Y-mAbs Therapeutics (YMAB) 10-Q 7 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Nov. 02, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	001-38650
Entity Registrant Name	Y-mAbs Therapeutics, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-4619612
Entity Address, Address Line One	230 Park Avenue
Entity Address, Address Line Two	Suite 3350
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10169
City Area Code	646
Local Phone Number	885-8505
Title of 12(b) Security	Common Stock
Trading Symbol	YMAB
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		43,668,130
Entity Central Index Key	0001722964
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
CURRENT ASSETS
Cash and cash equivalents	$ 114,526	$ 181,564
Accounts receivable, net	9,251	7,712
Inventories	6,242	5,512
Other current assets	3,225	7,473
Total current assets	133,244	202,261
Property and equipment, net	1,372	1,847
Operating lease right-of-use assets	2,169	3,842
Intangible assets, net	1,530	1,663
Other assets	5,600	3,170
TOTAL ASSETS	143,915	212,783
LIABILITIES
Accounts payable	13,723	13,552
Accrued liabilities	17,092	12,540
Operating lease liabilities, current portion	1,200	1,783
Total current liabilities	32,015	27,875
Accrued milestones	2,250	2,100
Operating lease liabilities, long-term portion	1,019	1,851
Other liabilities	733	851
TOTAL LIABILITIES	36,017	32,677
Commitments and contingencies (Note 9)
STOCKHOLDERS' EQUITY
Preferred stock, $0.0001 par value, 5,500,000 shares authorized and none issued at September 30, 2022 and December 31, 2021
Common stock, $0.0001 par value, 100,000,000 shares authorized at September 30, 2022 and December 31, 2021; 43,668,130 and 43,694,716 shares issued and outstanding at September 30, 2022 and December 31, 2021, respectively	4	4
Additional paid in capital	540,392	519,206
Accumulated other comprehensive income	4,702	1,371
Accumulated deficit	(437,200)	(340,475)
TOTAL STOCKHOLDERS' EQUITY	107,898	180,106
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 143,915	$ 212,783

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized shares	5,500,000	5,500,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, authorized shares	100,000,000	100,000,000
Common stock, shares issued	43,668,130	43,694,716
Common stock, shares outstanding	43,668,130	43,694,716

Consolidated Statements of Net

Consolidated Statements of Net Income (Loss) and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
REVENUES
Total revenues	$ 12,537	$ 8,965	$ 33,820	$ 25,299
OPERATING COSTS AND EXPENSES
Cost of goods sold	2,475	550	5,447	843
License royalties			100	210
Research and development	22,453	23,131	71,785	64,488
Selling, general, and administrative	13,626	13,988	50,146	39,433
Total operating costs and expenses	38,554	37,669	127,478	104,974
Loss from operations	(26,017)	(28,704)	(93,658)	(79,675)
OTHER INCOME / (LOSS), NET
Gain from sale of priority review voucher, net				62,010
Interest and other loss	(1,509)	(154)	(3,067)	(717)
NET LOSS	(27,526)	(28,858)	(96,725)	(18,382)
Other comprehensive income
Foreign currency translation	1,598	238	3,331	751
COMPREHENSIVE LOSS	$ (25,928)	$ (28,620)	$ (93,394)	$ (17,631)
Net income / (loss) per share attributable to common stockholders, basic (in dollars per share)	$ (0.63)	$ (0.66)	$ (2.21)	$ (0.43)
Net income / (loss) per share attributable to common stockholders, diluted (in dollars per share)	$ (0.63)	$ (0.66)	$ (2.21)	$ (0.43)
Weighted average common shares outstanding, basic (in shares)	43,718,351	43,598,350	43,715,451	43,019,217
Weighted average common shares outstanding, diluted (in shares)	43,718,351	43,598,350	43,715,451	43,019,217
Product
REVENUES
Total revenues	$ 12,537	$ 8,965	$ 32,820	$ 23,299
License
REVENUES
Total revenues			$ 1,000	$ 2,000

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Balance at the beginning of period at Dec. 31, 2020	$ 4	$ 391,558	$ (526)	$ (285,200)	$ 105,836
Balance at the beginning of period (in shares) at Dec. 31, 2020	40,688,447
Increase (Decrease) in Stockholders' Equity
Issuance of common stock to investors, net of issuance costs		107,725			107,725
Issuance of common stock to investors, net of issuance costs (in shares)	2,804,878
Exercise of stock options		110			110
Exercise of stock options (in shares)	46,000
Stock-based compensation expense		4,698			4,698
Stock-based compensation expense (in shares)	9,094
Foreign currency translation			435		435
Net loss				33,413	33,413
Balance at the end of period at Mar. 31, 2021	$ 4	504,091	(91)	(251,787)	252,217
Balance at the end of period (in shares) at Mar. 31, 2021	43,548,419
Balance at the beginning of period at Dec. 31, 2020	$ 4	391,558	(526)	(285,200)	105,836
Balance at the beginning of period (in shares) at Dec. 31, 2020	40,688,447
Increase (Decrease) in Stockholders' Equity
Net loss					(18,382)
Balance at the end of period at Sep. 30, 2021	$ 4	514,198	225	(303,582)	210,845
Balance at the end of period (in shares) at Sep. 30, 2021	43,643,916
Balance at the beginning of period at Mar. 31, 2021	$ 4	504,091	(91)	(251,787)	252,217
Balance at the beginning of period (in shares) at Mar. 31, 2021	43,548,419
Increase (Decrease) in Stockholders' Equity
Exercise of stock options		131			131
Exercise of stock options (in shares)	28,332
Stock-based compensation expense		4,827			4,827
Stock-based compensation expense (in shares)	199
Foreign currency translation			78		78
Net loss				(22,937)	(22,937)
Balance at the end of period at Jun. 30, 2021	$ 4	509,049	(13)	(274,724)	234,316
Balance at the end of period (in shares) at Jun. 30, 2021	43,576,950
Increase (Decrease) in Stockholders' Equity
Exercise of stock options		248			248
Exercise of stock options (in shares)	66,160
Stock-based compensation expense		4,901			4,901
Stock-based compensation expense (in shares)	806
Foreign currency translation			238		238
Net loss				(28,858)	(28,858)
Balance at the end of period at Sep. 30, 2021	$ 4	514,198	225	(303,582)	210,845
Balance at the end of period (in shares) at Sep. 30, 2021	43,643,916
Balance at the beginning of period at Dec. 31, 2021	$ 4	519,206	1,371	(340,475)	$ 180,106
Balance at the beginning of period (in shares) at Dec. 31, 2021	43,694,716				43,694,716
Increase (Decrease) in Stockholders' Equity
Exercise of stock options		32			$ 32
Exercise of stock options (in shares)	16,000
Stock-based compensation expense		5,091			5,091
Stock-based compensation expense (in shares)	7,449
Foreign currency translation			311		311
Net loss				(28,068)	(28,068)
Balance at the end of period at Mar. 31, 2022	$ 4	524,329	1,682	(368,543)	157,472
Balance at the end of period (in shares) at Mar. 31, 2022	43,718,165
Balance at the beginning of period at Dec. 31, 2021	$ 4	519,206	1,371	(340,475)	$ 180,106
Balance at the beginning of period (in shares) at Dec. 31, 2021	43,694,716				43,694,716
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (in shares)					20,000
Retirement of treasury shares - refer to Note 10					$ (963)
Net loss					(96,725)
Balance at the end of period at Sep. 30, 2022	$ 4	540,392	4,702	(437,200)	$ 107,898
Balance at the end of period (in shares) at Sep. 30, 2022	43,668,130				43,668,130
Balance at the beginning of period at Mar. 31, 2022	$ 4	524,329	1,682	(368,543)	$ 157,472
Balance at the beginning of period (in shares) at Mar. 31, 2022	43,718,165
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense		13,633			13,633
Stock-based compensation expense (in shares)	1,873
Foreign currency translation			1,422		1,422
Net loss				(41,131)	(41,131)
Balance at the end of period at Jun. 30, 2022	$ 4	537,962	3,104	(409,674)	131,396
Balance at the end of period (in shares) at Jun. 30, 2022	43,720,038
Increase (Decrease) in Stockholders' Equity
Exercise of stock options		52			52
Exercise of stock options (in shares)	4,000
Stock-based compensation expense		3,341			3,341
Stock-based compensation expense (in shares)	1,979
Retirement of treasury shares - refer to Note 10		(963)			(963)
Retirement of treasury shares - refer to Note 10 (in shares)	(57,887)
Foreign currency translation			1,598		1,598
Net loss				(27,526)	(27,526)
Balance at the end of period at Sep. 30, 2022	$ 4	$ 540,392	$ 4,702	$ (437,200)	$ 107,898
Balance at the end of period (in shares) at Sep. 30, 2022	43,668,130				43,668,130

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (96,725)	$ (18,382)
Adjustments to reconcile net loss to net cash used in operating activities:
Gain from sale of priority review voucher, net		(62,010)
Depreciation and amortization	609	491
Stock-based compensation	22,065	14,426
Foreign currency transactions	3,698	751
Changes in assets and liabilities:
Accounts receivable, net	(1,539)	(7,264)
Inventories	(730)	(4,787)
Other current assets	2,919	4,930
Other assets	(2,430)	(1,461)
Accounts payable	171	1,652
Accrued liabilities and other	4,702	2,961
NET CASH USED IN OPERATING ACTIVITIES	(67,260)	(68,693)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of property and equipment		(512)
Net proceeds from sale of priority review voucher		62,010
NET CASH PROVIDED BY INVESTING ACTIVITIES		61,498
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from issuance of common stock, net of issuance costs		107,725
Proceeds from exercised stock options	84	489
NET CASH PROVIDED BY FINANCING ACTIVITIES	84	108,214
Effect of exchange rates on cash and cash equivalents	138	77
NET INCREASE / (DECREASE) IN CASH AND CASH EQUIVALENTS	(67,038)	101,096
Cash and cash equivalents at the beginning of period	181,564	114,634
Cash and cash equivalents at the end of period	114,526	$ 215,730
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES
Intangible assets acquisition in accrued milestones	1,500
Right-of-use assets obtained in exchange for lease obligations	347
Acquisition of treasury shares upon repayment of secured promissory note - refer to Note 10	$ 963

ORGANIZATION AND DESCRIPTION OF

ORGANIZATION AND DESCRIPTION OF BUSINESS	9 Months Ended
	Sep. 30, 2022
ORGANIZATION AND DESCRIPTION OF BUSINESS
ORGANIZATION AND DESCRIPTION OF BUSINESS	NOTE 1—ORGANIZATION AND DESCRIPTION OF BUSINESS Y-mAbs Therapeutics, Inc. (“we,” “us,” “our,” the “Company,” or “Y-mAbs”) is a commercial-stage biopharmaceutical company focused on the development and commercialization of novel, antibody based therapeutic products for the treatment of cancer. The Company is leveraging its proprietary antibody platforms and deep expertise in the field of antibodies to develop a broad portfolio of innovative medicines and has several ongoing clinical trials in progress. The Company is headquartered in New York and was incorporated on April 30, 2015 under the laws of the State of Delaware.

BASIS OF PRESENTATION

BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 2022
BASIS OF PRESENTATION
BASIS OF PRESENTATION	NOTE 2—BASIS OF PRESENTATION Except for the quarter ended March 31, 2021, the Company has incurred losses since inception. Operations of the Company are subject to certain risks and uncertainties, including, among others, uncertainty of drug candidate development; technological uncertainty; uncertainty regarding patents and proprietary rights; uncertainty in obtaining the U.S. Food and Drug Administration (“FDA”) approval in the United States and regulatory approval in other jurisdictions; marketing or sales capability or experience; uncertainty in getting adequate payer coverage and reimbursement; dependence on key personnel; compliance with government regulations and the need to obtain additional financing. The Company’s drug candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance reporting capabilities. The Company’s drug candidates are in various stages of development. DANYELZA (naxitamab-gqgk) was approved by the FDA in November 2020, but there can be no assurance that the Company’s other research and development efforts will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development and commercialization efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. The Company’s consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities in the ordinary course of business. The Company has experienced negative cash flows from operations since inception, and had an accumulated deficit of $437,200,000 as of September 30, 2022 and $340,475,000 as of December 31, 2021. Through September 30, 2022, the Company has funded its operations primarily through proceeds from sales of shares of its common stock, including its initial public offering in September 2018 and its subsequent public offerings in November 2019 and February 2021, as well as additional funding from the sales of DANYELZA and from the sale of the DANYELZA PRV. On February 22, 2021, the Company announced the closing of its public offering of 2,804,878 shares of its common stock, at a public offering price of $41.00 per share, which included the exercise in full of the underwriters’ option to purchase 365,853 additional shares of common stock. The aggregate gross proceeds to the Company, before deducting underwriting discounts and commissions and offering expenses payable by the Company, were approximately $115,000,000. As of September 30, 2022, the Company had cash and cash equivalents of $114,526,000, and as of December 31, 2021 the Company had cash and cash equivalents of $181,564,000. As of the issuance date of the consolidated financial statements for the third quarter ended September 30, 2022, the Company expects that its cash and cash equivalents at September 30, 2022 will be sufficient to fund its operating expenses and capital expenditure requirements through at least the next 12 months, irrespective of whether any additional product approvals are obtained. The Company may raise additional capital to fund future operations through the sale of its securities, incurring debt, entering into licensing or collaboration agreements with partners, grants or other sources of financing. Sufficient funds may not be available to the Company on attractive terms or at all when needed from any such financing. If successful commercialization of DANYELZA and our product candidates for which we may obtain regulatory approvals and marketing authorizations, either directly or with a collaborator or distributor and FDA approval for omburtamab does not occur or is significantly delayed, and the Company is unable to obtain additional financing from these or other sources when needed, it will likely be necessary to take other actions to enhance the Company’s liquidity position which may include significantly reducing the current rate of spending through delaying or scaling back current operations, or suspending certain research and development programs and other operational programs. The accompanying unaudited consolidated financial statements reflect the accounts of the Company and its wholly owned subsidiaries and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information, Accounting Standards Codification (“ASC”) Topic 270-10 and the instructions to Quarterly Report on Form 10-Q. Accordingly, these consolidated financial statements do not include all of the information and notes required by GAAP for complete financial statements. The unaudited interim consolidated financial statements include all adjustments (consisting only of normal recurring nature) necessary in the judgment of management for a fair statement of the results for the periods presented. All intercompany balances and transactions have been eliminated. The Company has evaluated subsequent events through the date of this filing. Operating results for the three and nine month periods ended September 30, 2022 are not necessarily indicative of the results that may be expected for the year ended December 31, 2022, any other interim periods, or any future year or period. The December 31, 2021 consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. You should read these unaudited interim consolidated financial statements in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021. ​

