Curis (CRIS) 10-Q 7 May 24 2024 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2024	Apr. 30, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	000-30347
Entity Registrant Name	CURIS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3505116
Entity Address, Address Line One	128 Spring Street
Entity Address, Address Line Two	Building C - Suite 500
Entity Address, City or Town	Lexington
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02421
City Area Code	617
Local Phone Number	503-6500
Title of 12(b) Security	Common Stock, Par Value $0.01 per share
Trading Symbol	CRIS
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	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		5,894,085
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001108205
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 29,956	$ 26,681
Short-term investments	10,764	29,653
Accounts receivable	2,154	2,794
Prepaid expenses and other current assets	3,192	1,780
Total current assets	46,066	60,908
Property and equipment, net	370	434
Restricted cash, long-term	544	544
Operating lease right-of-use asset	2,704	3,056
Other assets	3,358	3,358
Goodwill	8,982	8,982
Total assets	62,024	77,282
Current liabilities:
Accounts payable	3,628	3,172
Accrued liabilities	6,326	9,040
Current portion of operating lease liability	1,349	1,305
Total current liabilities	11,303	13,517
Long-term operating lease liability	1,137	1,489
Liability related to the sale of future royalties, net	40,122	42,606
Total liabilities	52,562	57,612
Stockholders’ equity:
Preferred stock, $0.01 par value—5,000,000 shares authorized, no shares issued and outstanding at March 31, 2024 and December 31, 2023	0	0
Common stock, $0.01 par value—22,781,250 shares authorized, 5,894,085 shares issued and outstanding at March 31, 2024 and December 31, 2023	59	59
Additional paid-in capital	1,217,351	1,215,792
Accumulated deficit	(1,208,286)	(1,196,410)
Accumulated other comprehensive gain	338	229
Total stockholders’ equity	9,462	19,670
Total liabilities and stockholders’ equity	$ 62,024	$ 77,282
Common stock issued (in shares)	5,894,085	5,894,085
Common stock outstanding (in shares)	5,894,085	5,894,085
Common stock authorized (in shares)	22,781,250	22,781,250

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock authorized (in shares)	5,000,000	5,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (in shares)	22,781,250	22,781,250
Common stock issued (in shares)	5,894,085	5,894,085
Common stock outstanding (in shares)	5,894,085	5,894,085

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenues, net	$ 2,086	$ 2,297
Operating expenses:
Cost of royalties	47	24
Research and development	9,617	9,140
General and administrative	4,891	4,760
Total operating expenses	14,555	13,924
Loss from operations	(12,469)	(11,627)
Other income:
Interest income	515	652
Income (expense) related to the sale of future royalties	78	(584)
Total other income	593	68
Net loss	$ (11,876)	$ (11,559)
Net loss per common share (basic ) (in dollars per share)	$ (2.05)	$ (2.39)
Net loss per common share (diluted) (in dollars per share)	$ (2.05)	$ (2.39)
Weighted average common shares (basic) (in shares)	5,783,585	4,830,763
Weighted average common shares (diluted) (in shares)	5,783,585	4,830,763
Net loss	$ (11,876)	$ (11,559)
Other comprehensive income:
Unrealized gain on marketable securities	109	195
Comprehensive loss	$ (11,767)	$ (11,364)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income
Beginning balance (in shares) at Dec. 31, 2022		4,830,464
Beginning balance at Dec. 31, 2022	$ 46,552	$ 48	$ 1,195,687	$ (1,148,997)	$ (186)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	1,395		1,395
Issuance of common stock under employee benefit plans (in shares)		516
Issuance of common stock under employee benefit plans	8	$ 1	7
Unrealized gain on marketable securities	195				195
Net loss	(11,559)			(11,559)
Ending balance (in shares) at Mar. 31, 2023		4,830,980
Ending balance at Mar. 31, 2023	$ 36,591	$ 49	1,197,089	(1,160,556)	9
Beginning balance (in shares) at Dec. 31, 2023	5,894,085	5,894,085
Beginning balance at Dec. 31, 2023	$ 19,670	$ 59	1,215,792	(1,196,410)	229
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	1,559		1,559
Unrealized gain on marketable securities	109				109
Net loss	$ (11,876)			(11,876)
Ending balance (in shares) at Mar. 31, 2024	5,894,085	5,894,085
Ending balance at Mar. 31, 2024	$ 9,462	$ 59	$ 1,217,351	$ (1,208,286)	$ 338

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (11,876)	$ (11,559)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	64	64
Non-cash lease expense	354	324
Stock-based compensation expense	1,559	1,395
Non-cash activity related to the sale of future royalties	(78)	(77)
Amortization of premiums and discounts on investments	84	(145)
Changes in operating assets and liabilities:
Accounts receivable	640	661
Prepaid expenses and other assets	(1,413)	(610)
Accounts payable and accrued liabilities	(2,258)	(1,984)
Operating lease liability	(308)	(268)
Total adjustments	(1,356)	(640)
Net cash used in operating activities	(13,232)	(12,199)
Cash flows from investing activities:
Purchase of investments	(10,737)	(17,682)
Sales and maturities of investments	29,650	43,925
Net cash provided by investing activities	18,913	26,243
Cash flows from financing activities:
Proceeds from issuance of common stock	0	7
Payment of liability of future royalties, net of imputed interest	(2,406)	(2,013)
Net cash used by financing activities	(2,406)	(2,006)
Net increase in cash and cash equivalents and restricted cash	3,275	12,038
Cash and cash equivalents and restricted cash, beginning of period	27,225	20,293
Cash and cash equivalents and restricted cash, end of period	30,500	32,331
Supplemental cash flow data:
Cash paid for interest	$ 0	$ 661

