Celldex Therapeutics (CLDX) 10-Q 9 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Oct. 31, 2022
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	000-15006
Entity Registrant Name	CELLDEX THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3191702
Entity Address, Address Line One	Perryville III Building
Entity Address, Address Line Two	53 Frontage Road
Entity Address, Address Line Three	Suite 220
Entity Address, City or Town	Hampton
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	08827
City Area Code	908
Local Phone Number	200-7500
Title of 12(b) Security	Common Stock, par value $.001
Trading Symbol	CLDX
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		47,099,831
Entity Central Index Key	0000744218
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 18,583	$ 39,143
Marketable securities	304,888	369,107
Accounts and other receivables	189	172
Prepaid and other current assets	10,939	2,417
Total current assets	334,599	410,839
Property and equipment, net	3,753	3,551
Operating lease right-of-use assets, net	3,580	2,970
Intangible assets, net	27,190	27,190
Other assets	104	104
Total assets	369,226	444,654
Current liabilities:
Accounts payable	2,272	1,228
Accrued expenses	11,425	12,000
Current portion of operating lease liabilities	1,438	1,746
Current portion of other long-term liabilities	1,152	1,554
Total current liabilities	16,287	16,528
Long-term portion of operating lease liabilities	2,190	1,296
Other long-term liabilities	5,333	7,354
Total liabilities	23,810	25,178
Commitments and contingent liabilities
Stockholders' equity:
Convertible preferred stock, $.01 par value; 3,000,000 shares authorized; no shares issued and outstanding at September 30, 2022 and December 31, 2021		0
Common stock, $.001 par value; 297,000,000 shares authorized; [ ] and 46,730,198 shares issued and outstanding at September 30, 2022 and December 31, 2021, respectively	47	47
Additional paid-in capital	1,574,926	1,561,142
Accumulated other comprehensive income	(112)	1,894
Accumulated deficit	(1,229,445)	(1,143,607)
Total stockholders' equity	345,416	419,476
Total liabilities and stockholders' equity	$ 369,226	$ 444,654

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
CONDENSED CONSOLIDATED BALANCE SHEETS
Convertible Preferred Stock, Par Value (in dollars per share)	$ 0.01	$ 0.01
Convertible Preferred Stock, Shares Authorized	3,000,000	3,000,000
Convertible Preferred Stock, Shares Issued	0	0
Convertible Preferred Stock, Shares Outstanding	0	0
Common Stock, Par Value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, Shares Authorized	297,000,000	297,000,000
Common Stock, Shares Issued	47,096,063	46,730,198
Common Stock, Shares Outstanding	47,096,063	46,730,198

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenues:
Total revenues	$ 407	$ 153	$ 744	$ 4,317
Operating expenses:
Research and development	21,572	13,557	59,359	38,633
General and administrative	6,531	5,821	20,596	14,247
Intangible asset impairment		3,500		3,500
Gain on fair value remeasurement of contingent consideration	0	(1,901)	(6,862)	(1,160)
Litigation settlement related loss			15,000
Total operating expenses	28,103	20,977	88,093	55,220
Operating loss	(27,696)	(20,824)	(87,349)	(50,903)
Investment and other income, net	912	145	1,511	313
Net loss before income tax benefit	(26,784)	(20,679)	(85,838)	(50,590)
Income tax benefit		227		227
Net loss	$ (26,784)	$ (20,452)	$ (85,838)	$ (50,363)
Basic net loss per common share	$ (0.57)	$ (0.45)	$ (1.83)	$ (1.21)
Diluted net loss per common share	$ (0.57)	$ (0.45)	$ (1.83)	$ (1.21)
Shares used in calculating basic net loss per share	46,916	45,453	46,806	41,582
Shares used in calculating diluted net loss per share	46,916	45,453	46,806	41,582
Comprehensive loss:
Net loss	$ (26,784)	$ (20,452)	$ (85,838)	$ (50,363)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities	305	(44)	(2,006)	(41)
Comprehensive loss	(26,479)	(20,496)	(87,844)	(50,404)
Product development and licensing agreements
Revenues:
Total revenues			30	29
Contracts and grants
Revenues:
Total revenues	$ 407	$ 153	$ 714	$ 4,288

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss	$ (20,452)	$ (85,838)	$ (50,363)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		2,223	2,291
Amortization and premium of marketable securities, net		1,366	(3,407)
Loss (gain) on sale or disposal of assets		1	(23)
Intangible asset impairment	3,500		3,500
Gain on fair value remeasurement of contingent consideration	(1,901)	(6,862)	(1,160)
Non-cash income tax benefit	(227)		(227)
Stock-based compensation expense		11,103	5,813
Changes in operating assets and liabilities:
Accounts and other receivables		(17)	1,549
Prepaid and other current assets		(7,928)	(2,261)
Accounts payable and accrued expenses		720	1,757
Other liabilities		3,262	(3,855)
Net cash used in operating activities		(81,970)	(46,386)
Cash flows from investing activities:
Sales and maturities of marketable securities		192,866	129,000
Purchases of marketable securities		(132,613)	(325,342)
Acquisition of property and equipment		(1,593)	(895)
Proceeds from sale or disposal of assets		69	25
Net cash provided by (used in) investing activities		58,729	(197,212)
Cash flows from financing activities:
Net proceeds from stock issuances			269,893
Proceeds from issuance of stock from employee benefit plans		2,681	2,053
Net cash provided by financing activities		2,681	271,946
Net (decrease) increase in cash and cash equivalents		(20,560)	28,348
Cash and cash equivalents at beginning of period		39,143	43,836
Cash and cash equivalents at end of period	$ 72,184	18,583	72,184
Non-cash investing activities
Accrued construction in progress		$ 38	$ 46