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2022
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	NOTE 3—SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The Company’s significant accounting policies are detailed in its Annual Report on Form 10-K for the year ended December 31, 2021. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, net product revenues, the accrual for research and development expenses, the accrual of milestone and royalty payments, and the valuation of stock options. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, including expenses, manufacturing, clinical trials, research and development costs and employee-related amounts, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat COVID-19, as well as the economic impact on local, regional, national and international markets. Cash and Cash Equivalents The Company considers all highly liquid instruments with original maturities of three months or less from date of purchase to be cash equivalents. All cash and cash equivalents are held in highly rated securities including a treasury money market fund, which is unrestricted as to withdrawal or use. To date, the Company has not experienced any losses on its cash and cash equivalents. The carrying amount of cash and cash equivalents approximates its fair value due to its short-term and liquid nature. The Company maintains cash balances in excess of insured limits. The Company monitors the financial performance, credit ratings and liquidity of the money market fund to timely assess and respond to any changes in the asset values of the fund. The Company does not anticipate any losses with respect to such cash balances. Trade Accounts Receivables The Company’s trade accounts receivable balance consists of amounts due from sales of its approved product, DANYELZA. Receivables from product sales are recorded net of allowances which generally include chargebacks, doubtful accounts, rebates, returns, and discounts. The allowance is based primarily on assessment of specific identifiable customer accounts considered at risk or uncollectible, as well as an analysis of current receivables aging and expected future write-offs. The Company has not historically experienced any significant credit losses. All customer accounts are actively managed, and no material losses are currently expected. The Company has not experienced any write-offs related to its customers and has not recognized any allowance for doubtful accounts nor reversed any allowances in the nine months ended September 30, 2022. Concentration of Credit Risk The Company’s product sales are made through arrangements primarily with three national specialty distributors in the United States. As of September 30, 2022, the receivables balances from such distributors totaled 99% of the Company’s outstanding accounts receivable. The Company has contractual payment terms with each of its customers and the Company monitors their financial performance, historical payment terms and credit worthiness to timely assess and respond to any changes in their credit profile. Inventory The Company values its inventories at the lower of cost or net realizable value on a first-in, first-out basis. The Company’s inventory cost includes amounts related to materials, third party contract manufacturing, third party packaging services, freight, labor costs for personnel involved in the manufacturing process, and indirect overhead costs. Raw and intermediate materials that may be utilized for both commercial and clinical programs are identical and given the alternative future use such amounts are initially classified as inventory. Amounts in inventory associated with clinical development programs are charged to research and development expense when the product enters the research and development process and can no longer be used for commercial purposes and, therefore, does not have an alternative future use. The Company capitalizes inventory costs related to products to be sold in the ordinary course of business. The Company makes a determination of capitalizing inventory costs for a product based on, among other factors, status of regulatory approval, information regarding safety, efficacy and expectations relating to commercial sales and recoverability of costs. For DANYELZA, the Company commenced capitalization of inventory beginning at the receipt of FDA approval. Prior to FDA approval, the Company expensed such costs as part of research and development expenses. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their estimated realizable value in the period in which the impairment occurs. Such impairment charges, should they occur, are recorded within cost of goods sold. The determination of whether inventory costs will be realizable requires estimates by management. Other than the $1,200,000 recorded in the three and nine months ended September 30, 2022, as discussed further in NOTE 6— INVENTORIES, there were no other material inventory write-downs in the three and nine months ended September 30, 2022. Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. ​ • Level 1 — Unadjusted quoted prices for identical assets or liabilities in active markets; • Level 2 — Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability; and • Level 3 — Unobservable inputs for the asset or liability, which include management's own assumption about the assumptions market participants would use in pricing the asset or liability, including assumptions about risk. Cash equivalents held in money market funds are valued using other significant observable inputs, which represent a Level 2 measurement within the fair value hierarchy. The Company has no other cash equivalents. The following tables present the Company’s fair value hierarchy for its cash equivalents, which are measured at fair value on a recurring basis (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at September 30, 2022 Using: ​ Level 1 Level 2 Level 3 Total Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ — ​ $ 105,274 ​ $ — ​ $ 105,274 Total ​ $ — ​ $ 105,274 ​ $ — ​ $ 105,274 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2021 Using: ​ Level 1 Level 2 Level 3 Total Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ — ​ $ 166,729 ​ $ — ​ $ 166,729 Total ​ $ — ​ $ 166,729 ​ $ — ​ $ 166,729 ​ During the nine months ended September 30, 2022, there were no transfers Level 3 Operating Leases The Company determines if an arrangement includes a lease at inception. Operating lease right-of-use assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the net present value of lease payments, the Company uses its estimated incremental borrowing rate based on information available at the lease commencement date. Because most of the Company’s leases do not provide an implicit rate of return, an incremental borrowing rate is used based on the information available at the commencement date in determining the present value of lease payments on an individual lease basis. The Company’s incremental borrowing rate for a lease is the estimated rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. The Company’s leases may include options to extend or terminate the lease which are included in the lease term when it is reasonably certain that it will exercise any such options. None of the Company’s leases contain any residual value guarantees. Lease expense is recognized on a straight-line basis over the expected lease term. Related variable lease costs incurred are not material to the Company. The Company currently elects the short-term lease recognition exemption for all leases that qualify. This means, for those leases that qualify, the Company will not recognize right-of-use assets or liabilities, and this includes not recognizing right-of-use assets or liabilities for existing short-term leases of those assets in transition. The Company also elects the practical expedient to not separate lease and non-lease components for all of its leases. The Company has made an accounting policy election to account for each separate lease component of a contract and its associated non-lease components as a single lease component. See the Lease Agreements section in NOTE 9—LICENSE AGREEMENTS AND COMMITMENTS Revenue Recognition Product revenue The Company recognizes revenue from sales of DANYELZA at a point in time when its customer is deemed to have obtained control of the product, which generally occurs upon receipt at the end-user hospital. ​ The amount of revenue the Company recognizes from sales of DANYELZA varies due to rebates, chargebacks and discounts provided under governmental and other programs, distribution related fees and other sales-related deductions. In order to determine those deductions, the Company estimates, utilizing the expected value method, the amount of revenue that it will ultimately be entitled to. This estimate is based upon contracts with customers and government agencies, statutorily-defined discounts applicable to government-funded programs, estimated payor mix, and other relevant factors. Calculating these amounts involves estimates and judgments, and the Company reviews these estimates quarterly. If actual results vary from its original estimates, the Company will adjust these estimates quarterly, which would affect net product revenue and earnings in the period such variances occur. ​ ● Rebates and chargebacks ​ The Company contracts with United States governmental agencies to enable DANYELZA to be eligible for coverage under the various programs administered by the agencies. The Company estimates the rebates and chargebacks to be provided and deducts these estimated amounts from its gross product revenues. These reserves are recorded in the same period the revenue is recognized, resulting in a reduction of product revenue and the establishment of accrued liabilities for the rebates and a reduction of accounts receivable for the chargebacks. The Company develops estimates for rebates and chargebacks based upon (i) the Company’s contracts with these agencies, (ii) the government-mandated discounts applicable to government-funded programs, and (iii) information obtained from hospitals and third party consultants regarding the payor mix. The Company’s liability for these rebates and chargebacks mainly consists of claims for which invoices have not yet been received and paid. The Company does not maintain material levels of inventory in the wholesale or retail channel. ​ ● Discounts and distribution-related fees ​ The Company provides invoice discounts on DANYELZA sales to its distributors for prompt payment and fees for distribution services and invoice discounts reduce the original accounts receivable balances. The payment terms for sales to distributors generally include a 2% discount for prompt payment or fees for distribution services which are based on contractual rates agreed with the respective distributors. Based on historical data and experiences with the distributors, the Company expects its distributors to earn these discounts and fees and deduct the full amount of these discounts and fees from the Company’s gross product revenue at the time such revenues are recognized. ​ ● Returns ​ The Company offers its customers limited product return rights for damaged, defective, or expiring products. The Company estimates returns on sales of DANYELZA mainly based on information provided to the Company from the hospitals and distributors. The return reserves are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and an establishment of an accrued liability. ​ License revenue In May 2021, the Company entered into an exclusive distribution agreement with Adium Pharma S.A. (“Adium”) for Adium to be the exclusive distributor in Latin America of the Company’s antibodies omburtamab, if approved, and DANYELZA. As part of this agreement, the Company received and recognized a non-refundable up-front fee of $2,000,000 for the transfer of the license and know-how related to the product indications during the nine month period ended September 2021. The Company may also receive regulatory-based milestone payments up to an aggregate of $3,000,000. In April 2022, the Company received the first of these milestone payments, a non-refundable fee of $1,000,000 that was payable upon submission by the Company for the updated FDA BLA dossier for DANYELZA. In addition, the Company is entitled to royalties based upon the net sales generated by Adium related to the product in Latin America. The Company considered the license to be distinct from other promises within the arrangement based on the rights and know-how transferred, late-stage development of the underlying indications and anticipated lack of significant involvement required from the joint steering committee associated with the indications. The future potential regulatory milestone amounts were not included in the transaction price, as they were all determined to be fully constrained following the concepts of ASC 606. As part of the Company’s evaluation of the regulatory milestones constraint, the Company determined that the achievement of such milestones are contingent upon regulatory approvals which are not within the Company’s control and therefore not deemed probable. The Company expects that the sales-based milestone payments and royalty arrangements will be recognized when the related sales occur or the milestone is achieved. The Company reevaluates the transaction price each quarter and as uncertain events are resolved or other changes in circumstances occur, the Company assesses whether this resolves the constraint and revenue will be recognized. Segment Information The Company is engaged solely in the discovery, development, distribution and commercialization of novel antibody-based therapeutic products for the treatment of cancer. Accordingly, the Company has determined that it operates in one operating segment. Recently Issued Accounting Pronouncements – Adopted From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, (“FASB”), and are adopted by the Company as of the specific effective date. The Company adopted ASU 2020-10, ASU 2021-04 and ASU 2020-06 effective January 1, 2022, and the adoption of these new standards did not have a material impact on the Company’s consolidated financial statements or disclosures. The Company has evaluated accounting pronouncements recently issued but not yet adopted and believes that these pronouncements do not apply to the Company’s operations and therefore will not have a material impact on the Company’s consolidated financial statements or disclosures.

PRODUCT REVENUE

PRODUCT REVENUE	9 Months Ended
	Sep. 30, 2022
REVENUE RECOGNITION
REVENUE RECOGNITION	NOTE 4—PRODUCT REVENUE The Company’s product revenues were generated from sales of DANYELZA and totaled $12,537,000 and $32,820,000 for the three and nine months ended September 30, 2022, and $8,965,000 and $23,299,000 for the three and nine months ended September 30, 2021. ​ Revenue from product sales is recorded net of applicable provisions for rebates, chargebacks, discounts, distribution-related fees and other sales-related deductions. Accruals for chargebacks, discounts and distribution-related fees with contractual right of offset are recorded as a direct reduction to accounts receivable. Accruals for rebates, distribution-related fees without contractual right of offset and other sales-related deductions are recorded within accrued liabilities. As of September 30, 2022, the Company had recorded accounts receivable allowances of approximately $734,000 and accrued liabilities of $2,451,000 related to product sales during the nine months ended September 30, 2022. As of December 31, 2021, the Company had recorded accounts receivable allowances of approximately $486,000 and accrued liabilities of $2,615,000 related to product sales. ​ An analysis of the change in reserves for discounts and allowances is summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractual ​ ​ ​ ​ ​ ​ ​ Allowances and ​ ​ ​ ​ ​ ​ ​ Discounts ​ Government Rebates Returns ​ Total ​ (in thousands) Balance, December 31, 2021 $ 13 ​ $ 3,027 ​ $ 61 ​ $ 3,101 Current provisions relating to sales in current year ​ 65 ​ ​ 3,459 ​ ​ 379 ​ ​ 3,903 Payments/credits relating to sales in current year ​ (59) ​ ​ (2,653) ​ ​ (398) ​ ​ (3,110) Change in estimate ​ — ​ ​ (709) ​ ​ — ​ ​ (709) Balance, September 30, 2022 $ 19 ​ $ 3,124 ​ $ 42 ​ $ 3,185 ​ Substantially all of the Company’s product sales were in the United States. The Company had product sales to certain customers that accounted for more than 10% of total gross product revenue for the three and nine months ended September 30, 2022 and September 30, 2021. McKesson and AmerisourceBergen accounted for 78% and 14%, respectively, of the Company’s gross product revenue for the three months ended September 30, 2022. McKesson and AmerisourceBergen accounted for 66% and 24%, respectively, of the Company’s gross product revenue for the three months ended September 30, 2021. McKesson and AmerisourceBergen accounted for 69% and 16%, respectively, of the Company’s gross product revenue for the nine months ended September 30, 2022. McKesson and AmerisourceBergen accounted for 73% and 17%, respectively, of the Company’s gross product revenue for the nine months ended September 30, 2021. ​ During the quarter and nine months ended September 30, 2022 the Company recorded a change in estimate resulting in a benefit of $709,000 as the Company assessed claims data and reserves for historical earned periods.

