Curis (CRIS) 10-Q 4 Aug 20 2020 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2020	Jul. 28, 2020
Cover [Abstract]
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001108205
Current Fiscal Year End Date	--12-31
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
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		53,867,875

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 23,621	$ 15,430
Restricted cash, short-term	153	153
Investments	1	5,113
Accounts receivable	2,486	3,244
Prepaid expenses and other current assets	1,003	1,063
Total current assets	27,264	25,003
Property and equipment, net	737	154
Restricted cash, long-term	816	816
Operating lease right-of-use asset	7,149	149
Goodwill	8,982	8,982
Other assets	2	3
Total assets	44,950	35,107
Current liabilities:
Accounts payable	4,957	4,465
Accrued liabilities	2,097	1,910
Current portion of operating lease liability	1,852	166
Current portion long-term debt	445	0
Total current liabilities	9,351	6,541
Long-term operating lease liability	5,345	0
Liability related to the sale of future royalties, net	60,189	62,477
Long-term debt	445	0
Total liabilities	75,330	69,018
Stockholders’ deficit:
Common stock, $0.01 par value—151,875,000 shares authorized; 50,639,048 shares issued and outstanding at June 30, 2020; 101,250,000 shares authorized 33,241,793 shares issued and outstanding at December 31, 2019	506	332
Additional paid-in capital	1,002,512	982,738
Accumulated deficit	(1,033,398)	(1,016,981)
Total stockholders’ deficit	(30,380)	(33,911)
Total liabilities and stockholders’ deficit	$ 44,950	$ 35,107

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common stock par value (usd per share)	$ 0.01	$ 0.01
Common stock authorized (shares)	151,875,000	101,250,000
Common stock issued (shares)	50,639,048	33,241,793
Common stock outstanding (shares)	50,639,048	33,241,793

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues, net:
Total revenues, net	$ 2,360	$ 2,094	$ 5,068	$ 3,861
Costs and expenses:
Cost of royalties	122	89	247	197
Research and development	5,282	5,620	12,754	9,694
General and administrative	2,386	2,526	5,980	5,669
Total costs and expenses	7,790	8,235	18,981	15,560
Loss from operations	(5,430)	(6,141)	(13,913)	(11,699)
Other expense:
Loss on debt extinguishment	0	0	0	(3,495)
Interest income	5	235	55	343
Imputed interest expense related to the sale of future royalties	(1,284)	(1,287)	(2,581)	(1,417)
Interest expense, debt	0	0	0	(791)
Other income (expense), net	1	(20)	22	(38)
Total other expense	(1,278)	(1,072)	(2,504)	(5,398)
Net loss	(6,708)	(7,213)	(16,417)	(17,097)
Net loss	$ (6,708)	$ (7,213)	$ (16,417)	$ (17,097)
Net loss per common share (basic and diluted) (USD per share)	$ (0.17)	$ (0.22)	$ (0.44)	$ (0.52)
Weighted average common shares (basic and diluted) (shares)	39,517,045	33,154,566	36,985,117	33,158,222
Royalties
Revenues, net:
Total revenues, net	$ 2,446	$ 2,142	$ 4,961	$ 4,279
Other revenue
Revenues, net:
Total revenues, net	0	0	211	0
Contra revenue, net
Revenues, net:
Total revenues, net	$ (86)	$ (48)	$ (104)	$ (418)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Private PlacementCommon Stock	Private PlacementAdditional Paid-in Capital	Aspire Capital Fund, LLCCommon Stock	Aspire Capital Fund, LLCAdditional Paid-in Capital
Beginning balance (shares) at Dec. 31, 2018		33,159,253
Beginning balance at Dec. 31, 2018	$ (4,496)	$ 332	$ 980,012	$ (984,840)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cancellation of restricted stock awards	651		651
Net loss	(9,884)			(9,884)
Ending balance (shares) at Mar. 31, 2019		33,150,780
Ending balance at Mar. 31, 2019	(13,729)	$ 332	980,663	(994,724)
Beginning balance (shares) at Dec. 31, 2018		33,159,253
Beginning balance at Dec. 31, 2018	(4,496)	$ 332	980,012	(984,840)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cancellation of restricted stock awards (shares)		(8,473)
Net loss	(17,097)
Ending balance (shares) at Jun. 30, 2019		33,202,871
Ending balance at Jun. 30, 2019	(20,269)	$ 332	981,336	(1,001,937)
Beginning balance (shares) at Mar. 31, 2019		33,150,780
Beginning balance at Mar. 31, 2019	(13,729)	$ 332	980,663	(994,724)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cancellation of restricted stock awards	631		631
Issuance of stock under the Employee Stock Purchase Plan (shares)		52,091
Issuance of stock under Employee Stock Purchase Plan	42		42
Net loss	(7,213)			(7,213)
Ending balance (shares) at Jun. 30, 2019		33,202,871
Ending balance at Jun. 30, 2019	$ (20,269)	$ 332	981,336	(1,001,937)
Beginning balance (shares) at Dec. 31, 2019	33,241,793	33,241,793
Beginning balance at Dec. 31, 2019	$ (33,911)	$ 332	982,738	(1,016,981)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cancellation of restricted stock awards	625		625
Issuance of stock (shares)							3,340,516
Issuance of stock	2,726						$ 34	$ 2,692
Net loss	(9,709)			(9,709)
Ending balance (shares) at Mar. 31, 2020		36,582,309
Ending balance at Mar. 31, 2020	$ (40,269)	$ 366	986,055	(1,026,690)
Beginning balance (shares) at Dec. 31, 2019	33,241,793	33,241,793
Beginning balance at Dec. 31, 2019	$ (33,911)	$ 332	982,738	(1,016,981)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)	15,156
Net loss	$ (16,417)
Ending balance (shares) at Jun. 30, 2020	50,639,048	50,639,048
Ending balance at Jun. 30, 2020	$ (30,380)	$ 506	1,002,512	(1,033,398)
Beginning balance (shares) at Mar. 31, 2020		36,582,309
Beginning balance at Mar. 31, 2020	(40,269)	$ 366	986,055	(1,026,690)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cancellation of restricted stock awards	585		585
Issuance of stock (shares)					14,000,000
Issuance of stock	15,965				$ 140	$ 15,825
Issuance of stock under the Employee Stock Purchase Plan (shares)		41,583
Issuance of stock under Employee Stock Purchase Plan	29		29
Exercise of stock options (shares)		15,156
Exercise of stock options	18		18
Net loss	$ (6,708)			(6,708)
Ending balance (shares) at Jun. 30, 2020	50,639,048	50,639,048
Ending balance at Jun. 30, 2020	$ (30,380)	$ 506	$ 1,002,512	$ (1,033,398)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (16,417)	$ (17,097)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	64	67
Non-cash lease expense	31	(14)
Stock-based compensation expense	1,210	1,282
Amortization of debt issuance costs	0	8
Non-cash imputed interest expense related to the sale of future royalties	10	239
Non-cash interest expense (income) on investments	30	(48)
Loss on extinguishment of debt	0	3,495
Loss on disposal of fixed assets	0	7
Changes in operating assets and liabilities:
Accounts receivable	758	730
Prepaid expenses and other assets	60	8
Accounts payable and accrued and other liabilities	107	(2,579)
Total adjustments	2,270	3,195
Net cash used in operating activities	(14,147)	(13,902)
Cash flows from investing activities:
Purchase of investments	0	(8,017)
Sales and maturities of investments	5,082	600
Purchase of property and equipment	(499)	(41)
Net cash provided by (used in) investing activities	4,583	(7,458)
Cash flows from financing activities:
Proceeds from PPP Loan	890	0
Proceeds from common stock purchase agreement with Aspire Capital, net of issuance costs	2,726	0
Proceeds of direct placement	17,500	0
Payment of issuance costs on direct placement	(1,111)	0
Proceeds from royalty interest purchase agreement with Oberland Capital Management, LLC	0	65,000
Payment of issuance costs on royalty interest purchase agreement	0	(584)
Proceeds from issuance of common stock under the Company's share-based compensation plan	47	42
Payment of liability of future royalties, net of imputed interest	(2,297)	(528)
Payment on termination of credit agreement with HealthCare Royalty Partners, III, L.P.	0	(37,162)
Payments on Curis Royalty’s debt	0	(1,825)
Net cash provided by financing activities	17,755	24,943
Net decrease in cash and cash equivalents and restricted cash	8,191	3,583
Cash and cash equivalents and restricted cash, beginning of period	16,399	23,789
Cash and cash equivalents and restricted cash, end of period	24,590	27,372
Accrued issuance costs	424	0
Property and equipment purchases in accounts payable	147	0
Cash paid for interest	2,324	1,417
Non-cash commitment shares issued to Aspire Capital	900	0
Right-of-use assets obtained in exchange for lease liabilities	$ 7,260	$ 1,046