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2022
Basis of Presentation
Basis of Presentation	(1) Basis of Presentation ​ The accompanying unaudited condensed consolidated financial statements have been prepared by Celldex Therapeutics, Inc. (the “Company” or “Celldex”) in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and reflect the operations of the Company and its wholly-owned subsidiary. All intercompany balances and transactions have been eliminated in consolidation. ​ These interim financial statements do not include all the information and footnotes required by U.S. GAAP for annual financial statements and should be read in conjunction with the audited financial statements for the year ended December 31, 2021, which are included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 28, 2022. In the opinion of management, the interim financial statements reflect all normal recurring adjustments necessary to fairly state the Company’s financial position and results of operations for the interim periods presented. The year-end condensed balance sheet data presented for comparative purposes was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. ​ The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for any future interim period or the fiscal year ending December 31, 2022. ​ At September 30, 2022, the Company had cash, cash equivalents and marketable securities of $323.5 million. The Company has had recurring losses and incurred a loss of $85.8 million for the nine months ended September 30, 2022. Net cash used in operations for the nine months ended September 30, 2022 was $82.0 million. The Company believes that the cash, cash equivalents and marketable securities at the filing date of this Form 10-Q will be sufficient to meet estimated working capital requirements and fund planned operations for at least the next twelve months from the date of issuance of these financial statements. ​ During the next twelve months and beyond, the Company may take further steps to raise additional capital to meet its long-term liquidity needs including, but not limited to, one or more of the following: the licensing of drug candidates with existing or new collaborative partners, possible business combinations, issuance of debt, or the issuance of common stock or other securities via private placements or public offerings. Although the Company has been successful in raising capital in the past, there can be no assurance that additional financing will be available on acceptable terms, if at all, and the Company’s negotiating position in capital-raising efforts may worsen as existing resources are used. There is also no assurance that the Company will be able to enter into further collaborative relationships. Additional equity financings may be dilutive to the Company’s stockholders; debt financing, if available, may involve significant cash payment obligations and covenants that restrict the Company’s ability to operate as a business; and licensing or strategic collaborations may result in royalties or other terms which reduce the Company’s economic potential from products under development. The Company’s ability to continue funding its planned operations beyond twelve months from the issuance date is also dependent on the timing and manner of payment of amounts due under the Settlement Agreement with Shareholder Representative Services LLC (“SRS”) (refer to Note 13), in the event that the Company achieves the milestones related to those payments. The Company, at its option, may decide to pay those milestone payments in cash, shares of its common stock or a combination thereof. If the Company is unable to raise the funds necessary to meet its long-term liquidity needs, it may have to delay or discontinue the development of one or more programs, discontinue or delay ongoing or anticipated clinical trials, license out programs earlier than expected, raise funds at a significant discount or on other unfavorable terms, if at all, or sell all or a part of the Company. ​ COVID-19 continues to have an impact in the US and around the world. To date, we have managed delays and disruptions without significant impact in planned and ongoing preclinical and clinical trials, manufacturing or shipping. Potential impacts to our business include delays in planned and ongoing preclinical and clinical trials including enrollment of patients, disruptions in time and resources provided by independent clinical investigators, contract research organizations, and other third-party service providers, temporary closures of our facilities, disruptions or restrictions on our employees’ ability to travel, and delays in manufacturing and/or shipments to and from third-party suppliers and contract manufacturers for APIs and drug product. Any prolonged negative impacts to our business could materially impact our operating results and could lead to impairments of our intangible in-process research and development (“IPR&D”) assets with a carrying value of $27.2 million at September 30, 2022.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Significant Accounting Policies
Significant Accounting Policies	(2) Significant Accounting Policies ​ The significant accounting policies used in preparation of these condensed consolidated financial statements on Form 10-Q for the three and nine months ended September 30, 2022 are consistent with those discussed in Note 2 to the financial statements in our Annual Report on Form 10-K for the year ended December 31, 2021. ​ Recent Accounting Pronouncements ​ From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s consolidated financial statements upon adoption. ​ In June 2016, the FASB issued guidance on the Measurement of Credit Losses on Financial Instruments. The guidance requires that credit losses be reported using an expected losses model rather than the incurred losses model that is currently used, and establishes additional disclosures related to credit risks. For available-for-sale debt securities with unrealized losses, the standard now requires allowances to be recorded instead of reducing the amortized cost of the investment. This standard will be effective for the Company on January 1, 2023. The adoption of this new guidance is not expected to have a material impact on the Company’s consolidated financial statements and related disclosures. ​ ​

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2022
Fair Value Measurements
Fair Value Measurements	(3) Fair Value Measurements ​ The following tables set forth the Company’s financial assets and liabilities subject to fair value measurements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 Level 1 Level 2 Level 3 ​ ​ (In thousands) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds and cash equivalents ​ $ 10,729 ​ ​ — ​ $ 10,729 ​ ​ — Marketable securities ​ ​ 304,888 ​ ​ — ​ ​ 304,888 ​ ​ — ​ ​ $ 315,617 ​ ​ — ​ $ 315,617 ​ ​ — Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Kolltan acquisition contingent consideration ​ $ — ​ ​ — ​ ​ — ​ $ — ​ ​ $ — ​ ​ — ​ ​ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 Level 1 Level 2 Level 3 ​ ​ (In thousands) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds and cash equivalents ​ $ 26,220 ​ ​ — ​ $ 26,220 ​ ​ — Marketable securities ​ ​ 369,107 ​ ​ — ​ ​ 369,107 ​ ​ — ​ ​ $ 395,327 ​ ​ — ​ $ 395,327 ​ ​ — Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Kolltan acquisition contingent consideration ​ $ 6,862 ​ ​ — ​ ​ — ​ $ 6,862 ​ ​ $ 6,862 ​ ​ — ​ ​ — ​ $ 6,862 ​ The Company’s financial assets consist mainly of money market funds, cash equivalents and marketable securities and are classified as Level 2 within the valuation hierarchy. The Company values its marketable securities utilizing independent pricing services which normally derive security prices from recently reported trades for identical or similar securities, making adjustments based on significant observable transactions. At each balance sheet date, observable market inputs may include trade information, broker or dealer quotes, bids, offers or a combination of these data sources. ​ The following table reflects the activity for the Company’s contingent consideration liabilities measured at fair value using Level 3 inputs for the nine months ended September 30, 2022 (in thousands): ​ ​ ​ ​ ​ ​ ​ Other Liabilities: ​ ​ Contingent ​ Consideration Balance at December 31, 2021 ​ $ 6,862 Fair value adjustments included in operating expenses ​ (6,862) Balance at September 30, 2022 ​ $ — ​ The valuation technique used to measure fair value of the Company’s Level 3 liabilities, which consist of contingent consideration related to the acquisition of Kolltan Pharmaceuticals, Inc. (“Kolltan”) in 2016, was primarily an income approach. The significant unobservable inputs used in the fair value measurement of the contingent consideration are estimates including probability of success, discount rates and amount of time until the conditions of the milestone payments are met. ​ During the three and nine months ended September 30, 2022, the Company recorded a $0.0 million and $6.9 million gain on fair value remeasurement of contingent consideration, respectively, primarily due to the Company’s decision to deprioritize the CDX-1140 program. During the three and nine months ended September 30, 2021, the Company recorded a $1.9 million and $1.2 million gain on fair value remeasurement of contingent consideration, respectively, primarily due to updated assumptions for the TAM program, changes in discount rates and the passage of time. The assumptions related to determining the fair value of contingent consideration include a significant amount of judgment, and any changes in the underlying estimates could have a material impact on the amount of contingent consideration adjustment recorded in any given period. ​ The Company did not have any transfers in or out of Level 3 assets liabilities during

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2022
Marketable Securities
Marketable Securities	(4) Marketable Securities ​ The following is a summary of marketable debt securities, classified as available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Unrealized ​ ​ Amortized ​ ​ ​ ​ ​ ​ ​ Fair ​ Cost Gains Losses Value ​ ​ (In thousands) September 30, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Marketable securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and municipal obligations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturing in one year or less ​ $ 132,422 ​ $ — ​ $ (1,042) ​ $ 131,380 Maturing after one year through three years ​ ​ 3,912 ​ ​ — ​ ​ (71) ​ ​ 3,841 Total U.S. government and municipal obligations ​ $ 136,334 ​ $ — ​ $ (1,113) ​ $ 135,221 Corporate debt securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturing in one year or less ​ $ 168,698 ​ $ — ​ $ (1,548) ​ $ 167,150 Maturing after one year through three years ​ ​ 2,564 ​ ​ — ​ ​ (47) ​ ​ 2,517 Total corporate debt securities ​ $ 171,262 ​ $ — ​ $ (1,595) ​ $ 169,667 Total marketable securities ​ $ 307,596 ​ $ — ​ $ (2,708) ​ $ 304,888 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Unrealized ​ ​ Amortized ​ ​ ​ ​ ​ ​ ​ Fair ​ ​ Cost Gains Losses Value ​ ​ (In thousands) December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Marketable securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and municipal obligations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturing in one year or less ​ $ 80,674 ​ $ — ​ $ (133) ​ $ 80,541 Maturing after one year through three years ​ ​ 51,319 ​ ​ — ​ ​ (184) ​ ​ 51,135 Total U.S. government and municipal obligations ​ $ 131,993 ​ $ — ​ $ (317) ​ $ 131,676 Corporate debt securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturing in one year or less ​ $ 170,034 ​ $ — ​ $ (28) ​ $ 170,006 Maturing after one year through three years ​ ​ 67,782 ​ ​ — ​ ​ (357) ​ ​ 67,425 Total corporate debt securities ​ $ 237,816 ​ $ — ​ $ (385) ​ $ 237,431 Total marketable securities ​ $ 369,809 ​ $ — ​ $ (702) ​ $ 369,107 ​ The Company holds investment-grade marketable securities, and none were in a continuous unrealized loss position for more than twelve months as of September 30, 2022 and December 31, 2021. The unrealized losses are attributable to changes in interest rates and the Company does not believe any unrealized losses represent other-than-temporary impairments. Marketable securities include $0.7 million and $1.3 million in accrued interest at September 30, 2022 and December 31, 2021, respectively.