NET LOSS PER SHARE

NET LOSS PER SHARE	9 Months Ended
	Sep. 30, 2022
NET LOSS PER SHARE
NET LOSS PER SHARE	NOTE 5—NET LOSS PER SHARE Basic net loss per share (“EPS”) is calculated by dividing net income or loss attributable to common stockholders by the weighted average common stock outstanding. Diluted EPS is calculated by adjusting weighted average common shares outstanding for the dilutive effect of common stock options and restricted stock units. In periods in which a net loss is recorded, no effect is given to potentially dilutive securities, since the effect would be antidilutive. Securities that could potentially dilute basic EPS in the future were not included in the computation of diluted EPS because to do so would have been antidilutive. The calculations of basic and diluted net loss per share are as follows (in thousands, except per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, ​ Nine months ended September 30, ​ ​ 2022 ​ 2021 2022 ​ 2021 ​ ​ ​ (in thousands, except per share amounts) ​ ​ ​ ​ ​ Net income /(loss) (numerator) ​ $ (27,526) ​ $ (28,858) ​ $ (96,725) ​ $ (18,382) ​ Weighted-average shares (denominator), basic and diluted ​ 43,718 ​ 43,598 ​ 43,715 ​ 43,019 ​ Basic net income / (loss) per share ​ $ (0.63) ​ $ (0.66) ​ $ (2.21) ​ $ (0.43) ​ ​ Potentially dilutive securities excluded from the computation of diluted earnings per share relate to stock options outstanding and unvested restricted stock units (“RSUs”) totaled 7,119,332 shares as of September 30, 2022 and 5,832,317 shares as of September 30, 2021.

INVENTORIES

INVENTORIES	9 Months Ended
	Sep. 30, 2022
INVENTORIES
INVENTORIES	NOTE 6—INVENTORIES Inventories consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 ​ December 31, 2021 ​ ​ ​ ​ ​ ​ ​ Raw Materials ​ ​ 1,500 ​ ​ — Work In Progress ​ ​ 8,870 ​ ​ 4,741 Finished Goods ​ ​ 1,088 ​ ​ 771 Total Inventories ​ $ 11,458 ​ $ 5,512 ​ ​ ​ ​ ​ ​ ​ ​ Inventories are classified on the Consolidated Balance Sheets in each respective period (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 ​ December 31, 2021 CURRENT ASSETS ​ ​ ​ ​ ​ ​ Inventories ​ $ 6,242 ​ $ 5,512 Total recorded in Current Assets ​ ​ 6,242 ​ ​ 5,512 ​ ​ ​ ​ ​ ​ ​ NONCURRENT ASSETS ​ ​ ​ ​ ​ ​ Other assets ​ ​ 5,216 ​ ​ — Total recorded in Noncurrent Assets ​ ​ 5,216 ​ ​ — Total Inventories ​ $ 11,458 ​ $ 5,512 ​ As of September 30, 2022, the Company has classified $1,500,000 of raw material and $3,716,000 of work in progress inventories as noncurrent assets based on its current demand schedule and expectation that such inventory will be utilized in excess of one year from the balance sheet date. Changes in noncurrent assets are reflected on the consolidated statements of cash flows within the caption of other assets. ​ During the three and nine months ended September 30, 2022, the Company recorded a $1,200,000 charge in cost of goods sold related to a batch planned for commercial use that did not meet our quality specifications.

INTANGIBLE ASSETS, NET

INTANGIBLE ASSETS, NET	9 Months Ended
	Sep. 30, 2022
INTANGIBLE ASSETS, NET
INTANGIBLE ASSETS, NET	NOTE 7—INTANGIBLE ASSETS, NET The Company’s intangible assets, net as of September 30, 2022 totaled $1,530,000 and related to capitalized milestone payments accrued following FDA approval and commercialization of DANYELZA. The intangible assets net book value as of September 30, 2022 is net of $270,000 of accumulated amortization. The Company’s intangible assets, net as of December 31, 2021 totaled $1,663,000. The intangible assets net book value as of December 31, 2021 is net of $137,000 of accumulated amortization. Intangible assets are amortized on a straight-line basis based on a 10-year useful life of the assets. Annual amortization expense is expected to be $180,000 each year for the five 2022 to 2026 ​

ACCRUED LIABILITIES

ACCRUED LIABILITIES	9 Months Ended
	Sep. 30, 2022
ACCRUED LIABILITIES
ACCRUED LIABILITIES	NOTE 8—ACCRUED LIABILITIES Accrued short-term liabilities as of September 30, 2022 and December 31, 2021 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ 2022 ​ 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued licensing milestone and royalty payments ​ $ 1,593 ​ $ 3,090 Accrued clinical costs ​ 985 ​ 915 Accrued compensation and board fees ​ 4,073 ​ 1,877 Accrued manufacturing costs ​ ​ 6,466 ​ ​ 2,622 Accrued sales reserves ​ ​ 2,451 ​ ​ 2,615 Other ​ 1,524 ​ 1,421 Total ​ $ 17,092 ​ $ 12,540 ​

LICENSE AGREEMENTS AND COMMITME

LICENSE AGREEMENTS AND COMMITMENTS	9 Months Ended
	Sep. 30, 2022
LICENSE AGREEMENTS AND COMMITMENTS
LICENSE AGREEMENTS AND COMMITMENTS	NOTE 9—LICENSE AGREEMENTS AND COMMITMENTS The Company has entered into two license agreements and certain other agreements with Memorial Sloan Kettering Cancer Center (“MSK”). The license agreements, as previously disclosed in the Company’s Annual Report on Form 10-K, are the MSK License Agreement and the CD33 License Agreement. In addition, the Company entered into the SADA License Agreement with MSK and Massachusetts Institute of Technology (“MIT”) in 2020. Through a 2019 Settlement and Assumption and Assignment Agreement and Y-mAbs Sublicense Agreement (“SAAA”) with MabVax, Inc. (“MabVax”) and MSK, the Company has established a direct license (“MabVax Agreement”) with MSK relating to the GD2-GD3 Vaccine, which was originally sublicensed by the Company in 2018 from MabVax. These license agreements with MSK and MIT grant the Company certain patent rights and intellectual property rights, and in consideration thereof, the Company agreed to make certain payments and issue shares of the Company’s common stock to MSK and MIT. Certain of the payments are contingent milestone and royalty payments, as disclosed in the table below. Amounts disclosed in NOTE 8—ACCRUED LIABILITIES The Company has the following significant license agreements and related commitments which include all obligations that have been paid or accrued as of and for the three and nine months ended September 30, 2022 and 2021, and as of December 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued Accrued Accrued Accrued ​ ​ Cash paid Cash paid Expense Expense Expense Expense ​ liabilities liabilities liabilities liabilities ​ ​ Nine months ​ Nine months ​ Three months ​ Nine months ​ Three months ​ Nine months ​ Current ​ Non-current ​ Current ​ Non-current ​ ​ ended ​ ended ​ ended ​ ended ​ ended ​ ended ​ as of ​ as of ​ as of ​ as of ​ ​ September ​ September ​ September ​ September ​ September ​ September ​ September ​ September ​ December ​ December Agreements ​ 2022 ​ 2021 ​ 2022 ​ 2022 ​ 2021 ​ 2021 ​ 2022 ​ 2022 ​ 2021 ​ 2021 MSK ​ ​ $ 2,871 ​ ​ $ 1,480 ​ ​ $ 753 ​ ​ $ 2,513 ​ ​ $ 321 ​ ​ $ 531 ​ ​ $ 828 ​ ​ $ 1,950 ​ ​ $ 1,486 ​ ​ $ 1,650 CD33 ​ ​ — ​ ​ 100 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 150 ​ ​ 300 ​ ​ — ​ ​ 450 MabVax ​ ​ — ​ ​ 10 ​ ​ 10 ​ ​ 10 ​ ​ — ​ ​ 10 ​ ​ 10 ​ ​ — ​ ​ — ​ ​ — SADA ​ ​ 1,000 ​ ​ 1,000 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 605 ​ ​ — ​ ​ 1,605 ​ ​ — ​ The below table represents the maximum clinical, regulatory or sales-based milestones as reflected within the agreements, certain of which have been paid in prior periods or are accrued as presented in the table above (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maximum Maximum Maximum Agreements ​ ​ ​ Clinical Milestones ​ Regulatory Milestones ​ Sales-based Milestones ​ MSK ​ ​ ​ ​ ​ $ 2,450 ​ ​ $ 9,000 ​ ​ $ 20,000 ​ CD33 ​ ​ ​ ​ ​ 550 ​ ​ 500 ​ ​ 7,500 ​ MabVax ​ ​ ​ ​ ​ 200 ​ ​ 1,200 ​ ​ — ​ SADA ​ ​ ​ ​ ​ 4,730 ​ ​ 18,125 ​ ​ 23,750 ​ ​ Research and development is inherently uncertain and should such research and development fail the MSK License Agreement, the CD33 License Agreement, the SADA License Agreement and the MabVax Agreement are cancelable at the Company’s option. The Company will also consider the development risk and each party’s termination rights under the respective agreement when considering whether any clinical or regulatory based milestone payments, certain of which also contain time-based payment requirements, are probable. The Company records milestones in the period in which the contingent liability is probable and the amount is reasonably estimable. With respect to the SADA License Agreement, all time-based milestones coming due within 36 months of the effective date of the agreement, totaling $605,000, have been accrued, as this continues to represent the time period the Company expects will be required to gather necessary clinical data to determine which patent rights to further pursue, if any, under the SADA License Agreement. Other Agreements The Company has also entered into various other support agreements with MSK including a sponsored research agreement to provide research services related to the intellectual property licensed under the MSK License Agreement; a master data services agreement, for services provided by approximately five full-time employees at MSK, who are engaged in transferring clinical data, databases, regulatory files and other know-how included in the MSK License Agreement to the Company; a master clinical trial agreement pursuant to which the Company committed to fund certain clinical trials at MSK; two separate core facility service agreements pursuant to which the Company committed to obtaining certain laboratory services from MSK; and in October 2020 the Company entered into a SADA sponsored research agreement pursuant to which the Company agreed to pay MSK to provide research services over a period of three years related to the intellectual property licensed under the SADA License Agreement. For the three months ended September 30, 2022 and 2021, the Company incurred research and development expenses of $458,000 and $833,000, respectively, under these agreements. For the nine months ended September 30, 2022 and 2021, the Company incurred research and development expenses of $1,505,000 and $2,728,000, respectively, under these agreements. Lease Agreements In July 2019, the Company entered a development, manufacturing and supply agreement with SpectronRx in South Bend, Indiana, to secure access to clinical and commercial scale radiolabeling capacity for omburtamab. Under the terms of the agreement, SpectronRx has established a manufacturing unit designated for the Company within its existing facilities, at which both clinical and commercial supply of radiolabeled omburtamab can be produced. Since the Company possesses the right to substantially all the economic benefits and directs the use of the production area, the Company accounts for the payments related to the access to the manufacturing space under ASC 842 as an operating lease. The original term of the lease was two years from the commencement date of August 31, 2020, which was subsequently extended to December 2022. The extension resulted in an immaterial impact to the underlying right of use asset and lease liability. Upon the lease commencement date, the Company recorded $3,617,000 as right of use asset and $2,679,000 as lease liability In February 2019, the Company entered into a lease agreement in connection with its 4,548 square feet laboratory in New Jersey. In December 2019, the Company expanded the space with an additional 235 square feet. The original term of the lease was three years from the date the Company occupied the premises, with an option to extend for an additional two years which expires in January 2024, which the Company exercised and has included in the determination of the related lease liability. Fixed rent payable under the lease is approximately $144,000 per annum and is payable in equal monthly installments of approximately $12,000. In January 2018, the Company entered into a lease agreement in connection with its corporate headquarters in New York. The term of the lease is six years from the date the Company began to occupy the premises and expires in April 2024. Fixed rent payable under the lease is approximately $384,000 per annum and is payable in equal monthly installments of approximately $32,000, which are recognized on a straight-line basis. In February 2018, the Company entered into a lease agreement for certain office space in Denmark, which has been amended several times. The lease was renewed on November 1, 2021 with a four year term that expires in November 2025. The lease is payable in monthly installments of approximately $41,000, which are recognized on a straight-line basis. Total operating lease costs were $721,000 and $644,000 for the three months ended September 30, 2022 and 2021, respectively, and $2,127,000 and $1,936,000 for the nine months ended September 30, 2022 and 2021, respectively. For the three months ended September 30, 2022, the operating lease expenses were recorded as $657,000 in research and development expense and $64,000 in general and administrative expense. For the three months ended September 30, 2021, the expenses were recorded as $584,000 in research and development expense and $60,000 in general and administrative expense. For the nine months ended September 30, 2022, the expenses were recorded as $1,937,000 in research and development expense and $190,000 in general and administrative expense. For the nine months ended September 30, 2021, the expenses were recorded as $1,758,000 in research and development expense and $178,000 in general and administrative expense. Cash paid for amounts included in the measurement of lease liabilities for the three and nine months ended September 30, 2022 was $481,000 and $1,689,000, respectively, and cash paid for amounts included in the measurement of lease liabilities for the three and nine months ended September 30, 2021 was $548,000 and $1,641,000, respectively. These payments were included in net cash used in operating activities in the Company’s Consolidated Statements of Cash Flows. Maturities of operating lease liabilities as of September 30, 2022 were as follows (in thousands): ​ ​ ​ ​ ​ ​ Operating Leases ​ at September 30, 2022 Remainder of 2022 ​ $ 554 Years ending December 31, ​ ​ ​ 2023 ​ ​ 958 2024 ​ ​ 482 2025 ​ ​ 383 Total lease payments ​ ​ 2,377 Less: Imputed interest ​ ​ (158) Total operating lease liabilities as of September 30, 2022 ​ $ 2,219 ​ Maturities of operating leases as of December 31, 2021 were as follows (in thousands): ​ ​ ​ ​ ​ ​ Operating Leases Years ending December 31, at December 31, 2021 2022 ​ $ 1,953 2023 ​ ​ 1,025 2024 ​ ​ 550 2025 ​ ​ 445 Total lease payments ​ ​ 3,973 Less: Imputed interest ​ ​ (339) Total operating lease liabilities as of December 31, 2021 ​ $ 3,634 ​ Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, the Company uses its estimate of its incremental borrowing rate based on the information available at the lease commencement date. As of September 30, 2022, the weighted average remaining lease term is 2.18 years and the weighted average discount rate used to determine the operating lease liability was 6.8%. As of December 31, 2021, the weighted average remaining lease term was 2.62 years and the weighted average discount rate used to determine the operating lease liability was 6.5%. Former Chief Executive Officer Contractual Severance Related Benefits On April 27, 2022, the Company announced certain executive management changes. Effective April 22, 2022, Dr. Claus Møller stepped down from his positions as Chief Executive Officer and as a member of the Company’s Board of Directors. There were no disagreements with the Company expressed by Dr. Møller on any matters relating the Company’s operations, policies or practices. Dr. Møller’s contractual severance related benefits provided for cash compensation of Legal Matters We have been named a nominal defendant in a lawsuit filed in the U.S. District Court, Southern District of New York, on August 25, 2021, by one of our stockholders, Deborah Donoghue and in a related lawsuit filed in the U.S. District Court, Southern District of New York, on October 10, 2022 by one of our stockholders, Mark Rubenstein. The suits name our President, Interim Chief Executive Officer and Head of Business Development and Strategy, and member of our board of directors, Mr. Thomas Gad as an additional defendant, and they seek to compel Mr. Gad to disgorge alleged short swing profits stemming from a certain transaction involving our common stock undertaken by Mr. Gad on March 10, 2021 together with appropriate interest and costs of the lawsuit. On December 17, 2021, Mr. Gad filed a Motion to Dismiss the lawsuit by Ms. Donoghue. On August 8, 2022, the Court denied Mr. Gad’s Motion to Dismiss the lawsuit. As a result, the lawsuit by Ms. Donoghue has entered the discovery phase. Mark Rubenstein is represented by the same lawfirm as was Ms. Donoghue. Mr. Rubenstein had sought to intervene to continue the litigation instigated by Ms. Donahue on her passing, but was denied by the court. We are of the opinion that the claims are without merit and intend to maintain this position in the proceedings. In addition, we have been informed by Mr. Gad that he also believes the claims are without merit, that he has strong defenses against such claims and that he intends to vigorously defend the actions. We have assessed the proceedings and do not believe that it is probable that a gain or a liability will be realized by us. As a result, we did not record any loss or gain contingencies for this matter.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	9 Months Ended
	Sep. 30, 2022
STOCKHOLDERS' EQUITY
STOCKHOLDERS' EQUITY	NOTE 10—STOCKHOLDERS’ EQUITY Authorized Stock As of September 30, 2022 and December 31, 2021, the Company has authorized a total of 105,500,000 shares, 100,000,000 of which are common stock, par value $0.0001 per share, and 5,500,000 of which are preferred stock, par value $0.0001 per share. Common Stock Each share of common stock is entitled to one vote. Common stockholders are entitled to receive dividends, as may be declared by the board of directors, if any, subject to preferential dividend rights of the preferred stock, none of which have been issued. The Company had issued 43,668,130 shares of its common stock as of September 30, 2022 and 43,694,716 shares of its common stock as of December 31, 2021. Preferred Stock Preferred stock may be issued from time to time in one or more series with such designations, preferences and relative participating, optional or other special rights and qualifications, limitations or restrictions as approved by the Company’s Board of Directors. No preferred stock has been issued as of September 30, 2022 or December 31, 2021. Stock grant agreements with non-employees In April 2020, in connection with the SADA License Agreement, the Company entered into certain stock grant agreements pursuant to which it agreed to issue a total of 213,996 shares to two non-employee researchers who were involved in the development of the SADA-BiDE (2-step Self-Assembly and DisAssembly-Bispecific DOTA-Engaging antibody system) Pre-targeted Radioimmunotherapy Platform (the “SADA Technology”) licensed from MSK and MIT in consideration for their prior service. All 213,996 shares were issued in April 2020 into escrow with 40% of the shares immediately vesting at the time of issuance and the remaining 60% of the shares subject to vesting ratably over the next three years on the anniversary date of the agreement. In accordance with the terms of the agreement, during the nine months ended September 30, 2022, the non-employee researchers vested in an additional 20% of the awards. Therefore, as of September 30, 2022, the two non-employee researchers have vested in 80% of the total grant with the remaining 20% vesting on the anniversary date of the agreement in April 2023. The unvested shares are subject to forfeiture to the extent the SADA License Agreement is terminated prior to the vesting of the shares. There is no cash settlement feature, and no future service is required for the non-employee researchers to vest and receive the shares. In April 2020, the Company recognized $7,376,000, the fair value of the issued shares on the grant date, within research and development expense. There is no future expense related to these awards. In July 2020, pursuant to the stock grant agreements, the Company also loaned the two researchers a total of $2,610,000 related to their individual tax payments due in conjunction with the stock grants. Each of the loans are evidenced by a three year Secured Promissory Note, which matures in April 2023. The outstanding principal amounts of the loans, together with all accrued interest thereon at the rate of 1% per annum, is due and payable on the maturity date of the loans. The loans are secured by Pledge and Security Agreements, pursuant to which the researchers have pledged the shares as security for repayment of the loans with interest rates that are at market. In July 2022, one of the researchers repaid their Secured Promissory Note and accrued interest, which resulted in a de minimis loss compared to the amortized cost of the loan, in exchange for 57,887 shares that were pledged as part of their security. Upon receipt, the Company recorded treasury shares at an acquisition cost of $963,000, based on the share closing price on the settlement date. The Company subsequently cancelled the acquired treasury shares resulting in a reduction of outstanding common stock and a reduction of additional paid-in-capital totaling $963,000. The other loan is recorded at amortized cost, which approximates fair value due to the maturity dates of the loan. The remaining loan is included in other current assets on the Company’s Consolidated Balance Sheets as of September 30, 2022 and both loans are included in other assets on the Company’s Consolidated Balance Sheets as of December 31, 2021. Issuance of common stock On February 22, 2021, the Company completed a third public offering of its common stock pursuant to which the Company issued and sold 2,804,878 shares of its common stock at a price to the public of $41.00 per share which included the exercise in full of the underwriters’ option to purchase additional shares. The Company received aggregate gross proceeds from the public offering of $115,000,000, with aggregate net proceeds of approximately $107,725,000 after deducting underwriting discounts and commissions and offering expenses.