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business Curis, Inc. is a biotechnology company focused on the development of emavusertib (CA-4948), an orally available, small molecule inhibitor of Interleukin-1 receptor associated kinase, or IRAK4. Throughout these Condensed Consolidated Financial Statements, Curis, Inc. and its wholly owned subsidiaries are collectively referred to as the “Company” or “Curis”. The Company is party to a collaboration agreement with Genentech Inc. (“Genentech”), a member of the Roche Group, under which Genentech and F. Hoffmann-La Roche Ltd (“Roche”) are commercializing Erivedge® (vismodegib), a first-in-class orally administered small molecule Hedgehog signaling pathway antagonist. Erivedge is approved for the treatment of advanced basal cell carcinoma (“BCC”). The Company is party to an exclusive collaboration agreement with Aurigene Discovery Technologies Limited (“Aurigene”) for the discovery, development and commercialization of small molecule compounds in the areas of immuno-oncology and precision oncology, including emavusertib. The Company is subject to risks common to companies in the biotechnology industry as well as risks that are specific to the Company’s business, including, but not limited to: the Company’s ability to obtain adequate financing to fund its operations; the Company’s ability to continue as a going concern; the Company’s ability to advance and expand its research and development program for emavusertib; the Company’s ability to execute on its overall business strategies; the Company’s ability to obtain and maintain necessary intellectual property protection; development by the Company’s competitors of new or better technological innovations; the Company’s ability to comply with regulatory requirements; the Company’s ability to obtain and maintain applicable regulatory approvals and commercialize any approved drug candidates; and the ability of the Company and its wholly owned subsidiary, Curis Royalty, LLC (“Curis Royalty”), to satisfy the terms of the royalty interest purchase agreement (the “Oberland Purchase Agreement”) with entities managed by Oberland Capital Management, LLC (the “Purchasers”), and Lind SA LLC (the “Agent”), as collateral agent for the Purchasers. The Company’s future operating results will largely depend on the progress of emavusertib and the magnitude of payments that it may receive and make under its current and potential future collaborations. The results of the Company’s operations have varied and will likely continue to vary significantly from year to year and quarter to quarter and depend on a number of factors, including, but not limited to the timing, outcome and cost of the Company’s preclinical studies and clinical trials for its drug candidate. The Company will require substantial funds to maintain its research and development programs and support operations. The Company has incurred losses and cash outflows from operations since its inception. The Company had an accumulated deficit of $1.2 billion as of March 31, 2024, and incurred a net loss of $11.9 million and used $13.2 million of cash in operations for the three months ended March 31, 2024. The Company expects to continue to generate operating losses in the foreseeable future. In accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), the Company has concluded there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the Condensed Consolidated Financial Statements are issued. Based on the Company's $40.7 million of existing cash, cash equivalents and investments at March 31, 2024, recurring losses and cash outflows from operations since inception, an expectation of continuing losses and cash outflows from operations for the foreseeable future and the need to raise additional capital to finance the Company's future operations, the Company concluded it does not have sufficient cash on hand to support current operations within the next 12 months from the date of filing this Quarterly Report on Form 10-Q. These factors raise substantial doubt regarding the Company’s ability to continue as a going concern. The Company plans to seek additional funding through a number of potential avenues, including private or public equity financings, collaborations, or other strategic transactions as needed. The Company may not be able to obtain funding on acceptable terms, or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. The Company’s ability to raise additional funds will depend, among other factors, on financial, economic and market conditions, many of which are outside of its control and it may be unable to raise financing when needed, or on terms favorable to the Company. If necessary funds are not available, the Company will have to delay, reduce the scope of, or eliminate its development of emavusertib, potentially delaying the time to market for or preventing the marketing of emavusertib, which may have a material adverse effect on the Company’s operations and future prospects.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies (a) Basis of Presentation and Principles of Consolidation The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. These statements, however, are condensed and do not include all disclosures required by accounting principles generally accepted in the U.S. (“GAAP”) for complete financial statements and should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 as filed with the Securities and Exchange Commission (“SEC”) on February 8, 2024. In the opinion of the management of the Company, the unaudited Condensed Consolidated Financial Statements contain all adjustments (all of which were considered normal and recurring) necessary for a fair statement of the Company’s financial position at March 31, 2024; the results of operations for the three-month periods ended March 31, 2024 and 2023; stockholders' equity for the three-month periods ended March 31, 2024 and 2023; and the cash flows for the three-month periods ended March 31, 2024 and 2023. The Condensed Consolidated Balance Sheet at December 31, 2023 was derived from audited annual financial statements but does not contain all of the footnote disclosures from the annual financial statements. In accordance with FASB ASU No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), the Company has concluded there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the Condensed Consolidated Financial Statements are issued. On September 28, 2023, the Company effected a 1-for-20 reverse stock split of its common stock (the “Reverse Stock Split”). All references to shares of common stock outstanding, average number of shares outstanding and per share amounts in these Condensed Consolidated Financial Statements and notes to Condensed Consolidated Financial Statements have been restated to reflect the Reverse Stock Split on a retroactive basis. (b) Use of Estimates and Assumptions The preparation of the Company’s Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts and disclosure of revenue, expenses and certain assets and liabilities at the balance sheet date. Such estimates include the performance obligations under the Company’s collaboration agreements; the collectability of receivables; and the value of certain investments and liabilities. Actual results may differ from such estimates. These interim results are not necessarily indicative of results to be expected for a full year or subsequent interim periods. (c) Cash Equivalents, Restricted Cash, and Investments Cash equivalents consist of highly liquid investments purchased with original maturities of three months or less. All other investments are marketable securities. The Company classified $0.5 million of its cash as restricted cash as of both March 31, 2024 and December 31, 2023. These amounts represent the security deposit associated with the Company’s Lexington, Massachusetts headquarters. The Company’s short-term investments are marketable debt securities with original maturities of greater than three months from the date of purchase, but less than twelve months from the balance sheet date. Marketable securities consist of commercial paper, corporate bonds and notes, and/or government obligations. All of the Company’s investments have been designated available-for-sale and are stated at fair value. Unrealized gains and losses on investments are included in accumulated other comprehensive income (loss) as a separate component of stockholders’ equity. Realized gains and losses, dividends and interest income are included in other income (expense) in the period during which the securities are sold. Any premium or discount arising at purchase is amortized and/or accreted to interest income. (d) Leases The Company determines if an arrangement is a lease at contract inception. The Company made an accounting policy election to not recognize leases with an initial term of 12 months or less within its Condensed Consolidated Balance Sheets and to recognize those lease payments on a straight-line basis in its Condensed Consolidated Statements of Operations and Comprehensive Loss over the lease term. Operating lease assets represent the Company's right to use an underlying asset for the lease term and operating lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. As the Company’s lease does not provide an implicit interest rate, the Company uses its incremental borrowing rate, which is based on rates that would be incurred to borrow on a collateralized basis over a term equal to the lease payments in a similar economic environment, in determining the present value of lease payments. The lease payment used to determine the operating lease asset may include lease incentives, stated rent increases and was recognized as an operating lease right-of-use asset in the Condensed Consolidated Balance Sheets. The Company’s lease agreements may include both lease and non-lease components, which may be accounted for as a single lease component when the payments are fixed. Variable payments included in the lease agreement are expensed as incurred. The Company’s operating lease is reflected in operating lease right-of-use asset and operating lease liability in the Condensed Consolidated Balance Sheets. Lease expense for lease payments is recognized on a straight-line basis over the lease term. (e) Other Assets Other assets consist of long-term prepayments and deposits. (f) Revenue Recognition The Company applies the revenue recognition guidance in accordance with FASB Codification Topic 606, Revenue from Contracts with Customers. The Company recognizes royalty revenues related to Genentech’s and Roche’s sales of Erivedge. For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and where the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). The Company expects to continue recognizing royalty revenue from Genentech’s sales of Erivedge in the U.S. and Roche's sales of Erivedge outside of the U.S. (see Note 8, Research and Development Collaborations ). However, a significant portion of Erivedge royalties will be paid to the Purchasers pursuant to the Oberland Purchase Agreement (see Note 7, Liability Related to the Sale of Future Royalties ). (g) Segment Reporting The Company has determined that it operates in a single reportable segment, which is the research and development of innovative drug candidates for the treatment of human cancer. (h) New Accounting Pronouncements Issued, Not Yet Adopted In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which provides updates to qualitative and quantitative reportable segment disclosure requirements, including enhanced disclosures about significant segment expenses and increased interim disclosure requirements, among others. ASU No. 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods in fiscal years beginning after December 15, 2024. Early adoption is permitted, and the amendments should be applied retrospectively. The Company is currently evaluating the impact of the ASU on the Consolidated Financial Statement disclosures. In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures, which requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. ASU No. 2023-09 is effective for fiscal years beginning after December 15, 2024 and allows for adoption on a prospective basis, with a retrospective option. Early adoption is permitted. The Company is currently evaluating the impact of the ASU on the income tax disclosures within the Consolidated Financial Statements. In March 2024, the SEC approved a rule that will require registrants to provide certain climate-related information in their registration statements and annual reports. The rule requires information about a registrant's climate-related risks that are reasonably likely to have a material impact on its business, results of operations, or financial condition. The required information about climate-related risks also includes disclosure of a registrant's greenhouse gas emissions. In addition, the rules will require registrants to present certain climate-related financial metrics in their audited financial statements. On April 4, 2024, the SEC voluntarily stayed implementation of this new rule pending judicial review. The Company is evaluating the potential impact of this rule on the Consolidated Financial Statements and related disclosures.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company applies the provisions of FASB Codification 820, Fair Value Measurements (“ASC 820”) for its financial assets and liabilities that are re-measured and reported at fair value each reporting period and the non-financial assets and liabilities that are re-measured and reported at fair value on a non-recurring basis. Fair value is the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining fair value, the Company considers the principal or most advantageous market in which it would transact and considers assumptions that market participants would use when pricing the asset or liability. ASC 820 establishes a three-level valuation hierarchy for disclosure of fair value measurements. Financial assets and liabilities are categorized within the valuation hierarchy based upon the lowest level of input that is significant to the measurement of fair value. The three levels of the hierarchy are defined as follows: Level 1 Quoted prices in active markets for identical assets or liabilities. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. In accordance with the fair value hierarchy, the following tables show the fair value as of March 31, 2024 and December 31, 2023 of those financial assets and liabilities that are measured at fair value on a recurring basis, according to the valuation techniques the Company used to determine their fair value. (in thousands) Quoted Prices in Other Observable Unobservable Fair Value As of March 31, 2024: Cash equivalents: Money market funds $ 19,778 $ — $ — $ 19,778 U.S. treasury securities and government agency obligations — 7,205 — 7,205 Short-term investments: U.S. treasury securities and government agency obligations — 10,764 — 10,764 Total $ 19,778 $ 17,969 $ — $ 37,747 (in thousands) Quoted Prices in Other Observable Unobservable Fair Value As of December 31, 2023: Cash equivalents: Money market funds $ 16,780 $ — $ — $ 16,780 U.S. treasury securities and government agency obligations — 4,735 — 4,735 Corporate debt securities and commercial paper — 2,021 — 2,021 Short-term investments: Corporate debt securities and commercial paper — 12,996 — 12,996 U.S. treasury securities and government agency obligations — 16,657 — 16,657 Total $ 16,780 $ 36,409 $ — $ 53,189