Intangible Assets

Intangible Assets	9 Months Ended
	Sep. 30, 2022
Intangible Assets
Intangible Assets	(5) Intangible Assets ​ At September 30, 2022 and December 31, 2021, the carrying value of the Company’s indefinite-lived intangible assets was $27.2 million. Indefinite-lived intangible assets consist of acquired IPR&D related to the development of the anti-KIT program, including barzolvolimab (also referred to as CDX-0159), which was recorded in connection with the Kolltan acquisition. Barzolvolimab is in Phase 2 development. As of September 30, 2022, the IPR&D asset related to the anti-KIT program had not reached technological feasibility nor did the asset have alternative future uses. ​ The Company performs an impairment test on IPR&D assets at least annually, or more frequently if events or changes in circumstances indicate that IPR&D assets may be impaired. Due to the nature of IPR&D projects, the Company may experience future delays or failures to obtain regulatory approvals to conduct clinical trials, failures of such clinical trials or other failures to achieve a commercially viable product, and as a result, may recognize further impairment losses in the future. ​

Other Long-Term Liabilities

Other Long-Term Liabilities	9 Months Ended
	Sep. 30, 2022
Other Long-Term Liabilities
Other Long-Term Liabilities	(6) Other Long-Term Liabilities ​ Other long-term liabilities include the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2022 ​ 2021 ​ ​ (In thousands) Net deferred tax liabilities related to IPR&D (Note 11) ​ $ 1,613 ​ $ 1,613 Deferred Income From Sale of Tax Benefits ​ 4,650 ​ — Contingent milestones (Note 3 and Note 13) ​ ​ — ​ ​ 6,862 Deferred revenue (Note 10) ​ 222 ​ 433 Total ​ 6,485 ​ 8,908 Less current portion ​ (1,152) ​ (1,554) Long-term portion ​ $ 5,333 ​ $ 7,354 ​ In March 2022, the Company received approval from the New Jersey Economic Development Authority and agreed to sell New Jersey tax benefits of $5.0 million to an independent third party for $4.7 million. Under the agreement, the Company must maintain a base of operations in New Jersey for five years or the tax benefits must be paid back on a pro-rata basis based on the number of years completed.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2022
Stockholders' Equity
Stockholders' Equity	(7) Stockholders’ Equity ​ In May 2016, the Company entered into a controlled equity offering sales agreement (the “Cantor Agreement”) with Cantor Fitzgerald & Co. (“Cantor”) to allow the Company to issue and sell shares of its common stock from time to time through Cantor, acting as agent. At September 30, 2022, the Company had $50.0 million remaining in aggregate gross offering price available under the Company’s November 2020 prospectus. ​ The changes in Stockholders’ Equity during the three and nine months ended September 30, 2022 and 2021 are summarized below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ Common ​ Common ​ Additional ​ Other ​ ​ ​ ​ Total ​ ​ Stock ​ Stock Par ​ Paid-In ​ Comprehensive ​ Accumulated ​ Stockholders’ ​ Shares Value Capital Income Deficit Equity Consolidated balance at December 31, 2021 46,730,198 $ 47 $ 1,561,142 $ 1,894 $ (1,143,607) $ 419,476 Shares issued under stock option and employee stock purchase plans 24,150 — 304 — — 304 Stock-based compensation — — 3,153 — — 3,153 Unrealized loss on marketable securities — — — (1,782) — (1,782) Net loss — — — — (23,050) (23,050) Consolidated balance at March 31, 2022 46,754,348 $ 47 $ 1,564,599 $ 112 $ (1,166,657) $ 398,101 Shares issued under stock option and employee stock purchase plans ​ 10,355 ​ ​ — ​ ​ 71 ​ ​ — ​ ​ — ​ ​ 71 Stock-based compensation ​ — ​ ​ — ​ ​ 3,454 ​ ​ — ​ ​ — ​ ​ 3,454 Unrealized loss on marketable securities ​ — ​ ​ — ​ ​ — ​ ​ (529) ​ ​ — ​ ​ (529) Net loss ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (36,004) ​ ​ (36,004) Consolidated balance at June 30, 2022 ​ 46,764,703 ​ $ 47 ​ $ 1,568,124 ​ $ (417) ​ $ (1,202,661) ​ $ 365,093 Shares issued under stock option and employee stock purchase plans ​ 331,360 ​ ​ — ​ ​ 2,306 ​ ​ — ​ ​ — ​ ​ 2,306 Stock-based compensation ​ — ​ ​ — ​ ​ 4,496 ​ ​ — ​ ​ — ​ ​ 4,496 Unrealized gain on marketable securities ​ — ​ ​ — ​ ​ — ​ ​ 305 ​ ​ — ​ ​ 305 Net loss ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (26,784) ​ ​ (26,784) Consolidated balance at September 30, 2022 ​ 47,096,063 ​ $ 47 ​ $ 1,574,926 ​ $ (112) ​ $ (1,229,445) ​ $ 345,416 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ Common ​ Common ​ Additional ​ Other ​ ​ ​ ​ Total ​ ​ Stock ​ Stock Par ​ Paid-In ​ Comprehensive ​ Accumulated ​ Stockholders’ ​ ​ Shares ​ Value ​ Capital ​ Income ​ Deficit ​ Equity ​ ​ (In thousands, except share amounts) Consolidated balance at December 31, 2020 39,603,771 ​ $ 40 ​ $ 1,279,824 ​ $ 2,589 ​ $ (1,073,096) ​ $ 209,357 Shares issued under stock option and employee stock purchase plans 10,867 ​ — ​ 74 ​ — ​ — ​ 74 Stock-based compensation — ​ — ​ 1,275 ​ — ​ — ​ 1,275 Unrealized loss on marketable securities — ​ — ​ — ​ (2) ​ — ​ (2) Net loss — ​ — ​ — ​ — ​ (16,538) ​ (16,538) Consolidated balance at March 31, 2021 39,614,638 ​ $ 40 ​ $ 1,281,173 ​ $ 2,587 ​ $ (1,089,634) ​ $ 194,166 Shares issued under stock option and employee stock purchase plans 2,058 ​ — ​ (25) ​ — ​ — ​ (25) Stock-based compensation — ​ — ​ 1,509 ​ — ​ — ​ 1,509 Unrealized gain on marketable securities — ​ — ​ — ​ 5 ​ — ​ 5 Net loss — ​ — ​ — ​ — ​ (13,373) ​ (13,373) Consolidated balance at June 30, 2021 39,616,696 ​ $ 40 ​ $ 1,282,657 ​ $ 2,592 ​ $ (1,103,007) ​ $ 182,282 Shares issued under stock option and employee stock purchase plans ​ 201,406 ​ ​ — ​ ​ 2,004 ​ ​ — ​ ​ — ​ ​ 2,004 Shares issued in underwritten offering, net ​ 6,845,238 ​ ​ 7 ​ ​ 269,886 ​ ​ — ​ ​ — ​ ​ 269,893 Stock-based compensation ​ — ​ ​ — ​ ​ 3,029 ​ ​ — ​ ​ — ​ ​ 3,029 Unrealized loss on marketable securities ​ — ​ ​ — ​ ​ — ​ ​ (44) ​ ​ — ​ ​ (44) Net loss ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (20,452) ​ ​ (20,452) Consolidated balance at September 30, 2021 ​ 46,663,340 ​ $ 47 ​ $ 1,557,576 ​ $ 2,548 ​ $ (1,123,459) ​ $ 436,712 ​