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2022
SHARE-BASED COMPENSATION
SHARE-BASED COMPENSATION	NOTE 11—SHARE-BASED COMPENSATION 2015 Equity Incentive Plan The Company’s board of directors and stockholders have approved and adopted the 2015 Plan, which provided for the grant of incentive stock options, within the meaning of Section 422 of the Code (the Internal Revenue Code), to the Company’s employees and any parent and subsidiary corporations’ employees, and for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees, directors and consultants and its parent and subsidiary corporations’ employees and consultants. A total of 4,500,000 shares of the Company’s common stock were reserved for issuance pursuant to the 2015 Plan. Options granted under the 2015 Plan vest according to the schedule specified in the grant agreements, which is generally a four year period and generally become immediately exercisable upon the occurrence of a change in control, as defined. Upon the 2018 Equity Incentive Plan (the “2018 Plan”) becoming effective in September 2018, no further grants are allowed under the 2015 Plan. 2018 Equity Incentive Plan The Company’s board of directors and stockholders approved and adopted the 2018 Plan, which became effective upon the Company’s initial public offering in September 2018 and which provides for the grant of incentive stock options, within the meaning of Section 422 of the Code (the Internal Revenue Code), to the Company’s employees and any parent and subsidiary corporations’ employees, and for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees, directors and consultants and the Company’s parent and subsidiary corporations’ employees and consultants. A total of 5,500,000 shares of the Company’s common stock, inclusive of the awards previously granted under the 2015 Equity Incentive Plan, are reserved for issuance pursuant to the 2018 Plan. In addition, the number of shares available for issuance under the 2018 Plan will also include an annual increase on the first day of each fiscal year beginning in 2019, equal to 4% of the outstanding shares of common stock as of the last day of the Company’s immediately preceding fiscal year. The exercise price of options granted under the plans must at least be equal to the fair market value of the Company’s common stock on the date of grant. The term of an incentive stock option may not exceed 10 years , except that with respect to any participant who owns more than 10% of the voting power of all classes of the Company’s outstanding stock, the term must not exceed five years and the exercise price must equal at least 110% of the fair market value on the grant date. The administrator will determine the methods of payment of the exercise price of an option, which may include cash, shares or other property acceptable to the administrator, as well as other types of consideration permitted by applicable law. Options granted under the 2018 Plan vest according to the schedule specified in the grant agreements, which is generally between one and four years and generally become immediately exercisable upon the occurrence of a change in control, as defined. Stock Option Valuation For the three month periods ended September 30, 2022 and 2021, stock-based compensation for stock option grants were $3,257,000 and $4,829,000, respectively, for options granted to employees and directors. For the three months ended September 30, 2022, the expenses were recorded as $1,801,000 in research and development expense and $1,456,000 in selling, general, and administrative expense. For the three months ended September 30, 2021, the expenses were recorded as $1,827,000 in research and development expense and $3,002,000 in selling, general, and administrative expense. For the nine month periods ended September 30, 2022 and 2021, stock-based compensation for stock option grants were $21,822,000 and $14,209,000, respectively, for options granted to employees and directors. Stock-based compensation during the nine months ended September 30, 2022 includes $9,286,000 related to the departure of the former Chief Executive Officer, which was recorded upon his separation in the second quarter of 2022 based on the terms of his service agreement and is further described in NOTE 9—LICENSE AGREEMENTS AND COMMITMENTS The following table summarizes common stock options issued and outstanding: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Weighted ​ Aggregate ​ average ​ ​ ​ ​ average ​ intrinsic ​ remaining ​ ​ ​ ​ exercise ​ value ​ contractual ​ ​ Options ​ price ​ (in thousands) ​ life (years) Outstanding and expected to vest at December 31, 2021 6,687,128 ​ $ 22.43 ​ $ 26,412 ​ 7.21 Granted 635,000 ​ ​ 11.42 ​ ​ ​ ​ ​ Exercised ​ (20,000) ​ ​ 4.22 ​ ​ ​ ​ ​ Forfeited ​ (218,361) ​ ​ 29.27 ​ ​ ​ ​ ​ Outstanding and expected to vest at September 30, 2022 7,083,767 ​ $ 21.28 ​ $ 23,619 ​ 6.70 Exercisable at September 30, 2022 4,556,127 ​ $ 18.95 ​ $ 21,543 ​ 5.55 ​ The weighted average fair value of stock options granted for the three months ended September 30, 2022 and 2021 was $10.14 and $20.19, respectively. There were 210,000 and 102,000 stock options granted for the three months ended September 30, 2022 and 2021, respectively. The weighted average fair value of stock options granted for the nine months ended September 30, 2022 and 2021 was $7.88 and $20.85, respectively. There were 635,000 and 311,000 stock options granted for the nine months ended September 30, 2022 and 2021, respectively. Options granted in the three and nine months ended September 30, 2022, have a maximum contractual term of ten years. During the second quarter of 2022, 255,000 options were granted to senior executives and certain other employees under a retention program for their continued service to the Company over the next two years from the grant date. The options granted under the retention program have a vesting schedule in which 50% vest on the first first The above noted retention program also included a cash bonus payable to the same senior executives and other employees that is payable on the anniversary of the grant date provided that the respective recipient remains an employee of the Company through such date and subject further to the achievement by such date of the Company’s product candidate omburtamab having received marketing approval by the FDA. The Company did not record compensation expense related to the cash retention program in the three and nine months ended September 30, 2022, as the payment will not be deemed probable until the Company receives FDA approval for omburtamab. The aggregate value of the cash bonus portion of the retention program is $1,091,000 as of September 30, 2022. The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option pricing model. The Company’s public trading commenced in September 2018, and, as a result, there is only limited available historical volatility experience. Therefore, the Company estimates its expected share price volatility based on a combination of the historical volatility of a group of publicly traded peer companies and the historical volatility of the Y-mAbs share price, and the Company expects to continue to do so until such time as the Company has adequate historical data regarding the volatility of its own traded share price. The expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards as the Company has limited historical data to support the expected term assumption. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. The expected dividend yield is based on the fact that the Company has never paid cash dividends on shares of its common stock and does not expect to pay any cash dividends in the foreseeable future. There were no significant changes to the inputs included in the Black-Scholes option pricing model during the three and nine months ended September 30, 2022. As of September 30, 2022, the Company had $25,520,000 of unrecognized compensation expense related to employee stock options that are expected to vest over a period of 2.47 years. As of September 30, 2021, the Company had $44,357,000 of unrecognized compensation expense related to employee stock options that are expected to vest over a period of 2.61 years. Restricted Stock Unit Activity For the three months ended September 30, 2022 and September 30, 2021, stock-based compensation for restricted stock unit grants was $84,000 and $72,000, respectively. For the three months ended September 30, 2022, the expenses were recorded as $74,000 in research and development expense and $10,000 in selling, general, and administrative expense. For the three months ended September 30, 2021, the expenses were recorded as $63,000 in research and development expense and $9,000 in selling, general, and administrative expense. For the nine months ended September 30, 2022 and September 30, 2021, stock-based compensation for restricted stock unit grants was $242,000 and $217,000, respectively. For the nine months ended September 30, 2022, the expenses were recorded as $215,000 in research and development expense and $27,000 in selling, general, and administrative expense. For the nine months ended September 30, 2021, the expenses were recorded as $194,000 in research and development expense and $23,000 in selling, general, and administrative expense. The following table summarizes restricted stock units issued and outstanding: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Weighted ​ average ​ ​ ​ ​ ​ average ​ remaining ​ ​ ​ ​ ​ grant ​ vesting ​ ​ ​ Restricted Stock Units ​ price ​ life (years) ​ Outstanding and expected to vest at December 31, 2021 ​ 28,907 ​ $ 28.04 1.82 ​ Granted ​ 19,054 ​ ​ 9.92 ​ Vested ​ (11,314) ​ ​ 25.98 ​ ​ Forfeited ​ (1,082) ​ ​ 29.81 ​ ​ ​ Outstanding and expected to vest at September 30, 2022 ​ 35,565 ​ $ 18.42 2.00 ​ ​ As of September 30, 2022, the Company had $504,000 of unrecognized compensation related to employee restricted stock units that are expected to vest over a period of 2.00 years. As of September 30, 2021, the Company had $631,000 of unrecognized compensation related to employee restricted stock units that are expected to vest over a period of 1.91 years.

