Checkpoint Therapeutics (CKPT) 10-Q 14 Aug 23 2023 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2023	Aug. 10, 2023
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
Document Transition Report	false
Entity File Number	001-38128
Entity Registrant Name	CHECKPOINT THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-2568632
Entity Address, Address Line One	95 Sawyer Road
Entity Address, Address Line Two	Suite 110
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02453
City Area Code	781
Local Phone Number	652-4500
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	CKPT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Central Index Key	0001651407
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Amendment Flag	false
Class A Common Stock
Document and Entity Information
Entity Common Stock, Shares Outstanding		700,000
Common Stock
Document and Entity Information
Entity Common Stock, Shares Outstanding		20,893,485

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 7,421	$ 12,068
Prepaid expenses and other current assets	886	1,149
Other receivables - related party	31	73
Total current assets	8,338	13,290
Total Assets	8,338	13,290
Current Liabilities:
Accounts payable and accrued expenses	25,194	20,297
Accounts payable and accrued expenses - related party	2,453	1,306
Common stock warrant liabilities	3,961	11,170
Total current liabilities	31,608	32,773
Total Liabilities	31,608	32,773
Commitments and Contingencies
Stockholders' (Deficit) Equity
Common stock issuable, 0 and 368,907 shares as of June 30, 2023 and December 31, 2022, respectively		1,885
Additional paid-in capital	266,209	241,117
Accumulated deficit	(289,481)	(262,486)
Total Stockholders' (Deficit) Equity	(23,270)	(19,483)
Total Liabilities and Stockholders' (Deficit) Equity	8,338	13,290
Common No Class
Stockholders' (Deficit) Equity
Common Stock Value	$ 2	$ 1

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2023	Dec. 31, 2022
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	80,000,000	50,000,000
Common stock, shares issued	17,238,393	9,586,683
Common stock, shares outstanding	17,238,393	9,586,683
Common stock, shares subscribed but unissued	0	368,907
Class A Common Shares
Common stock, shares issued	700,000	700,000
Common stock, shares outstanding	700,000	700,000

Condensed Statements of Operati

Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Condensed Statements of Operations
Revenue - related party	$ 31	$ 18	$ 66	$ 70
Operating expenses:
Research and development	13,945	12,053	29,771	26,723
General and administrative	2,281	2,129	4,573	4,372
Total operating expenses	16,226	14,182	34,344	31,095
Loss from operations	(16,195)	(14,164)	(34,278)	(31,025)
Other income (expense)
Interest income	31	22	74	35
(Loss) gain on common stock warrant liabilities	(357)		7,209
Total other income (expense)	(326)	22	7,283	35
Net Loss	$ (16,521)	$ (14,142)	$ (26,995)	$ (30,990)
Loss per Share:
Basic net loss per common share outstanding	$ (1.05)	$ (1.62)	$ (1.97)	$ (3.59)
Diluted net loss per common share outstanding	$ (1.05)	$ (1.62)	$ (1.97)	$ (3.59)
Basic weighted average number of common shares outstanding	15,700,324	8,750,982	13,735,646	8,628,665
Diluted weighted average number of common shares outstanding	15,700,324	8,750,982	13,735,646	8,628,665

Condensed Statements of Stockho

Condensed Statements of Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Common Shares Class A Common Shares	Common Shares	Common Shares Issuable	Additional Paid-in Capital	Accumulated Deficit	Total
Balances at Dec. 31, 2021		$ 1	$ 6,598	$ 223,009	$ (199,862)	$ 29,746
Balances (in Shares) at Dec. 31, 2021	700,000	7,757,440
Issuance of common shares, net of offering costs - At-the-market offering				8,687		8,687
Issuance of common shares, net of offering costs - At-the-market offering (in Shares)		430,564
Issuance of common shares - Founders Agreement			(6,598)	6,811		213
Issuance of common shares - Founders Agreement (in Shares)		222,905
Stock-based compensation expense				1,504		1,504
Stock-based compensation expense (in Shares)		144,521
Net settlement of shares withheld for payment of employee taxes				(1,698)		(1,698)
Net settlement of shares withheld for payment of employee taxes (in shares)		(64,857)
Net loss					(30,990)	(30,990)
Balances at Jun. 30, 2022		$ 1		238,313	(230,852)	7,462
Balances (in Shares) at Jun. 30, 2022	700,000	8,490,575
Balances at Mar. 31, 2022		$ 1		236,925	(216,710)	20,216
Balances (in Shares) at Mar. 31, 2022	700,000	8,380,124
Issuance of common shares, net of offering costs - At-the-market offering				642		642
Issuance of common shares, net of offering costs - At-the-market offering (in Shares)		56,371
Issuance of common shares - Founders Agreement				17		17
Issuance of common shares - Founders Agreement (in Shares)		1,409
Stock-based compensation expense				729		729
Stock-based compensation expense (in Shares)		52,671
Net loss					(14,142)	(14,142)
Balances at Jun. 30, 2022		$ 1		238,313	(230,852)	7,462
Balances (in Shares) at Jun. 30, 2022	700,000	8,490,575
Balances at Dec. 31, 2022		$ 1	1,885	241,117	(262,486)	(19,483)
Balances (in Shares) at Dec. 31, 2022	700,000	9,586,683
Issuance of common shares, net of offering costs - Registered direct offering		$ 1		21,113		21,114
Issuance of common shares, net of offering costs - Registered direct offering (in Shares)		4,530,000
Issuance of common shares - Founders Agreement			$ (1,885)	2,443		558
Issuance of common shares - Founders Agreement (in Shares)		528,527
Stock-based compensation expense				1,536		1,536
Stock-based compensation expense (in Shares)		1,101,098
Exercise of prefunded and common stock warrants (in shares)		1,492,085
Net loss					(26,995)	(26,995)
Balances at Jun. 30, 2023		$ 2		266,209	(289,481)	(23,270)
Balances (in Shares) at Jun. 30, 2023	700,000	17,238,393
Balances at Mar. 31, 2023		$ 1		250,780	(272,960)	(22,179)
Balances (in Shares) at Mar. 31, 2023	700,000	13,201,070
Issuance of common shares, net of offering costs - Registered direct offering		$ 1		14,460		14,461
Issuance of common shares, net of offering costs - Registered direct offering (in Shares)		3,350,000
Issuance of common shares - Founders Agreement				402		402
Issuance of common shares - Founders Agreement (in Shares)		123,906
Stock-based compensation expense				567		567
Stock-based compensation expense (in Shares)		104,148
Exercise of prefunded and common stock warrants (in shares)		459,269
Net loss					(16,521)	(16,521)
Balances at Jun. 30, 2023		$ 2		$ 266,209	$ (289,481)	$ (23,270)
Balances (in Shares) at Jun. 30, 2023	700,000	17,238,393

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash Flows from Operating Activities:
Net loss	$ (26,995)	$ (30,990)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,536	1,504
Issuance of common shares - Founders Agreement	558	213
Gain on common stock warrant liabilities	(7,209)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	263	(202)
Other receivables - related party	42	(1)
Accounts payable and accrued expenses	4,651	(1,423)
Accounts payable and accrued expenses - related party	1,147	62
Net cash used in operating activities	(26,007)	(30,837)
Cash Flows from Financing Activities:
Net settlement of shares withheld for payment of employee taxes		(1,698)
Net cash provided by financing activities	21,360	6,989
Net decrease in cash and cash equivalents	(4,647)	(23,848)
Cash and cash equivalents at beginning of period	12,068	54,735
Cash and cash equivalents at end of period	7,421	30,887
Supplemental disclosure of noncash investing and financing activities:
Issuance of common shares - Founders Agreement	1,885	6,598
Issuance of common shares - Registered direct offering (offering costs incurred but not paid)	246
Registered direct offerings
Cash Flows from Financing Activities:
Proceeds from issuance of common shares	23,621
Payment of offering costs for the issuance of common shares	$ (2,261)
At-the-market offering
Cash Flows from Financing Activities:
Proceeds from issuance of common shares		8,910
Payment of offering costs for the issuance of common shares		$ (223)