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2022
Stock-Based Compensation
Stock-Based Compensation	(8) Stock-Based Compensation ​ A summary of stock option activity for the nine months ended September 30, 2022 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Weighted ​ ​ ​ ​ Average ​ Average ​ ​ ​ ​ Exercise ​ Remaining ​ ​ ​ ​ Price ​ Contractual ​ Shares Per Share Term (In Years) Options outstanding at December 31, 2021 4,077,667 ​ $ 30.02 ​ 8.0 Granted 1,584,900 ​ $ 22.89 ​ ​ Exercised (353,622) ​ $ 6.71 ​ ​ Canceled (118,974) ​ $ 50.12 ​ ​ Options outstanding at September 30, 2022 5,189,971 ​ $ 28.97 ​ 8.07 Options vested and expected to vest at September 30, 2022 5,031,072 ​ $ 29.21 ​ 8.05 Options exercisable at September 30, 2022 1,985,506 ​ $ 41.56 ​ 6.74 Shares available for grant under the 2021 Plan 1,838,291 ​ ​ ​ ​ ​ ​ The weighted average grant-date fair value of stock options granted during the three and nine months ended September 30, 2022 was $25.38 and $17.36, respectively. ​ The aggregate intrinsic value of stock options vested and expected to vest at September 30, 2022 was $45.6 million. The aggregate intrinsic value of stock options exercisable at September 30, 2022 was $23.6 million. As of September 30, 2022, total compensation cost related to non-vested employee, consultant and non-employee director stock options not yet recognized was approximately $46.7 million, net of estimated forfeitures, which is expected to be recognized as expense over a weighted average period of 2.8 ​ Stock-based compensation expense for the three and nine months ended September 30, 2022 and 2021 was recorded as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, ​ Nine months ended September 30, ​ 2022 2021 2022 2021 ​ ​ (In thousands) ​ (In thousands) Research and development ​ $ 2,342 ​ $ 1,504 ​ $ 5,754 ​ $ 2,927 General and administrative ​ 2,154 ​ 1,525 ​ 5,349 ​ 2,886 Total stock-based compensation expense ​ $ 4,496 ​ $ 3,029 ​ $ 11,103 ​ $ 5,813 ​ The fair values of employee, consultant and non-employee director stock options granted during the three and nine months ended September 30, 2022 and 2021 were valued using the Black-Scholes option pricing model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, ​ Nine months ended September 30, 2022 2021 2022 2021 Expected stock price volatility 91% ​ 98% ​ 90 – 97% ​ 97 – 98% Expected option term 6.0 Years ​ 6.0 Years ​ 6.0 Years ​ 6.0 Years Risk-free interest rate 2.9 – 3.5% ​ 1.1 – 1.2% ​ 1.7 – 3.6% ​ 0.8 – 1.3% Expected dividend yield None ​ None ​ None ​ None ​

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 30, 2022
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income	(9) Accumulated Other Comprehensive Income ​ The changes in accumulated other comprehensive income, which is reported as a component of stockholders’ equity, for the nine months ended September 30, 2022 are summarized below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ ​ ​ ​ Loss on ​ ​ ​ ​ ​ ​ ​ ​ Marketable ​ Foreign ​ ​ ​ ​ Securities Currency Items Total ​ ​ (In thousands) Balance at December 31, 2021 ​ $ (702) ​ $ 2,596 ​ $ 1,894 Other comprehensive loss ​ (2,006) ​ — ​ (2,006) Balance at September 30, 2022 ​ $ (2,708) ​ $ 2,596 ​ $ (112) ​ No amounts were reclassified out of accumulated other comprehensive income during the nine months ended September 30, 2022.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2022
Revenue.
Revenue	(10) Revenue ​ Contract and Grants Revenue ​ The Company has entered into agreements with Rockefeller University and Gilead Sciences pursuant to which the Company performs manufacturing and research and development services on a time-and-materials basis or at a negotiated fixed-price. The Company recognized $0.0 million and $0.2 million in revenue under these agreements during the three and nine months ended September 30, 2022, respectively, and $0.1 million and $4.0 million during the three and nine months ended September 30, 2021, respectively. ​ Contract Assets and Liabilities ​ At September 30, 2022 and December 31, 2021, the Company’s right to consideration under all contracts was considered unconditional, and as such, there were no recorded contract assets. At September 30, 2022, the Company had $0.2 million in contract liabilities recorded, which is expected to be recognized during the next 12 months as manufacturing and research and development services are performed. At December 31, 2021, the Company had $0.4 million in contract liabilities recorded. Revenue recognized from contract liabilities as of December 31, 2021 during the three and nine months ended September 30, 2022 was $0.2 million and $0.4 million, respectively.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2022
Income Taxes
Income Taxes	(11) Income Taxes ​ The Company has evaluated the positive and negative evidence bearing upon the realizability of its net deferred tax assets and considered its history of losses, ultimately concluding that it is “more likely than not” that the Company will not recognize the benefits of federal, state and foreign deferred tax assets and, as such, has maintained a full valuation allowance on its deferred tax assets as of September 30, 2022 and December 31, 2021. ​ The net deferred tax liability of $1.6 million at September 30, 2022 and December 31, 2021 relates to the temporary differences associated with the IPR&D intangible assets acquired in previous business combinations and is not deductible for tax purposes. Massachusetts, New Jersey, New York and Connecticut are the jurisdictions in which the Company primarily operates or has operated and has income tax nexus. The Company is not currently under examination by these or any other jurisdictions for any tax year.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2022
Net Loss Per Share
Net Loss Per Share	(12) Net Loss Per Share ​ Basic net loss per common share is based upon the weighted-average number of common shares outstanding during the period, excluding restricted stock that has been issued but is not yet vested. Diluted net loss per common share is based upon the weighted-average number of common shares outstanding during the period plus additional weighted-average potentially dilutive common shares outstanding during the period when the effect is dilutive. In periods in which the Company reports a net loss, there is no difference between basic and diluted net loss per share because dilutive shares of common stock are not assumed to have been issued as their effect is anti-dilutive. The potentially dilutive common shares that have not been included in the net loss per common share calculations because the effect would have been anti-dilutive are as follows: ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ 2022 2021 Stock Options 5,189,971 4,129,626 Restricted Stock — — ​ 5,189,971 4,129,626 ​