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	9 Months Ended
	Sep. 30, 2022
RELATED PARTY TRANSACTIONS
RELATED PARTY TRANSACTIONS	NOTE 12—RELATED PARTY TRANSACTIONS MSK is a shareholder of the Company. Under the MSK License Agreement, the SADA License Agreement, the CD33 License Agreement, the MabVax Agreement and various other supporting agreements with MSK, the Company has expensed costs in the total amount of $1,221,000 and $1,154,000 in the three months ended September 30, 2022 and 2021, respectively, for milestones, minimum royalties, and research and development costs. The Company expensed costs in the total amounts of $4,028,000 and $3,259,000 in the nine months ended September 30, 2022 and 2021, respectively, under these agreements with MSK. Please refer to NOTE 9—LICENSE AGREEMENTS AND COMMITMENTS

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2022
INCOME TAXES
INCOME TAXES	NOTE 13—INCOME TAXES The Company provided no current and deferred income taxes on net losses of $27,526,000 and $28,858,000 for the three month periods ended September 30, 2022 and 2021, respectively, and net losses of $96,725,000 and $18,382,000 for the nine month periods ended September 30, 2022 and 2021, respectively. The Company recognizes income tax benefits for tax positions determined more likely than not to be sustained upon examination, based on the technical merits of the positions. Unrecognized tax benefits were $0 and $304,000 at September 30, 2022 and December 31, 2021, respectively. As of September 30, 2022 and December 31, 2021, the Company did not have any interest or penalties accrued related to the total amount of unrecognized tax benefits. The Company’s tax returns for the years 2020, 2019, 2018, and 2017 are open for tax examination by U.S. federal and state and Danish tax authorities. During 2022, the review of the Company’s transfer pricing policies by the Danish Tax Authorities for tax years 2016 through 2020 was completed resulting in no material impacts to the Company’s income tax accounts. The Company maintains a full valuation allowance on its U.S. and foreign deferred tax assets. The assessment regarding whether a valuation allowance is required considers both positive and negative evidence when determining whether it is more likely than not that deferred tax assets are recoverable. In making this assessment, significant weight is given to evidence that can be objectively verified. In its evaluation, the Company considered its cumulative losses historically and in recent years and its forecasted losses in the near term as significant negative evidence. Based upon review of available positive and negative evidence, the Company determined that the negative evidence outweighed the positive evidence and a full valuation allowance on its U.S. and foreign deferred tax assets will be maintained. The Company will continue to assess the realizability of its deferred tax assets and will adjust the valuation allowance as needed.

OTHER BENEFITS

OTHER BENEFITS	9 Months Ended
	Sep. 30, 2022
OTHER BENEFITS
OTHER BENEFITS	NOTE 14—OTHER BENEFITS The Company has adopted a defined contribution 401(k) savings plan (“401(k) plan”) covering all U.S. employees of the Company. Participants may elect to defer a percentage of their pretax or after-tax compensation to the 401(k) plan, subject to defined limitations. The plan allows for a discretionary match by the Company. The Company made no matching contributions to the plan for the three or nine months ended September 30, 2022 and 2021. The Company has established a retirement program for employees of the Company’s Danish subsidiary pursuant to which all such employees can contribute an amount at their election from their base compensation and may receive contributions from the Company’s Danish subsidiary. No contributions from the Danish subsidiary were made for the three and nine months ended September 30, 2022 and 2021. In addition, health insurance benefits for the Company’s Danish employees are fully paid for by such employees. The Company’s Danish subsidiary does not incur any costs for these health insurance benefits.

GAIN FROM SALE OF PRIORITY REVI

GAIN FROM SALE OF PRIORITY REVIEW VOUCHER	9 Months Ended
	Sep. 30, 2022
GAIN FROM SALE OF PRIORITY REVIEW VOUCHER
GAIN FROM SALE OF PRIORITY REVIEW VOUCHER	NOTE 15 —GAIN FROM SALE OF PRIORITY REVIEW VOUCHER On December 28, 2020, the Company announced that it entered into a definitive agreement to sell its DANYELZA Priority Review Voucher, or PRV, to United Therapeutics Corporation for $105,000,000. The PRV was granted in conjunction with the approval by the FDA of DANYELZA, for the treatment of refractory/relapsed high-risk neuroblastoma. Under the terms of the Company’s license agreement with MSK, the Company retained 60% of the net proceeds received from the sale, and the remaining 40% was paid to MSK. The transaction closed on January 21, 2021 and once the substantive closing conditions included within the agreement were resolved the Company recognized a net gain of $62,010,000 during the nine months ended September 30, 2021 related to the sale. The Company did not recognize a corresponding gain during the three and nine months ended September 30, 2022.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	9 Months Ended
	Sep. 30, 2022
SUBSEQUENT EVENTS
SUBSEQUENT EVENTS	NOTE 16 — Subsequent Event The Company resubmitted its Biologics License Application (“BLA”), to the FDA for radiolabeled 131I omburtamab for central nervous system, leptomeningeal metastases from neuroblastoma in March 2022 and in May 2022, the FDA accepted our BLA for priority review. The FDA set an action date of November 30, 2022 under the Prescription Drug User Fee Act (“PDUFA”), and convened a meeting of its Oncologic Drugs Advisory Committee (the “Advisory Committee”), on October 28, 2022. The Advisory Committee voted 16 to 0 that the BLA did not provide sufficient evidence to conclude that omburtamab improves overall survival among the target patient population. The FDA is not bound by the Advisory Committee’s recommendations but generally takes the recommendation into consideration when making its decision, and the Company can provide no assurance that omburtamab will ultimately receive FDA approval.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2022
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, net product revenues, the accrual for research and development expenses, the accrual of milestone and royalty payments, and the valuation of stock options. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, including expenses, manufacturing, clinical trials, research and development costs and employee-related amounts, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat COVID-19, as well as the economic impact on local, regional, national and international markets.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid instruments with original maturities of three months or less from date of purchase to be cash equivalents. All cash and cash equivalents are held in highly rated securities including a treasury money market fund, which is unrestricted as to withdrawal or use. To date, the Company has not experienced any losses on its cash and cash equivalents. The carrying amount of cash and cash equivalents approximates its fair value due to its short-term and liquid nature. The Company maintains cash balances in excess of insured limits. The Company monitors the financial performance, credit ratings and liquidity of the money market fund to timely assess and respond to any changes in the asset values of the fund. The Company does not anticipate any losses with respect to such cash balances.
Trade Accounts Receivables	Trade Accounts Receivables The Company’s trade accounts receivable balance consists of amounts due from sales of its approved product, DANYELZA. Receivables from product sales are recorded net of allowances which generally include chargebacks, doubtful accounts, rebates, returns, and discounts. The allowance is based primarily on assessment of specific identifiable customer accounts considered at risk or uncollectible, as well as an analysis of current receivables aging and expected future write-offs. The Company has not historically experienced any significant credit losses. All customer accounts are actively managed, and no material losses are currently expected. The Company has not experienced any write-offs related to its customers and has not recognized any allowance for doubtful accounts nor reversed any allowances in the nine months ended September 30, 2022.
Concentration of Credit Risk	Concentration of Credit Risk The Company’s product sales are made through arrangements primarily with three national specialty distributors in the United States. As of September 30, 2022, the receivables balances from such distributors totaled 99% of the Company’s outstanding accounts receivable. The Company has contractual payment terms with each of its customers and the Company monitors their financial performance, historical payment terms and credit worthiness to timely assess and respond to any changes in their credit profile.
Inventory	Inventory The Company values its inventories at the lower of cost or net realizable value on a first-in, first-out basis. The Company’s inventory cost includes amounts related to materials, third party contract manufacturing, third party packaging services, freight, labor costs for personnel involved in the manufacturing process, and indirect overhead costs. Raw and intermediate materials that may be utilized for both commercial and clinical programs are identical and given the alternative future use such amounts are initially classified as inventory. Amounts in inventory associated with clinical development programs are charged to research and development expense when the product enters the research and development process and can no longer be used for commercial purposes and, therefore, does not have an alternative future use. The Company capitalizes inventory costs related to products to be sold in the ordinary course of business. The Company makes a determination of capitalizing inventory costs for a product based on, among other factors, status of regulatory approval, information regarding safety, efficacy and expectations relating to commercial sales and recoverability of costs. For DANYELZA, the Company commenced capitalization of inventory beginning at the receipt of FDA approval. Prior to FDA approval, the Company expensed such costs as part of research and development expenses. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their estimated realizable value in the period in which the impairment occurs. Such impairment charges, should they occur, are recorded within cost of goods sold. The determination of whether inventory costs will be realizable requires estimates by management. Other than the $1,200,000 recorded in the three and nine months ended September 30, 2022, as discussed further in NOTE 6— INVENTORIES, there were no other material inventory write-downs in the three and nine months ended September 30, 2022.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. ​ • Level 1 — Unadjusted quoted prices for identical assets or liabilities in active markets; • Level 2 — Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability; and • Level 3 — Unobservable inputs for the asset or liability, which include management's own assumption about the assumptions market participants would use in pricing the asset or liability, including assumptions about risk. Cash equivalents held in money market funds are valued using other significant observable inputs, which represent a Level 2 measurement within the fair value hierarchy. The Company has no other cash equivalents. The following tables present the Company’s fair value hierarchy for its cash equivalents, which are measured at fair value on a recurring basis (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at September 30, 2022 Using: ​ Level 1 Level 2 Level 3 Total Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ — ​ $ 105,274 ​ $ — ​ $ 105,274 Total ​ $ — ​ $ 105,274 ​ $ — ​ $ 105,274 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2021 Using: ​ Level 1 Level 2 Level 3 Total Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ — ​ $ 166,729 ​ $ — ​ $ 166,729 Total ​ $ — ​ $ 166,729 ​ $ — ​ $ 166,729 ​ During the nine months ended September 30, 2022, there were no transfers Level 3
Operating Leases	Operating Leases The Company determines if an arrangement includes a lease at inception. Operating lease right-of-use assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the net present value of lease payments, the Company uses its estimated incremental borrowing rate based on information available at the lease commencement date. Because most of the Company’s leases do not provide an implicit rate of return, an incremental borrowing rate is used based on the information available at the commencement date in determining the present value of lease payments on an individual lease basis. The Company’s incremental borrowing rate for a lease is the estimated rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. The Company’s leases may include options to extend or terminate the lease which are included in the lease term when it is reasonably certain that it will exercise any such options. None of the Company’s leases contain any residual value guarantees. Lease expense is recognized on a straight-line basis over the expected lease term. Related variable lease costs incurred are not material to the Company. The Company currently elects the short-term lease recognition exemption for all leases that qualify. This means, for those leases that qualify, the Company will not recognize right-of-use assets or liabilities, and this includes not recognizing right-of-use assets or liabilities for existing short-term leases of those assets in transition. The Company also elects the practical expedient to not separate lease and non-lease components for all of its leases. The Company has made an accounting policy election to account for each separate lease component of a contract and its associated non-lease components as a single lease component. See the Lease Agreements section in NOTE 9—LICENSE AGREEMENTS AND COMMITMENTS
Revenue Recognition	Revenue Recognition Product revenue The Company recognizes revenue from sales of DANYELZA at a point in time when its customer is deemed to have obtained control of the product, which generally occurs upon receipt at the end-user hospital. ​ The amount of revenue the Company recognizes from sales of DANYELZA varies due to rebates, chargebacks and discounts provided under governmental and other programs, distribution related fees and other sales-related deductions. In order to determine those deductions, the Company estimates, utilizing the expected value method, the amount of revenue that it will ultimately be entitled to. This estimate is based upon contracts with customers and government agencies, statutorily-defined discounts applicable to government-funded programs, estimated payor mix, and other relevant factors. Calculating these amounts involves estimates and judgments, and the Company reviews these estimates quarterly. If actual results vary from its original estimates, the Company will adjust these estimates quarterly, which would affect net product revenue and earnings in the period such variances occur. ​ ● Rebates and chargebacks ​ The Company contracts with United States governmental agencies to enable DANYELZA to be eligible for coverage under the various programs administered by the agencies. The Company estimates the rebates and chargebacks to be provided and deducts these estimated amounts from its gross product revenues. These reserves are recorded in the same period the revenue is recognized, resulting in a reduction of product revenue and the establishment of accrued liabilities for the rebates and a reduction of accounts receivable for the chargebacks. The Company develops estimates for rebates and chargebacks based upon (i) the Company’s contracts with these agencies, (ii) the government-mandated discounts applicable to government-funded programs, and (iii) information obtained from hospitals and third party consultants regarding the payor mix. The Company’s liability for these rebates and chargebacks mainly consists of claims for which invoices have not yet been received and paid. The Company does not maintain material levels of inventory in the wholesale or retail channel. ​ ● Discounts and distribution-related fees ​ The Company provides invoice discounts on DANYELZA sales to its distributors for prompt payment and fees for distribution services and invoice discounts reduce the original accounts receivable balances. The payment terms for sales to distributors generally include a 2% discount for prompt payment or fees for distribution services which are based on contractual rates agreed with the respective distributors. Based on historical data and experiences with the distributors, the Company expects its distributors to earn these discounts and fees and deduct the full amount of these discounts and fees from the Company’s gross product revenue at the time such revenues are recognized. ​ ● Returns ​ The Company offers its customers limited product return rights for damaged, defective, or expiring products. The Company estimates returns on sales of DANYELZA mainly based on information provided to the Company from the hospitals and distributors. The return reserves are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and an establishment of an accrued liability. ​ License revenue In May 2021, the Company entered into an exclusive distribution agreement with Adium Pharma S.A. (“Adium”) for Adium to be the exclusive distributor in Latin America of the Company’s antibodies omburtamab, if approved, and DANYELZA. As part of this agreement, the Company received and recognized a non-refundable up-front fee of $2,000,000 for the transfer of the license and know-how related to the product indications during the nine month period ended September 2021. The Company may also receive regulatory-based milestone payments up to an aggregate of $3,000,000. In April 2022, the Company received the first of these milestone payments, a non-refundable fee of $1,000,000 that was payable upon submission by the Company for the updated FDA BLA dossier for DANYELZA. In addition, the Company is entitled to royalties based upon the net sales generated by Adium related to the product in Latin America. The Company considered the license to be distinct from other promises within the arrangement based on the rights and know-how transferred, late-stage development of the underlying indications and anticipated lack of significant involvement required from the joint steering committee associated with the indications. The future potential regulatory milestone amounts were not included in the transaction price, as they were all determined to be fully constrained following the concepts of ASC 606. As part of the Company’s evaluation of the regulatory milestones constraint, the Company determined that the achievement of such milestones are contingent upon regulatory approvals which are not within the Company’s control and therefore not deemed probable. The Company expects that the sales-based milestone payments and royalty arrangements will be recognized when the related sales occur or the milestone is achieved. The Company reevaluates the transaction price each quarter and as uncertain events are resolved or other changes in circumstances occur, the Company assesses whether this resolves the constraint and revenue will be recognized.
Segment Information	Segment Information The Company is engaged solely in the discovery, development, distribution and commercialization of novel antibody-based therapeutic products for the treatment of cancer. Accordingly, the Company has determined that it operates in one operating segment.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements – Adopted From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, (“FASB”), and are adopted by the Company as of the specific effective date. The Company adopted ASU 2020-10, ASU 2021-04 and ASU 2020-06 effective January 1, 2022, and the adoption of these new standards did not have a material impact on the Company’s consolidated financial statements or disclosures. The Company has evaluated accounting pronouncements recently issued but not yet adopted and believes that these pronouncements do not apply to the Company’s operations and therefore will not have a material impact on the Company’s consolidated financial statements or disclosures.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	9 Months Ended
	Sep. 30, 2022
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Schedule of cash equivalents measured at fair value on recurring basis	The following tables present the Company’s fair value hierarchy for its cash equivalents, which are measured at fair value on a recurring basis (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at September 30, 2022 Using: ​ Level 1 Level 2 Level 3 Total Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ — ​ $ 105,274 ​ $ — ​ $ 105,274 Total ​ $ — ​ $ 105,274 ​ $ — ​ $ 105,274 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2021 Using: ​ Level 1 Level 2 Level 3 Total Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ — ​ $ 166,729 ​ $ — ​ $ 166,729 Total ​ $ — ​ $ 166,729 ​ $ — ​ $ 166,729