Organization and Description of

Organization and Description of Business Operations	6 Months Ended
	Jun. 30, 2023
Organization and Description of Business Operations
Organization and Description of Business Operations	Note 1 - Organization and Description of Business Operations Checkpoint Therapeutics, Inc. (the “Company” or “Checkpoint”) was incorporated in Delaware on November 10, 2014. Checkpoint is a clinical-stage immunotherapy and targeted oncology company focused on the acquisition, development and commercialization of novel treatments for patients with solid tumor cancers. The Company may acquire rights to these technologies by licensing the rights or otherwise acquiring an ownership interest in the technologies, funding their research and development and eventually either out-licensing or bringing the technologies to market. The Company may also enter into collaboration agreements with third and related parties including sponsored research agreements to develop these technologies for liquid tumors while retaining the rights in solid tumors. The Company is a majority-controlled subsidiary of Fortress Biotech, Inc. (“Fortress”). The Company’s common stock is listed on the NASDAQ Capital Market and trades under the symbol “CKPT.” December 2022 Reverse Stock Split On November 3, 2022, the holders of a majority of the voting power of the capital stock of the Company executed a written consent approving a grant of discretionary authority to the board of directors of the Company (the “Board”) to, without further stockholder approval, (i) effect a 1: 10 Pursuant to rules adopted by the Securities and Exchange Commission under the Securities Exchange Act of 1934, a Schedule 14C information statement will be filed with the Securities and Exchange Commission and sent or provided to the stockholders of the Company. The Reverse Stock Split will become effective no earlier than twenty (20) days from the mailing of the information statement to the common stockholders of record, and the Authorized Share Reduction will become effective once the Amendment is filed with the Secretary of State of the State of Delaware. All share and per share information has been retroactively adjusted to give effect to the Reverse Stock Split for all periods presented, unless otherwise indicated. Proportionate adjustments were made to the per share exercise price and/or the number of shares issuable upon the exercise or vesting of all stock options, restricted stock and warrants outstanding at December 6, 2022, which resulted in a proportional decrease in the number of shares of the Company’s common stock reserved for issuance upon exercise or vesting of such stock options, restricted stock and warrants, and, in the case of stock options and warrants, a proportional increase in the exercise price of all such stock options and warrants. No fractional shares were issued in connection with the Reverse Stock Split and stockholders who would otherwise be entitled to a fraction of one share received a proportional cash payment. ​ Liquidity, Capital Resources and Going Concern The Company has incurred substantial operating losses since its inception and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of June 30, 2023, the Company had an accumulated deficit of $289.5 million. In February 2023, the Company closed on a registered direct offering (“February 2023 Registered Direct Offering”) for the issuance and sale of an aggregate of 1,180,000 shares of its common stock at a purchase price of $5.25 per share in a registered direct offering. In addition, the offering includes 248,572 shares of common stock in the form of pre-funded warrants at a price of $5.2499 (the “Pre-Funded Warrants”). In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,428,572 shares of common stock and Series B warrants to purchase up to 1,428,572 shares of common stock (collectively, the “February 2023 Common Stock Warrants”). The Series A and B warrants are exercisable In April 2023, the Company closed on a registered direct offering (“April 2023 Registered Direct Offering”) for the issuance and sale of an aggregate of 1,700,000 shares of its common stock at a purchase price of $3.60 per share of common stock in a registered direct offering. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,700,000 shares of common stock and Series B warrants to purchase up to 1,700,000 shares of common stock (collectively, the “April 2023 Common Stock Warrants”). The Series A and B warrants are exercisable In May 2023, the Company closed on a registered direct offering (“May 2023 Registered Direct Offering”) for the issuance and sale of an aggregate of 1,650,000 shares of its common stock at a purchase price of $3.071 per share of common stock in a registered direct offering. In addition, the offering includes 1,606,269 shares of common stock in the form of Pre-Funded Warrants at a price of $3.0709. The common stock and the Pre-Funded Warrants were sold together with Series A warrants to purchase up to 3,256,269 shares of common stock and Series B warrants to purchase up to 3,256,269 shares of common stock (collectively, the “May 2023 Common Stock Warrants”). The Series A and B warrants are exercisable In July 2023, the Company closed on a registered direct offering (“July 2023 Registered Direct Offering”) for the issuance and sale of an aggregate of 2,427,186 shares of its common stock at a purchase price of $3.09 per share of common stock in a registered direct offering. In addition, the offering includes 809,062 shares of common stock in the form of Pre-Funded Warrants at a price of $3.0899. The common stock and the Pre-Funded Warrants were sold together with Series A warrants to purchase up to 3,236,248 shares of common stock and Series B warrants to purchase up to 3,236,248 shares of common stock (collectively, the “July 2023 Common Stock Warrants”). The Series A and B warrants are exercisabl The Company expects to continue to use the proceeds from previous financing transactions primarily for general corporate purposes, which may include financing the Company’s growth, developing new or existing product candidates, and funding capital expenditures, acquisitions, and investments. In accordance with Accounting Standards Codification (“ASC”) 205-40, Going Concern The Company believes, assuming no business or corporate development transactions are consummated, that its cash and cash equivalents are only sufficient to fund its operating expenses through the third quarter of 2023. Accordingly, the Company intends to continue its active discussions with third party pharmaceutical and biotechnology companies to evaluate potential partnerships or other types of corporate development transactions, including strategic mergers. The Company’s expectation to generate operating losses and negative operating cash flows in the future and the need for additional funding to support its planned operations raise substantial doubt regarding the Company’s ability to continue as a going concern for a period of one year after the date that these financial statements are issued. Management’s plans to alleviate the conditions that raise substantial doubt include reduced 2023 spending, including projected savings through delaying the development timelines of certain programs, the pursuit of additional cash resources through public or private equity or debt financings, and potential partnerships or other corporate development transactions. Management has concluded that the likelihood that its plan to successfully obtain sufficient funding from one or more of these sources, or adequately reduce expenditures, while reasonably possible, is less than probable. Accordingly, the Company has concluded that substantial doubt exists about the Company’s ability to continue as a going concern for a period of at least 12 months from the date of issuance of these financial statements. The Company’s estimate as to how long it expects its existing cash to be able to continue to fund its operations is based on assumptions that may prove to be wrong, and it could use its available capital resources sooner than it currently expects. Further, changing circumstances, some of which may be beyond its control, could cause the Company to consume capital faster than it currently anticipates, and it may need to seek additional funds sooner than planned. The Company cannot be certain that additional funding will be available to it on acceptable terms, or at all. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described above.

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 30, 2023
Significant Accounting Policies
Significant Accounting Policies	Note 2 - Significant Accounting Policies Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X of the Exchange Act. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim condensed financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. They may not include all of the information and notes required by GAAP for complete financial statements. Therefore, these condensed financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto for the year ended December 31, 2022, which were included in the Company’s Form 10-K, and filed with the SEC on March 31, 2023. The results of operations for any interim periods are not necessarily indicative of the results that may be expected for the entire fiscal year or any other interim period. 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 and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies to those previously disclosed in the 2022 Annual Report on Form 10-K. Cash and Cash Equivalents The Company considers highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Other Receivables - Related Party Other receivables consist of amounts due to the Company from TG Therapeutics, Inc. (“TGTX”), a related party, and are recorded at the invoiced amount. Research and Development Costs Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s behalf will be expensed as services are rendered or when the milestone is achieved. Research and development costs primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based compensation, payments made to third parties for license and milestone costs related to in-licensed products and technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings, laboratory costs and other supplies. In accordance with Accounting Standards Codification (“ASC”) 730-10-25-1, Research and Development Annual Equity Fee Under the Founders Agreement with Checkpoint dated March 17, 2015, and amended and restated in July 2016 and October 2017 (the “Founders Agreement”), Fortress is entitled to an annual equity fee on January 1 of each year equal to 2.5% of fully diluted outstanding equity of the Company, payable in Checkpoint common shares (“Annual Equity Fee”). The Annual Equity Fee was part of the consideration payable for formation of the Company, identification of certain assets, including the license contributed to Checkpoint by Fortress (see Note 4). The Company records the Annual Equity Fee in connection with the Founders Agreement with Fortress as contingent consideration. Contingent consideration is recorded when probable and reasonably estimable. Due to the nature of the Company’s assets and stage of development, future share prices and shares outstanding cannot be estimated prior to the issuance of the Annual Equity Fee. Due to these uncertainties, the Company has concluded that it is unable to reasonably estimate the contingent consideration until shares are actually issued on January 1 of each year. Pursuant to the Founders Agreement, the Company issued 368,907 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of Checkpoint on January 1, 2023. Because the number of outstanding shares issuable to Fortress was determinable on January 1, 2023 prior to the issuance of the December 31, 2022 financial statements, the Company recorded approximately $1.9 million in research and development expense and a credit to Common shares issuable - Founders Agreement during the year ended December 31, 2022. Stock-Based Compensation Expenses The Company expenses stock-based compensation over the requisite service period based on the estimated grant-date fair value of the awards and forfeiture rates. The Company accounts for forfeitures as they occur. The Company estimates the fair value of stock option grants using the Black-Scholes Model. The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the Condensed Statements of Operations based upon the underlying individual’s role at the Company. Common Stock Warrant Liability The Company has issued freestanding warrants to purchase shares of its common stock in connection with its financing activities and accounts for them in accordance with applicable accounting guidance as either liabilities or as equity instruments depending on the specific terms of the warrant agreements. Warrants classified as liabilities are remeasured each period they are outstanding. Any resulting gain or loss related to the change in the fair value of the warrant liability is recognized in gain (loss) on common stock warrant liabilities, a component of other income (expense), in the Condensed Statements of Operations. The Company estimates the fair value of common stock warrant liabilities using the Black-Scholes Model. The assumptions used in calculating the fair value represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. Fair Value Measurement The Company follows the accounting guidance in ASC 820 for its fair value measurements of financial assets and liabilities measured at fair value on a recurring basis. Under this accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to their liquid or short-term nature, such as accounts payable and accrued expenses. Revenue from Contracts with Customers The Company recognizes revenue under ASC 606, “ Revenue from Contracts with Customers ● Step 1: Identify the contract with the customer. ● Step 2: Identify the performance obligations in the contract. ● Step 3: Determine the transaction price. ● Step 4: Allocate the transaction price to the performance obligations in the contract. ● Step 5: Recognize revenue when the company satisfies a performance obligation. In order to identify the performance obligations in a contract with a customer, a company must assess the promised goods or services in the contract and identify each promised good or service that is distinct. A performance obligation meets ASC 606’s definition of a “distinct” good or service (or bundle of goods or services) if both of the following criteria are met: ● the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct); and ● the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract). If a good or service is not distinct, the good or service is combined with other promised goods or services until a bundle of goods or services is identified that is distinct. The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration promised in a contract with a customer may include fixed amounts, variable amounts, or both. When determining the transaction price, an entity must consider the effects of all of the following: ● variable consideration; ● constraining estimates of variable consideration; ● the existence of a significant financing component in the contract; ● noncash consideration; and ● consideration payable to a customer. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The transaction price allocated to each performance obligation is recognized when that performance obligation is satisfied, at a point in time or over time as appropriate. Revenue for a sales-based or usage-based royalty promised in exchange for a license of intellectual property is recognized only when (or as) the later of the following events occurs: a. the subsequent sale or usage occurs; and b. the performance obligation to which some or all of the sales-based or usage-based royalty has been allocated has been satisfied (or partially satisfied). Incremental contract costs are expensed when incurred when the amortization period of the asset that would have been recognized is one year or less; otherwise, incremental contract costs are recognized as an asset and amortized over time as services are provided to a customer. Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax effects attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and operating loss and tax credit carryforwards. The Company establishes a valuation allowance if management believes it is more likely than not that the deferred tax assets will not be recovered based on an evaluation of objective verifiable evidence. For tax positions that are more likely than not to be sustained upon audit, the Company recognizes the largest amount with a greater than 50% likelihood of being realized. The Company does not recognize any portion of the benefit for tax positions that are not more likely than not to be sustained upon audit. As of June 30, 2023 and December 31, 2022, the Company determined, based upon available evidence, that it is more likely than not that the net deferred tax asset will not be realized and, accordingly, has provided a full valuation allowance against its net deferred tax asset. Net Loss per Share Net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share does not reflect the effect of shares of common stock to be issued upon the exercise of stock options and warrants, as their inclusion would be anti-dilutive. The following table summarizes potentially dilutive securities outstanding at June 30, 2023 and 2022 that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ 2023 2022 Warrants (Note 6) 17,873,125 ​ 1,249 Stock options (Note 6) 127,000 ​ 31,000 Unvested restricted stock (Note 6) ​ 1,333,211 ​ 388,321 Unvested restricted stock units (Note 6) 619,884 ​ — Total 19,953,220 ​ 420,570 ​ Comprehensive Loss The Company has no components of comprehensive loss other than net loss. Thus, comprehensive loss is the same as net loss for the periods presented. Recently Issued Accounting Pronouncements During the six-month period ended June 30, 2023, there were no new accounting pronouncements or updates to recently issued accounting pronouncements as disclosed in the Company’s Form 10-K for the year ended December 31, 2022 that affect the Company’s present or future results of operations, overall financial condition, liquidity or disclosures.