Nature of Business

Nature of Business	6 Months Ended
	Jun. 30, 2020
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 first-in-class and innovative therapeutics for the treatment of cancer. Throughout these Condensed Consolidated Financial Statements, Curis, Inc. and its wholly owned subsidiaries are collectively referred to as “the Company,” or “Curis.” The Company conducts its research and development programs both internally and through strategic collaborations. The Company’s clinical stage drug candidates are: • CA-4948 which is being tested in a Phase 1 dose escalating clinical trial in patients with non-Hodgkin lymphomas, including those with Myeloid Differentiation Primary Response 88 (“MYD88”), alterations. The Company reported preliminary clinical data from the study in December 2019. The Company is also conducting a separate Phase 1 trial for acute myeloid leukemia and myelodysplastic syndromes and announced in July 2020 that the first patient had been dosed. The Company is planning a combination study of CA-4948 and ibrutinib, a BTK inhibitor, in non-Hodgkin lymphomas with planned enrollment commencing in the second half of 2020. • CI-8993, a monoclonal antibody designed to antagonize the V-domain Ig suppressor of T cell activation (“VISTA”) signaling pathway. In June 2020, the Company announced the U.S. Food and Drug Administration (“FDA”) had cleared its Investigational New Drug (“IND”) application for CI-8993. The Company plans to begin clinical testing in a Phase 1a/1b trial in patients with solid tumors in the second half of 2020. • Fimepinostat, which has been granted Orphan Drug Designation and Fast Track Designation for the treatment of DLBCL by the FDA in April 2015 and May 2018, respectively. The Company began enrollment in a Phase 1 combination study with venetoclax in DLBCL patients, including patients with translocations in both MYC and the BCL2 gene, also referred to as double-hit lymphoma, or high-grade B-cell lymphoma (“HGBL”). In March 2020, the Company announced that although it observed no significant drug-drug interaction in its Phase 1 study of fimepinostat in combination with venetoclax, the Company did not see an efficacy signal that would warrant continuation of the study. Accordingly, no further patients will be enrolled in this study. The Company is currently evaluating future studies for fimepinostat. The Company's pipeline includes CA-170, for which the Company announced initial data from a clinical study in patients with mesothelioma, in conjunction with the Society of lmmunotherapy of Cancer conference in November 2019. Based on this data, no further patients will be enrolled in the study. The Company is currently evaluating future studies for CA-170. The Company’s pipeline also includes CA-327, which is a pre-IND stage oncology drug candidate. The Company is party to a collaboration with Genentech Inc. (“Genentech”), a member of the Roche Group, under which F. Hoffmann-La Roche Ltd (“Roche”) and Genentech are commercializing Erivedge® (vismodegib), a first-in-class orally administered small molecule Hedgehog signaling pathway inhibitor. Erivedge is approved for the treatment of advanced basal cell carcinoma (“BCC”). In January 2015, and as amended in September 2016 and February 2020, the Company entered into a collaboration, option and license agreement focused on immuno-oncology and selected precision oncology targets with Aurigene Discovery Technologies Limited (“Aurigene”). The collaboration with Aurigene is comprised of multiple programs, and the Company had the option to exclusively license each program, including data, intellectual property and compounds associated therewith, once a development candidate was nominated within such program. In October 2015, the Company exercised options to license two programs under this collaboration. The first licensed program is in the immuno-oncology field and the Company has named CA-170, an orally available small molecule antagonist of two immune checkpoints, VISTA and programmed death ligand-1 (“PDL1”), as the development candidate from this program. The second licensed program is in the precision oncology field and the Company has named CA-4948, an orally available small molecule inhibitor of Interleukin-1 receptor-associated kinase 4 (“IRAK4”) as the development candidate. In October 2016, the Company exercised its option to license a third program in the collaboration, and designated CA-327, a distinct orally available small molecule antagonist of two immune checkpoints PDL1 and T-cell immunoglobulin and mucin domain containing protein-3 (“TIM3”) as the development candidate from this program. In March 2018, the Company exercised its option to license a fourth program, which is an immuno-oncology program. In January 2020, Curis entered into an option and license agreement with ImmuNext, Inc. Pursuant to the terms of the option and license agreement, the Company has the option, exercisable for a specified period as set forth in the option and license agreement, to obtain an exclusive license to develop and commercialize certain VISTA antagonizing compounds, including ImmuNext's lead compound, CI-8993, and products containing these compounds in the field of oncology. 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 continue as a going concern; the Company’s ability to obtain adequate financing to fund its operations; the Company’s ability to advance and expand its research and development programs; the impacts of the COVID-19 pandemic and responsive actions related thereto; the Company’s relationship with Aurigene to support development of drug candidates under the parties’ collaboration agreement; the Company’s reliance on Roche and Genentech to successfully commercialize Erivedge in the approved indication of advanced BCC and to progress its clinical development in indications other than BCC; 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 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, (the “Agent”), a Delaware limited liability company managed by Oberland Capital Management, LLC, as collateral agent for the Purchasers; 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 dependence on key personnel; the Company’s ability to comply with regulatory requirements; the Company's ability to obtain and maintain applicable regulatory approvals and commercialize any approved product candidates: the Company’s ability to execute on its overall business strategies; and the Company’s ability to maintain its listing on the Nasdaq Global Stock Market. The Company’s future operating results will largely depend on the progress of drug candidates currently in its development pipeline 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 candidates; Aurigene’s ability to support advancement of development candidates under the Company’s collaboration with Aurigene, as well as the Company’s ability to further develop programs under this collaboration; Roche and Genentech’s ability to successfully commercialize Erivedge; and positive results in Roche and Genentech’s ongoing clinical trials. The Company has incurred net losses and negative cash flows from operations since its inception. As of June 30, 2020, the Company had an accumulated deficit of approximately $1.0 billion, and for the six months ended June 30, 2020, the Company incurred a net loss of $16.4 million and used $14.1 million of cash in operations. The Company expects to continue to generate operating losses in the foreseeable future. The Company anticipates that its $23.6 million of existing cash, cash equivalents and investments at June 30, 2020 should enable the Company to maintain its planned operations into the first half of 2021. Based on the Company's available cash resources, recurring losses and cash outflows from operations since inception, an expectation of continuing operating losses and cash outflows from operations for the foreseeable future and the need to raise additional capital to finance its 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 expects to finance its operations through its common stock purchase agreement with Aspire Capital Fund LLC (“Aspire Capital”), and its at-the-market sales agreement with JonesTrading Institutional Services LLC (“JonesTrading”), or other potential equity financings, debt financings or other capital sources. However, the Company may not be successful in securing additional financing on acceptable terms, or at all. Furthermore, high volatility in the capital markets resulting from the COVID-19 pandemic has had, and could continue to have, a negative impact on the price of the Company’s common stock, and could adversely impact the Company’s ability to raise additional funds. 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 some of its development programs, potentially delaying the time to market for or preventing the marketing of any of its product candidates. In addition, in light of the Company’s limited cash resources, it may seek to engage in one or more strategic alternatives, such as a strategic partnership with one or more parties, the licensing, sale or divestiture of some of its assets or proprietary technologies or the sale of the Company, but there can be no assurance that the Company would be able to enter into such a transaction or transactions on a timely basis or on terms favorable to it, or at all. COVID-19 Pandemic In December 2019, an outbreak of respiratory illness caused by a strain of novel coronavirus, COVID-19, began in China. That outbreak has led to millions of confirmed cases worldwide, including in the Unites States and other countries where the Company is conducting clinical trials or activities in support thereof. The World Health Organization declared the outbreak a global public health emergency on January 30, 2020 and declared it a pandemic on March 11, 2020. In addition to those who have been directly affected, billions more have been affected by governmental efforts around the world to slow the spread of the outbreak. The outbreak and government measures taken in response have also had a significant impact, both direct and indirect, on businesses and commerce. The Company has enrolled, and will seek to enroll, cancer patients in its clinical trials at sites located both in the United States and internationally, including in Germany. Many of the Company’s clinical trial sites have imposed restrictions on entry as a result of the COVID-19 pandemic, which has had and may continue to have a negative impact on the Company’s ability to conduct its clinical trials. The Company has had and may continue to face difficulties recruiting and retaining patients in its ongoing and planned clinical trials if patients are affected by the virus or are fearful of visiting or traveling to its clinical trial sites because of the outbreak. For example, all of the Company’s clinical trial sites for its ongoing Phase 1 clinical trial for CA-4948 in patients with non-Hodgkin lymphomas, including those with MYD88 alterations, are at large academic research hospitals that have imposed restrictions on entry which has, in some instances, prohibited and in other instances may potentially prohibit in the future, clinical trial monitors and patients from entering the trial sites. The Company is actively working with its clinical trial sites to follow FDA guidelines for conducting clinical trials during the COVID-19 pandemic, including performing remote monitoring to the extent possible and to arrange for the shipment of medicine directly from the clinical trial site to patients who are enrolled in its trials, if required; however, there is no assurance such arrangements will be successful. As a result, further enrollment in the Company’s ongoing clinical trial for CA-4948 in patients with non-Hodgkin lymphomas, including those with MYD88 alterations, has been and may continue to be delayed and patients currently enrolled in the trial may cease treatment due to the restrictions described above or fear of visiting or inability to visit the Company’s trial sites or other necessary medical facilities. In addition, the Company does not currently know the duration or to what degree medical facilities, including the Company’s clinical trial sites, will continue to be impacted by the pandemic. As a result, enrollment in this trial has been slower than expected and the timeline of this clinical trial may be delayed. In addition, in July 2020 the Company commenced enrollment for its Phase 1 clinical trial in CA-4948 in patients with acute myeloid leukemia and myelodysplastic syndromes. Clinical trial sites for this study have also imposed and may continue to impose restrictions similar to those described above. As a result, enrollment in this trial has been slower than expected and the Company may not be able to enroll this trial on its planned timeline, which would cause a delay in the overall timeline for this trial. Similarly, the Company has not initiated its planned Phase 1 clinical trial for CI-8993, and initiation and enrollment of this study may be delayed due to the factors discussed above. The Company and its collaborators, third-party contract manufacturers, contract research organizations and clinical sites could experience delays or disruptions in supply and release of product candidates and/or procuring items that are essential for its research and development activities, including, for example, raw materials used in the manufacturing of its product candidates, basic medical and laboratory supplies used in its clinical trials or preclinical studies, or animals that are used for preclinical testing, in each case, for which there may be shortages because of ongoing efforts to address the outbreak. Some of the Company’s product candidates, or materials contained therein, may come from facilities located in areas impacted by COVID-19, including India, China, and Europe. In addition, any disruptions could impact the supply, manufacturing or distribution of Erivedge, and sales of Erivedge may be negatively impacted by a decrease in new prescriptions as a result of a decline in patient medical visits due to the COVID-19 pandemic, which could negatively impact the amount and timing of any royalty revenue the Company may receive from Genentech related to Erivedge ® . The Company is also experiencing delays in closing down its clinical trial sites related to its fimepinostat and CA-170 trials due to restrictions on non-essential workers imposed at those sites in response to COVID-19, which has delayed the winding down of these trials and may result in additional costs and expenses. Additionally, the pandemic has already caused significant disruptions in the financial markets, and may continue to cause such disruptions, which could impact the Company’s ability to raise additional funds. The Company cannot be certain what the overall impact of the COVID-19 pandemic will be on its business. The COVID-19 pandemic has had and may continue to have an adverse effect on the Company’s business, financial condition, results of operations, and prospects. CARES Act PPP Loan On April 21, 2020, the Company entered into a promissory note evidencing an unsecured $0.9 million loan (the “PPP Loan”) under the Paycheck Protection Program (“PPP”), of the Coronavirus Aid, Relief, and Economic Security Act, (“CARES Act”). The PPP Loan was made by Silicon Valley Bank (“SVB”). The term of the PPP Loan is 24-months. The interest rate on the PPP Loan is 1%, which shall be deferred for the first six months of the term of the loan. The promissory note evidencing the PPP loan contains customary events of default relating to, among other things, payment defaults, breach of representations and warranties, or provisions of the promissory note, and cross-default provisions. The occurrence of an event of default may result in the repayment of all amounts outstanding, collection of all amounts the Company owes, and/or filing suit and obtaining judgment against the Company. Under the terms of the CARES Act and the Paycheck Protection Program Flexibility Act of 2020, PPP Loan recipients can apply for and be granted forgiveness for all or a portion of loans granted under the PPP. Such forgiveness will be determined, subject to limitations, based on the use of loan proceeds for payroll costs and mortgage interest, rent or utility costs