Investments

Investments	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Investments	Investments The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of March 31, 2024 are as follows: (in thousands) Amortized Unrealized Unrealized Fair Value Short-term investments: U.S. treasury securities and government agency obligations 10,764 — — 10,764 Total investments $ 10,764 $ — $ — $ 10,764 The weighted average remaining maturity of short-term investments was 0.5 years at March 31, 2024. The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of December 31, 2023 are as follows: (in thousands) Amortized Unrealized Unrealized Fair Value Short-term investments: Corporate debt securities and commercial paper $ 12,999 $ — $ (3) $ 12,996 U.S. treasury securities and government agency obligations 16,655 3 (1) 16,657 Total investments $ 29,654 $ 3 $ (4) $ 29,653 The weighted average maturity of short-term investments was 0.2 years at December 31, 2023. No credit losses on available-for-sale securities were recognized during the three months ended March 31, 2024 or 2023. In its evaluation to determine expected credit losses, management considered all available historical and current information, expectations of future economic conditions, the type of security, the credit rating of the security, and the size of the loss position, as well as other relevant information. The Company does not intend to sell, and is unlikely to be required to sell, any of these available-for-sale investments before their effective maturity or market price recovery.

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2024
Other Liabilities Disclosure [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consisted of the following: (in thousands) March 31, 2024 December 31, 2023 Employee related costs $ 1,532 $ 3,701 Research and development costs 3,523 4,163 Professional and legal fees 1,216 1,059 Other 55 117 Total $ 6,326 $ 9,040

Lease

Lease	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Lease	Lease The Company has a single lease for real estate, including laboratory and office space, and certain equipment, in Lexington, Massachusetts which commenced on May 1, 2020. A portion of the Company’s leased space is subject to an early termination option that becomes effective on the lease commencement date of a new lease for larger premises within the landlord’s commercial real estate portfolio (“New Lease”). The landlord has the option to early terminate the lease agreement by providing written notice to the Company eighteen months prior to December 31, 2025, or by June 30, 2024. The Company expects the lease to end as of December 31, 2025. As of March 31, 2024, the Company had an operating lease liability of $2.5 million and related right-of-use asset of $2.7 million related to its operating lease. As of December 31, 2023, the Company had an operating lease liability of $2.8 million and related right-of-use asset of $3.1 million related to its operating lease. The Company recorded lease cost of $0.4 million for each of the three months ended March 31, 2024 and 2023.