License Agreements

License Agreements	6 Months Ended
	Jun. 30, 2023
License Agreements
License Agreements	Note 3 – License Agreements Dana-Farber Cancer Institute In March 2015, the Company entered into an exclusive license agreement with Dana-Farber Cancer Institute (“Dana Farber”) to develop a portfolio of fully human immuno-oncology targeted antibodies. Dana-Farber is eligible to receive payments of up to an aggregate of approximately $21.5 million for each licensed product upon the Company’s successful achievement of certain clinical development, regulatory and first commercial sale milestones. In addition, Dana-Farber is eligible to receive up to an aggregate of $60.0 million upon the Company’s successful achievement of certain sales milestones based on aggregate net sales, in addition to royalty payments based on a tiered low to mid-single digit percentage of net sales. Dana-Farber also receives an annual license maintenance fee of $50,000, which is creditable against future milestone payments or royalties. The portfolio of antibodies licensed from Dana-Farber include antibodies targeting PD-L1, GITR and CAIX. In connection with the license agreement with Dana-Farber, the Company entered into a collaboration agreement with TGTX, which was amended and restated in June 2019, to develop and commercialize the anti-PD-L1 and anti-GITR antibody research programs in the field of hematological malignancies, while the Company retains the right to develop and commercialize these antibodies in solid tumors. Michael Weiss, Chairman of the Board of Directors of Checkpoint and Fortress’ Executive Vice Chairman, Strategic Development, is also the Executive Chairman, President and Chief Executive Officer and a stockholder of TGTX. The Company is eligible to receive substantive potential milestone payments for the anti-PD-L1 program of up to an aggregate of approximately $27.6 million upon TGTX’s successful achievement of certain clinical development, regulatory and first commercial sale milestones. This is comprised of up to approximately $8.4 million upon TGTX’s successful completion of clinical development milestones, and up to approximately $19.2 million upon regulatory filings and first commercial sales in specified territories. The Company is also eligible to receive substantive potential milestone payments for the anti-GITR antibody program of up to an aggregate of approximately $21.5 million upon TGTX’s successful achievement of certain clinical development, regulatory and first commercial sale milestones. This is comprised of up to approximately $7.0 million upon TGTX’s successful completion of clinical development milestones, and up to approximately $14.5 million upon first commercial sales in specified territories. In addition, the Company is eligible to receive up to an aggregate of $60.0 million upon TGTX’s successful achievement of certain sales milestones based on aggregate net sales for both programs, in addition to royalty payments based on a tiered low double-digit percentage of net sales. The Company also receives an annual license maintenance fee, which is creditable against future milestone payments or royalties. TGTX also pays the Company for its out-of-pocket costs of material used by TGTX for their development activities. For the three months ended June 30, 2023 and 2022, the Company recognized approximately $12,000 and $16,000, respectively, in revenue related to the collaboration agreement in the Condensed Statements of Operations. For the six months ended June 30, 2023 and 2022, the Company recognized approximately $41,000 and $47,000, respectively, in revenue related to the collaboration agreement in the Condensed Statements of Operations. Adimab, LLC In October 2015, Fortress entered into a collaboration agreement with Adimab, LLC (“Adimab”) to discover and optimize antibodies using their proprietary core technology platform. Under this agreement, Adimab optimized cosibelimab, the Company’s anti-PD-L1 antibody which it originally licensed from Dana-Farber. In January 2019, Fortress transferred the rights to the optimized antibody to the Company, and Checkpoint entered into a collaboration agreement directly with Adimab on the same day. Under the terms of the agreement, Adimab is eligible to receive payments from the Company of up to an aggregate of approximately $2.5 million upon various filings for regulatory approvals to commercialize the product. In addition, Adimab is eligible to receive royalty payments based on a tiered low single digit percentage of net sales. In February 2023 the Company expensed a non-refundable milestone payment of $2.2 million to research and development expenses upon the United States Food and Drug Administration’s filing acceptance of the Company’s Biologics License Application (“BLA”) for cosibelimab in metastatic or locally advanced cutaneous squamous cell carcinoma. NeuPharma, Inc. In March 2015, Fortress entered into an exclusive license agreement with NeuPharma, Inc. (“NeuPharma”) to develop and commercialize novel irreversible, 3rd generation EGFR inhibitors, including olafertinib, on a worldwide basis other than certain Asian countries. On the same date, Fortress assigned all of its right and interest in the EGFR inhibitors to the Company. NeuPharma is eligible to receive payments of up to an aggregate of approximately $39.0 million upon the Company’s successful achievement of certain clinical development and regulatory milestones in up to three indications, of which $22.5 million are due upon various regulatory approvals to commercialize the products. In addition, NeuPharma is eligible to receive payments of up to an aggregate of $40.0 million upon the Company’s successful achievement of certain sales milestones based on aggregate net sales, in addition to royalty payments based on a tiered mid to high-single digit percentage of net sales. Jubilant Biosys Limited In May 2016, the Company entered into a license agreement with Jubilant Biosys Limited (“Jubilant”), whereby the Company obtained an exclusive, worldwide license to Jubilant’s family of patents covering compounds that inhibit BET proteins such as BRD4, including CK-103. Jubilant is eligible to receive payments up to an aggregate of approximately $88.4 million upon the Company’s successful achievement of certain clinical development and regulatory milestones, of which $59.5 million are due upon various regulatory approvals to commercialize the products. In addition, Jubilant is eligible to receive payments up to an aggregate of $89.3 million upon the Company’s successful achievement of certain sales milestones based on aggregate net sales, in addition to royalty payments based on a tiered low to mid-single digit percentage of net sales. In connection with the license agreement with Jubilant, the Company entered into a sublicense agreement with TGTX, a related party, to develop and commercialize the compounds licensed in the field of hematological malignancies, while the Company retains the right to develop and commercialize these compounds in the field of solid tumors. The Company is eligible to receive substantive potential milestone payments up to an aggregate of approximately $87.4 million upon TGTX’s successful achievement of clinical development and regulatory milestones. This is comprised of up to approximately $25.5 million upon TGTX’s successful completion of three clinical development milestones for two licensed products, and up to approximately $61.9 million upon the achievement of five regulatory approvals and first commercial sales in specified territories for two licensed products. In addition, the Company is eligible to receive potential milestone payments up to an aggregate of $89.3 million upon TGTX’s successful achievement of certain sales milestones based on aggregate net sales by TGTX, for two licensed products, in addition to royalty payments based on a mid-single digit percentage of net sales by TGTX. TGTX also pays the Company 50% of Investigational New Drug enabling costs and patent expenses. For the three months ended June 30, 2023 and 2022, the Company recognized approximately $18,000 and $2,000, respectively, in revenue related to the sublicense agreement in the Condensed Statements of Operations. For the six months ended June 30, 2023 and 2022, the Company recognized approximately $24,000 and $23,000, respectively, in revenue related to the sublicense agreement in the Condensed Statements of Operations. The collaborations with TGTX each contain single material performance obligations under Topic 606, which is the granting of a license that is functional intellectual property. The Company’s performance obligation was satisfied at the point in time when TGTX had the ability to use and benefit from the right to use the intellectual property. The performance obligations of the original agreements were satisfied prior to the adoption of Topic 606. The performance obligation of the amendment to the collaboration agreement was satisfied in June 2019. The milestone payments are based on successful achievement of clinical development, regulatory, and sales milestones. Because these payments are contingent on the occurrence of a future event, they represent variable consideration and are constrained and included in the transaction price only when it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur. The sales-based royalty payments are recognized as revenue when the subsequent sales occur. The Company also receives variable consideration for certain research and development, out-of-pocket material costs, and patent maintenance related activities. These amounts are dependent upon the Company’s actual expenditures under the collaborations and are constrained and included in the transaction price only when it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur. As this revenue relates to an already satisfied performance obligation, it is recognized approximately when the amounts become due. For the six months ended June 30, 2023, the Company did not receive any milestone or royalty payments.