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
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 Article 8 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, 2019 as filed with the Securities and Exchange Commission (“SEC”), on March 19, 2020. In the opinion of the Company, the unaudited 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 June 30, 2020; the results of operations for the three and six-month periods ended June 30, 2020 and 2019; stockholders' deficit for the three and six-month periods ended June 30, 2020 and 2019; and the cash flows for the six-month periods ended June 30, 2020 and 2019. The Condensed Consolidated Balance Sheet at December 31, 2019 was derived from audited annual financial statements but does not contain all of the footnote disclosures from the annual financial statements. In accordance with Accounting Standards Update (“ASU”) 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40) , the Company has evaluated whether 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 Consolidated Financial Statements are issued. (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 certain assets and liabilities at the balance sheet date. Such estimates include the performance obligations under the Company’s collaboration agreements; the estimated repayment term of the Company’s debt and related short- and long-term classification; the fair value of the Company’s debt; the collectability of receivables; the carrying value of property and equipment; and the assumptions used in the Company’s valuation of stock-based compensation 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. The extent to which COVID-19 has had and may continue to have impacts on the Company’s business and financial results will depend on numerous evolving factors including, but not limited to: the magnitude and duration of the COVID-19 pandemic, the extent to which it will impact worldwide macroeconomic conditions including interest rates, employment rates and health insurance coverage, the speed of the anticipated recovery, and governmental and business responses to the pandemic. The Company assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to the Company and the unknown future impacts of COVID-19 as of June 30, 2020 and through the date of this report. The accounting matters assessed included, but were not limited to, the carrying value of goodwill. The Company’s future assessment of the magnitude and duration of the COVID-19 pandemic, as well as other factors, could result in additional material impacts to the Company’s consolidated financial statements in future reporting periods. (c) Cash Equivalents, Restricted Cash, and Investments The Company had cash and cash equivalents of $23.6 million and $15.4 million as of June 30, 2020 and December 31, 2019 respectively. The Company had cash and cash equivalents of $27.2 million as of June 30, 2019. Cash equivalents consist of short-term, highly liquid investments purchased with original maturities of three months or less. All other liquid investments are classified as marketable securities. The Company classified $1.0 million of its cash as restricted cash, as of June 30, 2020 and December 31, 2019. This amount represents the security deposit delivered to the respective landlords of the Company's former and current Lexington, Massachusetts headquarters. The Company classified $0.2 million of its cash as restricted cash, as of June 30, 2019. This amount represents the security deposit delivered to the landlord of the Company's former Lexington, Massachusetts headquarters. The Company's combined cash and restricted cash balances were $24.6 million and $27.4 million as of June 30, 2020, and 2019 respectively, as presented on the Company's Consolidated Statements of Cash Flows. 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, and long-term investments are marketable debt securities with original maturities of greater than twelve months from the balance sheet. Marketable securities consist of commercial paper, corporate bonds and notes, and government obligations. All of the Company’s investments have been designated available-for-sale and are stated at fair value. Unrealized gains and temporary 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. 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 most of the Company's leases do 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. Right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. 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 consolidated balance sheets. The Company's lease agreements may include both lease and non-lease components, which are 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 consolidated balance sheets. Lease expense for lease payments is recognized on a straight-line basis over the lease term. (e) Revenue Recognition The Company’s business strategy includes entering into collaborative license and development agreements with biotechnology and pharmaceutical companies for the development and commercialization of the Company’s drug candidates. The terms of the agreements typically include non-refundable license fees, funding of research and development, payments based upon achievement of clinical development and regulatory objectives, and royalties on product sales. License Fees and Multiple Element Arrangements If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, upfront fees allocated to the license at such time as the license is transferred to the licensee and the licensee is able to use, and benefit from, the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligations to determine whether the combined performance obligations are satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, upfront fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. If the Company is involved in a steering committee as part of a multiple element arrangement, the Company assesses whether its involvement constitutes a performance obligation or a right to participate. Steering committee services that are not determined to be distinct performance obligations are combined with other research services or performance obligations required under an arrangement, if any, in determining the level of effort required in an arrangement and the period over which the Company expects to complete its aggregate performance obligations. Appropriate methods of measuring progress include output methods and input methods. In determining the appropriate method for measuring progress, the Company considers the nature of service that the Company promises to transfer to the customer. When the Company decides on a method of measurement, the Company will apply that single method of measuring progress for each performance obligation satisfied over time and will apply that method consistently to similar performance obligations and in similar circumstances. If the Company cannot reasonably measure its progress toward complete satisfaction of a performance obligation because it lacks reliable information that would be required to apply an appropriate method of measuring progress, but the Company can reasonably estimate when the performance obligation ceases or the remaining obligations become inconsequential and perfunctory, then revenue is not recognized until the Company can reasonably estimate when the performance obligation ceases or becomes inconsequential. Revenue is then recognized over the remaining estimated period of performance. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement. Contingent Research Milestone Payments Accounting Standards Codification (“ASC”) 606 constrains the amount of variable consideration included in the transaction price in that either all, or a portion, of an amount of variable consideration should be included in the transaction price. The variable consideration amount should be included 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 assessment of whether variable consideration should be constrained is largely a qualitative one that has two elements: the likelihood of a change in estimate, and the magnitude thereof. Variable consideration is not constrained if the potential reversal of cumulative revenue recognized is not significant, for example. If the consideration in a contract includes a variable amount, the Company will estimate the amount of consideration in exchange for transfer of promised goods or services. The consideration also can vary if the Company’s entitlement to the consideration is contingent on the occurrence or nonoccurrence of a future event. The Company considers contingent research milestone payments to fall under the scope of variable consideration, which should be estimated for revenue recognition purposes at the inception of the contract and reassessed ongoing at the end of each reporting period. The Company assesses whether contingent research milestones should be considered variable consideration that should be constrained and thus not part of the transaction price. This includes an assessment of the probability that all or some of the milestones revenue could be reversed when the uncertainty around whether or not the achievement of each milestone is resolved, and the amount of reversal could be significant. GAAP provides factors to consider when assessing whether variable consideration should be constrained. All of the factors should be considered, and no factor is determinative. The Company considers all relevant factors. Reimbursement of Costs Reimbursement of research and development costs by third party collaborators is recognized as revenue over time provided the Company has determined that it transfers control (i.e. performs the services) of a service over time and, therefore, satisfies a performance obligation according to the provisions outlined in ASC 606-10-25-27, Revenue Recognition . Royalty Revenue Since the first quarter of 2012, the Company has recognized 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 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 in other markets where Genentech and Roche successfully obtain marketing approval, if any (see Note 9, Research and Development Collaborations ). However, a portion of Erivedge royalties will be paid to the Purchasers under the Oberland Purchase Agreement (see Note 8, Liability Related to the Sale of Future Royalties ). Contra Revenue, Net Contra revenue, net represents shared costs, primarily related to intellectual property, with the Company's collaboration partners, and reserves for potential royalty reductions. With respect to each of the foregoing areas of revenue recognition, the Company exercises significant judgment in determining whether an arrangement contains multiple elements, and, if so, how much revenue is allocable to each element. In addition, the Company exercises its judgment in determining when its significant obligations have been met under such agreements and the specific time periods over which it recognized revenue, such as non-refundable, up-front license fees. To the extent that actual facts and circumstances differ from its initial judgment, its revenue recognition with respect to such transactions would change accordingly and any such change could affect its reported financial results. Summary During the three and six months ended June 30, 2020 total gross revenues were 100% and 96%, respectively from the Company’s collaboration with Genentech. During the three and six months ended June 30, 2019, total gross revenues were 100% from the Company’s collaboration with Genentech. In addition to the revenues received from Genentech, the Company received a milestone payment from a previously out-licensed technology in the first quarter of 2020 and was recorded in other revenues. (f) Segment Reporting The Company operates in a single reportable segment, which is the research and development of innovative cancer therapeutics. The Company expects that any products that are successfully developed and commercialized would be used in the healthcare industry and would be regulated in the United States by the FDA and in overseas markets by similar regulatory authorities. (g) New Accounting Pronouncements Recently Adopted In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-13, Fair Value Measurement, which modified the disclosure requirements for fair value measurement under ASC 820. The standard was effective for annual reporting periods and interim periods within those annual periods, beginning after December 15, 2019, with early adoption permitted. The Company adopted the standard effective January 1, 2020 with no impact to its Condensed Consolidated Financial Statements. Issued, Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This standard requires that for most financial assets, losses be based on an expected loss approach which includes estimates of losses over the life of exposure that considers historical, current and forecasted information. Expanded disclosures related to the methods used to estimate the losses as well as a specific disaggregation of balances for financial assets are also required. The targeted transition relief standard allows filers an option to irrevocably elect the fair value option of ASC 825-10, Financial Instruments-Overall, applied on an instrument-by-instrument basis for eligible instruments. In November 2019 the effective date for smaller reporting companies was extended to January 1, 2023 with the issuance of ASU 2019-10 Financial Instruments-Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Effective Dates. The Company is currently evaluating the effects of this standard and does not expect that adoption of this standard will have a material impact on its consolidated financial statements.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company has adopted the provisions of the FASB Codification Topic 820, Fair Value Measurements and Disclosures (“Topic 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 consider assumptions that market participants would use when pricing the asset or liability. Topic 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 table shows the fair value as of June 30, 2020 and December 31, 2019 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. No financial assets or liabilities are measured at fair value on a nonrecurring basis at June 30, 2020 and 2019. Quoted Prices in Other Observable Unobservable Fair Value As of June 30, 2020: Cash equivalents: Money market funds $ 21,776 $ — $ — $ 21,776 Short-term investments: Corporate commercial paper, bonds and notes — 1 — 1 Total assets at fair value $ 21,776 $ 1 $ — $ 21,777 Quoted Prices in Other Observable Unobservable Fair Value As of December 31, 2019: Cash equivalents: Money market funds $ 10,684 $ — $ — $ 10,684 US government obligations — 550 — 550 Commercial paper — 300 — 300 Municipal bonds — 90 — 90 Short-term investments: Corporate commercial paper, bonds and notes — 5,113 — 5,113 Total assets at fair value $ 10,684 $ 6,053 $ — $ 16,737

Investments

Investments	6 Months Ended
	Jun. 30, 2020
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 June 30, 2020 were as follows: Amortized Unrealized Unrealized Fair Value Corporate bonds and notes – short-term $ 1 $ — $ — $ 1 Total investments $ 1 $ — $ — $ 1 Short-term investments have maturities ranging from one twelve The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of December 31, 2019 were as follows: Amortized Unrealized Unrealized Fair Value Corporate bonds and notes – short-term $ 5,113 $ — $ — $ 5,113 Total investments $ 5,113 $ — $ — $ 5,113 Short-term investments have maturities ranging from one twelve As of June 30, 2020, the Company did not have any debt securities in an unrealized loss position.

Accrued Liabilities

Accrued Liabilities	6 Months Ended
	Jun. 30, 2020
Other Liabilities Disclosure [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consisted of the following: June 30, 2020 December 31, 2019 Accrued compensation $ 1,179 $ 1,413 Professional fees 337 289 Accrued license fees 375 — Other 206 208 Total $ 2,097 $ 1,910

Debt

Debt	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Debt	DebtIn April, 2020, the Company entered into a promissory note evidencing an unsecured $0.9 million loan under the Paycheck Protection Program, of the Coronavirus Aid, Relief, and Economic Security Act. The PPP Loan was made by Silicon Valley Bank. The term of the PPP Loan is 24-months. The interest rate on the PPP Loan is 1%, which shall be deferred for the first six months of the term of the loan. As of June 30, 2020, the Company recorded short- and long-term debt related to the PPP Loan of $0.4 million and $0.4 million, respectively. As of December 31, 2019 the Company had no debt. See Note 1, Nature of Business, for more details regarding the PPP Loan.

Leases and Commitments

Leases and Commitments	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Leases and Commitments	Leases and Commitments The Company leases real estate, including laboratory and office space. The lease for the current real estate property used for office, research and laboratory space located at 128 Spring Street in Lexington, Massachusetts commenced on May 1, 2020 which is the date when the property became available for use to the Company. In accordance with the accounting requirements under ASC 842, the lease obligation was not recorded until its commencement. As of June 30, 2020, the Company had an operating lease liability of $7.2 million and related right-of-use asset of $7.1 million related to operating leases for real estate, including its corporate headquarters. As of June 30, 2020, the Company's lease had a remaining term of seven years. The weighted average remaining lease term and discount rate for the Company's operating leases was 6.8 years and 9.95% at June 30, 2020, respectively. Lease costs for the Company's operating leases were $0.4 million and $0.3 million for the three months ended June 30, 2020 and 2019, respectively. Lease costs for the Company's operating leases were $0.7 million and $0.5 million for the six months ended June 30, 2020 and 2019, respectively. No cash payments included in the measurement of operating lease liabilities were paid in the three months ended June 30, 2020. Cash paid for amounts included in the measurement of operating lease liabilities was $0.3 million for the three months ended June 30, 2019. Cash paid for amounts included in the measurement of operating lease liabilities were $0.2 million and $0.5 million for each of the six months ended June 30, 2020 and 2019, respectively. Maturity analysis of lease liabilities as of June 30, 2020 are as follows (in thousands): Year Remainder of the year ending December 31, 2020 $ 1,855 Year ending December 31, 2021 1,110 Year ending December 31, 2022 1,144 Year ending December 31, 2023 1,178 Year ending December 31, 2024 1,213 Thereafter 2,971 Total $ 9,471 Less interest 2,274 Operating lease liability $ 7,197