Kolltan Acquisition

Kolltan Acquisition	9 Months Ended
	Sep. 30, 2022
Kolltan Acquisition
Kolltan Acquisition	(13) Kolltan Acquisition ​ On November 29, 2016, the Company acquired all of the share and debt interests of Kolltan, a clinical-stage biopharmaceutical company, in exchange for 1,217,200 shares of the Company’s common stock plus contingent consideration in the form of development, regulatory approval and sales-based milestones (“Kolltan Milestones”) of up to $172.5 million payable in cash, in shares of Celldex’s common stock or a combination of both, in the sole discretion of Celldex and subject to provisions of the Agreement and Plan of Merger, dated November 1, 2016 (the “Merger Agreement”). ​ In October 2019, the Company received a letter from SRS, the hired representative of the former stockholders of Kolltan, notifying the Company that it objected to the Company’s characterization of the development, regulatory approval and sales-based Kolltan Milestones relating to CDX-0158 as having been abandoned and contending instead that the related milestone payments are due from Celldex to the Kolltan stockholder. ​ On August 18, 2020, Celldex filed a Verified Complaint in the Court of Chancery of the State of Delaware against SRS (acting in its capacity as the representative of the former stockholders of Kolltan pursuant to the Merger Agreement) seeking declaratory relief with respect to the rights and obligations of the parties relating to certain contingent milestone payments under the Merger Agreement relating to the discontinued CDX-0158 program (the “Litigation”). ​ On June 20, 2022, the Company entered into a binding settlement term sheet (the “Term Sheet”) with SRS, related to the Litigation, which, upon execution of a definitive settlement agreement and the payment of the Initial Payment (as defined below), would result in the joint dismissal, with prejudice, of all claims and counterclaims in the Litigation. The definitive settlement agreement between the Company and SRS was executed on July 15, 2022 (the “Settlement Agreement”) and the Company and SRS jointly filed a Stipulation of Dismissal with prejudice relating to the Litigation on July 19, 2022. ​ Pursuant to the terms of the Term Sheet and the Settlement Agreement, all milestone payments provided for by the Merger Agreement are replaced in their entirety with the following payments, each of which is payable only once: ​ (i) The Company paid $15.0 million upon execution of the Settlement Agreement (the “Initial Payment”). ​ (ii) The Company shall pay $15.0 million upon the Successful Completion (as defined in the Term Sheet) of a Phase 2 Clinical Trial (as defined in the Merger Agreement) of CDX-0159, subject to the $2.5 million contractual credit as set forth in the Merger Agreement. ​ (iii) The Company shall pay $52.5 million upon the first United States Food and Drug Administration or European Medicines Agency, or, in each case, any successor organization, regulatory approval of a Surviving Company Product (as defined the Term Sheet). ​ The above payment obligations replace, in their entirety, the contingent consideration in the form of development, regulatory approval and sales-based milestones of up to $172.5 million contained in the Merger Agreement. ​ Under the Settlement Agreement, each of the Company and SRS provided broad mutual releases of all claims relating to or arising out of the Merger Agreement, including without limitation, all claims brought in the Litigation or that could have been brought in the Litigation. ​ The Company paid the Initial Payment in cash during the three months ended September 30, 2022. Any future milestone payments related to the CDX-0159 program, which was subject to the Litigation, will be recorded when and if payment becomes probable and reasonably estimable in accordance with the loss contingency model under ASC 450. Milestones related to the remaining Surviving Company Products are measured at fair value (refer to Note 3). When and if any of the remaining payments described above become due, they shall be payable, at the Company’s sole election, in either cash or stock (as set forth in the Merger Agreement) or a combination thereof.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Significant Accounting Policies
Recent Accounting Pronouncements	Recent Accounting Pronouncements ​ From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s consolidated financial statements upon adoption. ​ In June 2016, the FASB issued guidance on the Measurement of Credit Losses on Financial Instruments. The guidance requires that credit losses be reported using an expected losses model rather than the incurred losses model that is currently used, and establishes additional disclosures related to credit risks. For available-for-sale debt securities with unrealized losses, the standard now requires allowances to be recorded instead of reducing the amortized cost of the investment. This standard will be effective for the Company on January 1, 2023. The adoption of this new guidance is not expected to have a material impact on the Company’s consolidated financial statements and related disclosures.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Measurements
Schedule of financial assets and liabilities subject to fair value measurements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 Level 1 Level 2 Level 3 ​ ​ (In thousands) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds and cash equivalents ​ $ 10,729 ​ ​ — ​ $ 10,729 ​ ​ — Marketable securities ​ ​ 304,888 ​ ​ — ​ ​ 304,888 ​ ​ — ​ ​ $ 315,617 ​ ​ — ​ $ 315,617 ​ ​ — Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Kolltan acquisition contingent consideration ​ $ — ​ ​ — ​ ​ — ​ $ — ​ ​ $ — ​ ​ — ​ ​ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 Level 1 Level 2 Level 3 ​ ​ (In thousands) Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds and cash equivalents ​ $ 26,220 ​ ​ — ​ $ 26,220 ​ ​ — Marketable securities ​ ​ 369,107 ​ ​ — ​ ​ 369,107 ​ ​ — ​ ​ $ 395,327 ​ ​ — ​ $ 395,327 ​ ​ — Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Kolltan acquisition contingent consideration ​ $ 6,862 ​ ​ — ​ ​ — ​ $ 6,862 ​ ​ $ 6,862 ​ ​ — ​ ​ — ​ $ 6,862
Schedule of the contingent consideration liabilities measured at fair value using Level 3 inputs	The following table reflects the activity for the Company’s contingent consideration liabilities measured at fair value using Level 3 inputs for the nine months ended September 30, 2022 (in thousands): ​ ​ ​ ​ ​ ​ ​ Other Liabilities: ​ ​ Contingent ​ Consideration Balance at December 31, 2021 ​ $ 6,862 Fair value adjustments included in operating expenses ​ (6,862) Balance at September 30, 2022 ​ $ —

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2022
Marketable Securities
Schedule of marketable debt securities, classified as available-for-sale	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Unrealized ​ ​ Amortized ​ ​ ​ ​ ​ ​ ​ Fair ​ Cost Gains Losses Value ​ ​ (In thousands) September 30, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Marketable securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and municipal obligations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturing in one year or less ​ $ 132,422 ​ $ — ​ $ (1,042) ​ $ 131,380 Maturing after one year through three years ​ ​ 3,912 ​ ​ — ​ ​ (71) ​ ​ 3,841 Total U.S. government and municipal obligations ​ $ 136,334 ​ $ — ​ $ (1,113) ​ $ 135,221 Corporate debt securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturing in one year or less ​ $ 168,698 ​ $ — ​ $ (1,548) ​ $ 167,150 Maturing after one year through three years ​ ​ 2,564 ​ ​ — ​ ​ (47) ​ ​ 2,517 Total corporate debt securities ​ $ 171,262 ​ $ — ​ $ (1,595) ​ $ 169,667 Total marketable securities ​ $ 307,596 ​ $ — ​ $ (2,708) ​ $ 304,888 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Unrealized ​ ​ Amortized ​ ​ ​ ​ ​ ​ ​ Fair ​ ​ Cost Gains Losses Value ​ ​ (In thousands) December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Marketable securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and municipal obligations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturing in one year or less ​ $ 80,674 ​ $ — ​ $ (133) ​ $ 80,541 Maturing after one year through three years ​ ​ 51,319 ​ ​ — ​ ​ (184) ​ ​ 51,135 Total U.S. government and municipal obligations ​ $ 131,993 ​ $ — ​ $ (317) ​ $ 131,676 Corporate debt securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturing in one year or less ​ $ 170,034 ​ $ — ​ $ (28) ​ $ 170,006 Maturing after one year through three years ​ ​ 67,782 ​ ​ — ​ ​ (357) ​ ​ 67,425 Total corporate debt securities ​ $ 237,816 ​ $ — ​ $ (385) ​ $ 237,431 Total marketable securities ​ $ 369,809 ​ $ — ​ $ (702) ​ $ 369,107