Related Party Agreements

Related Party Agreements	6 Months Ended
	Jun. 30, 2023
Related Party Agreements
Related Party Agreements	Note 4 – Related Party Agreements Founders Agreement and Management Services Agreement with Fortress Effective March 17, 2015, the Company entered into a Founders Agreement with Fortress, which was amended in July 2016 and October 2017. The Founders Agreement provides, that in exchange for the time and capital expended in the formation of Checkpoint and the identification of specific assets the acquisition of which resulted in the formation of a viable emerging growth life science company, the Company assumed $2.8 million in debt that Fortress accumulated under a promissory note through National Securities Corporation for expenses and costs of forming Checkpoint. Further, the Company shall: (i) issue annually to Fortress, on January 1 of each year, shares of common stock equal to two and one-half percent (2.5%) of the fully diluted outstanding equity of Checkpoint at the time of issuance; (ii) pay an equity fee in shares of common stock, payable within five (5) business days of the closing of any equity or debt financing for Checkpoint or any of its respective subsidiaries that occurs after the effective date of the Founders Agreement and ending on the date when Fortress no longer has majority voting control in Checkpoint’s voting equity, equal to two and one-half percent (2.5%) of the gross amount of any such equity or debt financing; and (iii) pay a cash fee equal to four and one half percent (4.5%) of Checkpoint’s annual net sales, payable on an annual basis, within ninety (90) days of the end of each calendar year. In the event of a change in control (as it is defined in the Founders Agreement), Checkpoint will pay a one-time change in control fee equal to five times (5x) the product of (i) monthly net sales for the twelve (12) months immediately preceding the change in control and (ii) four and one-half percent (4.5%). The Founders Agreement has a term of fifteen years, after which it automatically renews for one-year periods unless Fortress gives the Company notice of termination. The Founders Agreement will also automatically terminate upon a change of control. Effective March 17, 2015, the Company entered into a Management Services Agreement (the “MSA”) with Fortress. Pursuant to the terms of the MSA, for a period of five (5) years, Fortress will render advisory and consulting services to the Company. Services provided under the MSA may include, without limitation, (i) advice and assistance concerning any and all aspects of Checkpoint’s operations, clinical trials, financial planning and strategic transactions and financings and (ii) conducting relations on behalf of the Company with accountants, attorneys, financial advisors and other professionals (collectively, the “Services”). The Company is obligated to utilize clinical research services, medical education, communication and marketing services and investor relations/public relation services of companies or individuals designated by Fortress, provided those services are offered at market prices. However, the Company is not obligated to take or act upon any advice rendered from Fortress and Fortress shall not be liable for any of the Company’s actions or inactions based upon their advice. Fortress and its affiliates, including all members of its Board of Directors, have been contractually exempt from fiduciary duties to the Company relating to corporate opportunities. In consideration for the Services, the Company will pay Fortress an annual consulting fee of $0.5 million (the “Annual Consulting Fee”), payable in advance in equal quarterly installments on the first business day of each calendar quarter in each year, provided, however, that such Annual Consulting Fee shall be increased to $1.0 million for each calendar year in which the Company has net assets in excess of $100 million at the beginning of the calendar year. The MSA shall be automatically extended for additional five-year periods unless Fortress or the Company provides notice to the other party of its desire not to automatically extend the term. For the three months ended June 30, 2023 and 2022, the Company recognized $125,000, respectively, in expense on its Condensed Statements of Operations related to the MSA. For the six months ended June 30, 2023 and 2022, the Company recognized $250,000, respectively, in expense on its Condensed Statements of Operations related to the MSA. Caribe BioAdvisors, LLC In December 2016, the Company entered into an advisory agreement effective January 1, 2017 with Caribe BioAdvisors, LLC (“Caribe”), owned by Michael Weiss, to provide the advisory services of Mr. Weiss as Chairman of the Board. Pursuant to the agreement, Caribe will be paid an annual cash fee of $60,000, in addition to any and all annual equity incentive grants paid to members of the board. In June 2023, Mr. Weiss assigned the agreement to Hawkins BioVentures, LLC. For the three months ended June 30, 2023 and 2022, the Company recognized approximately $27,000 and $28,000, respectively, in expense in its Condensed Statements of Operations related to the advisory agreement, including approximately $12,000 and $13,000 in expense related to annual equity incentive grants. For the six months ended June 30, 2023 and 2022, the Company recognized approximately $54,000 and $55,000, respectively, in expense in its Condensed Statements of Operations related to the advisory agreement, including approximately $24,000 and $25,000 in expense related to annual equity incentive grants.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies
Commitments and Contingencies	Note 5 – Commitments and Contingencies Leases The Company is not a party to any leases for office space or equipment. License Agreements The Company has undertaken to make contingent milestone payments to the licensors of its portfolio of product candidates. In addition, the Company would pay royalties to such licensors based on a percentage of net sales of each product candidate following regulatory marketing approval (See Note 3). Litigation The Company recognizes a liability for a contingency when it is probable that liability has been incurred and when the amount of loss can be reasonably estimated. When a range of probable loss can be estimated, the Company accrues the most likely amount of such loss, and if such amount is not determinable, then the Company accrues the minimum of the range of probable loss. As of June 30, 2023, and December 31, 2022, there was no litigation against the Company.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2023
Stockholders' Equity
Stockholders' Equity	Note 6 – Stockholders’ Equity Common Stock At the Company’s 2023 Annual Meeting of Stockholders held on June 12, 2023, its stockholders approved an amendment to its certificate of incorporation to increase the number of authorized shares of common stock available to issue by 30,000,000 to 80,000,000 with a par value of $0.0001 per share, of which 700,000 shares are designated as “Class A common stock.” The amendment was filed with the Secretary of State of the State of Delaware on June 14, 2023. As of June 30, 2023 and December 31, 2022, there were 700,000 shares of Class A common stock held by Fortress. The holders of common stock are entitled to one vote per share of common stock held. The Class A common stockholders are entitled to a number of votes per share equal to 1.1 times a fraction, the numerator of which is the sum of the shares of outstanding common stock and the denominator of which is the number of shares of Class A common stock. Accordingly, the holder of shares of Class A common stock will be able to control or significantly influence all matters requiring approval by our stockholders, including the election of directors and the approval of mergers or other business combination transactions. Each share of Class A common stock is convertible, at the option of the holder thereof, into one (1) fully paid and non-assessable share of common stock subject to adjustment for stock splits and combinations. In November 2020, the Company filed a shelf registration statement on Form S-3 (the “November 2020 Form S-3”), which was declared effective in December 2020 (File No. 333-251005). Under the November 2020 Form S-3, the Company may sell up to a total of $100 million of its securities. In connection with the November 2020 Form S-3, the Company entered into an ATM with Cantor Fitzgerald & Co., Ladenburg Thalmann & Co. Inc. and H.C. Wainwright & Co., LLC (each an “Agent” and collectively, the “Agents”) relating to the sale of shares of common stock. Under the ATM, the Company pays the Agents a commission rate of up to 3.0% of the gross proceeds from the sale of any shares of common stock. Pursuant to the Founders Agreement, the Company issued 368,907 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of Checkpoint on January 1, 2023 (see Notes 2 and 4). In February 2023, the Company closed on a registered direct offering for the issuance and sale of an aggregate of 1,180,000 shares of its common stock at a purchase price of $5.25 per share of common stock. In addition, the offering includes 248,572 shares of common stock in the form of Pre-Funded Warrants at a price of $5.2499. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,428,572 shares of common stock and Series B warrants to purchase up to 1,428,572 shares of common stock. The Series A and B warrants are exercisable In February 2023, the Pre-Funded Warrants from the February 2023 Registered Direct Offering were fully exercised. In March 2023, the Company filed a registration statement on Form S-3 to register the February 2023 Common Stock Warrants, which was declared effective May 5, 2023. In April 2023, the Company closed on a registered direct offering for the issuance and sale of an aggregate of 1,700,000 shares of its common stock at a purchase price of $3.60 per share of common stock. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,700,000 shares of common stock and Series B warrants to purchase up to 1,700,000 shares of common stock. The Series A and B warrants are exercisable As of June 30, 2023, approximately $8.7 million of securities remain available for sale under the November 2020 Form S-3. In March 2023, the Company filed a shelf registration statement on Form S-3 (the “March 2023 Form S-3”), which was declared effective May 5, 2023 (File No. 333-270843). Under the March 2023 Form S-3, the Company may sell up to a total of $150 million of its securities. In May 2023, the Company closed on a registered direct offering for the issuance and sale of an aggregate of 1,650,000 shares of its common stock at a purchase price of $3.071 per share of common stock. In addition, the offering includes 1,606,269 shares of common stock in the form of Pre-Funded Warrants at a price of $3.0709. The common stock and the Pre-Funded Warrants were sold together with Series A warrants to purchase up to 3,256,269 shares of common stock and Series B warrants to purchase up to 3,256,269 shares of common stock. The Series A and B warrants are exercisable As of June 30, 2023, 459,269 of the Pre-Funded Warrants from the May 2023 Registered Direct Offering were fully exercised. As of June 30, 2023, approximately $120.9 million of securities remain available for sale under the March 2023 Form S-3. Pursuant to the Founders Agreement, the Company issued to Fortress 2.5% of the aggregate number of shares of common stock issued in the registered direct offerings noted above. Accordingly, the Company issued 159,620 shares of common stock to Fortress and recorded expense of approximately $0.6 million related to this grant, which is included in general and administrative expenses in the Company’s Condensed Statements of Operations for the six months ended June 30, 2023. The Company may offer the securities under the Form S-3’s from time to time in response to market conditions or other circumstances if it believes such a plan of financing is in the best interests of its stockholders. Equity Incentive Plan The Company has in effect the Amended and Restated 2015 Incentive Plan (“2015 Incentive Plan”). The 2015 Incentive Plan was adopted in March 2015 by our stockholders. Under the 2015 Incentive Plan, the compensation committee of the Company’s board of directors is authorized to grant stock-based awards to directors, officers, employees and consultants. An amendment to the 2015 Incentive Plan was approved by stockholders in June 2023 to increase the shares available for issuance to 6,000,000 shares. The plan expires 10 years from the effective date of the amendment and limits the term of each option to no more than 10 years from the date of grant. As of June 30, 2023, 3,496,830 shares are available for issuance under the 2015 Incentive Plan. Restricted Stock Awards Certain employees, directors and consultants have been awarded restricted stock. The restricted stock vesting consists of milestone and time-based vesting. The following table summarizes restricted stock award activity for the six months ended June 30, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ Number of ​ Grant Date Fair ​ Shares Value Non-vested at December 31, 2022 ​ 378,897 ​ $ 26.15 Granted ​ 1,103,698 ​ ​ 2.33 Forfeited ​ (45,100) ​ ​ 6.89 Vested ​ (104,284) ​ ​ 24.99 Non-vested at June 30, 2023 ​ 1,333,211 ​ $ 7.17 ​ As of June 30, 2023, there was $3.6 million of total unrecognized compensation cost related to non-vested restricted stock, which is expected to be recognized over a weighted-average period of 2.1 years. This amount does not include, as of June 30, 2023, 196,733 shares of restricted stock outstanding which are performance-based and vest upon achievement of certain corporate milestones. The expense for time-based vesting awards is recognized over the vesting period of the award. Stock-based compensation for milestone awards will be measured at grant date and recorded if and when it is probable that the milestone will be achieved. Restricted Stock Units The following table summarizes restricted stock units activity for the six months ended June 30, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ Number of ​ Grant Date Fair ​ ​ Shares ​ Value Non-vested at December 31, 2022 85,000 ​ $ 10.50 Granted 577,384 ​ 2.25 Vested ​ (42,500) ​ ​ 10.50 Non-vested at June 30, 2023 619,884 ​ $ 2.82 ​ As of June 30, 2023, all restricted stock units outstanding are performance-based and vest upon achievement of certain corporate milestones. The expense for milestone awards will be measured and recorded if and when it is probable that the milestone will be achieved. Stock Options The following table summarizes stock option award activity for the six months ended June 30, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ Remaining ​ ​ ​ ​ Weighted Average ​ Contractual Life ​ Stock Options Exercise Price (in years) Outstanding as of December 31, 2022 ​ 27,000 ​ $ 31.35 ​ 6.44 Granted ​ 100,000 ​ ​ 2.81 ​ — Outstanding as of June 30, 2023 ​ 127,000 ​ $ 8.88 ​ 9.10 Vested and exercisable as of June 30, 2023 ​ 19,500 ​ $ 24.68 ​ 6.54 ​ Upon the exercise of stock options, the Company will issue new shares of its common stock. The Company used the Black-Scholes Model for determining the estimated fair value of stock-based compensation related to stock options. The table below summarizes the assumptions used: ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Six Months Ended June 30, ​ ​ 2023 ​ 2022 Risk-free interest rate 3.73 % 1.30 % Expected dividend yield — — ​ Expected term in years 10.0 10.0 ​ Expected volatility 83.48 % 100.65 % ​ Warrants A summary of warrant activities for the six months ended June 30, 2023 is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ Remaining ​ ​ ​ ​ Weighted Average ​ Contractual Life ​ Warrants Exercise Price (in years) Outstanding as of December 31, 2022 ​ 4,357,597 ​ $ 3.37 ​ 3.26 Granted ​ 15,007,613 ​ ​ 3.05 ​ — Exercised ​ (1,492,085) ​ ​ — ​ — Outstanding as of June 30, 2023 ​ 17,873,125 ​ $ 3.39 ​ 3.03 ​ Upon the exercise of warrants, the Company will issue new shares of its common stock. Stock-Based Compensation The following table summarizes stock-based compensation expense for the three and six months ended June 30, 2023 and 2022 ($ in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the three months ended June 30, ​ For the six months ended June 30, ​ 2023 2022 2023 2022 Research and development ​ $ 187 ​ $ 229 ​ $ 577 ​ $ 476 General and administrative ​ 380 ​ 500 ​ 959 ​ 1,028 Total stock-based compensation expense ​ $ 567 ​ $ 729 ​ $ 1,536 ​ $ 1,504 ​