Liability Related to the Sale o

Liability Related to the Sale of Future Royalties	6 Months Ended
	Jun. 30, 2020
Nonmonetary Transactions [Abstract]
Liability Related to the Sale of Future Royalties	Liability Related to the Sale of Future Royalties On March 22, 2019, the Company and Curis Royalty entered into the royalty interest purchase agreement (“Oberland Purchase Agreement”) with entities managed by Oberland Capital Management, LLC (the “Purchasers”) pursuant to which 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, at closing the Purchasers paid to Curis Royalty $65.0 million less certain transaction expenses. Curis Royalty will also be entitled to receive up to approximately $70.7 million in milestone payments based on sales of Erivedge as follows: (i) $17.2 million if the Purchasers and Curis Royalty receive aggregate royalty payments pursuant to the Oberland Purchase Agreement in excess of $18.0 million during the calendar year 2021, subject to certain exceptions and (ii) $53.5 million if the Purchasers receive payments pursuant to the Oberland Purchase Agreement in excess of $117.0 million on or prior to December 31, 2026. Concurrently with the closing of the Oberland Purchase Agreement, Curis Royalty used a portion of the proceeds to terminate and repay its prior loan with HealthCare Royalty. In connection with such termination, Curis Royalty paid approximately $37.2 million to satisfy its remaining loan obligations to HealthCare Royalty, including approximately $33.8 million in principal balance on the loan and $3.4 million in accrued and unpaid interest and prepayment fees. Curis Royalty also used a portion of the proceeds to pay transaction costs of approximately $0.3 million, resulting in net proceeds of approximately $27.5 million. 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 (the “Purchased Receivables”), at a price (the “Put/Call Price”), equal to a percentage, beginning at a low triple digit percentage and increasing over time up to a low mid triple digit percentage 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. 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. As a result of its obligation to pay future royalties to Oberland, the Company recorded the proceeds from this transaction as a liability on its Condensed Consolidated Balance Sheet that will be accounted for using the interest method over the estimated life of the Oberland Purchase Agreement. As a result, the Company imputes interest on the transaction and recorded imputed interest expense at the estimated interest rate. Its estimate of the interest rate under the agreement is based on the amount of royalty payments expected to be received by Oberland over the life of the arrangement. 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 its initial estimates or the timing of such payments is materially different than its original estimates, the Company will adjust 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 8.3%. The Company incurred $0.6 million of transaction costs in connection with the agreement. These transaction costs will be amortized to imputed interest expense over the estimated term of the Oberland Purchase Agreement. The following table shows the activity with respect to the liability related to the sale of future royalties during the six months ended June 30, 2020. Carrying value of liability related to the sale of future royalties at January 1, 2020 $ 62,477 Amortization of capitalized issuance costs 31 Imputed interest expense recognized for the six months ended June 30, 2020 2,551 Less: payments to Oberland Capital, LLC (4,870) Carrying value of liability related to the sale of future royalties at June 30, 2020 $ 60,189 The following table shows the activity with respect to the liability related to the sale of future royalties from the inception of the Oberland Purchase Agreement through December 31, 2019 Liability related to the sale of future royalties at March 22, 2019 $ 65,000 Capitalized issuance costs (584) Imputed interest expense recognized for the year ended December 31, 2019 4,055 Less: payments to Oberland Capital, LLC (5,994) Carrying value of liability related to the sale of future royalties at December 31, 2019 $ 62,477

Research and Development Collab

Research and Development Collaborations	6 Months Ended
	Jun. 30, 2020
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 technologies to Genentech for human therapeutic use. The primary focus of the collaborative research plan has been to develop molecules that inhibit the Hedgehog pathway for the treatment of various cancers. The collaboration is currently focused on the development of Erivedge, which is being commercialized by Genentech in the U.S. and by Genentech’s parent company, Roche, in several other countries for the treatment of advanced BCC. Pursuant to the agreement, the Company is eligible to receive up to an aggregate of $115.0 million in contingent cash milestone payments, exclusive of royalty payments, in connection with the development of Erivedge or another small molecule Hedgehog pathway inhibitor, assuming the successful achievement by Genentech and Roche of specified clinical development and regulatory objectives. Of this amount, the Company has received $59.0 million in cash milestone payments as of June 30, 2020. In addition to these payments and 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, including when a competing product that binds to the same molecular target as Erivedge is approved by the applicable regulatory authority in another country, and is being sold in such country, by a third party for use in the same indication as Erivedge, or, when there is no issued intellectual property covering Erivedge in a territory in which sales are recorded. In 2015, the FDA and the European Medicine Agency’s Committee for Medicinal Products for Human Use, approved another Hedgehog signaling pathway inhibitor, Odomzo® (“sonidegib”), which is marketed by Sun Pharmaceutical Industries Ltd., for use in locally advanced BCC. Beginning in the fourth quarter of 2015, Genentech applied the 2% royalty reduction on U.S. sales of Erivedge as a result of the first commercial sale of Odomzo® in the U.S. and the Company anticipates that Genentech will reduce by 2% royalties on net sales of Erivedge outside of the United States on a country-by-country basis to the extent that sonidegib is approved by the applicable country's regulatory authority and is being sold in such country. However, pursuant to the Oberland Purchase Agreement, Curis has retained its rights with respect to the 2% of royalties that are subject to such reduction in countries where such reduction has not occurred, subject to the terms and conditions of the Oberland Purchase Agreement. The Company recognized $2.4 million and $2.1 million in royalty revenue under the Genentech collaboration during the three months ended June 30, 2020 and 2019, respectively. The Company recognized $5.0 million and $4.3 million in royalty revenue under the Genentech collaboration during the six months ended June 30, 2020 and 2019, respectively. The Company also recorded costs of royalty revenues within the costs and expenses section of its Condensed Consolidated Statements of Operations and Comprehensive Loss of $0.1 million and $0.2 million, during both of the three and six months ended June 30, 2020 and 2019, respectively. Cost of royalty revenues comprises 5% of the royalty payments that Curis Royalty receives from Genentech, through February 2022, which the Company is obligated to pay to university licensors. Under this collaboration, the Company is obligated to reimburse Genentech, and the Company records contra-revenues in its Condensed Consolidated Statements of Operations and Comprehensive Loss. The Company will continue to recognize revenue for expense reimbursement as such reimbursable expenses are incurred, provided that the provisions of ASC 606 are met. Genentech incurred immaterial expense during the three and six months ended June 30, 2020, and 2019, respectively. The Company recorded a receivable from Genentech under this collaboration, comprised primarily of Erivedge royalties earned in the first half of 2020 and 2019, respectively. The receivable recorded in the Company's current assets section of its Condensed Consolidated Balance Sheets amounted to $2.5 million and $3.2 million as of June 30, 2020 and December 31, 2019, respectively. As previously discussed in Note 8, Liability Related to the Sale of Future Royalties a 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 In January 2015, the Company entered into 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. In connection with the collaboration agreement, the Company issued to Aurigene 3,424,026 shares of its common stock valued at $24.3 million in partial consideration for the rights granted to the Company under the collaboration agreement, which the Company recognized as expense during the year ended December 31, 2015. The shares were issued pursuant to a stock purchase agreement with Aurigene dated January 18, 2015. In September 2016 the Company and Aurigene entered into an amendment to the collaboration agreement. Under the terms of the amendment, in exchange for the issuance by the Company to Aurigene of 2,041,666 shares of its common stock, Aurigene waived payment of up to a total of $24.5 million in potential milestones and other payments associated with the first four programs in the collaboration that may have become due from the Company under the collaboration agreement. To the extent any of these waived milestones or other payments are not payable by the Company, for example in the event one or more of the milestone events do not occur, the Company will have the right to deduct the unused waived amount from any one or more of the milestone payment obligations tied to achievement of commercial milestone events. The amendment also provides that, in the event supplemental program activities are performed by Aurigene, the Company will provide up to $2.0 million of additional funding for each of the third and fourth licensed program. The shares were issued pursuant to a stock purchase agreement with Aurigene dated September 7, 2016. In February 2020 the Company and Aurigene further amended their collaboration agreement. Under the terms of the amended agreement, Aurigene will fund and conduct a Phase 2b/3 randomized study evaluating CA-170, in combination with chemoradiation, in approximately 240 patients with non-squamous non-small cell lung cancer. In turn, Aurigene receives rights to develop and commercialize CA-170 in Asia, in addition to its existing rights in India and Russia, based on the terms of the original agreement. The Company retains U.S., European Union, and rest of world rights to CA-170, and 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 June 30, 2020, the Company had 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 CA-4948, an orally available small molecule inhibitor of IRAK4. 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, an orally available small molecule antagonist of VISTA and PDL1. 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, an orally available small molecule antagonist of PDL1 and TIM3. 4. In March 2018, the Company exercised its option to license a fourth program, which is an immuno-oncology program. For each of the Company's 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. Since January 2015, the Company has paid $14.5 million in research payments and has waived $19.5 million in milestone payments under the terms of the 2016 amendment. For each of the IRAK4, PD1/VISTA,PD1/TIM3 programs, and the fourth immuno-oncology program: the Company has remaining unpaid or unwaived payment obligations of $42.5 million per program, related to regulatory approval and commercial sales milestones, plus specified additional payments for approvals for additional indications, if any. In addition to the collaboration agreement, in June 2017, the Company entered into a master development and manufacturing agreement with Aurigene for the supply of drug substance and drug product. The Company paid $0.2 million and an immaterial amount less than $0.1 million related to Aurigene for the three month periods ended June 30, 2020 and 2019, respectively. (c) ImmuNext On January 6, 2020, the Company entered into an option and license agreement with ImmuNext (the “ImmuNext Agreement”). Under the terms of the ImmuNext Agreement, the Company agreed to engage in a collaborative effort with ImmuNext, and to conduct a Phase 1a/1b clinical trial of CI-8993. In exchange, ImmuNext granted the Company an exclusive option, exercisable until the earlier of (a) four years after January 6, 2020 and (b) 90 days after database lock for the first Phase 1a/1b trial in which the endpoints are satisfied (the “Option Period”), to obtain an exclusive, worldwide license to develop and commercialize certain VISTA antagonizing compounds and products containing these compounds (the “VISTA Compounds and Products”) in the field of oncology. A joint steering committee composed of representatives from each of the parties will manage the non-clinical and clinical development of the VISTA Compounds and Products during the Option Period, including, but not limited to, the approval of the plan for the Phase 1a/1b trial. During the Option Period, the Company will conduct the Phase 1a/1b trial and ImmuNext will conduct certain agreed upon non-clinical research activities to support the Phase 1a/1b trial. Additionally, the Company will assign to ImmuNext all right, title and interest in and to, inventions made by the Company alone or jointly with ImmuNext in conducting clinical and non-clinical activities under the ImmuNext Agreement and any patent rights covering those inventions. If the option is exercised, ImmuNext will assign to the Company (i) all such inventions that were made solely by the Company and any patent rights covering those inventions that were assigned by the Company to ImmuNext during the Option Period and (ii) a joint ownership interest in all such inventions that were made jointly by the Company and ImmuNext and patent rights covering those inventions that were assigned by the Company to ImmuNext during the Option Period, except for any of those inventions that relates to certain compounds to which ImmuNext has retained exclusive rights. In consideration of the grant of the option, the Company made an upfront payment to ImmuNext of $1.3 million which is included in research and development expense as the acquired intellectual property is not yet completed. If the Company elects to exercise the option, the Company has agreed to pay to ImmuNext an option exercise fee of $20.0 million. If the Company elects to exercise the option, ImmuNext will be eligible to receive up to $4.6 million in potential development milestones, up to $84.3 million in potential regulatory approval milestones, and up to $125.0 million in potential sales milestone payments from the Company. In addition, ImmuNext is eligible to receive tiered royalties on annual net sales on a product-by-product and country-by-country basis, at percentage rates ranging from high single digits to low double digits, subject to specified adjustments. The royalty payment obligations under the ImmuNext Agreement with respect to a product in a country will expire on the later of (i) expiration of the last-to-expire valid claim of the ImmuNext patents or jointly owned patents covering the manufacture, use or sale of such product in such country, (ii) the expiration of all regulatory exclusivity for such product in such country, and (iii) 10 years from the first commercial sale of such product in such country. In partial consideration for drug substance, technical advice, and maintenance of ImmuNext’s existing IND and access to ImmuNext’s technology, the Company has agreed to make semi-annual maintenance fee payments of $0.4 million to ImmuNext during the Option Period. In addition, the Company has agreed to reimburse ImmuNext for certain documented external costs and expenses incurred by ImmuNext in carrying out non-clinical research activities approved by the joint steering committee, up to $0.3 million per calendar year, unless otherwise agreed to by both parties in writing. In addition, the Company has agreed to pay ImmuNext a low double-digit percentage of sublicense revenue received by the Company or its Affiliates.

