (Details) € in Thousands	Jul. 20, 2022 USD ($)	Aug. 05, 2021 USD ($)	Nov. 30, 2020 USD ($)	Jul. 30, 2020 USD ($)	Jul. 31, 2022 USD ($)	Aug. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 EUR (€)
Organization And Basis Of Presentation [Line Items]
Asset purchase agreement, variable consideration								$ 30,000,000					$ 30,000,000
Payments to refund license agreement deposits	$ 3,000,000
Qilu Pharmaceutical Co., Ltd. \| Licensing Agreements
Organization And Basis Of Presentation [Line Items]
Upfront payment				$ 12,000,000
Total milestone payments				$ 23,000,000
Royalty payment, percentage				12.00%
University of Zurich
Organization And Basis Of Presentation [Line Items]
Royalty payment obligation, percent													4.00%	4.00%
Third party maximum ownership, percent													10.00%	10.00%
Third party minimum ownership, percent													2.00%	2.00%
Expenses related to achievement of development milestone						$ 500,000	$ 300,000
University of Zurich \| Collaborative Arrangement, Revenue Based on Clinical Development Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone													$ 500,000
Micromet AG
Organization And Basis Of Presentation [Line Items]
Royalty payment obligation, percent													3.50%	3.50%
Expenses related to achievement of development milestone									$ 600,000	€ 500	$ 900,000	€ 700	$ 51,770	€ 50
Potential milestone payments													$ 2,600,000	€ 2,400
License agreement, royalty payment, reduction, conditions not met													1.50%	1.50%
License maintenance fees \| €														€ 50
XOMA Ireland Limited
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone													$ 250,000
Royalty payment obligation, percent													2.50%	2.50%
Third party maximum ownership, percent													50.00%	50.00%
Third party minimum ownership, percent													1.75%	1.75%
Roche
Organization And Basis Of Presentation [Line Items]
Other receivable, asset purchase agreement								30,000,000					$ 30,000,000
Proceeds from execution of asset purchase agreement					$ 40,000,000
Roche \| EBI-031
Organization And Basis Of Presentation [Line Items]
Other receivable, asset purchase agreement					$ 70,000,000
Qilu Pharmaceutical Co., Ltd.
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone													$ 200,000
Royalty period				12 years
License termination fee						$ 1,400,000
License termination payment								$ 1,200,000
MENA License Agreement \| Licensing Agreements
Organization And Basis Of Presentation [Line Items]
Upfront payment			$ 3,000,000
Eczacibasi Pharmaceuticals Marketing Agreement
Organization And Basis Of Presentation [Line Items]
Potential milestone payments		$ 2,000,000
Transaction price		$ 1,500,000
Eczacibasi Pharmaceuticals Marketing Agreement \| TURKEY
Organization And Basis Of Presentation [Line Items]
Royalty revenue, percentage		0.30

RESTRUCTURING AND RELATED ACTIVITIES - Narrative (Details) - 2021 Restructuring Plan	Aug. 30, 2021 position
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated	18
Number of positions eliminated, period percent	35.00%

RESTRUCTURING AND RELATED ACTIVITIES - Schedule of Restructuring Reserve by Type of Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 1,497
Restructuring charge	11,764	$ 5,528	$ 0
Cash payments	(1,497)
Ending Balance	0	$ 1,497
2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charge	11,764
Cash payments	(6,031)
Ending Balance	5,733
Severance and benefits costs \| 2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charge	6,976
Contract termination and other associated costs \| 2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charge	$ 4,788

SUBSEQUENT EVENTS (Details)	Mar. 02, 2023
Scenario, Forecast
Subsequent Event [Line Items]
Reverse stock split, conversion ratio	0.05