Other Long-Term Liabilities (Ta

Other Long-Term Liabilities (Tables)	9 Months Ended
	Sep. 30, 2022
Other Long-Term Liabilities
Schedule of other long-term liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2022 ​ 2021 ​ ​ (In thousands) Net deferred tax liabilities related to IPR&D (Note 11) ​ $ 1,613 ​ $ 1,613 Deferred Income From Sale of Tax Benefits ​ 4,650 ​ — Contingent milestones (Note 3 and Note 13) ​ ​ — ​ ​ 6,862 Deferred revenue (Note 10) ​ 222 ​ 433 Total ​ 6,485 ​ 8,908 Less current portion ​ (1,152) ​ (1,554) Long-term portion ​ $ 5,333 ​ $ 7,354

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2022
Stockholders' Equity
Schedule of Shareholder's equity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ Common ​ Common ​ Additional ​ Other ​ ​ ​ ​ Total ​ ​ Stock ​ Stock Par ​ Paid-In ​ Comprehensive ​ Accumulated ​ Stockholders’ ​ Shares Value Capital Income Deficit Equity Consolidated balance at December 31, 2021 46,730,198 $ 47 $ 1,561,142 $ 1,894 $ (1,143,607) $ 419,476 Shares issued under stock option and employee stock purchase plans 24,150 — 304 — — 304 Stock-based compensation — — 3,153 — — 3,153 Unrealized loss on marketable securities — — — (1,782) — (1,782) Net loss — — — — (23,050) (23,050) Consolidated balance at March 31, 2022 46,754,348 $ 47 $ 1,564,599 $ 112 $ (1,166,657) $ 398,101 Shares issued under stock option and employee stock purchase plans ​ 10,355 ​ ​ — ​ ​ 71 ​ ​ — ​ ​ — ​ ​ 71 Stock-based compensation ​ — ​ ​ — ​ ​ 3,454 ​ ​ — ​ ​ — ​ ​ 3,454 Unrealized loss on marketable securities ​ — ​ ​ — ​ ​ — ​ ​ (529) ​ ​ — ​ ​ (529) Net loss ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (36,004) ​ ​ (36,004) Consolidated balance at June 30, 2022 ​ 46,764,703 ​ $ 47 ​ $ 1,568,124 ​ $ (417) ​ $ (1,202,661) ​ $ 365,093 Shares issued under stock option and employee stock purchase plans ​ 331,360 ​ ​ — ​ ​ 2,306 ​ ​ — ​ ​ — ​ ​ 2,306 Stock-based compensation ​ — ​ ​ — ​ ​ 4,496 ​ ​ — ​ ​ — ​ ​ 4,496 Unrealized gain on marketable securities ​ — ​ ​ — ​ ​ — ​ ​ 305 ​ ​ — ​ ​ 305 Net loss ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (26,784) ​ ​ (26,784) Consolidated balance at September 30, 2022 ​ 47,096,063 ​ $ 47 ​ $ 1,574,926 ​ $ (112) ​ $ (1,229,445) ​ $ 345,416 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ Common ​ Common ​ Additional ​ Other ​ ​ ​ ​ Total ​ ​ Stock ​ Stock Par ​ Paid-In ​ Comprehensive ​ Accumulated ​ Stockholders’ ​ ​ Shares ​ Value ​ Capital ​ Income ​ Deficit ​ Equity ​ ​ (In thousands, except share amounts) Consolidated balance at December 31, 2020 39,603,771 ​ $ 40 ​ $ 1,279,824 ​ $ 2,589 ​ $ (1,073,096) ​ $ 209,357 Shares issued under stock option and employee stock purchase plans 10,867 ​ — ​ 74 ​ — ​ — ​ 74 Stock-based compensation — ​ — ​ 1,275 ​ — ​ — ​ 1,275 Unrealized loss on marketable securities — ​ — ​ — ​ (2) ​ — ​ (2) Net loss — ​ — ​ — ​ — ​ (16,538) ​ (16,538) Consolidated balance at March 31, 2021 39,614,638 ​ $ 40 ​ $ 1,281,173 ​ $ 2,587 ​ $ (1,089,634) ​ $ 194,166 Shares issued under stock option and employee stock purchase plans 2,058 ​ — ​ (25) ​ — ​ — ​ (25) Stock-based compensation — ​ — ​ 1,509 ​ — ​ — ​ 1,509 Unrealized gain on marketable securities — ​ — ​ — ​ 5 ​ — ​ 5 Net loss — ​ — ​ — ​ — ​ (13,373) ​ (13,373) Consolidated balance at June 30, 2021 39,616,696 ​ $ 40 ​ $ 1,282,657 ​ $ 2,592 ​ $ (1,103,007) ​ $ 182,282 Shares issued under stock option and employee stock purchase plans ​ 201,406 ​ ​ — ​ ​ 2,004 ​ ​ — ​ ​ — ​ ​ 2,004 Shares issued in underwritten offering, net ​ 6,845,238 ​ ​ 7 ​ ​ 269,886 ​ ​ — ​ ​ — ​ ​ 269,893 Stock-based compensation ​ — ​ ​ — ​ ​ 3,029 ​ ​ — ​ ​ — ​ ​ 3,029 Unrealized loss on marketable securities ​ — ​ ​ — ​ ​ — ​ ​ (44) ​ ​ — ​ ​ (44) Net loss ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (20,452) ​ ​ (20,452) Consolidated balance at September 30, 2021 ​ 46,663,340 ​ $ 47 ​ $ 1,557,576 ​ $ 2,548 ​ $ (1,123,459) ​ $ 436,712

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Stock-Based Compensation
Schedule of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Weighted ​ ​ ​ ​ Average ​ Average ​ ​ ​ ​ Exercise ​ Remaining ​ ​ ​ ​ Price ​ Contractual ​ Shares Per Share Term (In Years) Options outstanding at December 31, 2021 4,077,667 ​ $ 30.02 ​ 8.0 Granted 1,584,900 ​ $ 22.89 ​ ​ Exercised (353,622) ​ $ 6.71 ​ ​ Canceled (118,974) ​ $ 50.12 ​ ​ Options outstanding at September 30, 2022 5,189,971 ​ $ 28.97 ​ 8.07 Options vested and expected to vest at September 30, 2022 5,031,072 ​ $ 29.21 ​ 8.05 Options exercisable at September 30, 2022 1,985,506 ​ $ 41.56 ​ 6.74 Shares available for grant under the 2021 Plan 1,838,291 ​ ​ ​ ​ ​ ​
Schedule of stock-based compensation expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, ​ Nine months ended September 30, ​ 2022 2021 2022 2021 ​ ​ (In thousands) ​ (In thousands) Research and development ​ $ 2,342 ​ $ 1,504 ​ $ 5,754 ​ $ 2,927 General and administrative ​ 2,154 ​ 1,525 ​ 5,349 ​ 2,886 Total stock-based compensation expense ​ $ 4,496 ​ $ 3,029 ​ $ 11,103 ​ $ 5,813 ​
Schedule of assumptions used for the fair value of employee stock options granted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three months ended September 30, ​ Nine months ended September 30, 2022 2021 2022 2021 Expected stock price volatility 91% ​ 98% ​ 90 – 97% ​ 97 – 98% Expected option term 6.0 Years ​ 6.0 Years ​ 6.0 Years ​ 6.0 Years Risk-free interest rate 2.9 – 3.5% ​ 1.1 – 1.2% ​ 1.7 – 3.6% ​ 0.8 – 1.3% Expected dividend yield None ​ None ​ None ​ None