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Common Stock	Common Stock (a) 2020 Registered Direct Offering In June 2020, the Company entered into a securities purchase agreement with certain institutional investors, pursuant to which the Company issued and sold, in a registered direct offering, an aggregate of 14,000,000 shares of the Company's common stock at a purchase price per share of $1.25, for aggregate gross proceeds of $17.5 million, before deducting fees of approximately $1.0 million paid to the placement agent and other estimated offering expenses of approximately $0.5 million paid by the Company. JonesTrading acted as the exclusive placement agent for the transaction, and the shares were offered by the Company pursuant to its universal shelf registration statement on Form S-3, which was filed with the SEC on May 3, 2018 and declared effective by the SEC on May 17, 2018 (File No. 333-224627), and a prospectus supplement thereunder. (b) 2020 Charter Amendment On June 4, 2020, the Company's stockholders approved an increase to the number of authorized shares of its common stock from 101,250,000 shares to 151,875,000 shares. The Company filed an amendment to its certificate of incorporation on June 4, 2020 to effect such an increase. (c) 2020 Sales Agreement with JonesTrading Institutional Services LLC On March 4, 2020, the Company entered into a Capital on Demand™ Sales Agreement (the “Sales Agreement”) with JonesTrading to sell from time to time up to $30.0 million of the Company’s common stock through an “at-the-market” equity offering program under which JonesTrading will act as sales agent. Subject to the terms and conditions of the Sales Agreement, JonesTrading could 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 of 1933, as amended (the “Securities Act”), including sales made directly on the Nasdaq Global Market, on any other existing trading market for the common stock or to or through a market maker other than on an exchange. In addition, with the Company’s prior written approval, JonesTrading may also sell the common stock by any other method permitted by law, including in privately negotiated transactions. Pursuant to the terms of the Sales Agreement, the aggregate compensation payable to JonesTrading is 3% of the gross proceeds from sales of the common stock sold by JonesTrading pursuant to the Sales Agreement. Each party agreed in the Sales Agreement to provide indemnification and contribution against certain liabilities, including liabilities under the Securities Act, subject to the terms of the Sales Agreement. The Company did not sell any shares of common stock under this Sales Agreement during the three or six months ended June 30, 2020. (d) Aspire Capital Fund LLC On February 26, 2020, the Company entered into a common stock purchase agreement (the “Agreement”) for the sale of up to $30.0 million of the Company's common stock with Aspire Capital Fund. Under the terms of the Agreement, Aspire Capital made an initial investment of $3.0 million through the purchase of 2,693,965 shares of the Company's common stock. In addition, Aspire Capital has committed to purchasing up to an additional $27.0 million in shares of the Company's common stock at the Company’s request, from time to time during a 30-month period at prices based on the market price at the time of each sale, subject to specified terms and limitations. As consideration for Aspire Capital’s obligation under the Agreement, the Company issued 646,551 shares of common stock to Aspire Capital as a commitment fee. Under the terms of the Agreement, the Company has the right to sell up to 150,000 shares of common stock per day to Aspire Capital, which total may be increased by mutual agreement up to an additional 2,000,000 shares per day. The extent to which the Company relies on Aspire Capital as a source of funding will depend on a number of factors, including the prevailing market price of its common stock and the extent to which it is able to secure working capital from other sources. Pursuant to the terms of the Agreement, the aggregate number of shares that the Company can sell to Aspire Capital under the Agreement may exceed 6,645,034 (the “Exchange Cap”) shares of its common stock (which is equal to approximately 19.9% of the common stock outstanding on the date of the purchase agreement), including the shares purchased by Aspire Capital and issued to Aspire Capital as consideration in connection with entering into the Agreement only if (i) stockholder approval is obtained to issue more, in which case the Exchange Cap would not apply, or (ii) stockholder approval is not obtained and at any time the Exchange Cap is reached and at all times thereafter the average price paid for all shares issued under the purchase agreement (including the shares issued as consideration to Aspire Capital in connection with entering into the agreement) is equal to or greater than $1.34, or the Minimum Price. In June 2020, the Company’s stockholders approved the issuance of up to $27.0 million in additional shares of common stock to Aspire Capital pursuant to the Agreement, resulting in the removal of the Exchange Cap. There are no warrants, derivatives, or other share classes associated with this Agreement. The Company will control the timing and amount of the further sale of its common stock to Aspire Capital. There are no restrictions on future financings and there are no financial covenants, participation rights, rights of first refusal, or penalties in the Agreement. The Company has the right to terminate the Agreement at any time without any additional cost or penalty. The Company also entered into a Registration Rights Agreement with Aspire Capital in connection with its entry into the Agreement. (e) 2019 Charter Amendment On May 23, 2019, the Company's stockholders approved an increase to the number of authorized shares of its common stock from 67,500,000 shares to 101,250,000 shares. The Company filed an amendment to its certificate of incorporation on May 23, 2019 to effect such increase. (f) 2015 Sales Agreement with Cowen and Company, LLC On July 2, 2015, the Company entered into a sales agreement with Cowen and Company, LLC (“Cowen”), pursuant to which the Company could sell from time to time up to $30.0 million of the Company’s common stock through an “at-the-market” equity offering program under which Cowen acted as sales agent. Subject to the terms and conditions of the sales agreement, Cowen could sell the common stock by methods deemed to be an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, including sales made directly on the Nasdaq Global Market, on any other existing trading market for the common stock or to or through a market maker other than on an exchange. In addition, with the Company’s prior written approval, Cowen could also sell the common stock by any other method permitted by law, including in negotiated transactions. Pursuant to the terms of the agreement, the aggregate compensation payable to Cowen was 3% of the gross sales price of the common stock sold by Cowen pursuant to the sales agreement. Each party agreed in the sales agreement to provide indemnification and contribution against certain liabilities, including liabilities under the Securities Act, subject to the terms of the sales agreement. The Company did not sell shares of common stock under this sales agreement during 2020. As of December 31, 2019, the Company sold an aggregate of 420,796 shares of common stock pursuant to this sales agreement, for net proceeds of $6.2 million.

Stock Plans and Stock Based Com

Stock Plans and Stock Based Compensation	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Stock Plans and Stock Based Compensation	Stock Plans and Stock Based Compensation As of June 30, 2020, the Company had two shareholder-approved, share-based compensation plans: (i) the Amended and Restated 2010 Employee Stock Purchase Plan (“ESPP”), adopted by the Company's board of directors in April 2017 and approved by shareholders in June 2017, and (ii) the Third Amended and Restated 2010 Stock Incentive Plan, (“2010 Plan”), adopted by the Board of Directors in March 2018 and approved by shareholders in May 2018. New employees are typically issued options as an inducement equity award under Nasdaq Listing Rule 5635(c)(4) outside of the 2010 Plan. The Third 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. On May 23, 2019, the Company’s shareholders approved an amendment to the 2010 Plan to reserve an additional 4,700,000 shares of common stock for issuance under the 2010 Plan, and on June 4, 2020 the Company's shareholders approved a second amendment to the 2010 Plan to reserve an additional 1,300,000 shares of common stock for issuance under the 2010 Plan. The Company can issue up to 12,190,000 shares of its common stock pursuant to awards granted under the 2010 Plan. Options become exercisable as 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 one share of stock subject to awards granted as options and stock appreciation rights, will cause one 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 June 30, 2020 the Company had 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 Global Market on the grant date. As of June 30, 2020, 2,878,896 shares remained available for grant under the 2010 Plan. During the six months ended June 30, 2020, the Company’s board of directors granted options to purchase a total of 2,648,150 shares of the Company’s common stock to the officers and employees of the Company, under the 2010 Plan or in the form of inducement awards pursuant to Nasdaq Marketplace Rules. Of these options, options to purchase 878,150 shares were granted to non-officer employees and vest as to 25% of the shares underlying the award on the first anniversary of the grant date and as to an additional 6.25% of the shares underlying the award at the end of each subsequent quarter, based upon continued employment over a four Additionally, the Company’s board of directors authorized a grant of options to purchase 1,520,000 shares of the Company’s common stock to its officers in March 2020. Such stock options have an exercise price equal to $1.26 per share, the closing price of the Company’s common stock on the Nasdaq Global Market on the date of grant, and will vest and become exercisable as to 25% of the shares underlying the award on the first anniversary of the grant date and as to an additional 6.25% of the shares underlying the award at the end of each subsequent quarter, based upon continued employment over a four During the first quarter of 2020, the Company’s board of directors granted options to its non-employee directors to purchase 720,000 shares of common stock under the 2010 Plan, which will vest and become exercisable one Nonstatutory Inducement Grants For certain new employees the Company issues options as an inducement equity award under Nasdaq Listing Rule 5635(c)(4) outside of the 2010 Plan. Each option will 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 in each subsequent quarter, based upon continued employment over a four Employee and Director Grants Vesting Tied to Service Conditions In determining the fair value of stock options, the Company generally uses the Black-Scholes option pricing model. The Black-Scholes option pricing model employs the following key assumptions for employee and director options awarded during the six months ended June 30, 2020 and 2019 based on the assumptions noted in the following table: Six Months Ended 2020 2019 Expected term (years) – employees and officers 5.5 5.5 Expected term (years) – directors 5.5 5.5 Risk free interest rate 0.4-1.7% 2.5-2.6% Expected Volatility 81 % 79 % Expected Dividends None None The expected volatility is based on the annualized daily historical volatility of the Company’s stock price for a time period consistent with the expected term of each grant. Management believes that the historical volatility of the Company’s stock price best represents the future volatility of the stock price. The risk free interest rate is based on the U.S. Treasury yield in effect at the time of grant for the expected term of the respective grant. The Company has not historically paid cash dividends, and does not expect to pay cash dividends in the foreseeable future. The expected terms and stock price volatility utilized in the calculation involve management’s best estimates at that time, both of which impact the fair value of the option calculated under the Black-Scholes methodology and, ultimately, the expense that will be recognized over the life of the option. GAAP also requires that the Company recognize compensation expense for only the portion of options that are expected to vest. Therefore, management calculated an estimated annual pre-vesting forfeiture rate that is derived from historical employee termination behavior since the inception of the Company, as adjusted. If the actual number of forfeitures differs from those estimated by management, additional adjustments to compensation expense may be required in future periods. A summary of stock option activity under the 2010 Plan, the 2000 Stock Incentive Plan, the 2000 Director Stock Option Plan and nonstatutory inducement awards are summarized as follows: Number of Weighted Weighted Aggregate Intrinsic Value Unvested, December 31, 2019 6,158,026 $ 3.43 8.33 Granted 3,368,150 1.27 Exercised (15,156) 1.17 Canceled (348,812) 2.89 Outstanding, June 30, 2020 9,162,208 $ 2.66 8.47 $ — Exercisable at June 30, 2020 3,226,482 $ 4.78 7.27 $ — Vested and unvested expected to vest at June 30, 2020 8,051,410 $ 2.83 8.37 $ — The weighted average grant date fair values of the stock options granted during the six months ended June 30, 2020 and 2019 were $0.75 and $0.79, respectively. As of June 30, 2020, there was approximately $3.9 million of unrecognized compensation cost related to unvested employee stock option awards outstanding, net of the impact of estimated forfeitures that is expected to be recognized as expense over a weighted average period of 2.61 years. The intrinsic value of employee stock options exercised during the six months ended June 30, 2020 was immaterial. There were no options exercised during the six months ended June 30, 2019. The following table presents a summary of unvested restricted stock awards (“RSAs”) under the 2010 Plan as of June 30, 2020: Number of Weighted Unvested, December 31, 2019 30,937 $ 3.45 Awarded — — Vested (10,313) 3.45 Forfeited — — Unvested, June 30, 2020 20,624 $ 3.45 As of June 30, 2020, there were 20,624 shares outstanding covered by RSAs that are expected to vest. The weighted average fair value of these shares of restricted stock was $3.45 per share and the aggregate fair value of these shares of restricted stock was approximately $0.1 million. As of June 30, 2020, there were approximately $0.1 million of unrecognized compensation costs, net of estimated forfeitures, related to RSAs granted to officers, which are expected to be recognized as expense over a remaining weighted average period of 1.56 years. Second Amended and Restated 2010 Employee Stock Purchase Plan The Company has reserved 2,000,000 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 six two two six ESPP compensation expense for the three and six months ended June 30, 2020 and 2019 was not material. Total Stock Based Compensation Expense For the three and six months ended June 30, 2020 and 2019, 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, including expense related to its ESPP: Three Months Ended Six Months Ended 2020 2019 2020 2019 Research and development expenses $ 185 $ 123 $ 355 $ 299 General and administrative expenses 400 508 855 983 Total stock based compensation expense $ 585 $ 631 $ 1,210 $ 1,282