Common Stock Warrant Liabilitie

Common Stock Warrant Liabilities	6 Months Ended
	Jun. 30, 2023
Common Stock Warrant Liabilities
Common Stock Warrant Liabilities	Note 7 – Common Stock Warrant Liabilities On December 16, 2022, the Company closed on an offering for the sale of shares of its common stock and pre-funded warrants as part of a registered direct offering. The common stock and the pre-funded warrants were sold together with Series A and Series B common stock warrants. The Company also issued the placement agent warrants to purchase shares (collectively, the “December 2022 Common Stock Warrants and Placement Agent Warrants”). The Company accounts for warrants as either equity-classified or liability-classified instruments based on an assessment of the warrant’s specific terms and applicable authoritative guidance in ASC 480, Distinguishing Liabilities from Equity Derivatives and Hedging - Contracts in Entity’s Own Equity The Company deemed the December 2022 Common Stock Warrants and Placement Agent Warrants to be classified as liabilities on the balance sheet as they contain terms for redemption of the underlying security that are outside its control. The December 2022 Common Warrants and Placement Agent Warrants were recorded at the time of closing at a fair value, determined by using the Black-Scholes Model. As the total fair value of the common stock warrant liability exceeded the total proceeds, no proceeds were allocated to the common stock and pre-funded warrants issued as part of the transaction. The Company revalued the December 2022 Common Stock Warrants and Placement Agent Warrants at December 31, 2022, resulting in a fair value of $11.2 million. The Company revalued the December 2022 Common Stock Warrants and Placement Agent Warrants at June 30, 2023 using the Black-Scholes Model. This resulted in a decrease in common stock warrant liability of $7.2 million, with an offsetting gain recorded to gain on common stock warrant liabilities in the Condensed Statements of Operations. ​ ​ ​ ​ ​ Common Stock Warrant liabilities at December 31, 2022 $ 11,170 Change in fair value of Common Stock Warrant liabilities ​ ​ (7,209) Common Stock Warrant liabilities at June 30, 2023 ​ $ 3,961 ​ The Company used the Black-Scholes Model for determining the estimated fair value of the common stock warrant liabilities. A summary of the weighted average (in aggregate) significant unobservable inputs used in measuring the warrant liability is determined using Level 3 inputs as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, Series A Warrants ​ 2023 ​ 2022 Exercise price ​ $ 4.08 ​ $ 4.08 ​ Volatility ​ 90.7 % 89.4 % Expected life ​ 4.5 ​ 5.0 ​ Risk-free rate ​ 4.1 % 4.0 % Dividend yield ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, Series B Warrants ​ 2023 ​ 2022 Exercise price ​ $ 4.08 ​ $ 4.08 ​ Volatility ​ 108.2 % 82.4 % Expected life ​ 1.0 ​ 1.5 ​ Risk-free rate ​ 5.4 % 4.7 % Dividend yield ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, Placement Agent Warrants ​ 2023 ​ 2022 Exercise price ​ $ 5.41 ​ $ 5.41 ​ Volatility ​ 90.7 % 89.4 % Expected life ​ 4.5 ​ 5.0 ​ Risk-free rate ​ 4.1 % 4.0 % Dividend yield ​ — ​ — ​ ​

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	6 Months Ended
	Jun. 30, 2023
Accounts Payable and Accrued Expenses
Accounts Payable and Accrued Expenses	Note 8 - Accounts Payable and Accrued Expenses At June 30, 2023 and December 31, 2022, accounts payable and accrued expenses consisted of the following ($ in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2023 2022 Accounts payable ​ $ 8,058 ​ $ 11,535 Accrued compensation ​ ​ 700 ​ 1,195 Research and development ​ 16,149 ​ 7,289 Other ​ 287 ​ 278 Total accounts payable and accrued expenses ​ $ 25,194 ​ $ 20,297 ​

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2023
Subsequent Events
Subsequent Events	Note 9 – Subsequent Events ​ In July 2023, the Company closed on the July 2023 Registered Direct Offering for the issuance and sale of an aggregate of 2,427,186 shares of its common stock at a purchase price of $3.09 per share of common stock in a registered direct offering. In addition, the offering includes 809,062 shares of common stock in the form of Pre-Funded Warrants at a price of $3.0899. The common stock and the Pre-Funded Warrants were sold together with Series A warrants to purchase up to 3,236,248 shares of common stock and Series B warrants to purchase up to 3,236,248 shares of common stock. The Series A and B warrants are exercisable

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2023
Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X of the Exchange Act. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim condensed financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. They may not include all of the information and notes required by GAAP for complete financial statements. Therefore, these condensed financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto for the year ended December 31, 2022, which were included in the Company’s Form 10-K, and filed with the SEC on March 31, 2023. The results of operations for any interim periods are not necessarily indicative of the results that may be expected for the entire fiscal year or any other interim period.
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 and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies to those previously disclosed in the 2022 Annual Report on Form 10-K.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies to those previously disclosed in the 2022 Annual Report on Form 10-K.
Cash and Cash Equivalents	Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies to those previously disclosed in the 2022 Annual Report on Form 10-K.
Other Receivables - Related Party	Other Receivables - Related Party Other receivables consist of amounts due to the Company from TG Therapeutics, Inc. (“TGTX”), a related party, and are recorded at the invoiced amount.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s behalf will be expensed as services are rendered or when the milestone is achieved. Research and development costs primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based compensation, payments made to third parties for license and milestone costs related to in-licensed products and technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings, laboratory costs and other supplies. In accordance with Accounting Standards Codification (“ASC”) 730-10-25-1, Research and Development
Annual Equity Fee	Annual Equity Fee Under the Founders Agreement with Checkpoint dated March 17, 2015, and amended and restated in July 2016 and October 2017 (the “Founders Agreement”), Fortress is entitled to an annual equity fee on January 1 of each year equal to 2.5% of fully diluted outstanding equity of the Company, payable in Checkpoint common shares (“Annual Equity Fee”). The Annual Equity Fee was part of the consideration payable for formation of the Company, identification of certain assets, including the license contributed to Checkpoint by Fortress (see Note 4). The Company records the Annual Equity Fee in connection with the Founders Agreement with Fortress as contingent consideration. Contingent consideration is recorded when probable and reasonably estimable. Due to the nature of the Company’s assets and stage of development, future share prices and shares outstanding cannot be estimated prior to the issuance of the Annual Equity Fee. Due to these uncertainties, the Company has concluded that it is unable to reasonably estimate the contingent consideration until shares are actually issued on January 1 of each year. Pursuant to the Founders Agreement, the Company issued 368,907 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of Checkpoint on January 1, 2023. Because the number of outstanding shares issuable to Fortress was determinable on January 1, 2023 prior to the issuance of the December 31, 2022 financial statements, the Company recorded approximately $1.9 million in research and development expense and a credit to Common shares issuable - Founders Agreement during the year ended December 31, 2022.
Stock-Based Compensation Expenses	Stock-Based Compensation Expenses The Company expenses stock-based compensation over the requisite service period based on the estimated grant-date fair value of the awards and forfeiture rates. The Company accounts for forfeitures as they occur. The Company estimates the fair value of stock option grants using the Black-Scholes Model. The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the Condensed Statements of Operations based upon the underlying individual’s role at the Company.
Common Stock Warrant Liability	Common Stock Warrant Liability The Company has issued freestanding warrants to purchase shares of its common stock in connection with its financing activities and accounts for them in accordance with applicable accounting guidance as either liabilities or as equity instruments depending on the specific terms of the warrant agreements. Warrants classified as liabilities are remeasured each period they are outstanding. Any resulting gain or loss related to the change in the fair value of the warrant liability is recognized in gain (loss) on common stock warrant liabilities, a component of other income (expense), in the Condensed Statements of Operations. The Company estimates the fair value of common stock warrant liabilities using the Black-Scholes Model. The assumptions used in calculating the fair value represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment.
Fair Value Measurement	Fair Value Measurement The Company follows the accounting guidance in ASC 820 for its fair value measurements of financial assets and liabilities measured at fair value on a recurring basis. Under this accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to their liquid or short-term nature, such as accounts payable and accrued expenses.
Revenue from Contracts with Customers	Revenue from Contracts with Customers The Company recognizes revenue under ASC 606, “ Revenue from Contracts with Customers ● Step 1: Identify the contract with the customer. ● Step 2: Identify the performance obligations in the contract. ● Step 3: Determine the transaction price. ● Step 4: Allocate the transaction price to the performance obligations in the contract. ● Step 5: Recognize revenue when the company satisfies a performance obligation. In order to identify the performance obligations in a contract with a customer, a company must assess the promised goods or services in the contract and identify each promised good or service that is distinct. A performance obligation meets ASC 606’s definition of a “distinct” good or service (or bundle of goods or services) if both of the following criteria are met: ● the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct); and ● the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract). If a good or service is not distinct, the good or service is combined with other promised goods or services until a bundle of goods or services is identified that is distinct. The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration promised in a contract with a customer may include fixed amounts, variable amounts, or both. When determining the transaction price, an entity must consider the effects of all of the following: ● variable consideration; ● constraining estimates of variable consideration; ● the existence of a significant financing component in the contract; ● noncash consideration; and ● consideration payable to a customer. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The transaction price allocated to each performance obligation is recognized when that performance obligation is satisfied, at a point in time or over time as appropriate. Revenue for a sales-based or usage-based royalty promised in exchange for a license of intellectual property is recognized only when (or as) the later of the following events occurs: a. the subsequent sale or usage occurs; and b. the performance obligation to which some or all of the sales-based or usage-based royalty has been allocated has been satisfied (or partially satisfied). Incremental contract costs are expensed when incurred when the amortization period of the asset that would have been recognized is one year or less; otherwise, incremental contract costs are recognized as an asset and amortized over time as services are provided to a customer.
Income Taxes	Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax effects attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and operating loss and tax credit carryforwards. The Company establishes a valuation allowance if management believes it is more likely than not that the deferred tax assets will not be recovered based on an evaluation of objective verifiable evidence. For tax positions that are more likely than not to be sustained upon audit, the Company recognizes the largest amount with a greater than 50% likelihood of being realized. The Company does not recognize any portion of the benefit for tax positions that are not more likely than not to be sustained upon audit. As of June 30, 2023 and December 31, 2022, the Company determined, based upon available evidence, that it is more likely than not that the net deferred tax asset will not be realized and, accordingly, has provided a full valuation allowance against its net deferred tax asset.
Net Loss per Share	Net Loss per Share Net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share does not reflect the effect of shares of common stock to be issued upon the exercise of stock options and warrants, as their inclusion would be anti-dilutive. The following table summarizes potentially dilutive securities outstanding at June 30, 2023 and 2022 that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ 2023 2022 Warrants (Note 6) 17,873,125 ​ 1,249 Stock options (Note 6) 127,000 ​ 31,000 Unvested restricted stock (Note 6) ​ 1,333,211 ​ 388,321 Unvested restricted stock units (Note 6) 619,884 ​ — Total 19,953,220 ​ 420,570 ​
Comprehensive Loss	Comprehensive Loss The Company has no components of comprehensive loss other than net loss. Thus, comprehensive loss is the same as net loss for the periods presented.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements During the six-month period ended June 30, 2023, there were no new accounting pronouncements or updates to recently issued accounting pronouncements as disclosed in the Company’s Form 10-K for the year ended December 31, 2022 that affect the Company’s present or future results of operations, overall financial condition, liquidity or disclosures.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2023
Significant Accounting Policies
Summary of potentially dilutive securities outstanding, that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ 2023 2022 Warrants (Note 6) 17,873,125 ​ 1,249 Stock options (Note 6) 127,000 ​ 31,000 Unvested restricted stock (Note 6) ​ 1,333,211 ​ 388,321 Unvested restricted stock units (Note 6) 619,884 ​ — Total 19,953,220 ​ 420,570