PRODUCT REVENUE (Tables)

PRODUCT REVENUE (Tables)	9 Months Ended
	Sep. 30, 2022
REVENUE RECOGNITION
Change in reserves for discounts and allowances	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractual ​ ​ ​ ​ ​ ​ ​ Allowances and ​ ​ ​ ​ ​ ​ ​ Discounts ​ Government Rebates Returns ​ Total ​ (in thousands) Balance, December 31, 2021 $ 13 ​ $ 3,027 ​ $ 61 ​ $ 3,101 Current provisions relating to sales in current year ​ 65 ​ ​ 3,459 ​ ​ 379 ​ ​ 3,903 Payments/credits relating to sales in current year ​ (59) ​ ​ (2,653) ​ ​ (398) ​ ​ (3,110) Change in estimate ​ — ​ ​ (709) ​ ​ — ​ ​ (709) Balance, September 30, 2022 $ 19 ​ $ 3,124 ​ $ 42 ​ $ 3,185

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2022
NET LOSS PER SHARE
Schedule of basic and diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, ​ Nine months ended September 30, ​ ​ 2022 ​ 2021 2022 ​ 2021 ​ ​ ​ (in thousands, except per share amounts) ​ ​ ​ ​ ​ Net income /(loss) (numerator) ​ $ (27,526) ​ $ (28,858) ​ $ (96,725) ​ $ (18,382) ​ Weighted-average shares (denominator), basic and diluted ​ 43,718 ​ 43,598 ​ 43,715 ​ 43,019 ​ Basic net income / (loss) per share ​ $ (0.63) ​ $ (0.66) ​ $ (2.21) ​ $ (0.43) ​

INVENTORIES (Tables)

INVENTORIES (Tables)	9 Months Ended
	Sep. 30, 2022
INVENTORIES
Schedule of inventories	Inventories consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 ​ December 31, 2021 ​ ​ ​ ​ ​ ​ ​ Raw Materials ​ ​ 1,500 ​ ​ — Work In Progress ​ ​ 8,870 ​ ​ 4,741 Finished Goods ​ ​ 1,088 ​ ​ 771 Total Inventories ​ $ 11,458 ​ $ 5,512 ​ ​ ​ ​ ​ ​ ​ ​ Inventories are classified on the Consolidated Balance Sheets in each respective period (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 ​ December 31, 2021 CURRENT ASSETS ​ ​ ​ ​ ​ ​ Inventories ​ $ 6,242 ​ $ 5,512 Total recorded in Current Assets ​ ​ 6,242 ​ ​ 5,512 ​ ​ ​ ​ ​ ​ ​ NONCURRENT ASSETS ​ ​ ​ ​ ​ ​ Other assets ​ ​ 5,216 ​ ​ — Total recorded in Noncurrent Assets ​ ​ 5,216 ​ ​ — Total Inventories ​ $ 11,458 ​ $ 5,512

ACCRUED LIABILITIES (Tables)

ACCRUED LIABILITIES (Tables)	9 Months Ended
	Sep. 30, 2022
ACCRUED LIABILITIES
Summary of accrued short-term liabilities	Accrued short-term liabilities as of September 30, 2022 and December 31, 2021 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ 2022 ​ 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued licensing milestone and royalty payments ​ $ 1,593 ​ $ 3,090 Accrued clinical costs ​ 985 ​ 915 Accrued compensation and board fees ​ 4,073 ​ 1,877 Accrued manufacturing costs ​ ​ 6,466 ​ ​ 2,622 Accrued sales reserves ​ ​ 2,451 ​ ​ 2,615 Other ​ 1,524 ​ 1,421 Total ​ $ 17,092 ​ $ 12,540

LICENSE AGREEMENTS AND COMMIT_2

LICENSE AGREEMENTS AND COMMITMENTS (Tables)	9 Months Ended
	Sep. 30, 2022
Agreements
Maturities of operating lease liabilities	Maturities of operating lease liabilities as of September 30, 2022 were as follows (in thousands): ​ ​ ​ ​ ​ ​ Operating Leases ​ at September 30, 2022 Remainder of 2022 ​ $ 554 Years ending December 31, ​ ​ ​ 2023 ​ ​ 958 2024 ​ ​ 482 2025 ​ ​ 383 Total lease payments ​ ​ 2,377 Less: Imputed interest ​ ​ (158) Total operating lease liabilities as of September 30, 2022 ​ $ 2,219 ​ Maturities of operating leases as of December 31, 2021 were as follows (in thousands): ​ ​ ​ ​ ​ ​ Operating Leases Years ending December 31, at December 31, 2021 2022 ​ $ 1,953 2023 ​ ​ 1,025 2024 ​ ​ 550 2025 ​ ​ 445 Total lease payments ​ ​ 3,973 Less: Imputed interest ​ ​ (339) Total operating lease liabilities as of December 31, 2021 ​ $ 3,634
MSK, CD33, MabVax and SADA License Agreements
Agreements
Summary of significant license agreements, related commitments and milestone information	The Company has the following significant license agreements and related commitments which include all obligations that have been paid or accrued as of and for the three and nine months ended September 30, 2022 and 2021, and as of December 31, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued Accrued Accrued Accrued ​ ​ Cash paid Cash paid Expense Expense Expense Expense ​ liabilities liabilities liabilities liabilities ​ ​ Nine months ​ Nine months ​ Three months ​ Nine months ​ Three months ​ Nine months ​ Current ​ Non-current ​ Current ​ Non-current ​ ​ ended ​ ended ​ ended ​ ended ​ ended ​ ended ​ as of ​ as of ​ as of ​ as of ​ ​ September ​ September ​ September ​ September ​ September ​ September ​ September ​ September ​ December ​ December Agreements ​ 2022 ​ 2021 ​ 2022 ​ 2022 ​ 2021 ​ 2021 ​ 2022 ​ 2022 ​ 2021 ​ 2021 MSK ​ ​ $ 2,871 ​ ​ $ 1,480 ​ ​ $ 753 ​ ​ $ 2,513 ​ ​ $ 321 ​ ​ $ 531 ​ ​ $ 828 ​ ​ $ 1,950 ​ ​ $ 1,486 ​ ​ $ 1,650 CD33 ​ ​ — ​ ​ 100 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 150 ​ ​ 300 ​ ​ — ​ ​ 450 MabVax ​ ​ — ​ ​ 10 ​ ​ 10 ​ ​ 10 ​ ​ — ​ ​ 10 ​ ​ 10 ​ ​ — ​ ​ — ​ ​ — SADA ​ ​ 1,000 ​ ​ 1,000 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 605 ​ ​ — ​ ​ 1,605 ​ ​ — The below table represents the maximum clinical, regulatory or sales-based milestones as reflected within the agreements, certain of which have been paid in prior periods or are accrued as presented in the table above (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maximum Maximum Maximum Agreements ​ ​ ​ Clinical Milestones ​ Regulatory Milestones ​ Sales-based Milestones ​ MSK ​ ​ ​ ​ ​ $ 2,450 ​ ​ $ 9,000 ​ ​ $ 20,000 ​ CD33 ​ ​ ​ ​ ​ 550 ​ ​ 500 ​ ​ 7,500 ​ MabVax ​ ​ ​ ​ ​ 200 ​ ​ 1,200 ​ ​ — ​ SADA ​ ​ ​ ​ ​ 4,730 ​ ​ 18,125 ​ ​ 23,750 ​

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2022
SHARE-BASED COMPENSATION
Schedule of common stock options issued and outstanding	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Weighted ​ Aggregate ​ average ​ ​ ​ ​ average ​ intrinsic ​ remaining ​ ​ ​ ​ exercise ​ value ​ contractual ​ ​ Options ​ price ​ (in thousands) ​ life (years) Outstanding and expected to vest at December 31, 2021 6,687,128 ​ $ 22.43 ​ $ 26,412 ​ 7.21 Granted 635,000 ​ ​ 11.42 ​ ​ ​ ​ ​ Exercised ​ (20,000) ​ ​ 4.22 ​ ​ ​ ​ ​ Forfeited ​ (218,361) ​ ​ 29.27 ​ ​ ​ ​ ​ Outstanding and expected to vest at September 30, 2022 7,083,767 ​ $ 21.28 ​ $ 23,619 ​ 6.70 Exercisable at September 30, 2022 4,556,127 ​ $ 18.95 ​ $ 21,543 ​ 5.55
Schedule of restricted stock units issued and outstanding	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Weighted ​ average ​ ​ ​ ​ ​ average ​ remaining ​ ​ ​ ​ ​ grant ​ vesting ​ ​ ​ Restricted Stock Units ​ price ​ life (years) ​ Outstanding and expected to vest at December 31, 2021 ​ 28,907 ​ $ 28.04 1.82 ​ Granted ​ 19,054 ​ ​ 9.92 ​ Vested ​ (11,314) ​ ​ 25.98 ​ ​ Forfeited ​ (1,082) ​ ​ 29.81 ​ ​ ​ Outstanding and expected to vest at September 30, 2022 ​ 35,565 ​ $ 18.42 2.00 ​