Liability Related to the Sale o

Liability Related to the Sale of Future Royalties	3 Months Ended
	Mar. 31, 2024
Nonmonetary Transactions [Abstract]
Liability Related to the Sale of Future Royalties	Liability Related to the Sale of Future Royalties In March 2019, the Company and Curis Royalty entered into the royalty interest purchase agreement (“Oberland Purchase Agreement”) with TPC Investments I LP and TPC Investments II LP (the "Purchasers"), each of which is a Delaware limited partnership managed by Oberland Capital Management, LLC, and Lind SA LLC ("Agent"), a Delaware limited liability company managed by Oberland Capital Management, LLC, as collateral agent for the Purchasers. The Company sold to the Purchasers a portion of its rights to receive royalties from Genentech on potential net sales of Erivedge. As upfront consideration for the purchase of the royalty rights, the Purchasers paid to Curis Royalty $65.0 million less certain transaction expenses. Curis Royalty will also be entitled to receive up to $53.5 million in milestone payments based on sales of Erivedge if the Purchasers receive payments pursuant to the Oberland Purchase Agreement in excess of $117.0 million on or prior to December 31, 2026. The Oberland Purchase Agreement provides that after the occurrence of an event of default as defined under the security agreement by Curis Royalty, the Purchasers shall have the option, for a period of 180 days, to require Curis Royalty to repurchase a portion of certain royalty and royalty related payments, excluding a portion of non-U.S. royalties retained by Curis Royalty (referred to as the “Purchased Receivables”), at a price (referred to as the “Put/Call Price”), equal to 250% of the sum of the upfront purchase price and any portion of the milestone payments paid in a lump sum by the Purchasers, if any, minus certain payments previously received by the Purchasers with respect to the Purchased Receivables. The Company concluded that this put option is an embedded derivative that requires bifurcation from the deferred royalty obligation and evaluates the fair value of the put option each reporting period. The estimated fair value of the put option is immaterial as of both March 31, 2024 and December 31, 2023. Additionally, Curis Royalty shall have the option at any time to repurchase the Purchased Receivables at the Put/Call Price as of the date of such repurchase. No events of default occurred as of March 31, 2024. As a result of the obligation to pay future royalties to the Purchasers, the Company recorded the proceeds as a liability on its Condensed Consolidated Balance Sheets. It accounts for the liability and interest expense using the interest method over the expected life of the Oberland Purchase Agreement. As a result, the Company imputes interest on the transaction and records imputed interest expense at the estimated interest rate. The Company’s estimate of the interest rate under the Oberland Purchase Agreement is based on the amount of royalty payments expected to be received by the Purchasers over the life of the Oberland Purchase Agreement. The projected amount of royalty payments expected to be paid to the Purchasers involves the use of significant estimates and assumptions with respect to the revenue growth rate in the Company’s projections of sales of Erivedge. The Company periodically assesses the expected royalty payments to Curis Royalty from Genentech using a combination of historical results and forecasts from market data sources. To the extent such payments are greater or less than the current estimates or the timing of such payments is materially different than the original estimates, the Company prospectively adjusts the amortization of the liability. The Company determined the fair value of the liability related to the sale of future royalties at the time of the Oberland Purchase Agreement to be $65.0 million, with a current effective annual imputed interest rate of zero. The Company incurred $0.6 million of transaction costs in connection with the Oberland Purchase Agreement. These transaction costs will be amortized to imputed interest expense over the estimated term of the Oberland Purchase Agreement. The carrying value of the liability related to the sale of future royalties approximates fair value as of March 31, 2024 and is based on the Company’s current estimates of future royalties expected to be paid to the Purchasers over the life of the arrangement, which are considered Level 3 inputs. The following table shows the activity with respect to the liability related to the sale of future royalties during the three months ended March 31, 2024. (in thousands) Carrying value of liability related to the sale of future royalties at January 1, 2024 $ 42,606 Other (78) Less: payments to the Purchasers (2,406) Carrying value of liability related to the sale of future royalties at March 31, 2024 $ 40,122 In March 2023, Curis and Curis Royalty received a letter from counsel to Oberland Capital Management, LLC, the Purchasers and the Agent alleging certain defaults of the Oberland Purchase Agreement and demanding cure of one of the asserted defaults. The Purchasers have not attempted to exercise the put option. Curis and Curis Royalty dispute these allegations. If Oberland elects to pursue these claims, and if Curis and Curis Royalty are unsuccessful in defending against these claims, it could have a material adverse impact on Curis and Curis Royalty, including their ability to continue as a going concern. The Company has not received any further communication on this topic from counsel to Oberland Capital Management, LLC, the Purchasers or the Agent since the March 2023 letter. As of March 31, 2024, the estimated amount of the Put/Call Price is $50.9 million.

Research and Development Collab

Research and Development Collaborations	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Research and Development Collaborations	Research and Development Collaborations (a) Genentech In June 2003, the Company licensed its proprietary Hedgehog pathway antagonist technologies to Genentech for human therapeutic use. The primary focus of the collaboration is Erivedge, which is being commercialized by Genentech in the U.S. and by Genentech’s parent company, Roche, outside of the U.S. for the treatment of advanced BCC. Pursuant to the collaboration agreement, the Company is entitled to a royalty on net sales of Erivedge that ranges from 5% to 7.5%. The royalty rate applicable to Erivedge may be decreased by 2% on a country-by-country basis in certain specified circumstances. Cost of royalties comprises payments to university licensors and was not material for the three months ended March 31, 2024 and 2023. The Company has account receivables from Genentech under this collaboration of $2.1 million and $2.7 million as of March 31, 2024 and December 31, 2023, respectively, in its Condensed Consolidated Balance Sheets. As previously discussed in Note 7, Liability Related to the Sale of Future Royalties, a significant portion of royalty revenues received from Genentech on net sales of Erivedge will be paid to the Purchasers pursuant to the Oberland Purchase Agreement. (b) Aurigene The Company is party to an exclusive collaboration agreement with Aurigene for the discovery, development and commercialization of small molecule compounds in the areas of immuno-oncology and selected precision oncology targets. Under the collaboration agreement, Aurigene granted the Company an option to obtain exclusive, royalty-bearing licenses to relevant Aurigene technology to develop, manufacture and commercialize products containing certain of such compounds anywhere in the world, except for India and Russia, which are territories retained by Aurigene. Additionally, Aurigene retains the rights to develop and commercialize CA-170 in Asia, and the Company is entitled to receive royalty payments on potential future sales of CA-170 in Asia at percentage rates ranging from the high single digits up to 10%, subject to specified reductions. As of March 31, 2024, the Company has exercised its option to license the following four programs under the collaboration: 1. IRAK4 Program - a precision oncology program of small molecule inhibitors of IRAK4. The development candidate is emavusertib. 2. PD1/VISTA Program - an immuno-oncology program of small molecule antagonists of PD1 and VISTA immune checkpoint pathways. The development candidate is CA-170. 3. PD1/TIM3 Program - an immuno-oncology program of small molecule antagonists of PD1 and TIM3 immune checkpoint pathways. The development candidate is CA-327. 4. An immuno-oncology program. For each of the licensed programs (as described above) the Company is obligated to use commercially reasonable efforts to develop, obtain regulatory approval for, and commercialize at least one product in each of the U.S., specified countries in the European Union and Japan, and Aurigene is obligated to use commercially reasonable efforts to perform its obligations under the development plan for such licensed program in an expeditious manner.

Common Stock

Common Stock	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Common Stock	Common Stock Sales Agreement with Cantor Fitzgerald & Co. and JonesTrading Institutional Services LLC In March 2021, the Company entered into a sales agreement (the “2021 Sales Agreement”) with Cantor Fitzgerald & Co. (“Cantor”) and JonesTrading Institutional Services LLC (“JonesTrading”). In February 2024, the Company entered into an amended and restated sales agreement with Cantor and JonesTrading (the “2024 Sales Agreement”), which supersedes the 2021 Sales Agreement. Pursuant to the 2024 Sales Agreement, the Company can sell from time to time shares of the Company’s common stock through an “at-the-market offering” program under which Cantor and JonesTrading act as sales agents. Subject to the terms and conditions of the 2024 Sales Agreement, Cantor and JonesTrading can sell the common stock by any method deemed to be an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act. Pursuant to the terms of the 2024 Sales Agreement, the aggregate compensation payable to each of Cantor and JonesTrading is 3% of the gross proceeds from sales of the common stock sold by Cantor or JonesTrading, as applicable. The Company did not sell any shares of common stock under the 2024 Sales Agreement during the three months ended March 31, 2024. As of March 31, 2024, $100.0 million of shares of common stock remained available for sale under the 2024 Sales Agreement.