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2023
Stockholders' Equity
Summary of restricted stock award activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ Number of ​ Grant Date Fair ​ Shares Value Non-vested at December 31, 2022 ​ 378,897 ​ $ 26.15 Granted ​ 1,103,698 ​ ​ 2.33 Forfeited ​ (45,100) ​ ​ 6.89 Vested ​ (104,284) ​ ​ 24.99 Non-vested at June 30, 2023 ​ 1,333,211 ​ $ 7.17
Summary of restricted stock units activity	​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ Number of ​ Grant Date Fair ​ ​ Shares ​ Value Non-vested at December 31, 2022 85,000 ​ $ 10.50 Granted 577,384 ​ 2.25 Vested ​ (42,500) ​ ​ 10.50 Non-vested at June 30, 2023 619,884 ​ $ 2.82
Summary of stock option award activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ Remaining ​ ​ ​ ​ Weighted Average ​ Contractual Life ​ Stock Options Exercise Price (in years) Outstanding as of December 31, 2022 ​ 27,000 ​ $ 31.35 ​ 6.44 Granted ​ 100,000 ​ ​ 2.81 ​ — Outstanding as of June 30, 2023 ​ 127,000 ​ $ 8.88 ​ 9.10 Vested and exercisable as of June 30, 2023 ​ 19,500 ​ $ 24.68 ​ 6.54
Summary of stock options assumptions used	​ ​ ​ ​ ​ ​ ​ ​ ​ For the Six Months Ended June 30, ​ ​ 2023 ​ 2022 Risk-free interest rate 3.73 % 1.30 % Expected dividend yield — — ​ Expected term in years 10.0 10.0 ​ Expected volatility 83.48 % 100.65 %
Summary of warrant activities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ Remaining ​ ​ ​ ​ Weighted Average ​ Contractual Life ​ Warrants Exercise Price (in years) Outstanding as of December 31, 2022 ​ 4,357,597 ​ $ 3.37 ​ 3.26 Granted ​ 15,007,613 ​ ​ 3.05 ​ — Exercised ​ (1,492,085) ​ ​ — ​ — Outstanding as of June 30, 2023 ​ 17,873,125 ​ $ 3.39 ​ 3.03
Summary of stock-based compensation expense	The following table summarizes stock-based compensation expense for the three and six months ended June 30, 2023 and 2022 ($ in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the three months ended June 30, ​ For the six months ended June 30, ​ 2023 2022 2023 2022 Research and development ​ $ 187 ​ $ 229 ​ $ 577 ​ $ 476 General and administrative ​ 380 ​ 500 ​ 959 ​ 1,028 Total stock-based compensation expense ​ $ 567 ​ $ 729 ​ $ 1,536 ​ $ 1,504

Common Stock Warrant Liabilit_2

Common Stock Warrant Liabilities (Tables)	6 Months Ended
	Jun. 30, 2023
Common Stock Warrant Liabilities
Summary of common stock warrant liabilities	​ ​ ​ ​ ​ Common Stock Warrant liabilities at December 31, 2022 $ 11,170 Change in fair value of Common Stock Warrant liabilities ​ ​ (7,209) Common Stock Warrant liabilities at June 30, 2023 ​ $ 3,961
Summary of the weighted average (in aggregate) significant unobservable inputs used in measuring the warrant liability that are categorized within Level 3 of the fair value hierarchy	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, Series A Warrants ​ 2023 ​ 2022 Exercise price ​ $ 4.08 ​ $ 4.08 ​ Volatility ​ 90.7 % 89.4 % Expected life ​ 4.5 ​ 5.0 ​ Risk-free rate ​ 4.1 % 4.0 % Dividend yield ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, Series B Warrants ​ 2023 ​ 2022 Exercise price ​ $ 4.08 ​ $ 4.08 ​ Volatility ​ 108.2 % 82.4 % Expected life ​ 1.0 ​ 1.5 ​ Risk-free rate ​ 5.4 % 4.7 % Dividend yield ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, Placement Agent Warrants ​ 2023 ​ 2022 Exercise price ​ $ 5.41 ​ $ 5.41 ​ Volatility ​ 90.7 % 89.4 % Expected life ​ 4.5 ​ 5.0 ​ Risk-free rate ​ 4.1 % 4.0 % Dividend yield ​ — ​ — ​

Accounts Payable and Accrued _2

Accounts Payable and Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2023
Accounts Payable and Accrued Expenses
Schedule of accounts payable and accrued expenses	At June 30, 2023 and December 31, 2022, accounts payable and accrued expenses consisted of the following ($ in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2023 2022 Accounts payable ​ $ 8,058 ​ $ 11,535 Accrued compensation ​ ​ 700 ​ 1,195 Research and development ​ 16,149 ​ 7,289 Other ​ 287 ​ 278 Total accounts payable and accrued expenses ​ $ 25,194 ​ $ 20,297

Organization and Description _2

Organization and Description of Business Operations (Details) $ / shares in Units, $ in Thousands		1 Months Ended
	Nov. 03, 2022 Vote shares	Jul. 31, 2023 USD ($) $ / shares shares	May 31, 2023 USD ($) $ / shares shares	Apr. 30, 2023 USD ($) $ / shares shares	Feb. 28, 2023 USD ($) $ / shares shares	Jun. 30, 2023 USD ($) Vote multiplier shares	Dec. 31, 2022 USD ($)
Organization and Description of Business Operations
Reverse stock split, conversion ratio	0.1
Number of votes per share | Vote						1
Multiplier to calculate voting rights per class A common share	13.5					1.1
Percentage of voting power held by shareholders who signed the written consent to effect a reverse stock split	58%
Period after mailing of information statement to the common stockholders of record, that the reverse stock split will become effective	20 days
Accumulated deficit | $						$ (289,481)	$ (262,486)
Common Shares
Organization and Description of Business Operations
Number of shares held by shareholders who signed the written consent to effect a reverse stock split	10,914,552
Number of votes per share | Vote	1
February 2023 Registered Direct Offering
Organization and Description of Business Operations
Number of shares issued and sold					1,180,000
Purchase price per share | $ / shares					$ 5.25
Number of warrants issued					248,572
Gross proceeds | $					$ 7,500
Net proceeds from offering | $					6,700
Amount of commissions and other transaction costs | $					$ 800
February 2023 Registered Direct Offering | Pre-Funded Warrants
Organization and Description of Business Operations
Number of warrants issued					248,572
Price of warrant | $ / shares					$ 5.2499
February 2023 Registered Direct Offering | Series A warrants
Organization and Description of Business Operations
Expiration term of warrants (in years)					5 years
Price of warrant | $ / shares					$ 5
Number of warrants issued and sold to purchase shares					1,428,572
February 2023 Registered Direct Offering | Series A warrants | Maximum
Organization and Description of Business Operations
Number of shares issued and sold					1,428,572
February 2023 Registered Direct Offering | Series B warrants
Organization and Description of Business Operations
Expiration term of warrants (in years)					18 months
Price of warrant | $ / shares					$ 5
Number of warrants issued and sold to purchase shares					1,428,572
February 2023 Registered Direct Offering | Series B warrants | Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares					1,428,572
April 2023 Registered Direct Offering
Organization and Description of Business Operations
Number of shares issued and sold				1,700,000
Purchase price per share | $ / shares				$ 3.60
Gross proceeds | $				$ 6,100
Net proceeds from offering | $				5,500
Amount of commissions and other transaction costs | $				$ 600
April 2023 Registered Direct Offering | Series A warrants
Organization and Description of Business Operations
Expiration term of warrants (in years)				5 years
Price of warrant | $ / shares				$ 3.35
Number of warrants issued and sold to purchase shares				1,700,000
April 2023 Registered Direct Offering | Series A warrants | Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares				1,700,000
April 2023 Registered Direct Offering | Series B warrants
Organization and Description of Business Operations
Expiration term of warrants (in years)				18 months
Price of warrant | $ / shares				$ 3.35
Number of warrants issued and sold to purchase shares				1,700,000
April 2023 Registered Direct Offering | Series B warrants | Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares				1,700,000
May 2023 Registered Direct Offering
Organization and Description of Business Operations
Number of shares issued and sold			1,650,000
Purchase price per share | $ / shares			$ 3.071
Number of warrants issued			1,606,269
Price of warrant | $ / shares			$ 3.0709
Gross proceeds | $			$ 10,000
Net proceeds from offering | $			9,100
Amount of commissions and other transaction costs | $			$ 900
May 2023 Registered Direct Offering | Pre-Funded Warrants
Organization and Description of Business Operations
Number of warrants issued			1,606,269
Price of warrant | $ / shares			$ 3.0709
May 2023 Registered Direct Offering | Series A warrants
Organization and Description of Business Operations
Expiration term of warrants (in years)			5 years
Price of warrant | $ / shares			$ 2.821
May 2023 Registered Direct Offering | Series A warrants | Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares			3,256,269
May 2023 Registered Direct Offering | Series B warrants
Organization and Description of Business Operations
Expiration term of warrants (in years)			18 months
Price of warrant | $ / shares			$ 2.821
Number of warrants issued and sold to purchase shares			3,256,269
May 2023 Registered Direct Offering | Series B warrants | Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares			3,256,269
July 2023 Registered Direct Offering | Subsequent Event
Organization and Description of Business Operations
Number of shares issued and sold		2,427,186
Purchase price per share | $ / shares		$ 3.09
Gross proceeds | $		$ 10,000
Net proceeds from offering | $		9,100
Amount of commissions and other transaction costs | $		$ 900
July 2023 Registered Direct Offering | Pre-Funded Warrants | Subsequent Event
Organization and Description of Business Operations
Price of warrant | $ / shares		$ 3.0899
Number of warrants issued and sold to purchase shares		809,062
July 2023 Registered Direct Offering | Series A warrants | Subsequent Event
Organization and Description of Business Operations
Expiration term of warrants (in years)		5 years
Price of warrant | $ / shares		$ 2.84
July 2023 Registered Direct Offering | Series A warrants | Maximum | Subsequent Event
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares		3,236,248
July 2023 Registered Direct Offering | Series B warrants | Subsequent Event
Organization and Description of Business Operations
Expiration term of warrants (in years)		18 months
Price of warrant | $ / shares		$ 2.84
July 2023 Registered Direct Offering | Series B warrants | Maximum | Subsequent Event
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares		3,236,248
Class A Common Shares
Organization and Description of Business Operations
Number of shares held by shareholders who signed the written consent to effect a reverse stock split	7,000,000
Number of votes per share | Vote	1.1
2015 Incentive Plan
Organization and Description of Business Operations
Number of shares available for issuance authorized						6,000,000
2015 Incentive Plan | Maximum
Organization and Description of Business Operations
Number of shares available for issuance authorized	3,000,000
2015 Incentive Plan | Minimum
Organization and Description of Business Operations
Number of shares available for issuance authorized	900,000