Loss Per Common Share

Loss Per Common Share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Loss Per Common Share	Loss Per Common ShareBasic 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 and six months ended June 30, 2020 and 2019, because the effect of the potential 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 9,162,208 and 5,940,813 as of June 30, 2020 and 2019, respectively.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions (a) Agreement with Head of Research and Development - Robert E. Martell, M.D., Ph.D. On October, 17, 2018, the Company entered into an exclusive option and license agreement with Epi-Cure Pharmaceuticals, Inc., (“Epi-Cure”) a privately held early stage biotechnology company. Robert E. Martell, M.D., Ph.D., the Company’s Head of Research and Development and a former director of the Company, is a founder of Epi-Cure, was formerly an officer and director of Epi-Cure, and is currently a holder of a convertible promissory note to Epi-Cure. Under the terms of the option and license agreement, Epi-Cure has granted Curis an exclusive option to certain program compounds that may arise during the initial research and development period, and any extension thereof. Upon execution of the option and license agreement, the Company paid Epi-Cure an upfront payment of $0.1 million for legal and consulting costs incurred by Epi-Cure in connection with the transaction. In July 2019, the Company extended the research and development period of the program until April 2020, as permitted under the terms of the agreement. Under the terms of the agreement, Epi-Cure will have primary responsibility for conducting research and development activities and Curis was responsible for funding up to $0.5 million of the research and development program costs and expenses during the initial research and development period. After the end of the research and development period, which ended in April 2020, Curis had sixty days to elect to exercise its option to license the program compounds. In June 2020, the Company decided not to exercise its option to license the program compounds, and the agreement expired. For the three months ended June 30, 2020, and 2019 Curis expensed less than $0.1 million and $0.1 million, respectively, of fees related to this agreement. For the six months ended June 30, 2020, and 2019 Curis expensed $0.2 million and $0.1 million, respectively, of fees related to this agreement. (b) Agreement with David Tuck, M.D.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with the instructions to Form 10-Q and Article 8 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, 2019 as filed with the Securities and Exchange Commission (“SEC”), on March 19, 2020.
Use of Estimates	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 certain assets and liabilities at the balance sheet date. Such estimates include the performance obligations under the Company’s collaboration agreements; the estimated repayment term of the Company’s debt and related short- and long-term classification; the fair value of the Company’s debt; the collectability of receivables; the carrying value of property and equipment; and the assumptions used in the Company’s valuation of stock-based compensation and the value of certain investments and liabilities. Actual results may differ from such estimates.
Cash Equivalents, Restricted Cash, and Investments	Cash equivalents consist of short-term, highly liquid investments purchased with original maturities of three months or less. All other liquid investments are classified as marketable securities. 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, and long-term investments are marketable debt securities with original maturities of greater than twelve months from the balance sheet. Marketable securities consist of commercial paper, corporate bonds and notes, and government obligations. All of the Company’s investments have been designated available-for-sale and are stated at fair value. Unrealized gains and temporary 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. 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 most of the Company's leases do 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. Right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. 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 consolidated balance sheets. The Company's lease agreements may include both lease and non-lease components, which are accounted for as a single lease component when the payments are fixed. Variable payments included in the lease agreement are expensed as incurred.
Revenue Recognition	Revenue Recognition The Company’s business strategy includes entering into collaborative license and development agreements with biotechnology and pharmaceutical companies for the development and commercialization of the Company’s drug candidates. The terms of the agreements typically include non-refundable license fees, funding of research and development, payments based upon achievement of clinical development and regulatory objectives, and royalties on product sales. License Fees and Multiple Element Arrangements If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, upfront fees allocated to the license at such time as the license is transferred to the licensee and the licensee is able to use, and benefit from, the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligations to determine whether the combined performance obligations are satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, upfront fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. If the Company is involved in a steering committee as part of a multiple element arrangement, the Company assesses whether its involvement constitutes a performance obligation or a right to participate. Steering committee services that are not determined to be distinct performance obligations are combined with other research services or performance obligations required under an arrangement, if any, in determining the level of effort required in an arrangement and the period over which the Company expects to complete its aggregate performance obligations. Appropriate methods of measuring progress include output methods and input methods. In determining the appropriate method for measuring progress, the Company considers the nature of service that the Company promises to transfer to the customer. When the Company decides on a method of measurement, the Company will apply that single method of measuring progress for each performance obligation satisfied over time and will apply that method consistently to similar performance obligations and in similar circumstances. If the Company cannot reasonably measure its progress toward complete satisfaction of a performance obligation because it lacks reliable information that would be required to apply an appropriate method of measuring progress, but the Company can reasonably estimate when the performance obligation ceases or the remaining obligations become inconsequential and perfunctory, then revenue is not recognized until the Company can reasonably estimate when the performance obligation ceases or becomes inconsequential. Revenue is then recognized over the remaining estimated period of performance. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement. Contingent Research Milestone Payments Accounting Standards Codification (“ASC”) 606 constrains the amount of variable consideration included in the transaction price in that either all, or a portion, of an amount of variable consideration should be included in the transaction price. The variable consideration amount should be included 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 assessment of whether variable consideration should be constrained is largely a qualitative one that has two elements: the likelihood of a change in estimate, and the magnitude thereof. Variable consideration is not constrained if the potential reversal of cumulative revenue recognized is not significant, for example. If the consideration in a contract includes a variable amount, the Company will estimate the amount of consideration in exchange for transfer of promised goods or services. The consideration also can vary if the Company’s entitlement to the consideration is contingent on the occurrence or nonoccurrence of a future event. The Company considers contingent research milestone payments to fall under the scope of variable consideration, which should be estimated for revenue recognition purposes at the inception of the contract and reassessed ongoing at the end of each reporting period. The Company assesses whether contingent research milestones should be considered variable consideration that should be constrained and thus not part of the transaction price. This includes an assessment of the probability that all or some of the milestones revenue could be reversed when the uncertainty around whether or not the achievement of each milestone is resolved, and the amount of reversal could be significant. GAAP provides factors to consider when assessing whether variable consideration should be constrained. All of the factors should be considered, and no factor is determinative. The Company considers all relevant factors. Reimbursement of Costs Reimbursement of research and development costs by third party collaborators is recognized as revenue over time provided the Company has determined that it transfers control (i.e. performs the services) of a service over time and, therefore, satisfies a performance obligation according to the provisions outlined in ASC 606-10-25-27, Revenue Recognition . Royalty Revenue Since the first quarter of 2012, the Company has recognized 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 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 in other markets where Genentech and Roche successfully obtain marketing approval, if any (see Note 9, Research and Development Collaborations ). However, a portion of Erivedge royalties will be paid to the Purchasers under the Oberland Purchase Agreement (see Note 8, Liability Related to the Sale of Future Royalties ). Contra Revenue, Net Contra revenue, net represents shared costs, primarily related to intellectual property, with the Company's collaboration partners, and reserves for potential royalty reductions. With respect to each of the foregoing areas of revenue recognition, the Company exercises significant judgment in determining whether an arrangement contains multiple elements, and, if so, how much revenue is allocable to each element. In addition, the Company exercises its judgment in determining when its significant obligations have been met under such agreements and the specific time periods over which it recognized revenue, such as non-refundable, up-front license fees. To the extent that actual facts and circumstances differ from its initial judgment, its revenue recognition with respect to such transactions would change accordingly and any such change could affect its reported financial results.
Segment Reporting	Segment ReportingThe Company operates in a single reportable segment, which is the research and development of innovative cancer therapeutics. The Company expects that any products that are successfully developed and commercialized would be used in the healthcare industry and would be regulated in the United States by the FDA and in overseas markets by similar regulatory authorities.
New Accounting Pronouncements	New Accounting Pronouncements Recently Adopted In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-13, Fair Value Measurement, which modified the disclosure requirements for fair value measurement under ASC 820. The standard was effective for annual reporting periods and interim periods within those annual periods, beginning after December 15, 2019, with early adoption permitted. The Company adopted the standard effective January 1, 2020 with no impact to its Condensed Consolidated Financial Statements. Issued, Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This standard requires that for most financial assets, losses be based on an expected loss approach which includes estimates of losses over the life of exposure that considers historical, current and forecasted information. Expanded disclosures related to the methods used to estimate the losses as well as a specific disaggregation of balances for financial assets are also required. The targeted transition relief standard allows filers an option to irrevocably elect the fair value option of ASC 825-10, Financial Instruments-Overall, applied on an instrument-by-instrument basis for eligible instruments. In November 2019 the effective date for smaller reporting companies was extended to January 1, 2023 with the issuance of ASU 2019-10 Financial Instruments-Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Effective Dates. The Company is currently evaluating the effects of this standard and does not expect that adoption of this standard will have a material impact on its consolidated financial statements.
Fair Value Measurements	Fair Value of Financial Instruments The Company has adopted the provisions of the FASB Codification Topic 820, Fair Value Measurements and Disclosures (“Topic 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 consider assumptions that market participants would use when pricing the asset or liability. Topic 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)	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of Financial Assets or Liabilities Measured at Fair Value on Recurring Basis	In accordance with the fair value hierarchy, the following table shows the fair value as of June 30, 2020 and December 31, 2019 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. No financial assets or liabilities are measured at fair value on a nonrecurring basis at June 30, 2020 and 2019. Quoted Prices in Other Observable Unobservable Fair Value As of June 30, 2020: Cash equivalents: Money market funds $ 21,776 $ — $ — $ 21,776 Short-term investments: Corporate commercial paper, bonds and notes — 1 — 1 Total assets at fair value $ 21,776 $ 1 $ — $ 21,777 Quoted Prices in Other Observable Unobservable Fair Value As of December 31, 2019: Cash equivalents: Money market funds $ 10,684 $ — $ — $ 10,684 US government obligations — 550 — 550 Commercial paper — 300 — 300 Municipal bonds — 90 — 90 Short-term investments: Corporate commercial paper, bonds and notes — 5,113 — 5,113 Total assets at fair value $ 10,684 $ 6,053 $ — $ 16,737