Stock Plans and Stock-Based Com

Stock Plans and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock Plans and Stock-Based Compensation	Stock Plans and Stock-Based Compensation As of March 31, 2024, the Company had two stockholder-approved, stock-based compensation plans: (i) the Fourth Amended and Restated 2010 Stock Incentive Plan (“2010 Plan”) and (ii) the Amended and Restated 2010 Employee Stock Purchase Plan (“ESPP”). New employees are generally issued options as an inducement equity award under Nasdaq Listing Rule 5635(c)(4) outside of the 2010 Plan (“Inducement Awards”). The Fourth Amended and Restated 2010 Stock Incentive Plan The 2010 Plan permits the granting of incentive and non-qualified stock options and stock awards to employees, officers, directors, and consultants of the Company and its subsidiaries at prices determined by the Company’s board of directors. The Company can issue up to 1,159,500 shares of its common stock pursuant to awards granted under the 2010 Plan. Options vest and become exercisable based on a schedule determined by the board of directors and expire up to ten years from the date of grant. The 2010 Plan uses a “fungible share” concept under which each share of stock subject to awards granted as options and stock appreciation rights (“SARs”) will cause one share per share under the award to be removed from the available share pool, while each share of stock subject to awards granted as restricted stock, restricted stock units, other stock-based awards or performance awards where the price charged for the award is less than 100% of the fair market value of the Company’s common stock will cause 1.3 shares per share under the award to be removed from the available share pool. As of March 31, 2024, the Company has only granted options to purchase shares of the Company’s common stock with an exercise price equal to the closing market price of the Company’s common stock on the Nasdaq Capital Market on the grant date and issued restricted stock awards ("RSAs") at no cost to Company employees, excluding officers. As of March 31, 2024, 14,902 shares remained available for grant under the 2010 Plan. During the three months ended March 31, 2024, the Company’s board of directors granted options to purchase 277,970 shares of the Company’s common stock to the employees of the Company under the 2010 Plan, excluding officers. These options vest and become exercisable as to 25% of the shares underlying the award after the first year and as to an additional 6.25% of the shares underlying the award in each subsequent quarter, based upon continued employment over a four year period, and are exercisable at a price equal to the closing market price of the Company’s common stock on the grant date. In January 2024, the Company's board of directors approved the grant of options to its executive officers and non-employee directors to purchase 200,950 shares of common stock. These stock option grants were approved subject to and contingent upon approval by the Company's stockholders of the Fifth Amended and Restated 2010 Stock Incentive Plan. The shareholders will vote on the proposal for the adoption of the Fifth Amended and Restated 2010 Stock Incentive Plan at the annual meeting of stockholders scheduled for May 21, 2024. Inducement Awards The Company grants Inducement Awards to certain new employees. These options generally vest as to 25% of the shares underlying the option on the first anniversary of the grant date, and as to an additional 6.25% of the shares underlying the option on each successive quarter thereafter. During the three months ended March 31, 2024, the Company’s board of directors granted Inducement Awards to purchase 5,800 shares of common stock. These options are granted at an exercise price that equals the closing market price of the Company’s common stock on the grant date. Stock Options A summary of stock option activity under the 2010 Plan and Inducement Awards are summarized as follows: Number of Weighted Weighted Aggregate Intrinsic Value Outstanding, December 31, 2023 840,880 $ 47.58 7.16 Granted 283,770 11.64 Exercised — — Canceled/Forfeited (12,262) 78.49 Outstanding, March 31, 2024 1,112,388 $ 38.07 7.66 $ 17 Exercisable at March 31, 2024 538,662 $ 55.19 6.08 $ — Vested and unvested expected to vest at March 31, 2024 1,112,388 $ 38.07 7.66 $ 17 The weighted average grant date fair values of the stock options granted during the three months ended March 31, 2024 and 2023 were $10.01 and $11.80, respectively, and were calculated using the following estimated assumptions under the Black-Scholes option pricing model: Three Months Ended 2024 2023 Expected term (years) 6 5.5 Risk free interest rate 3.9% - 4.1% 3.6% Expected volatility 115% - 116% 115% - 116% Expected dividends None None As of March 31, 2024, there was $9.5 million of unrecognized compensation cost related to unvested employee stock option awards outstanding, which is expected to be recognized as expense over a weighted average period of 2.97 years. There were no employee stock options exercised during the three months ended March 31, 2024. The intrinsic value of employee stock options exercised during the three months ended March 31, 2023 was not material. Restricted Stock Awards The following table presents a summary of unvested RSAs under the 2010 Plan as of March 31, 2024: Number of Shares Weighted Average Grant Date Fair Value Unvested, December 31, 2023 110,500 $ 18.20 Awarded — — Vested — — Forfeited — — Unvested, March 31, 2024 110,500 $ 18.20 As of March 31, 2024, there were 110,500 shares outstanding underlying RSAs that are expected to vest. As of March 31, 2024, there was $1.1 million of unrecognized compensation costs related to RSAs, which are expected to be recognized as expense over a remaining weighted average period of 1.11 years. Amended and Restated 2010 Employee Stock Purchase Plan The Company has reserved 100,000 shares of common stock for issuance under the ESPP. Eligible employees may purchase shares of the Company’s common stock at 85% of the lower closing market price of the common stock at the beginning of the enrollment period or ending date of the purchase period within a two-year enrollment period, as defined. The Company has four six-month purchase periods per each two-year enrollment period. If, within any one of the four purchase periods in an enrollment period, the purchase period ending stock price is lower than the stock price at the beginning of the enrollment period, the two-year enrollment resets at the new lower stock price. During the three months ended March 31, 2024 and 2023, no shares were issued under the ESPP. As of March 31, 2024, there were 26,631 shares available for future purchase under the ESPP. Stock-Based Compensation Expense For the three months ended March 31, 2024 and 2023, the Company recorded stock-based compensation expense to the following line items in its costs and expenses section of the Condensed Consolidated Statements of Operations and Comprehensive Loss: Three Months Ended (in thousands) 2024 2023 Research and development expenses $ 809 $ 629 General and administrative expenses 750 766 Total stock-based compensation expense $ 1,559 $ 1,395