Significant Accounting Polici_4

Significant Accounting Policies (Details) - USD ($) $ in Millions		6 Months Ended	12 Months Ended
	Jan. 01, 2023	Jun. 30, 2023	Dec. 31, 2022	Mar. 17, 2015
Significant Accounting Policies
Percentage of shares issued for offering and annual equity fee				2.50%
Fortress Biotech, Inc
Significant Accounting Policies
Percentage of shares issued for offering and annual equity fee	2.50%
Number of shares issued and sold	368,907	159,620
Research and development
Significant Accounting Policies
Value of common stock shares issued			$ 1.9

Significant Accounting Polici_5

Significant Accounting Policies - Net Loss per Share (Details) - $ / shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	May 31, 2023
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	19,953,220	420,570
May 2023 Registered Direct Offering
Significant Accounting Policies
Price of warrant			$ 3.0709
May 2023 Registered Direct Offering | Pre-Funded Warrants
Significant Accounting Policies
Price of warrant			$ 3.0709
Warrants
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	17,873,125	1,249
Stock options
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	127,000	31,000
Unvested restricted stock
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	1,333,211	388,321
Unvested restricted stock units
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	619,884

License Agreements (Details)

License Agreements (Details)	1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2015 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Feb. 28, 2023 USD ($)	Jan. 31, 2019 USD ($)	May 31, 2016 USD ($) item
NeuPharma, Inc. | Additional sales milestone
License Agreements
Maximum potential milestone payments	$ 40,000,000
NeuPharma, Inc. | Clinical and development milestone
License Agreements
Maximum potential milestone payments	39,000,000
NeuPharma, Inc. | Regulatory approvals to commercialize the products
License Agreements
Maximum potential milestone payments	22,500,000
Dana-Farber Cancer Institute
License Agreements
Maintenance fee	50,000
Dana-Farber Cancer Institute | First commercial sale milestone
License Agreements
Maximum potential milestone payments	21,500,000
Dana-Farber Cancer Institute | Additional sales milestone
License Agreements
Maximum potential milestone payments	$ 60,000,000
Revenue recognition milestone payments		$ 60,000,000		$ 60,000,000
Jubilant Biosys Limited | Additional sales milestone
License Agreements
Maximum potential milestone payments								$ 89,300,000
Jubilant Biosys Limited | Clinical and development milestone
License Agreements
Maximum potential milestone payments								88,400,000
Jubilant Biosys Limited | Regulatory approvals to commercialize the products
License Agreements
Maximum potential milestone payments								$ 59,500,000
Adimab, LLC | PD-L1 | Research and development
License Agreements
Non-Refundable milestone payment						$ 2,200,000
Adimab, LLC | Clinical and development milestone
License Agreements
Maximum potential milestone payments							$ 2,500,000
Collaboration Agreement With TGTX
License Agreements
Revenue recognition milestone revenue recognized		12,000,000	$ 16,000,000	41,000	$ 47,000
Collaboration Agreement With TGTX | First commercial sale milestone | PD-L1
License Agreements
Revenue recognition milestone payments		27,600,000		27,600,000
Collaboration Agreement With TGTX | First commercial sale milestone | PD-L1 GITR
License Agreements
Revenue recognition milestone payments		21,500,000		21,500,000
Collaboration Agreement With TGTX | Clinical and development milestone | PD-L1 GITR
License Agreements
Revenue recognition milestone payments		7,000,000		7,000,000
Collaboration Agreement With TGTX | Commercial sales In specified territories | PD-L1
License Agreements
Revenue recognition milestone payments		19,200,000		19,200,000
Collaboration Agreement With TGTX | Commercial sales In specified territories | PD-L1 GITR
License Agreements
Revenue recognition milestone payments		14,500,000		14,500,000
Collaboration Agreement With TGTX | Clinical development and regulatory milestones | PD-L1
License Agreements
Revenue recognition milestone payments		8,400,000		8,400,000
Sublicense Agreement with TGTX
License Agreements
Research and development cost								50%
Number of clinical development milestones | item								3
Number of licensed products | item								2
Sublicense Agreement with TGTX | Additional sales milestone
License Agreements
Revenue recognition milestone payments								$ 89,300,000
Sublicense Agreement with TGTX | Clinical and development milestone
License Agreements
Revenue recognition milestone payments								25,500,000
Sublicense Agreement with TGTX | Five regulatory approvals and first commercial sales
License Agreements
Revenue recognition milestone payments								61,900,000
Sublicense Agreement with TGTX | Clinical development and regulatory milestones
License Agreements
Revenue recognition milestone payments								$ 87,400,000
Collaboration Agreement With GITR
License Agreements
Revenue recognition milestone revenue recognized		$ 18,000,000	$ 2,000,000	$ 24,000	$ 23,000

Related Party Agreements (Detai

Related Party Agreements (Details)		1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 17, 2015 USD ($) item	Dec. 31, 2016 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)
Fortress Biotech, Inc | Founders Agreement
Related Party Agreements
Long term debt	$ 2,800,000
Issuance of common stock, percentage of outstanding diluted equity	2.50%
Number of business days	5 days
Voting equity, percentage of equity or debt financing	2.50%
Cash fee, percentage of annual net sales	4.50%
Cash fees, maximum number of days	90 days
Control fees, number of times | item	5
Control fees, monthly net sales	12 months
Cash fee, percentage of monthly net sales	4.50%
Agreement term	15 years
Agreement renewal term	1 year
Fortress Biotech, Inc | Management Services Agreement
Related Party Agreements
Number of period	5 years
Annual consulting fee	$ 500,000
Increase in annual consulting fee	1,000,000
Excess in net assets value	$ 100,000,000
Agreement extension term	5 years
Costs and expenses, related party			$ 125,000	$ 125,000	$ 250,000	$ 250,000
Caribe Bioadvisors LLC
Related Party Agreements
Annual advisory service fee		$ 60,000
Costs and expenses, related party			27,000	28,000	54,000	55,000
Caribe Bioadvisors LLC | Equity Incentive Grants
Related Party Agreements
Costs and expenses, related party			$ 12,000	$ 13,000	$ 24,000	$ 25,000

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Commitments and Contingencies
Litigation	$ 0	$ 0

Stockholders' Equity - Restrict

Stockholders' Equity - Restricted Stock Awards (Details) - Restricted Stock	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Stockholders' Equity
Non-vested beginning balance | shares	378,897
Number of Shares, Granted | shares	1,103,698
Number of Shares, Forfeited | shares	(45,100)
Number of Shares, Vested | shares	(104,284)
Non-vested ending balance | shares	1,333,211
Weighted Average Exercise Price, beginning balance | $ / shares	$ 26.15
Weighted Average Grant Date Fair Value, Granted | $ / shares	2.33
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	6.89
Weighted Average Grant Date Fair Value, Vested | $ / shares	24.99
Weighted Average Exercise Price , ending balance | $ / shares	$ 7.17

Stockholders' Equity - Restri_2

Stockholders' Equity - Restricted Stock Units (Details) - Unvested restricted stock units	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Number of Shares
Non-vested beginning balance | shares	85,000
Number of Shares, Granted | shares	577,384
Number of Shares, Vested | shares	(42,500)
Non-vested ending balance | shares	619,884
Weighted Average Grant Date Fair Value
Weighted Average Exercise Price, beginning balance | $ / shares	$ 10.50
Weighted Average Exercise Price Granted | $ / shares	2.25
Weighted Average Grant Date Fair Value, Vested | $ / shares	10.50
Weighted Average Exercise Price , ending balance | $ / shares	$ 2.82

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options (Details) - Stock Options - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Stockholders' Equity
Stock options, Outstanding (beginning)	27,000
Stock options, Granted	100,000
Stock options, Outstanding (ending)	127,000	27,000
Vested and exercisable as of June 30, 2023	19,500
Weighted Average Exercise Price, Outstanding (beginning)	$ 31.35
Weighted Average Exercise Price, Granted	2.81
Weighted Average Exercise Price, Outstanding (ending)	8.88	$ 31.35
Weighted Average Exercise Price, Vested and exercisable as of June 30, 2023	$ 24.68
Weighted Average Remaining Contractual Life, Outstanding (in years)	9 years 1 month 6 days	6 years 5 months 8 days
Weighted Average Remaining Contractual Life, Vested and exercisable as of June 30, 2023 (in years)	6 years 6 months 14 days

Stockholders' Equity - Black-Sc

Stockholders' Equity - Black-Scholes Model (Details)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Stockholders' Equity
Risk-free interest rate	3.73%	1.30%
Expected term in years	10 years	10 years
Expected volatility	83.48%	100.65%

Stockholders' Equity - Warrants

Stockholders' Equity - Warrants (Details) - Warrants - $ / shares	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Warrants, Outstanding beginning balance	4,357,597
Warrants, Granted	15,007,613
Warrants, Exercised	(1,492,085)
Warrants, Outstanding ending balance	17,873,125
Warrants, Weighted Average Exercise Price, beginning balance	$ 3.37
Weighted Average Exercise Price, Granted	3.05
Warrants, Weighted Average Exercise Price, Exercised	0
Warrants, Weighted Average Exercise Price, ending balance	$ 3.39
Warrants, Remaining contractual life	3 years 10 days	3 years 3 months 3 days

Stockholders' Equity - Stock-Ba

Stockholders' Equity - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Stockholders' Equity
Total stock-based compensation expense	$ 567	$ 729	$ 1,536	$ 1,504
Research and development
Stockholders' Equity
Total stock-based compensation expense	187	229	577	476
General and administrative
Stockholders' Equity
Total stock-based compensation expense	$ 380	$ 500	$ 959	$ 1,028