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2022
Accumulated Other Comprehensive Income
Schedule of changes in accumulated other comprehensive income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ ​ ​ ​ ​ Loss on ​ ​ ​ ​ ​ ​ ​ ​ Marketable ​ Foreign ​ ​ ​ ​ Securities Currency Items Total ​ ​ (In thousands) Balance at December 31, 2021 ​ $ (702) ​ $ 2,596 ​ $ 1,894 Other comprehensive loss ​ (2,006) ​ — ​ (2,006) Balance at September 30, 2022 ​ $ (2,708) ​ $ 2,596 ​ $ (112)

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2022
Net Loss Per Share
Schedule of potentially dilutive common shares that have not been included in the net loss per common share calculations because the effect would have been anti-dilutive	​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ 2022 2021 Stock Options 5,189,971 4,129,626 Restricted Stock — — ​ 5,189,971 4,129,626

Basis of Presentation (Details)

Basis of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Basis of Presentation
Cash, cash equivalents and marketable securities	$ 323,500						$ 323,500
Net loss	(26,784)	$ (36,004)	$ (23,050)	$ (20,452)	$ (13,373)	$ (16,538)	(85,838)	$ (50,363)
Net cash used in operations							(81,970)	$ (46,386)
Indefinite-lived intangible assets	$ 27,200						$ 27,200		$ 27,200

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Liabilities:
Kolltan acquisition contingent consideration		$ 6,862
Fair value | Level 3
Liabilities:
Kolltan acquisition contingent consideration	$ 0	6,862
Fair Value Measurements. | Level 1
Liabilities:
Kolltan acquisition contingent consideration	0
Total financial liabilities at fair value	0
Fair Value Measurements. | Level 2
Assets:
Money market funds and cash equivalents	10,729	26,220
Marketable securities	304,888	369,107
Total financial assets at fair value	315,617	395,327
Liabilities:
Kolltan acquisition contingent consideration	0
Total financial liabilities at fair value	0
Fair Value Measurements. | Level 3
Liabilities:
Kolltan acquisition contingent consideration	0	6,862
Total financial liabilities at fair value	0	6,862
Fair Value Measurements. | Fair value
Assets:
Money market funds and cash equivalents	10,729	26,220
Marketable securities	304,888	369,107
Total financial assets at fair value	315,617	395,327
Liabilities:
Kolltan acquisition contingent consideration	0	6,862
Total financial liabilities at fair value	$ 0	$ 6,862

Fair Value Measurements - Conti

Fair Value Measurements - Contingent Consideration Liabilities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)
Contingent consideration liabilities measured at fair value
Balance at beginning of period	$ 6,862
Fair value | Level 3
Contingent consideration liabilities measured at fair value
Balance at beginning of period	6,862
Fair value adjustments included in operating expenses	(6,862)
Balance at end of period	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Fair value measurements
Gain on Fair Value Remeasurement of Contingent Consideration	$ 0	$ 1,901	$ 6,862	$ 1,160
Fair value
Fair value measurements
Asset transfer out of level 3			0
Asset transfer into level 3			0
Liabilities transfers out of level 3			$ 0

Marketable Securities (Details)

Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized Cost
Amortized Cost	$ 307,596	$ 369,809
Gross Unrealized Gains
Gross Unrealized Gains		0
Gross Unrealized Losses
Gross Unrealized Losses	(2,708)	(702)
Fair Value
Fair Value	304,888	369,107
U.S. government and municipal obligations
Amortized Cost
Maturing in one year or less	132,422	80,674
Maturing after one year through three years	3,912	51,319
Amortized Cost	136,334	131,993
Gross Unrealized Gains
Maturing in one year or less		0
Maturing after one year through three years		0
Gross Unrealized Gains		0
Gross Unrealized Losses
Maturing in one year or less	(1,042)	(133)
Maturing after one year through three years	(71)	(184)
Gross Unrealized Losses	(1,113)	(317)
Fair Value
Maturing in one year or less	131,380	80,541
Maturing after one year through three years	3,841	51,135
Fair Value	135,221	131,676
Corporate debt securities
Amortized Cost
Maturing in one year or less	168,698	170,034
Maturing after one year through three years	2,564	67,782
Amortized Cost	171,262	237,816
Gross Unrealized Gains
Maturing in one year or less		0
Maturing after one year through three years		0
Gross Unrealized Gains		0
Gross Unrealized Losses
Maturing in one year or less	(1,548)	(28)
Maturing after one year through three years	(47)	(357)
Gross Unrealized Losses	(1,595)	(385)
Fair Value
Maturing in one year or less	167,150	170,006
Maturing after one year through three years	2,517	67,425
Fair Value	$ 169,667	$ 237,431

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Marketable Securities
Number of investment-grade securities in unrealized loss position over 12 months	$ 0	$ 0
Accrued interest	$ 700	$ 1,300

Intangible Assets (Details)

Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2022	Dec. 31, 2021
Intangible Assets
Indefinite-lived intangible assets			$ 27,200	$ 27,200
Intangible asset impairment	$ 3,500	$ 3,500

Other Long-Term Liabilities (De

Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Other Long-Term Liabilities
Net deferred tax liabilities related to IPR&D (Note 11)	$ 1,613	$ 1,613
Deferred Income From Sale of Tax Benefits	4,650
Contingent milestones (Note 3 and Note 13)		6,862
Deferred revenue (Note 10)	222	433
Total	6,485	8,908
Less current portion	(1,152)	(1,554)
Long-term portion	$ 5,333	$ 7,354

Other Long-Term Liabilities- Ne

Other Long-Term Liabilities- New Jersey tax benefits (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Interest and Other Income		$ 912	$ 145	$ 1,511	$ 313
New Jersey tax benefits
Amount of tax benefit	$ 5,000
Proceeds from sale of tax credits	$ 4,700
Base of operations requirement (in years)	5 years