Loss Per Common Share

Loss Per Common Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Loss Per Common Share	Loss Per Common Share Basic and diluted loss per common share is computed by dividing net loss attributable to common stockholders by the weighted average number of common shares outstanding during the period. Diluted net loss per common share is the same as basic net loss per common share for the three months ended March 31, 2024 and 2023, because the effect of adjusting the weighted average number of common shares outstanding during the period for the potential dilutive effect of common stock equivalents would be antidilutive due to the Company’s net loss position for these periods. Antidilutive securities consist of stock options outstanding of 1,112,388 and 875,034 as of March 31, 2024 and 2023, respectively, and unvested RSAs of 110,500 as of March 31, 2024.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net loss	$ (11,876)	$ (11,559)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. These statements, however, are condensed and do not include all disclosures required by accounting principles generally accepted in the U.S. (“GAAP”) for complete financial statements and should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 as filed with the Securities and Exchange Commission (“SEC”) on February 8, 2024.
Use of Estimates and Assumptions	Use of Estimates and Assumptions The preparation of the Company’s Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts and disclosure of revenue, expenses and certain assets and liabilities at the balance sheet date. Such estimates include the performance obligations under the Company’s collaboration agreements; the collectability of receivables; and the value of certain investments and liabilities. Actual results may differ from such estimates. These interim results are not necessarily indicative of results to be expected for a full year or subsequent interim periods.
Cash Equivalents, Restricted Cash, and Investments	Cash Equivalents, Restricted Cash, and Investments Cash equivalents consist of highly liquid investments purchased with original maturities of three months or less. All other investments are marketable securities. The Company classified $0.5 million of its cash as restricted cash as of both March 31, 2024 and December 31, 2023. These amounts represent the security deposit associated with the Company’s Lexington, Massachusetts headquarters. The Company’s short-term investments are marketable debt securities with original maturities of greater than three months from the date of purchase, but less than twelve months from the balance sheet date. Marketable securities consist of commercial paper, corporate bonds and notes, and/or government obligations. All of the Company’s investments have been designated available-for-sale and are stated at fair value. Unrealized gains and losses on investments are included in accumulated other comprehensive income (loss) as a separate component of stockholders’ equity. Realized gains and losses, dividends and interest income are included in other income (expense) in the period during which the securities are sold. Any premium or discount arising at purchase is amortized and/or accreted to interest income.
Leases	Leases The Company determines if an arrangement is a lease at contract inception. The Company made an accounting policy election to not recognize leases with an initial term of 12 months or less within its Condensed Consolidated Balance Sheets and to recognize those lease payments on a straight-line basis in its Condensed Consolidated Statements of Operations and Comprehensive Loss over the lease term. Operating lease assets represent the Company's right to use an underlying asset for the lease term and operating lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. As the Company’s lease does not provide an implicit interest rate, the Company uses its incremental borrowing rate, which is based on rates that would be incurred to borrow on a collateralized basis over a term equal to the lease payments in a similar economic environment, in determining the present value of lease payments. The lease payment used to determine the operating lease asset may include lease incentives, stated rent increases and was recognized as an operating lease right-of-use asset in the Condensed Consolidated Balance Sheets. The Company’s lease agreements may include both lease and non-lease components, which may be accounted for as a single lease component when the payments are fixed. Variable payments included in the lease agreement are expensed as incurred.
Other Assets	Other Assets Other assets consist of long-term prepayments and deposits.
Revenue Recognition	Revenue Recognition The Company applies the revenue recognition guidance in accordance with FASB Codification Topic 606, Revenue from Contracts with Customers. The Company recognizes royalty revenues related to Genentech’s and Roche’s sales of Erivedge. For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and where the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). The Company expects to continue recognizing royalty revenue from Genentech’s sales of Erivedge in the U.S. and Roche's sales of Erivedge outside of the U.S. (see Note 8, Research and Development Collaborations ). However, a significant portion of Erivedge royalties will be paid to the Purchasers pursuant to the Oberland Purchase Agreement (see Note 7, Liability Related to the Sale of Future Royalties ).
Segment Reporting	Segment Reporting The Company has determined that it operates in a single reportable segment, which is the research and development of innovative drug candidates for the treatment of human cancer.
New Accounting Pronouncements	New Accounting Pronouncements Issued, Not Yet Adopted In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which provides updates to qualitative and quantitative reportable segment disclosure requirements, including enhanced disclosures about significant segment expenses and increased interim disclosure requirements, among others. ASU No. 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods in fiscal years beginning after December 15, 2024. Early adoption is permitted, and the amendments should be applied retrospectively. The Company is currently evaluating the impact of the ASU on the Consolidated Financial Statement disclosures. In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures, which requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. ASU No. 2023-09 is effective for fiscal years beginning after December 15, 2024 and allows for adoption on a prospective basis, with a retrospective option. Early adoption is permitted. The Company is currently evaluating the impact of the ASU on the income tax disclosures within the Consolidated Financial Statements. In March 2024, the SEC approved a rule that will require registrants to provide certain climate-related information in their registration statements and annual reports. The rule requires information about a registrant's climate-related risks that are reasonably likely to have a material impact on its business, results of operations, or financial condition. The required information about climate-related risks also includes disclosure of a registrant's greenhouse gas emissions. In addition, the rules will require registrants to present certain climate-related financial metrics in their audited financial statements. On April 4, 2024, the SEC voluntarily stayed implementation of this new rule pending judicial review. The Company is evaluating the potential impact of this rule on the Consolidated Financial Statements and related disclosures.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company applies the provisions of FASB Codification 820, Fair Value Measurements (“ASC 820”) for its financial assets and liabilities that are re-measured and reported at fair value each reporting period and the non-financial assets and liabilities that are re-measured and reported at fair value on a non-recurring basis. Fair value is the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining fair value, the Company considers the principal or most advantageous market in which it would transact and considers assumptions that market participants would use when pricing the asset or liability. ASC 820 establishes a three-level valuation hierarchy for disclosure of fair value measurements. Financial assets and liabilities are categorized within the valuation hierarchy based upon the lowest level of input that is significant to the measurement of fair value. The three levels of the hierarchy are defined as follows: Level 1 Quoted prices in active markets for identical assets or liabilities. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	In accordance with the fair value hierarchy, the following tables show the fair value as of March 31, 2024 and December 31, 2023 of those financial assets and liabilities that are measured at fair value on a recurring basis, according to the valuation techniques the Company used to determine their fair value. (in thousands) Quoted Prices in Other Observable Unobservable Fair Value As of March 31, 2024: Cash equivalents: Money market funds $ 19,778 $ — $ — $ 19,778 U.S. treasury securities and government agency obligations — 7,205 — 7,205 Short-term investments: U.S. treasury securities and government agency obligations — 10,764 — 10,764 Total $ 19,778 $ 17,969 $ — $ 37,747 (in thousands) Quoted Prices in Other Observable Unobservable Fair Value As of December 31, 2023: Cash equivalents: Money market funds $ 16,780 $ — $ — $ 16,780 U.S. treasury securities and government agency obligations — 4,735 — 4,735 Corporate debt securities and commercial paper — 2,021 — 2,021 Short-term investments: Corporate debt securities and commercial paper — 12,996 — 12,996 U.S. treasury securities and government agency obligations — 16,657 — 16,657 Total $ 16,780 $ 36,409 $ — $ 53,189

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Schedule of Amortized Cost, Unrealized Gains and Losses and Fair Value of Investments Available-for-Sale	The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of March 31, 2024 are as follows: (in thousands) Amortized Unrealized Unrealized Fair Value Short-term investments: U.S. treasury securities and government agency obligations 10,764 — — 10,764 Total investments $ 10,764 $ — $ — $ 10,764 The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of December 31, 2023 are as follows: (in thousands) Amortized Unrealized Unrealized Fair Value Short-term investments: Corporate debt securities and commercial paper $ 12,999 $ — $ (3) $ 12,996 U.S. treasury securities and government agency obligations 16,655 3 (1) 16,657 Total investments $ 29,654 $ 3 $ (4) $ 29,653

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2024
Other Liabilities Disclosure [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following: (in thousands) March 31, 2024 December 31, 2023 Employee related costs $ 1,532 $ 3,701 Research and development costs 3,523 4,163 Professional and legal fees 1,216 1,059 Other 55 117 Total $ 6,326 $ 9,040