BASIS OF PRESENTATION - Accumul

BASIS OF PRESENTATION - Accumulated deficit (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
BASIS OF PRESENTATION
Accumulated deficit	$ (437,200)	$ (340,475)

BASIS OF PRESENTATION - Seconda

BASIS OF PRESENTATION - Secondary public offering (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Feb. 22, 2021	Mar. 31, 2021
Common Stock
Issuance of stock
Issuance of common stock, Stock offering (in shares)		2,804,878
Secondary public offering, February 22, 2021
Issuance of stock
Aggregate gross proceeds	$ 115,000
Secondary public offering, February 22, 2021 | Common Stock
Issuance of stock
Issuance of common stock, Stock offering (in shares)	2,804,878
Share price (in dollars per share)	$ 41
Secondary public offering, February 22, 2021, Underwriters' option | Common Stock
Issuance of stock
Issuance of common stock, Stock offering (in shares)	365,853

BASIS OF PRESENTATION - Cash an

BASIS OF PRESENTATION - Cash and cash equivalents (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
BASIS OF PRESENTATION
Cash and cash equivalents	$ 114,526	$ 181,564

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Credit Risk (Details) - Credit Concentration Risk - Accounts Receivable - Three Customers	9 Months Ended
	Sep. 30, 2022 customer
Concentration risk
Number of customers	3
Concentration risk percentage (as a percent)	99%

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Inventory (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Inventory write-downs	$ 1,200	$ 1,200

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair Value Measurement (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Fair value measurements
Level 1 to Level 2 Transfers	$ 0
Level 2 to Level 1 Transfers	0
Transfers into Level 3	0
Transfers out of Level 3	0
Recurring
Fair value measurements
Cash equivalents	105,274	$ 166,729
Recurring | Money market funds
Fair value measurements
Cash equivalents	105,274	166,729
Recurring | Level 2
Fair value measurements
Cash equivalents	105,274	166,729
Recurring | Level 2 | Money market funds
Fair value measurements
Cash equivalents	$ 105,274	$ 166,729

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition - Product revenue (Details)	9 Months Ended
	Sep. 30, 2022
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Discount for prompt payment (as a percent)	2%

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition - License revenue (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	May 31, 2021
Agreements
Revenue		$ 12,537	$ 8,965	$ 33,820	$ 25,299
License
Agreements
Revenue				$ 1,000	2,000
License | Distribution Agreement | Adium
Agreements
Maximum regulatory milestones						$ 3,000
License, Transfer of license and know-how | Distribution Agreement | Adium
Agreements
Revenue					$ 2,000
License, Milestone | Distribution Agreement | Adium
Agreements
Revenue	$ 1,000

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Segment (Details)	9 Months Ended
	Sep. 30, 2022 segment
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Number of Operating Segments	1

PRODUCT REVENUE - Discounts and

PRODUCT REVENUE - Discounts and Allowances (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue
Revenue	$ 12,537	$ 8,965	$ 33,820	$ 25,299
Change in reserves for discounts and allowances
Discounts, Balance at beginning of period			13
Discounts, Current provisions relating to sales in current year			65
Discounts, Payments/credits relating to sales in current year			(59)
Discounts, Balance at end of period	19		19
Contractual Allowances and Government Rebates, Balance at beginning of period			3,027
Contractual Allowances and Government Rebates, Current provisions relating to sales in current year			3,459
Contractual Allowances and Government Rebates, Payments/credits relating to sales in current year			(2,653)
Contractual Allowances and Government Rebates, Change in estimate	(709)		(709)
Contractual Allowances and Government Rebates, Balance at end of period	3,124		3,124
Returns, Balance at beginning of period			61
Returns, Current provisions relating to sales in current year			379
Returns, Payments/credits relating to sales in current year			(398)
Returns, Balance at end of period	42		42
Reserves for discounts and allowances, Balance at beginning of period			3,101
Reserves for discounts and allowances, Current provisions relating to sales in current year			3,903
Reserves for discounts and allowances, Payments/credits relating to sales in current year			(3,110)
Reserves for discounts and allowances, Change in estimate			(709)
Reserves for discounts and allowances, Balance at end of period	3,185		3,185
Accounts receivable
Change in reserves for discounts and allowances
Reserves for discounts and allowances, Balance at beginning of period			486
Reserves for discounts and allowances, Balance at end of period	734		734
Accrued liabilities
Change in reserves for discounts and allowances
Reserves for discounts and allowances, Balance at beginning of period			2,615
Reserves for discounts and allowances, Balance at end of period	2,451		2,451
Product
Revenue
Revenue	12,537	8,965	32,820	23,299
Product, DANYELZA
Revenue
Revenue	$ 12,537	$ 8,965	$ 32,820	$ 23,299

PRODUCT REVENUE - Concentration

PRODUCT REVENUE - Concentrations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Concentration risk
Contractual Allowances and Government Rebates, Change in estimate resulting in benefit	$ 709		$ 709
McKesson | Customer Concentration Risk | Revenue | Product
Concentration risk
Concentration risk percentage (as a percent)	78%	66%	69%	73%
AmerisourceBergen | Customer Concentration Risk | Revenue | Product
Concentration risk
Concentration risk percentage (as a percent)	14%	24%	16%	17%

NET LOSS PER SHARE - Basic and

NET LOSS PER SHARE - Basic and diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
NET LOSS PER SHARE
Net income /(loss) (numerator), Basic (in dollars)	$ (27,526)	$ (28,858)	$ (96,725)	$ (18,382)
Net income /(loss) (numerator), Diluted (in dollars)	$ (27,526)	$ (28,858)	$ (96,725)	$ (18,382)
Weighted-average shares (denominator), basic (in shares)	43,718,351	43,598,350	43,715,451	43,019,217
Weighted-average shares (denominator), diluted (in shares)	43,718,351	43,598,350	43,715,451	43,019,217
Basic net income / (loss) per share (in dollars per share)	$ (0.63)	$ (0.66)	$ (2.21)	$ (0.43)

NET LOSS PER SHARE - Anti-dilut

NET LOSS PER SHARE - Anti-dilutive securities (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
NET LOSS PER SHARE
Potentially dilutive securities outstanding	7,119,332	5,832,317

INVENTORIES (Details)

INVENTORIES (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Dec. 31, 2021
Inventories
Raw Materials	$ 1,500	$ 1,500
Work in Process	8,870	8,870	$ 4,741
Finished Goods	1,088	1,088	771
Total Inventories	11,458	11,458	5,512
CURRENT ASSETS
Inventories, Current	6,242	6,242	5,512
NONCURRENT ASSETS
Inventories, Noncurrent	5,216	5,216
Inventory write-downs	1,200	1,200
Current Assets
CURRENT ASSETS
Inventories, Current	6,242	6,242	$ 5,512
Noncurrent Assets
Inventories
Raw Materials	1,500	1,500
Work in Process	3,716	3,716
NONCURRENT ASSETS
Inventories, Noncurrent	$ 5,216	$ 5,216

INTANGIBLE ASSETS, NET (Details

INTANGIBLE ASSETS, NET (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
INTANGIBLE ASSETS, NET
Intangible assets, net	$ 1,530	$ 1,663
Accumulated amortization	$ 270	$ 137
Amortization period	10 years
Forecasted amortization expense
2022	$ 180
2023	180
2024	180
2025	180
2026	$ 180

ACCRUED LIABILITIES (Details)

ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Accrued short-term liabilities
Accrued licensing, milestone payments	$ 1,593	$ 3,090
Accrued clinical costs	985	915
Accrued compensation and board fees	4,073	1,877
Accrued manufacturing costs	6,466	2,622
Accrued sales reserves	2,451	2,615
Other	1,524	1,421
Total	$ 17,092	$ 12,540

LICENSE AGREEMENTS AND COMMIT_3

LICENSE AGREEMENTS AND COMMITMENTS - License Agreements (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) agreement	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) agreement	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Financial statement information
Accrued liabilities, current	$ 17,092,000		$ 17,092,000		$ 12,540,000
Gross intangible assets related to Danyelza	$ 1,530,000		$ 1,530,000		1,663,000
MSK
Agreements
Number of license agreements | agreement	2		2
MSK License Agreement
Financial statement information
Cash paid			$ 2,871,000	$ 1,480,000
Expense	$ 753,000	$ 321,000	2,513,000	531,000
Accrued liabilities, current	828,000		828,000		1,486,000
Accrued liabilities, noncurrent	1,950,000		1,950,000		1,650,000
Milestones
Maximum Clinical Milestones	2,450,000		2,450,000
Maximum Regulatory Milestones	9,000,000		9,000,000
Maximum Sales-based Milestones	20,000,000		20,000,000
CD33 License Agreement
Financial statement information
Cash paid				100,000
Accrued liabilities, current	150,000		150,000
Accrued liabilities, noncurrent	300,000		300,000		450,000
Milestones
Maximum Clinical Milestones	550,000		550,000
Maximum Regulatory Milestones	500,000		500,000
Maximum Sales-based Milestones	7,500,000		7,500,000
MabVax Agreement
Financial statement information
Cash paid				10,000
Expense	10,000		10,000	10,000
Accrued liabilities, current	10,000		10,000
Milestones
Maximum Clinical Milestones	200,000		200,000
Maximum Regulatory Milestones	1,200,000		1,200,000
SADA License Agreement
Financial statement information
Cash paid			1,000,000	$ 1,000,000
Accrued liabilities, current	605,000		605,000		$ 1,605,000
Milestones
Maximum Clinical Milestones	4,730,000		4,730,000
Maximum Regulatory Milestones	18,125,000		18,125,000
Maximum Sales-based Milestones	23,750,000		$ 23,750,000
Period for which all time-based milestones coming due have been accrued			36 months
Time-based milestone payments coming due, Accrued liabilities	$ 605,000		$ 605,000

LICENSE AGREEMENTS AND COMMIT_4

LICENSE AGREEMENTS AND COMMITMENTS - Other agreements (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) employee agreement	Sep. 30, 2021 USD ($) employee agreement
Agreements
Research and development		$ 22,453	$ 23,131	$ 71,785	$ 64,488
Other Agreements with MSK
Agreements
Research and development		$ 458	$ 833	$ 1,505	$ 2,728
Core Facility Service Agreements
Agreements
Number of service agreements | agreement				2	2
Sponsored Research Agreement
Agreements
Research service period	3 years
Researchers, Employees of MSK | Master Data Services Agreement
Agreements
Number of individuals | employee				5	5

LICENSE AGREEMENTS AND COMMIT_5

LICENSE AGREEMENTS AND COMMITMENTS - Lease agreements (Details) $ in Thousands	1 Months Ended
	Aug. 31, 2020 USD ($)	Feb. 28, 2019 USD ($) ft²	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Nov. 01, 2021 USD ($)	Dec. 31, 2019 ft²	Jan. 31, 2018 USD ($)
Leases
Operating lease right-of-use assets			$ 2,169	$ 3,842
Lease liabilities			$ 2,219	$ 3,634
Operating Lease, Liability, Statement of Financial Position			Operating lease liabilities, current portion, Operating lease liabilities, long-term portion	Operating lease liabilities, current portion, Operating lease liabilities, long-term portion
Manufacturing facility, Indiana
Leases
Lease term	2 years
Operating lease right-of-use assets	$ 3,617
Lease liabilities	$ 2,679
Operating Lease, Liability, Statement of Financial Position	Operating lease liabilities, current portion, Operating lease liabilities, long-term portion
Difference between right of use asset and lease liability recognized	$ 938
Access fee monthly installment	117
Amount of additional access fees to be paid in monthly installments	$ 350
Laboratory, New Jersey
Leases
Leased area (in square feet) | ft²		4,548
Additional leased area (in square feet) | ft²						235
Lease term		3 years
Option to extend		true
Option to extend, period		2 years
Fixed rent payable per annum		$ 144
Lease payable per month		$ 12
Corporate headquarters, New York
Leases
Lease term							6 years
Fixed rent payable per annum							$ 384
Lease payable per month							$ 32
Office space, Denmark
Leases
Lease term					4 years
Lease payable per month					$ 41

LICENSE AGREEMENTS AND COMMIT_6

LICENSE AGREEMENTS AND COMMITMENTS - Lease costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Leases
Total operating lease costs	$ 721	$ 644	$ 2,127	$ 1,936
Cash paid for amounts included in the measurement of lease liabilities	481	548	1,689	1,641
Research and development expense
Leases
Total operating lease costs	657	584	1,937	1,758
Selling, general, and administrative expense
Leases
Total operating lease costs	$ 64	$ 60	$ 190	$ 178

LICENSE AGREEMENTS AND COMMIT_7

LICENSE AGREEMENTS AND COMMITMENTS - Lease maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Future minimum commitments under all non-cancelable operating leases
Remainder of year	$ 554
First fiscal year	958	$ 1,953
Second fiscal year	482	1,025
Third fiscal year	383	550
Fourth fiscal year		445
Total lease payments	2,377	3,973
Less: Imputed interest	(158)	(339)
Total operating lease liabilities at end of period	$ 2,219	$ 3,634
Operating Lease, Liability, Statement of Financial Position	Operating lease liabilities, current portion, Operating lease liabilities, long-term portion	Operating lease liabilities, current portion, Operating lease liabilities, long-term portion