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Common Stock
Balance, beginning	$ 365,093	$ 398,101	$ 419,476	$ 182,282	$ 194,166	$ 209,357	$ 419,476	$ 209,357
Balance (in shares)			46,730,198				46,730,198
Shares issued under stock option and employee stock purchase plans	2,306	71	$ 304	2,004		74
Shares issued under stock option and employee stock purchase plans					(25)
Shares issued in underwritten offering, net				269,893
Stock-based compensation	4,496	3,454	3,153	3,029	1,509	1,275
Unrealized gain (loss) on marketable securities	305	(529)	(1,782)	(44)	5	(2)	$ (2,006)	(41)
Net loss	(26,784)	(36,004)	(23,050)	(20,452)	(13,373)	(16,538)	(85,838)	(50,363)
Balance, ending	$ 345,416	365,093	398,101	436,712	182,282	194,166	$ 345,416	436,712
Balance (in shares)	47,096,063						47,096,063
Aggregate gross offering price available	$ 50,000						$ 50,000
Common Stock
Common Stock
Balance, beginning	$ 47	$ 47	$ 47	$ 40	$ 40	$ 40	$ 47	$ 40
Balance (in shares)	46,764,703	46,754,348	46,730,198	39,616,696	39,614,638	39,603,771	46,730,198	39,603,771
Shares issued under stock option and employee stock purchase plans (in shares)	331,360	10,355	24,150	201,406	2,058	10,867
Shares issued in underwritten offering, net				$ 7
Shares issued in underwritten offering, net (in shares)				6,845,238
Balance, ending	$ 47	$ 47	$ 47	$ 47	$ 40	$ 40	$ 47	$ 47
Balance (in shares)	47,096,063	46,764,703	46,754,348	46,663,340	39,616,696	39,614,638	47,096,063	46,663,340
Additional Paid-In Capital
Common Stock
Balance, beginning	$ 1,568,124	$ 1,564,599	$ 1,561,142	$ 1,282,657	$ 1,281,173	$ 1,279,824	$ 1,561,142	$ 1,279,824
Shares issued under stock option and employee stock purchase plans	2,306	71	304	2,004		74
Shares issued under stock option and employee stock purchase plans					(25)
Shares issued in underwritten offering, net				269,886
Stock-based compensation	4,496	3,454	3,153	3,029	1,509	1,275
Balance, ending	1,574,926	1,568,124	1,564,599	1,557,576	1,282,657	1,281,173	1,574,926	1,557,576
Accumulated Other Comprehensive Income.
Common Stock
Balance, beginning	(417)	112	1,894	2,592	2,587	2,589	1,894	2,589
Unrealized gain (loss) on marketable securities	305	(529)	(1,782)	(44)	5	(2)
Balance, ending	(112)	(417)	112	2,548	2,592	2,587	(112)	2,548
Accumulated Deficit
Common Stock
Balance, beginning	(1,202,661)	(1,166,657)	(1,143,607)	(1,103,007)	(1,089,634)	(1,073,096)	(1,143,607)	(1,073,096)
Net loss	(26,784)	(36,004)	(23,050)	(20,452)	(13,373)	(16,538)
Balance, ending	$ (1,229,445)	$ (1,202,661)	$ (1,166,657)	$ (1,123,459)	$ (1,103,007)	$ (1,089,634)	$ (1,229,445)	$ (1,123,459)

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - Stock Options - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Shares
Options outstanding at beginning of the period (in shares)	4,077,667
Granted (in shares)	1,584,900
Exercised (in shares)	(353,622)
Canceled (in shares)	(118,974)
Options outstanding at the end of the period (in shares)	5,189,971	4,077,667
Options vested and expected to vest at the end of the period (in shares)	5,031,072
Options exercisable at the end of the period (in shares)	1,985,506
Shares available for grant under the 2021 Plan	1,838,291
Weighted Average Exercise Price Per Share
Options outstanding at beginning of the period (in dollars per share)	$ 30.02
Granted (in dollars per share)	22.89
Exercised (in dollars per share)	6.71
Canceled (in dollars per share)	50.12
Options outstanding at the end of the period (in dollars per share)	28.97	$ 30.02
Options vested and expected to Vest at the end of the period (in dollars per share)	29.21
Options exercisable at the end of the period (in dollars per share)	$ 41.56
Weighted Average Remaining Contractual Term (In Years)
Options outstanding at the end of the period	8 years 25 days	8 years
Options vested and expected to vest at the end of the period	8 years 18 days
Options exercisable at the end of the period	6 years 8 months 26 days

Stock-Based Compensation - Empl

Stock-Based Compensation - Employee Stock Option and Incentive Plan Activity Additional Information (Details) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022 USD ($) $ / shares	Sep. 30, 2022 USD ($) $ / shares
Additional information
Weighted average grant-date fair value (in dollars per share) | $ / shares	$ 25.38	$ 17.36
Intrinsic value of options vested and expected to vest	$ 45.6	$ 45.6
Intrinsic value of options exercisable	23.6	23.6
Compensation cost not yet recognized	$ 46.7	$ 46.7
Weighted average period compensation cost is expected to be recognized (in years)		0 years

Stock-Based Compensation - Expe

Stock-Based Compensation - Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Stock-based compensation expense
Total stock-based compensation expense	$ 4,496	$ 3,029	$ 11,103	$ 5,813
Research and development
Stock-based compensation expense
Total stock-based compensation expense	2,342	1,504	5,754	2,927
General and administrative
Stock-based compensation expense
Total stock-based compensation expense	$ 2,154	$ 1,525	$ 5,349	$ 2,886

Stock-Based Compensation - Valu

Stock-Based Compensation - Valuation (Details) - Stock Options	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Black-Scholes option with following assumptions:
Expected stock price volatility (as a percent)	91%	98%
Expected stock price volatility, minimum (as a percent)		98%	90%	97%
Expected stock price volatility, maximum (as a percent)			97%	98%
Expected option term	6 years	6 years	6 years	6 years
Risk-free interest rate, minimum (as a percent)	2.90%	1.10%	1.70%	0.80%
Risk-free interest rate, maximum (as a percent)	3.50%	1.20%	3.60%	1.30%
Expected dividend yield (as a percent)	0%	0%	0%	0%

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)
Accumulated Other Comprehensive Income
Balance, beginning	$ 419,476
Balance, ending	345,416
Amounts reclassified from AOCI	0
Unrealized Loss on Marketable Securities
Accumulated Other Comprehensive Income
Balance, beginning	(702)
Other comprehensive loss	(2,006)
Balance, ending	(2,708)
Foreign Currency Items
Accumulated Other Comprehensive Income
Balance, beginning	2,596
Balance, ending	2,596
Accumulated Other Comprehensive Income.
Accumulated Other Comprehensive Income
Balance, beginning	1,894
Other comprehensive loss	(2,006)
Balance, ending	$ (112)

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Revenue
Revenues	$ 407	$ 153	$ 744	$ 4,317
Contract assets	0		0		$ 0
Contract liability	222		222		$ 433
Revenue, contract liabilities	200		400
Contracts and grants
Revenue
Revenues	407	153	714	4,288
Rockefeller University And Gilead Sciences | Contracts and grants
Revenue
Revenues	$ 0	$ 100	$ 200	$ 4,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Income Taxes
Net deferred tax liability	$ 1,613	$ 1,613

Net Loss Per Share (Details)

Net Loss Per Share (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Anti-dilutive securities
Potentially dilutive common shares not been included in net loss per common share calculations because the effect would have been anti-dilutive	5,189,971	4,129,626
Stock Options
Anti-dilutive securities
Potentially dilutive common shares not been included in net loss per common share calculations because the effect would have been anti-dilutive	5,189,971	4,129,626

Kolltan Acquisition (Details)

Kolltan Acquisition (Details) - USD ($) $ in Millions	Jun. 20, 2022	Nov. 29, 2016
Kolltan Acquisition
Execution of the settlement agreement	$ 15
European medicines agency
Kolltan Acquisition
Business contingent amount payable	52.5
Clinical Trial
Kolltan Acquisition
Execution of the settlement agreement	15
Contractual credit merger agreement	2.5
Specified development, regulatory approvals or sales-based milestones
Kolltan Acquisition
Business contingent amount payable	$ 172.5
Kolltan
Kolltan Acquisition
Shares issued as part of consideration (in shares)		1,217,200
Kolltan | Specified development, regulatory approvals or sales-based milestones
Kolltan Acquisition
Potential milestone payments		$ 172.5