Liability Related to the Sale_2

Liability Related to the Sale of Future Royalties (Tables)	3 Months Ended
	Mar. 31, 2024
Nonmonetary Transactions [Abstract]
Schedule of Liability Related to the Sale of Future Royalties	The following table shows the activity with respect to the liability related to the sale of future royalties during the three months ended March 31, 2024. (in thousands) Carrying value of liability related to the sale of future royalties at January 1, 2024 $ 42,606 Other (78) Less: payments to the Purchasers (2,406) Carrying value of liability related to the sale of future royalties at March 31, 2024 $ 40,122

Stock Plans and Stock-Based C_2

Stock Plans and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Stock Option	A summary of stock option activity under the 2010 Plan and Inducement Awards are summarized as follows: Number of Weighted Weighted Aggregate Intrinsic Value Outstanding, December 31, 2023 840,880 $ 47.58 7.16 Granted 283,770 11.64 Exercised — — Canceled/Forfeited (12,262) 78.49 Outstanding, March 31, 2024 1,112,388 $ 38.07 7.66 $ 17 Exercisable at March 31, 2024 538,662 $ 55.19 6.08 $ — Vested and unvested expected to vest at March 31, 2024 1,112,388 $ 38.07 7.66 $ 17
Schedule of Valuation Assumptions Used to Calculate Fair Value of Employee Options Awarded	the following estimated assumptions under the Black-Scholes option pricing model: Three Months Ended 2024 2023 Expected term (years) 6 5.5 Risk free interest rate 3.9% - 4.1% 3.6% Expected volatility 115% - 116% 115% - 116% Expected dividends None None
Schedule of Restricted Stock Awards	The following table presents a summary of unvested RSAs under the 2010 Plan as of March 31, 2024: Number of Shares Weighted Average Grant Date Fair Value Unvested, December 31, 2023 110,500 $ 18.20 Awarded — — Vested — — Forfeited — — Unvested, March 31, 2024 110,500 $ 18.20
Schedule of Stock-Based Compensation Expense	For the three months ended March 31, 2024 and 2023, the Company recorded stock-based compensation expense to the following line items in its costs and expenses section of the Condensed Consolidated Statements of Operations and Comprehensive Loss: Three Months Ended (in thousands) 2024 2023 Research and development expenses $ 809 $ 629 General and administrative expenses 750 766 Total stock-based compensation expense $ 1,559 $ 1,395

Nature of Business (Details)

Nature of Business (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ 1,208,286		$ 1,196,410
Net loss	11,876	$ 11,559
Cash used in operations	13,232	$ 12,199
Cash, cash equivalents, and investments	$ 40,700

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) $ in Millions		3 Months Ended
	Sep. 28, 2023	Mar. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Stockholders' equity, reverse stock split	0.05
Restricted cash | $		$ 0.5	$ 0.5
Number of reportable segments | segment		1

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Short-term investments:
Total	$ 37,747	$ 53,189
Corporate debt securities and commercial paper
Short-term investments:
Short-term investments:		12,996
U.S. treasury securities and government agency obligations
Short-term investments:
Short-term investments:	10,764	16,657
Money market funds
Cash equivalents:
Cash Equivalents	19,778	16,780
U.S. treasury securities and government agency obligations
Cash equivalents:
Cash Equivalents	7,205	4,735
Commercial Paper | Corporate debt securities and commercial paper
Cash equivalents:
Cash Equivalents		2,021
Quoted Prices in Active Markets (Level 1)
Short-term investments:
Total	19,778	16,780
Quoted Prices in Active Markets (Level 1) | Corporate debt securities and commercial paper
Short-term investments:
Short-term investments:		0
Quoted Prices in Active Markets (Level 1) | U.S. treasury securities and government agency obligations
Short-term investments:
Short-term investments:	0	0
Quoted Prices in Active Markets (Level 1) | Money market funds
Cash equivalents:
Cash Equivalents	19,778	16,780
Quoted Prices in Active Markets (Level 1) | U.S. treasury securities and government agency obligations
Cash equivalents:
Cash Equivalents	0	0
Quoted Prices in Active Markets (Level 1) | Commercial Paper | Corporate debt securities and commercial paper
Cash equivalents:
Cash Equivalents		0
Other Observable Inputs (Level 2)
Short-term investments:
Total	17,969	36,409
Other Observable Inputs (Level 2) | Corporate debt securities and commercial paper
Short-term investments:
Short-term investments:		12,996
Other Observable Inputs (Level 2) | U.S. treasury securities and government agency obligations
Short-term investments:
Short-term investments:	10,764	16,657
Other Observable Inputs (Level 2) | Money market funds
Cash equivalents:
Cash Equivalents	0	0
Other Observable Inputs (Level 2) | U.S. treasury securities and government agency obligations
Cash equivalents:
Cash Equivalents	7,205	4,735
Other Observable Inputs (Level 2) | Commercial Paper | Corporate debt securities and commercial paper
Cash equivalents:
Cash Equivalents		2,021
Unobservable Inputs (Level 3)
Short-term investments:
Total	0	0
Unobservable Inputs (Level 3) | Corporate debt securities and commercial paper
Short-term investments:
Short-term investments:		0
Unobservable Inputs (Level 3) | U.S. treasury securities and government agency obligations
Short-term investments:
Short-term investments:	0	0
Unobservable Inputs (Level 3) | Money market funds
Cash equivalents:
Cash Equivalents	0	0
Unobservable Inputs (Level 3) | U.S. treasury securities and government agency obligations
Cash equivalents:
Cash Equivalents	$ 0	0
Unobservable Inputs (Level 3) | Commercial Paper | Corporate debt securities and commercial paper
Cash equivalents:
Cash Equivalents		$ 0

Investments - Schedule of Amort

Investments - Schedule of Amortized Cost, Unrealized Gains and Losses and Fair Value of Investments Available-for-Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 10,764	$ 29,654
Unrealized Gain	0	3
Unrealized Loss	0	(4)
Fair Value	10,764	29,653
U.S. treasury securities and government agency obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10,764	16,655
Unrealized Gain	0	3
Unrealized Loss	0	(1)
Fair Value	$ 10,764	16,657
Corporate debt securities and commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		12,999
Unrealized Gain		0
Unrealized Loss		(3)
Fair Value		$ 12,996

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Range of maturities	6 months	2 months 12 days
Debt securities, available-for-sale, credit loss	$ 0		$ 0
Fair value of available-for-sale investments in a continuous unrealized loss position for 12 months or longer	$ 0	$ 0

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Other Liabilities Disclosure [Abstract]
Employee related costs	$ 1,532	$ 3,701
Research and development costs	3,523	4,163
Professional and legal fees	1,216	1,059
Other	55	117
Total	$ 6,326	$ 9,040

Lease (Details)

Lease (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Operating lease, liability	$ 2,500		$ 2,800
Operating lease right-of-use asset	2,704		$ 3,056
Operating lease, expense	400	$ 400
Operating lease payments	$ 400	$ 400
Weighted average discount rate	10%
128 Spring Street Lease Amendment
Lessee, Lease, Description [Line Items]
Lessor option to terminate, written notice period	18 months