LICENSE AGREEMENTS AND COMMIT_8

LICENSE AGREEMENTS AND COMMITMENTS - Lease term and discount rate (Details)	Sep. 30, 2022	Dec. 31, 2021
LICENSE AGREEMENTS AND COMMITMENTS
Weighted average remaining lease term	2 years 2 months 4 days	2 years 7 months 13 days
Weighted average discount rate	6.80%	6.50%

LICENSE AGREEMENTS AND COMMIT_9

LICENSE AGREEMENTS AND COMMITMENTS - Severance Related Benefits (Details) - Former Chief Executive Officer $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)
Severance Agreement
Cash compensation for salary and certain benefits continuation	$ 1,589
Stock-based compensation expenses	9,286
Total charge related to executive management change to be recorded during 2022	$ 10,875

LICENSE AGREEMENTS AND COMMI_10

LICENSE AGREEMENTS AND COMMITMENTS - Legal matters (Details) - individual	Oct. 10, 2022	Aug. 25, 2021
Lawsuit filed by shareholder in the U.S. District Court, Southern District of New York, on August 25, 2021
Legal Matters
Number of stockholders that filed lawsuit		1
Lawsuit filed by shareholder in the U.S. District Court, Southern District of New York on October 10, 2022
Legal Matters
Number of stockholders that filed lawsuit	1

STOCKHOLDERS' EQUITY - Authoriz

STOCKHOLDERS' EQUITY - Authorized, Common and Preferred Stock (Details)	9 Months Ended
	Sep. 30, 2022 USD ($) Vote $ / shares shares	Dec. 31, 2021 $ / shares shares
STOCKHOLDERS' EQUITY
Total shares authorized	105,500,000	105,500,000
Common stock, authorized shares	100,000,000	100,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Preferred stock, authorized shares	5,500,000	5,500,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Number of votes per common share | Vote	1
Common stock dividends issued | $	$ 0
Common stock, shares issued	43,668,130	43,694,716
Preferred stock, shares issued	0	0

STOCKHOLDERS' EQUITY - Stock gr

STOCKHOLDERS' EQUITY - Stock grant agreements with non-employees (Details)	1 Months Ended			3 Months Ended	9 Months Ended	30 Months Ended
	Jul. 31, 2022 USD ($) individual shares	Jul. 31, 2020 USD ($) individual	Apr. 30, 2020 USD ($) individual shares	Sep. 30, 2022 USD ($) shares	Sep. 30, 2022 USD ($) individual	Sep. 30, 2022 USD ($)
Share-Based Compensation Awards
Treasury shares at acquisition cost (in dollars)	$ 963,000
Retirement of treasury shares, Reduction in outstanding stock and reduction of APIC (in dollars)				$ 963,000	$ 963,000
Researchers, Employees of MSK
Share-Based Compensation Awards
Number of individuals that repaid note | individual	1
SADA License Agreement | Researchers, Employees of MSK
Share-Based Compensation Awards
Number of individuals | individual		2
Notes receivable, noncurrent		$ 2,610,000
Notes receivable term		3 years
Notes receivable interest rate (as a percent)		1%
SADA License Agreement | Nonemployees | Researchers, Employees of MSK
Share-Based Compensation Awards
Number of individuals | individual			2		2
Vesting (as a percent)			40%		20%	80%
Remaining vesting percentage			60%	20%	20%	20%
SADA License Agreement | Nonemployees | Researchers, Employees of MSK | Research and development expense
Share-Based Compensation Awards
Non-cash expense in connection with equity issuance to non-employees			$ 7,376,000
Unrecognized compensation				$ 0	$ 0	$ 0
SADA License Agreement | Nonemployees | Researchers, Employees of MSK | Tranche two
Share-Based Compensation Awards
Vesting period			3 years
Common Stock
Share-Based Compensation Awards
Number of shares exchanged | shares	57,887			57,887
Common Stock | SADA License Agreement | Nonemployees | Researchers, Employees of MSK
Share-Based Compensation Awards
Shares agreed to be issued | shares			213,996
Issuance of common stock to non-employees (in shares) | shares			213,996

STOCKHOLDERS' EQUITY - Issuance

STOCKHOLDERS' EQUITY - Issuance of common stock (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	9 Months Ended
	Feb. 22, 2021	Mar. 31, 2021	Sep. 30, 2021
Issuance of stock
Proceeds from issuance of common stock, net			$ 107,725
Secondary public offering, February 22, 2021
Issuance of stock
Aggregate gross proceeds	$ 115,000
Proceeds from issuance of common stock, net	$ 107,725
Common Stock
Issuance of stock
Issuance of common stock, Stock offering (in shares)		2,804,878
Common Stock | Secondary public offering, February 22, 2021
Issuance of stock
Issuance of common stock, Stock offering (in shares)	2,804,878
Share price (in dollars per share)	$ 41

SHARE-BASED COMPENSATION - 2015

SHARE-BASED COMPENSATION - 2015 Plan (Details) - 2015 Plan - shares	Sep. 30, 2018	Dec. 31, 2015
Share-Based Compensation Awards
Shares reserved for issuance pursuant to the plan		4,500,000
Shares available for grant	0

SHARE-BASED COMPENSATION - 2018

SHARE-BASED COMPENSATION - 2018 Plan (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2022 shares	Sep. 30, 2022 shares
Stock options
Share-Based Compensation Awards
Term of award	10 years	10 years
2018 Plan
Share-Based Compensation Awards
Shares reserved for issuance pursuant to the plan	5,500,000	5,500,000
Annual increase on share reserve (as a percent)		4%
2018 Plan | Stock options | Minimum
Share-Based Compensation Awards
Vesting period		1 year
2018 Plan | Stock options | Maximum
Share-Based Compensation Awards
Vesting period		4 years
2018 Plan | Stock options | Employees and nonemployees owning less than 10% of voting power
Share-Based Compensation Awards
Term of award		10 years
2018 Plan | Stock options | Participants owning more than 10% of voting power
Share-Based Compensation Awards
Term of award		5 years
2018 Plan | Stock options | Participants owning more than 10% of voting power | Minimum
Share-Based Compensation Awards
Ownership (as a percent)	10%	10%
Option price as percentage of fair market value of common stock on the date of grant		110%

SHARE-BASED COMPENSATION - Stoc

SHARE-BASED COMPENSATION - Stock-based compensation expense - Options (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Former Chief Executive Officer
Share-Based Compensation Awards
Stock-based compensation expenses			$ 9,286
Stock options
Share-Based Compensation Awards
Stock-based compensation expenses	$ 3,257	$ 4,829	21,822	$ 14,209
Stock options | Research and development expense
Share-Based Compensation Awards
Stock-based compensation expenses	1,801	1,827	5,582	5,271
Stock options | Selling, general, and administrative
Share-Based Compensation Awards
Stock-based compensation expenses	$ 1,456	$ 3,002	$ 16,240	$ 8,938

SHARE-BASED COMPENSATION - St_2

SHARE-BASED COMPENSATION - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Options
Outstanding at beginning of period (in shares)			6,687,128
Granted (in shares)	210,000	102,000	635,000	311,000
Exercised (in shares)			(20,000)
Forfeited, shares (in shares)			(218,361)
Outstanding at end of period (in shares)	7,083,767		7,083,767		6,687,128
Exercisable at end of period (in shares)	4,556,127		4,556,127
Weighted average exercise price
Outstanding at beginning of period (in dollars per share)			$ 22.43
Granted (in dollars per share)			11.42
Exercised (in dollars per share)			4.22
Forfeited (in dollars per share)			29.27
Outstanding at end of period (in dollars per share)	$ 21.28		21.28		$ 22.43
Exercisable at end of period (in dollars per share)	$ 18.95		$ 18.95
Aggregate intrinsic value and Weighted average remaining contractual life (years)
Outstanding (in dollars)	$ 23,619		$ 23,619		$ 26,412
Exercisable (in dollars)	$ 21,543		$ 21,543
Outstanding (in years)			6 years 8 months 12 days		7 years 2 months 15 days
Exercisable (in years)			5 years 6 months 18 days

SHARE-BASED COMPENSATION - St_3

SHARE-BASED COMPENSATION - Stock option grants (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-Based Compensation Awards
Weighted average grant-date fair value of stock options granted (in dollars per share)	$ 10.14		$ 20.19	$ 7.88	$ 20.85
Granted (in shares)	210,000		102,000	635,000	311,000
Aggregate value of cash bonus portion of retention program	$ 1,091			$ 1,091
Senior executives and certain other employees under retention program
Share-Based Compensation Awards
Granted (in shares)		255,000
Employees not included under retention program
Share-Based Compensation Awards
Granted (in shares)		170,000
Tranche two | Employees not included under retention program
Share-Based Compensation Awards
Vesting period		36 months
Stock options
Share-Based Compensation Awards
Term of award	10 years			10 years
Stock options | Senior executives and certain other employees under retention program
Share-Based Compensation Awards
Service period		2 years
Expected term (in years)		5 years 9 months
Risk-free interest rate (as a percent)		2.80%
Stock options | Employees not included under retention program
Share-Based Compensation Awards
Expected term (in years)		6 years 3 months
Risk-free interest rate (as a percent)		2.80%
Stock options | Tranche one | Senior executives and certain other employees under retention program
Share-Based Compensation Awards
Vesting period		1 year
Vesting (as a percent)		50%
Stock options | Tranche one | Employees not included under retention program
Share-Based Compensation Awards
Vesting period		1 year
Vesting (as a percent)		25%

SHARE-BASED COMPENSATION - St_4

SHARE-BASED COMPENSATION - Stock option unrecognized compensation (Details) - Stock options - Employees - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Unrecognized compensation related to employee stock options
Unrecognized compensation	$ 25,520	$ 44,357
Expected vesting period	2 years 5 months 19 days	2 years 7 months 9 days

SHARE-BASED COMPENSATION - Rest

SHARE-BASED COMPENSATION - Restricted Stock Unit Activity (Details) - RSUs - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Restricted stock units issued and outstanding
Outstanding and expected to vest at beginning of period (in shares)			28,907
Granted (in shares)			19,054
Vested (in shares)			(11,314)
Forfeited (in shares)			(1,082)
Outstanding and expected to vest at end of period (in shares)	35,565		35,565		28,907
Weighted average grant price
Weighted average grant price, Outstanding and expected to vest, Beginning of period (in dollars per share)			$ 28.04
Weighted average grant price, Granted (in dollars per share)			9.92
Weighted average grant price, Vested (in dollars per share)			25.98
Weighted average grant price, Forfeited (in dollars per share)			29.81
Weighted average grant price, Outstanding and expected to vest, End of period (in dollars per share)	$ 18.42		$ 18.42		$ 28.04
Unrecognized compensation	$ 504	$ 631	$ 504	$ 631
Weighted average remaining vesting life			2 years	1 year 10 months 28 days	1 year 9 months 25 days
Stock-based compensation expenses	84	72	$ 242	$ 217
Research and development expense
Weighted average grant price
Stock-based compensation expenses	74	63	215	194
Selling, general, and administrative
Weighted average grant price
Stock-based compensation expenses	$ 10	$ 9	$ 27	$ 23

RELATED PARTY TRANSACTIONS (Det

RELATED PARTY TRANSACTIONS (Details) - Shareholder, MSK - MSK License Agreement, SADA License Agreement, CD33 License Agreement, MabVax Agreement, and other supporting agreements with MSK - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Related party transactions
Expensed costs	$ 1,221	$ 1,154	$ 4,028	$ 3,259
Due to related parties	4,761		4,761		$ 6,191
Due to related parties, Accounts payable	275		275		748
Due to related parties, Accrued liabilities	$ 4,486		$ 4,486		$ 5,443

INCOME TAXES - Loss before inco

INCOME TAXES - Loss before income taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income tax expense
Provision for (benefit from) income tax	$ 0	$ 0	$ 0	$ 0
Domestic and foreign loss before income taxes:
Losses before taxes	$ (27,526)	$ (28,858)	$ (96,725)	$ (18,382)

INCOME TAXES - Uncertain tax po

INCOME TAXES - Uncertain tax positions (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
INCOME TAXES
Unrecognized tax benefits	$ 0	$ 304

OTHER BENEFITS (Details)

OTHER BENEFITS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
UNITED STATES
Benefit plan
Employer matching contribution to defined contribution plan (as a percent)	0%	0%	0%	0%
DENMARK
Benefit plan
Employer matching contribution to defined contribution plan (as a percent)	0%	0%	0%	0%
Costs for employee health insurance benefits	$ 0	$ 0	$ 0	$ 0

GAIN FROM SALE OF PRIORITY RE_2

GAIN FROM SALE OF PRIORITY REVIEW VOUCHER (Details) - USD ($) $ in Thousands		9 Months Ended
	Jan. 21, 2021	Sep. 30, 2021
Disposal
Net gain recognized		$ 62,010
Priority Review Voucher | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Disposal
Consideration	$ 105,000
Percentage of net proceeds from monetization entitled to be retained	60%
Percentage of net proceeds from monetization to be paid to MSK	40%
Net gain recognized		$ 62,010

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - Subsequent Event	Oct. 28, 2022 Vote
Subsequent Events
Number of votes by FDA Advisory Committee that BLA did not provide sufficient evidence to conclude	16
Number of votes by FDA Advisory Committee that BLA provided sufficient evidence to conclude	0