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) $ / shares in Units, $ in Thousands

1 Months Ended

3 Months Ended

6 Months Ended

Jan. 01, 2023 shares

Jul. 31, 2023 USD ($) $ / shares shares

May 31, 2023 USD ($) $ / shares shares

Apr. 30, 2023 USD ($) $ / shares shares

Feb. 28, 2023 USD ($) $ / shares shares

Jun. 30, 2023 USD ($) Vote multiplier $ / shares shares

Jun. 30, 2022 USD ($)

Jun. 30, 2023 USD ($) Vote multiplier $ / shares shares

Jun. 30, 2022 USD ($)

Jun. 12, 2023 $ / shares shares

Mar. 31, 2023 USD ($)

Dec. 31, 2022 $ / shares shares

Nov. 03, 2022 Vote shares

Nov. 30, 2020 USD ($)

Mar. 17, 2015

Stockholders' Equity

Common stock, increase in the number of authorized shares (in shares)

30,000,000

Common stock, shares authorized

80,000,000

80,000,000

80,000,000

50,000,000

Common stock, par value (in dollars per share) | $ / shares

$ 0.0001

$ 0.0001

$ 0.0001

$ 0.0001

Common stock, shares outstanding

17,238,393

17,238,393

9,586,683

Number of votes per share | Vote

1

1

Multiplier to calculate voting rights per class A common share

1.1

1.1

13.5

Number of non assessable shares issued upon conversion

1

1

Shelf registration statement, maximum authorized securities | $

$ 100,000

Issuance of common shares - Founders agreement | $

$ 402

$ 17

$ 558

$ 213

Equity Method Investment, Annual Equity Fee, Percentage

2.50%

Non-vested restricted stock

Stockholders' Equity

Total unrecognized compensation cost related to non-vested | $

$ 3,600

$ 3,600

Weighted average period (in years)

2 years 1 month 6 days

Performance Shares

Stockholders' Equity

Restricted stock outstanding non-vested

196,733

196,733

2015 Incentive Plan

Stockholders' Equity

Number of shares available for issuance authorized

6,000,000

6,000,000

Plans expires (in years)

10 years

Shares are available for issuance

3,496,830

3,496,830

Maximum | 2015 Incentive Plan

Stockholders' Equity

Number of shares available for issuance authorized

3,000,000

Minimum | 2015 Incentive Plan

Stockholders' Equity

Number of shares available for issuance authorized

900,000

At the market offering (ATM)

Stockholders' Equity

Percentage of annual equity fee

2.50%

Number of shares issued and sold

368,907

Gross proceeds | $

8,910

Amount of commissions and other transaction costs | $

$ 223

February 2023 Registered Direct Offering

Stockholders' Equity

Purchase price per share | $ / shares

$ 5.25

Number of shares issued and sold

1,180,000

Number of warrants issued

248,572

Gross proceeds | $

$ 7,500

Net proceeds from offering | $

6,700

Amount of commissions and other transaction costs | $

$ 800

February 2023 Registered Direct Offering | Pre-Funded Warrants

Stockholders' Equity

Number of warrants issued

248,572

Price of warrant | $ / shares

$ 5.2499

February 2023 Registered Direct Offering | Series A warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,428,572

Price of warrant | $ / shares

$ 5

Expiration term of warrants (in years)

5 years

February 2023 Registered Direct Offering | Series B warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,428,572

Price of warrant | $ / shares

$ 5

Expiration term of warrants (in years)

18 months

February 2023 Registered Direct Offering | Maximum | Series A warrants

Stockholders' Equity

Number of shares issued and sold

1,428,572

February 2023 Registered Direct Offering | Maximum | Series B warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,428,572

April 2023 Direct Offering

Stockholders' Equity

Purchase price per share | $ / shares

$ 3.60

Commissions and other transaction costs | $

$ 600

Shelf registration statement remaining authorized securities | $

$ 8,700

$ 8,700

$ 150,000

Number of shares issued and sold

1,700,000

Gross proceeds | $

$ 6,100

Net proceeds from offering | $

5,500

Amount of commissions and other transaction costs | $

$ 600

April 2023 Direct Offering | Series A warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,700,000

Price of warrant | $ / shares

$ 3.35

Expiration term of warrants (in years)

5 years

April 2023 Direct Offering | Series B warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,700,000

Price of warrant | $ / shares

$ 3.35

Expiration term of warrants (in years)

18 months

April 2023 Direct Offering | Maximum | Series A warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,700,000

April 2023 Direct Offering | Maximum | Series B warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,700,000

May 2023 Registered Direct Offering

Stockholders' Equity

Purchase price per share | $ / shares

$ 3.071

Number of shares issued and sold

1,650,000

Number of warrants issued

1,606,269

Price of warrant | $ / shares

$ 3.0709

Gross proceeds | $

$ 10,000

Net proceeds from offering | $

9,100

Amount of commissions and other transaction costs | $

$ 900

May 2023 Registered Direct Offering | Pre-Funded Warrants

Stockholders' Equity

Number of warrants issued

1,606,269

Price of warrant | $ / shares

$ 3.0709

Class of Warrant or Right, Exercised

459,269

May 2023 Registered Direct Offering | Series A warrants

Stockholders' Equity

Price of warrant | $ / shares

$ 2.821

Expiration term of warrants (in years)

5 years

May 2023 Registered Direct Offering | Series B warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,256,269

Price of warrant | $ / shares

$ 2.821

Expiration term of warrants (in years)

18 months

May 2023 Registered Direct Offering | Maximum | Series A warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,256,269

May 2023 Registered Direct Offering | Maximum | Series B warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,256,269

July 2023 Registered Direct Offering | Subsequent Event

Stockholders' Equity

Purchase price per share | $ / shares

$ 3.09

Number of shares issued and sold

2,427,186

Gross proceeds | $

$ 10,000

Net proceeds from offering | $

9,100

Amount of commissions and other transaction costs | $

$ 900

July 2023 Registered Direct Offering | Subsequent Event | Pre-Funded Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

809,062

Price of warrant | $ / shares

$ 3.0899

July 2023 Registered Direct Offering | Subsequent Event | Series A warrants

Stockholders' Equity

Price of warrant | $ / shares

$ 2.84

Expiration term of warrants (in years)

5 years

July 2023 Registered Direct Offering | Subsequent Event | Series B warrants

Stockholders' Equity

Price of warrant | $ / shares

$ 2.84

Expiration term of warrants (in years)

18 months

July 2023 Registered Direct Offering | Maximum | Subsequent Event | Series A warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,236,248

July 2023 Registered Direct Offering | Maximum | Subsequent Event | Series B warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,236,248

Fortress

Stockholders' Equity

Issuance of common shares - Founders agreement | $

600

Shelf registration statement remaining authorized securities | $

$ 120,900

$ 120,900

Percentage of annual equity fee

2.50%

Equity Method Investment, Annual Equity Fee, Percentage

2.50%

Number of shares issued and sold

368,907

159,620

Agent

Stockholders' Equity

Commission rate

3%

Common Class A

Stockholders' Equity

Common stock, shares authorized

700,000

Common stock, shares outstanding

700,000

700,000

700,000

Common Stock Warrant Liabilit_3

Common Stock Warrant Liabilities (Details) - Common Stock Warrant Liabilities $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)
Common Stock Warrant Liabilities
Balance at the beginning	$ 11,170
Change in fair value of Common Stock Warrant liabilities	(7,209)
Balance at the end	$ 3,961

Common Stock Warrant Liabilit_4

Common Stock Warrant Liabilities - Summary of the weighted average (in aggregate) significant unobservable inputs used in measuring the warrant liability that are categorized within Level 3 of the fair value hierarchy (Details) - Level 3	Jun. 30, 2023 Y $ / shares	Dec. 31, 2022 Y $ / shares
Series A warrants | Exercise price
Common Stock Warrant Liabilities
Measurement input | $ / shares	4.08	4.08
Series A warrants | Volatility
Common Stock Warrant Liabilities
Measurement input	0.907	0.894
Series A warrants | Expected life
Common Stock Warrant Liabilities
Measurement input | Y	4.5	5
Series A warrants | Risk-free rate
Common Stock Warrant Liabilities
Measurement input	0.041	0.040
Series B warrants | Exercise price
Common Stock Warrant Liabilities
Measurement input | $ / shares	4.08	4.08
Series B warrants | Volatility
Common Stock Warrant Liabilities
Measurement input	1.082	0.824
Series B warrants | Expected life
Common Stock Warrant Liabilities
Measurement input | Y	1	1.5
Series B warrants | Risk-free rate
Common Stock Warrant Liabilities
Measurement input	0.054	0.047
Placement agent warrants | Exercise price
Common Stock Warrant Liabilities
Measurement input | $ / shares	5.41	5.41
Placement agent warrants | Volatility
Common Stock Warrant Liabilities
Measurement input	0.907	0.894
Placement agent warrants | Expected life
Common Stock Warrant Liabilities
Measurement input | Y	4.5	5
Placement agent warrants | Risk-free rate
Common Stock Warrant Liabilities
Measurement input	0.041	0.040

Common Stock Warrant Liabilit_5

Common Stock Warrant Liabilities - Additional Information (Details) - December 2022 Direct Offering - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Common Stock Warrant Liabilities
Fair value of common stock warrants and placement agent warrants		$ 11.2
Common Stock Warrant Liabilities
Common Stock Warrant Liabilities
Increase in common stock warrant liability	$ 7.2

Accounts Payable and Accrued _3

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Accounts Payable and Accrued Expenses
Accounts payable	$ 8,058	$ 11,535
Accrued compensation	700	1,195
Research and development	16,149	7,289
Other	287	278
Total accounts payable and accrued expenses	$ 25,194	$ 20,297

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - July 2023 Registered Direct Offering $ / shares in Units, $ in Millions	1 Months Ended
	Jul. 31, 2023 USD ($) $ / shares shares
Subsequent Events
Number of shares issued and sold | shares	2,427,186
Purchase price per share | $ / shares	$ 3.09
Gross proceeds | $	$ 10
Net proceeds from offering | $	9.1
Amount of commissions and other transaction costs | $	$ 0.9
Series A warrants
Subsequent Events
Expiration term of warrants (in years)	5 years
Price of warrant | $ / shares	$ 2.84
Series B warrants
Subsequent Events
Expiration term of warrants (in years)	18 months
Price of warrant | $ / shares	$ 2.84
Pre-Funded Warrants
Subsequent Events
Number of warrants issued and sold to purchase shares | shares	809,062
Price of warrant | $ / shares	$ 3.0899
Maximum | Series A warrants
Subsequent Events
Number of warrants issued and sold to purchase shares | shares	3,236,248
Maximum | Series B warrants
Subsequent Events
Number of warrants issued and sold to purchase shares | shares	3,236,248