Liability Related to the Sale_3

Liability Related to the Sale of Future Royalties - Narrative (Details) - USD ($) $ in Millions	1 Months Ended
	Mar. 31, 2019	Mar. 31, 2024
Nonmonetary Transaction [Line Items]
Non-cash interest rate	0%
Transaction fees	$ 0.6
Oberland Capital
Nonmonetary Transaction [Line Items]
Transaction expenses	$ 65
Purchaser default option period	180 days
Percentage of royalty purchase agreement	250%
Estimated price amount		$ 50.9
Oberland Capital | Aggregate Net Royalties Prior to 2027
Nonmonetary Transaction [Line Items]
Cash proceeds from royalty purchase agreement	$ 53.5
Royalty amount threshold	$ 117

Liability Related to the Sale_4

Liability Related to the Sale of Future Royalties - Schedule of Liability Related to the Sale of Future Royalties (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Nonmonetary Transaction [Roll Forward]
Carrying value of liability related to the sale of future royalties at January 1, 2024	$ 42,606
Other	(78)
Less: payments to the Purchasers	(2,406)
Carrying value of liability related to the sale of future royalties at March 31, 2024	$ 40,122

Research and Development Coll_2

Research and Development Collaborations (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Jun. 30, 2003	Mar. 31, 2024 USD ($) program	Dec. 31, 2023 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		$ 2,154	$ 2,794
Number of program licensed | program		4
Genentech, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty rate decrease	2%
Accounts receivable		$ 2,100	$ 2,700
Genentech, Inc. | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty on net sales	5%
Genentech, Inc. | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty on net sales	7.50%
Aurigene | IRAK4, PD1/VISTA, and PD1/TIM3 Programs
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Waived payment of milestone and other payments (up to)		$ 42,500
Aurigene | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty fees receivable (as a percent)		10%

Common Stock (Details)

Common Stock (Details) - Common Stock - Cantor Fitzgerald & Co - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2021
Class of Stock [Line Items]
Compensation fee		3%
Sale of stock remaining authorized amount	$ 100

Stock Plans and Stock-Based C_3

Stock Plans and Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2024 shares	Mar. 31, 2024 USD ($) purchase_period plan $ / shares shares	Mar. 31, 2023 $ / shares	Dec. 31, 2023 shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shareholder-approved, share-based compensation plans | plan		2
Granted (in shares)		283,770
Weighted average grant-date fair values of stock options (in dollars per share) | $ / shares		$ 10.01	$ 11.80
Unrecognized compensation cost, net of estimated forfeitures | $		$ 9.5
Unrecognized compensation cost, weighted average period for recognition		2 years 11 months 19 days
Exercise of stock options (in shares)		0
Amended and Restated 2010 Stock Incentive Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares authorized (in shares)		1,159,500
Period of time options are exercisable		10 years
Number of shares under award to be removed from share pool		14,902
2010 Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Granted (in shares)		277,970
Employee Stock Purchase Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Issuance of stock under ESPP (in shares)		0
Stock Options, or Stock Appreciation Rights | Amended and Restated 2010 Stock Incentive Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares removed from pool (in shares per share)		1
Restricted Stock, RSUs, Other Stock-Based Awards, or Performance Awards | Amended and Restated 2010 Stock Incentive Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares removed from pool (in shares per share)		1.3
Price charged for award based on fair market value percentage (less than)		100%
Stock Options
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period (years)		4 years
Awarded (in shares)		5,800
Stock Options | 2010 Plan | Non-Employee Directors
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Granted (in shares)	200,950
Stock Options | 2010 Plan | Tranche One
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Percentage of vested shares which are exercisable under stock option		25%
Stock Options | 2010 Plan | Tranche Two
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Percentage of vested shares which are exercisable under stock option		6.25%
Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Awarded (in shares)		0
Unrecognized compensation cost, weighted average period for recognition		1 year 1 month 9 days
Outstanding shares (in shares)		110,500		110,500
Compensation expense related to employee and director stock option grants | $		$ 1.1
Employee Stock | Employee Stock Purchase Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares authorized (in shares)		100,000
Price charged for award based on fair market value percentage (less than)		85%
Enrollment period		2 years
Number of purchase periods per year | purchase_period		4
Term of purchase periods		6 months
Shares available for future purchase under ESPP (in shares)		26,631

Stock Plans and Stock-Based C_4

Stock Plans and Stock-Based Compensation - Schedule of Stock Option (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Number of Shares
Beginning balance (in shares)	840,880
Granted (in shares)	283,770
Exercised (in shares)	0
Canceled/Forfeited (in shares)	(12,262)
Ending balance (in shares)	1,112,388	840,880
Exercisable at end of period (in shares)	538,662
Vested and unvested expected to vest at end of period (in shares)	1,112,388
Weighted Average Exercise Price per Share
Beginning balance (in dollars per share)	$ 47.58
Granted (in dollars per share)	11.64
Exercised (in dollars per share)	0
Canceled/Forfeited (in dollars per share)	78.49
Ending balance (in dollars per share)	38.07	$ 47.58
Exercisable at end of period (in dollars per share)	55.19
Vested and unvested expected to vest at end of period (in dollars per share)	$ 38.07
Weighted Average Remaining Contractual Life
Outstanding at end of period	7 years 7 months 28 days	7 years 1 month 28 days
Exercisable at end of period	6 years 29 days
Vested and unvested expected to vest at end of period	7 years 7 months 28 days
Aggregate Intrinsic Value
Outstanding at end of period	$ 17
Exercisable at end of period	0
Vested and unvested expected to vest at end of period	$ 17

Stock Plans and Stock-Based C_5

Stock Plans and Stock-Based Compensation - Schedule of Valuation Assumptions Used to Calculate Fair Value of Employee Options Awarded (Details) - Stock Options	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Expected term (years)	6 years	5 years 6 months
Minimum risk-free interest rate (percent)	3.90%	3.60%
Maximum risk-free interest rate (percent)	4.10%
Minimum volatility (percent)	115%	115%
Maximum volatility (percent)	116%	116%

Stock Plans and Stock-Based C_6

Stock Plans and Stock-Based Compensation - Schedule of Restricted Stock Awards (Details) - Restricted Stock	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of Shares
Beginning balance (in shares) | shares	110,500
Awarded (in shares) | shares	0
Vested (in shares) | shares	0
Forfeited (in shares) | shares	0
Ending balance (in shares) | shares	110,500
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 18.20
Awarded (in dollars per share) | $ / shares	0
Vested (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	0
Ending balance (in dollars per share) | $ / shares	$ 18.20

Stock Plans and Stock-Based C_7

Stock Plans and Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock-based compensation expense	$ 1,559	$ 1,395
Research and development expenses
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock-based compensation expense	809	629
General and administrative expenses
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock-based compensation expense	$ 750	$ 766

Loss Per Common Share (Details)

Loss Per Common Share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding shares (in shares)	110,500		110,500
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	1,112,388	875,034