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Schedule of Amortized Cost of Unrealized Gains and Losses and Fair Value of Investments	The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of June 30, 2020 were as follows: Amortized Unrealized Unrealized Fair Value Corporate bonds and notes – short-term $ 1 $ — $ — $ 1 Total investments $ 1 $ — $ — $ 1 The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of December 31, 2019 were as follows: Amortized Unrealized Unrealized Fair Value Corporate bonds and notes – short-term $ 5,113 $ — $ — $ 5,113 Total investments $ 5,113 $ — $ — $ 5,113

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	6 Months Ended
	Jun. 30, 2020
Other Liabilities Disclosure [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following: June 30, 2020 December 31, 2019 Accrued compensation $ 1,179 $ 1,413 Professional fees 337 289 Accrued license fees 375 — Other 206 208 Total $ 2,097 $ 1,910

Leases and Commitments (Tables)

Leases and Commitments (Tables)	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Remaining Lease Commitments	Maturity analysis of lease liabilities as of June 30, 2020 are as follows (in thousands): Year Remainder of the year ending December 31, 2020 $ 1,855 Year ending December 31, 2021 1,110 Year ending December 31, 2022 1,144 Year ending December 31, 2023 1,178 Year ending December 31, 2024 1,213 Thereafter 2,971 Total $ 9,471 Less interest 2,274 Operating lease liability $ 7,197

Liability Related to the Sale_2

Liability Related to the Sale of Future Royalties (Tables)	6 Months Ended
	Jun. 30, 2020
Nonmonetary Transactions [Abstract]
Schedule of Liability Due to Non-Cash Transaction	The following table shows the activity with respect to the liability related to the sale of future royalties during the six months ended June 30, 2020. Carrying value of liability related to the sale of future royalties at January 1, 2020 $ 62,477 Amortization of capitalized issuance costs 31 Imputed interest expense recognized for the six months ended June 30, 2020 2,551 Less: payments to Oberland Capital, LLC (4,870) Carrying value of liability related to the sale of future royalties at June 30, 2020 $ 60,189 The following table shows the activity with respect to the liability related to the sale of future royalties from the inception of the Oberland Purchase Agreement through December 31, 2019 Liability related to the sale of future royalties at March 22, 2019 $ 65,000 Capitalized issuance costs (584) Imputed interest expense recognized for the year ended December 31, 2019 4,055 Less: payments to Oberland Capital, LLC (5,994) Carrying value of liability related to the sale of future royalties at December 31, 2019 $ 62,477

Stock Plans and Stock Based C_2

Stock Plans and Stock Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Key Assumptions for Options Awarded	The Black-Scholes option pricing model employs the following key assumptions for employee and director options awarded during the six months ended June 30, 2020 and 2019 based on the assumptions noted in the following table: Six Months Ended 2020 2019 Expected term (years) – employees and officers 5.5 5.5 Expected term (years) – directors 5.5 5.5 Risk free interest rate 0.4-1.7% 2.5-2.6% Expected Volatility 81 % 79 % Expected Dividends None None
Schedule of Stock Option Activity	A summary of stock option activity under the 2010 Plan, the 2000 Stock Incentive Plan, the 2000 Director Stock Option Plan and nonstatutory inducement awards are summarized as follows: Number of Weighted Weighted Aggregate Intrinsic Value Unvested, December 31, 2019 6,158,026 $ 3.43 8.33 Granted 3,368,150 1.27 Exercised (15,156) 1.17 Canceled (348,812) 2.89 Outstanding, June 30, 2020 9,162,208 $ 2.66 8.47 $ — Exercisable at June 30, 2020 3,226,482 $ 4.78 7.27 $ — Vested and unvested expected to vest at June 30, 2020 8,051,410 $ 2.83 8.37 $ —
Schedule of Restricted Stock Award Activity	The following table presents a summary of unvested restricted stock awards (“RSAs”) under the 2010 Plan as of June 30, 2020: Number of Weighted Unvested, December 31, 2019 30,937 $ 3.45 Awarded — — Vested (10,313) 3.45 Forfeited — — Unvested, June 30, 2020 20,624 $ 3.45
Schedule of Stock-Based Compensation Expense	For the three and six months ended June 30, 2020 and 2019, 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, including expense related to its ESPP: Three Months Ended Six Months Ended 2020 2019 2020 2019 Research and development expenses $ 185 $ 123 $ 355 $ 299 General and administrative expenses 400 508 855 983 Total stock based compensation expense $ 585 $ 631 $ 1,210 $ 1,282

Nature of Business (Details)

Nature of Business (Details) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Jun. 30, 2020USD ($)segment	Jun. 30, 2019USD ($)	Apr. 30, 2020USD ($)	Apr. 21, 2020USD ($)	Dec. 31, 2019USD ($)	Mar. 31, 2018program	Oct. 31, 2016program	Oct. 31, 2015program
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of reportable segments | segment					1
Retained earnings (accumulated deficit)	$ (1,033,398)				$ (1,033,398)				$ (1,016,981)
Net loss	6,708	$ 9,709	$ 7,213	$ 9,884	16,417	$ 17,097
Cash used in operations					14,147	$ 13,902
Cash, cash equivalents, and investments	$ 23,600				$ 23,600
Aurigene
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of programs licensed in collaboration agreement | program										4	3	2
Cares Act PPP Loan | Commercial Paper | Silicon Valley Bank
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Unsecured loan							$ 900	$ 900
Unsecured loan term (months)							24 months	24 months
Unsecured loan interest rate (percent)							1.00%	1.00%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020USD ($)	Jun. 30, 2020USD ($)segment	Jun. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash and cash equivalents	$ 23,621	$ 23,621	$ 27,200	$ 15,430
Restricted cash	1,000	1,000	200	1,000
Cash and restricted balances	$ 24,590	$ 24,590	$ 27,372	$ 16,399	$ 23,789
Number of reportable segments | segment		1
Customer Concentration Risk | Genentech, Inc.
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Concentration risk (as a percent)	100.00%	96.00%	100.00%

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Short-term investments:
Corporate commercial paper, bonds and notes	$ 1	$ 5,113
Corporate commercial paper, bonds and notes
Short-term investments:
Corporate commercial paper, bonds and notes	1	5,113
Fair Value, Measurements, Recurring
Short-term investments:
Total assets at fair value	21,777	16,737
Fair Value, Measurements, Recurring | Corporate commercial paper, bonds and notes
Short-term investments:
Corporate commercial paper, bonds and notes	1	5,113
Fair Value, Measurements, Recurring | Money market funds
Cash equivalents:
Cash equivalents	21,776	10,684
Fair Value, Measurements, Recurring | US government obligations
Cash equivalents:
Cash equivalents		550
Fair Value, Measurements, Recurring | Commercial paper
Cash equivalents:
Cash equivalents		300
Fair Value, Measurements, Recurring | Municipal bonds
Cash equivalents:
Cash equivalents		90
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1)
Short-term investments:
Total assets at fair value	21,776	10,684
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Corporate commercial paper, bonds and notes
Short-term investments:
Corporate commercial paper, bonds and notes	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Money market funds
Cash equivalents:
Cash equivalents	21,776	10,684
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | US government obligations
Cash equivalents:
Cash equivalents		0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Commercial paper
Cash equivalents:
Cash equivalents		0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Municipal bonds
Cash equivalents:
Cash equivalents		0
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2)
Short-term investments:
Total assets at fair value	1	6,053
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2) | Corporate commercial paper, bonds and notes
Short-term investments:
Corporate commercial paper, bonds and notes	1	5,113
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2) | Money market funds
Cash equivalents:
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2) | US government obligations
Cash equivalents:
Cash equivalents		550
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2) | Commercial paper
Cash equivalents:
Cash equivalents		300
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2) | Municipal bonds
Cash equivalents:
Cash equivalents		90
Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3)
Short-term investments:
Total assets at fair value	0	0
Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) | Corporate commercial paper, bonds and notes
Short-term investments:
Corporate commercial paper, bonds and notes	0	0
Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) | Money market funds
Cash equivalents:
Cash equivalents	$ 0	0
Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) | US government obligations
Cash equivalents:
Cash equivalents		0
Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) | Commercial paper
Cash equivalents:
Cash equivalents		0
Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) | Municipal bonds
Cash equivalents:
Cash equivalents		$ 0

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Weighted-average maturity of short-term investments	1 month 6 days	1 month 6 days
Debt securities in an unrealized loss position	$ 0
Short-term Investments | Minimum
Debt Securities, Available-for-sale [Line Items]
Maturity range for short-term investments	1 month	1 month
Short-term Investments | Maximum
Debt Securities, Available-for-sale [Line Items]
Maturity range for short-term investments	12 months	12 months

Investments - Amortized Cost of

Investments - Amortized Cost of Unrealized Gains and Losses and Fair Value of Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1	$ 5,113
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	1	5,113
Corporate bonds and notes – short-term
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1	5,113
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	$ 1	$ 5,113

Accrued Liabilities - Summary (

Accrued Liabilities - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Other Liabilities Disclosure [Abstract]
Accrued compensation	$ 1,179	$ 1,413
Professional fees	337	289
Accrued license fees	375	0
Other	206	208
Accrued Liabilities, Current, Total	$ 2,097	$ 1,910

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Apr. 30, 2020	Apr. 21, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Current portion long-term debt	$ 445			$ 0
Long-term debt	445			$ 0
Silicon Valley Bank | Cares Act PPP Loan | Commercial paper
Debt Instrument [Line Items]
Unsecured loan		$ 900	$ 900
Unsecured loan term (months)		24 months	24 months
Unsecured loan interest rate (percent)		1.00%	1.00%
Current portion long-term debt	400
Long-term debt	$ 400

Leases and Commitments (Details

Leases and Commitments (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Leases [Abstract]
Operating lease liability	$ 7,197,000		$ 7,197,000
Operating lease right-of-use asset	$ 7,149,000		$ 7,149,000		$ 149,000
Remaining lease term (years)	7 years		7 years
Weighted average remaining lease term (years)	6 years 9 months 18 days		6 years 9 months 18 days
Weighted average discount rate (percent)	9.95%		9.95%
Operating lease cost	$ 500,000	$ 300,000	$ 700,000	$ 400,000
Operating lease payments	$ 0	$ 300,000	$ 200,000	$ 500,000

Leases and Commitments - Curren

Leases and Commitments - Current Lease Maturities (Details) $ in Thousands	Jun. 30, 2020USD ($)
Leases [Abstract]
Remainder of the year ending December 31, 2020	$ 1,855
Year ending December 31, 2021	1,110
Year ending December 31, 2022	1,144
Year ending December 31, 2023	1,178
Year ending December 31, 2024	1,213
Thereafter	2,971
Total	9,471
Less interest	2,274
Operating lease liability	$ 7,197

Liability Related to the Sale_3

Liability Related to the Sale of Future Royalties (Details) - USD ($) $ in Thousands	Mar. 22, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Nonmonetary Transaction [Line Items]
Proceeds from royalty interest purchase agreement with Oberland Capital Management, LLC		$ 0	$ 65,000
Payment towards debt obligations		0	$ 1,825
Transaction fees	$ 600
Non-cash interest rate (percent)	8.30%
Carrying value of liability related to the sale of future royalties at January 1, 2020	$ 65,000			$ 62,477
Amortization of capitalized issuance costs		31
Capitalized issuance costs				(584)
Imputed interest expense recognized for the six months ended June 30, 2020		2,551		4,055
Less: payments to Oberland Capital, LLC		(4,870)		(5,994)
Carrying value of liability related to the sale of future royalties at June 30, 2020		$ 60,189		$ 62,477
Oberland Capital
Nonmonetary Transaction [Line Items]
Proceeds from royalty interest purchase agreement with Oberland Capital Management, LLC	65,000
Cash proceeds from royalty purchase agreement	70,700
Purchaser default option period (days)		180 days
HealthCare Royalty Partners III, L.P.
Nonmonetary Transaction [Line Items]
Proceeds from royalty interest purchase agreement with Oberland Capital Management, LLC	27,500
Payment towards debt obligations	37,200
Repayment of debt, principal	33,800
Accrued and unpaid interest and prepayment fees	3,400
Transaction fees	300
Royalty Amounts in 2021 | Oberland Capital
Nonmonetary Transaction [Line Items]
Cash proceeds from royalty purchase agreement	17,200
Royalty amount threshold	18,000
Aggregate Net Royalties Prior to 2027 | Oberland Capital
Nonmonetary Transaction [Line Items]
Cash proceeds from royalty purchase agreement	53,500
Royalty amount threshold	$ 117,000

Research and Development Coll_2

Research and Development Collaborations - Narrative (Details)	Jan. 06, 2020USD ($)	Sep. 30, 2016USD ($)programshares	Jun. 30, 2003USD ($)	Jun. 30, 2020USD ($)product	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)productprogram	Jun. 30, 2019USD ($)	Dec. 31, 2015USD ($)shares	Feb. 29, 2020patient	Dec. 31, 2019USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues, net				$ 2,360,000	$ 2,094,000	$ 5,068,000	$ 3,861,000
Cost of royalties				122,000	89,000	247,000	197,000
Accounts receivable				2,486,000		2,486,000				$ 3,244,000
Value of common stock issued				506,000		$ 506,000				332,000
Number of program licensed | program		4				4
Royalties
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues, net				2,446,000	2,142,000	$ 4,961,000	4,279,000
Genentech, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amount received for specified clinical development and regulatory objectives				59,000,000		59,000,000
Percentage of royalty rate decrease			2.00%
Cost of royalties				$ 100,000	100,000	$ 200,000	200,000
Royalty rate, percentage of sales (percent)				5.00%		5.00%
Accounts receivable				$ 2,500,000		$ 2,500,000				$ 3,200,000
Genentech, Inc. | Royalties
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues, net				$ 2,400,000	2,100,000	$ 5,000,000	$ 4,300,000
Genentech, Inc. | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible to receive contingent cash payment for specified clinical development and regulatory objectives (up to)			$ 115,000,000
Percentage of royalty on net sales			7.50%
Genentech, Inc. | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty on net sales			5.00%
Aurigene
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Issued shares of common stock (in shares) | shares								3,424,026
Value of common stock issued								$ 24,300,000
Shares issued of common stock in exchange for waived payment (in shares) | shares		2,041,666
Waived payment of milestone and other payments (up to)		$ 24,500,000
Number of patients in trial | patient									240
Collaboration agreement, number of products required to commercialize (at least) | product				1		1
Milestone payments waived to date				$ 19,500,000		$ 19,500,000
Collaboration agreement expense				200,000
Aurigene | Programs three and four
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Agreement to provide additional funding, if options are exercised (up to)		$ 2,000,000
Payments made under collaboration arrangements				$ 14,500,000		14,500,000
Aurigene | IRAK4, PD1/VISTA,PD1/TIM3 Program
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Waived payment of milestone and other payments (up to)						$ 42,500,000
Aurigene | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration agreement expense					$ 100,000
ImmuNext
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment due	$ 1,300,000
Option exercise fee	$ 20,000,000
Expiration period (years)	10 years
Semi-annual maintenance fee payments	$ 400,000
Maximum reimbursable expenses	300,000
ImmuNext | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development milestone payments	4,600,000
Regulatory approval milestone payments	84,300,000
Sales milestone payments	$ 125,000,000
Asia | Aurigene | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty rate, percentage of sales (percent)									10.00%

Common Stock - Narrative (Detai

Common Stock - Narrative (Details) - USD ($)	Feb. 26, 2020	Jul. 02, 2015	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2019	Jun. 04, 2020	Jun. 03, 2020	Mar. 04, 2020	May 23, 2019	May 22, 2019
Class of Stock [Line Items]
Common stock authorized (shares)			151,875,000	151,875,000	151,875,000		101,250,000	101,250,000	151,875,000	101,250,000		101,250,000	67,500,000
Proceeds from common stock purchase agreement with Aspire Capital, net of issuance costs					$ 2,726,000	$ 0
Private Placement
Class of Stock [Line Items]
Proceeds from direct offering			$ 17,500,000
Fees payable expenses			1,000,000
Other estimated offering expenses payable expense			$ 500,000
Cowen | At-the-market sale facility
Class of Stock [Line Items]
Shares of common stock sold (shares)					0			420,796
Proceeds from common stock purchase agreement with Aspire Capital, net of issuance costs								$ 6,200,000
Compensation payable, percentage of gross sales price		3.00%
Aspire Capital Fund, LLC
Class of Stock [Line Items]
Common stock issued (shares)	2,693,965
Proceeds from common stock purchase agreement with Aspire Capital, net of issuance costs	$ 3,000,000
JonesTrading Institutional Services LLC
Class of Stock [Line Items]
Compensation fee (percent of gross proceeds)											3.00%
Maximum | Cowen | At-the-market sale facility
Class of Stock [Line Items]
Planned proceeds from sale of stock (up to)		$ 30,000,000
Common Stock | Private Placement
Class of Stock [Line Items]
Common stock issued (shares)							14,000,000
Sale price per share (usd per share)			$ 1.25	$ 1.25	$ 1.25
Common Stock | Aspire Capital Fund, LLC
Class of Stock [Line Items]
Authorized amount of stock repurchase	30,000,000
Remaining authorized stock purchase amount	$ 27,000,000
Purchase period (months)	30 months
Commitment fee (shares)	646,551
Stock purchase program, authorized per day (shares)			150,000	150,000	150,000
Stock purchase program, authorized per day, after mutual agreement (shares)			2,000,000	2,000,000	2,000,000
Maximum shares to be sold (shares)			6,645,034	6,645,034	6,645,034
Maximum shares to be sold (as a percent of outstanding shares)	19.90%
Minimum share price (usd per share)			$ 1.34	$ 1.34	$ 1.34
Additional shares authorized, value			$ 27,000,000
Common Stock | JonesTrading Institutional Services LLC
Class of Stock [Line Items]
Authorized amount											$ 30,000,000
Shares of common stock sold (shares)				0

Stock Plans and Stock Based C_3

Stock Plans and Stock Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	Jun. 04, 2020shares	May 23, 2019shares	Jan. 31, 2019$ / sharesshares	Jun. 30, 2020USD ($)$ / sharesshares	Mar. 31, 2020$ / sharesshares	Jun. 30, 2019USD ($)	Mar. 31, 2017purchase_period	Jun. 30, 2020USD ($)planpurchase_period$ / sharesshares	Jun. 30, 2019USD ($)$ / shares	Dec. 31, 2019$ / sharesshares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shareholder-approved, share-based compensation plans | plan								2
Number of options granted (shares)								3,368,150
Exercise price (USD per share) | $ / shares								$ 1.33
Awarded (shares)								250,000
Weighted average grant-date fair values of stock options (USD per share) | $ / shares								$ 0.75	$ 0.79
Unrecognized compensation cost, net of estimated forfeitures | $				$ 3,900				$ 3,900
Unrecognized compensation cost, weighted average period for recognition								2 years 7 months 9 days
Intrinsic values of employee stock options exercised | $									$ 0
Compensation expense related to employee and director stock option grants | $				$ 585		$ 631		$ 1,210	1,282
Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Exercise price (USD per share) | $ / shares								$ 0
Awarded (shares)								0
Outstanding shares (shares)				20,624				20,624		30,937
Weighted average fair value (USD per share) | $ / shares				$ 3.45				$ 3.45		$ 3.45
Fair value | $								$ 100
Stock options outstanding
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period of options (years)								4 years
Officers | Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period of options (years)								4 years
Officers and Non-Employee Directors | Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Unrecognized compensation cost, net of estimated forfeitures | $				$ 100				$ 100
Unrecognized compensation cost, weighted average period for recognition								1 year 6 months 21 days
Tranche one
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Percentage of vested shares which are exercisable under stock option								25.00%
Tranche two
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Percentage of vested shares which are exercisable under stock option								6.25%
Amended and Restated 2010 Stock Incentive Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares authorized (shares)				12,190,000				12,190,000
Shares awarded under plan (shares)								2,878,896
Amended and Restated 2010 Stock Incentive Plan | Stock Options, or Stock Appreciation Rights
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Expiration period (years)								10 years
Shares removed from pool (shares per share)								1
Amended and Restated 2010 Stock Incentive Plan | Restricted Stock, RSUs, Other Stock-Based Awards, or Performance Awards
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares removed from pool (shares per share)								1.3
Purchase price of common stock (percentage of fair market value)								100.00%
Amended and Restated 2010 Stock Incentive Plan | Employee Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Additional shares authorized (shares)	1,300,000	4,700,000
2010 Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted (shares)								2,648,150
2010 Plan | Officers
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted (shares)			1,520,000
Vesting period of options (years)			4 years
Exercise price (USD per share) | $ / shares			$ 1.26
2010 Plan | Non-Employee Directors
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted (shares)				0	720,000			0
Vesting period of options (years)					1 year
Exercise price (USD per share) | $ / shares					$ 1.26
2010 Plan | Tranche one
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Options granted to employees (shares)								878,150
Percentage of vested shares which are exercisable under stock option								25.00%
2010 Plan | Tranche one | Officers
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Percentage of vested shares which are exercisable under stock option			25.00%
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%
2010 Plan | Tranche two | Officers
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Percentage of vested shares which are exercisable under stock option			6.25%
Employee Stock Purchase Plan | Employee Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares authorized (shares)				2,000,000				2,000,000
Purchase price of common stock (percentage of fair market value)								85.00%
Enrollment period (years)								2 years
Number of purchase periods per year | purchase_period							2	4
Stock plan offering period (months)							6 months	6 months
Stock issued under employee stock purchase plans (shares)				41,583				41,583
Stock available under ESPPs (shares)				1,636,351				1,636,351
Compensation expense related to employee and director stock option grants | $				$ 0		$ 0		$ 0	$ 0

Stock Plans and Stock Based C_4

Stock Plans and Stock Based Compensation - Key Assumptions (Details)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Risk-free interest rate (minimum) (as a percent)	0.90%	2.50%
Risk-free interest rate (maximum) (as a percent)	1.70%	2.60%
Expected volatility (as a percent)	81.00%	79.00%
Employees and Officers
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Expected term (years)	5 years 6 months	5 years 6 months
Directors
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Expected term (years)	5 years 6 months	5 years 6 months

Stock Plans and Stock Based C_5

Stock Plans and Stock Based Compensation - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019$ / sharesshares
Number of Shares
Beginning balance (shares) | shares	6,158,026
Granted (shares) | shares	3,368,150
Exercised (shares) | shares	(15,156)
Canceled (shares) | shares	(348,812)
Ending balance (shares) | shares	9,162,208	6,158,026
Exercisable at end of period (shares) | shares	3,226,482
Vested and unvested expected to vest at end of period (shares) | shares	8,051,410
Weighted Average Exercise Price per Share
Beginning balance (USD per share) | $ / shares	$ 3.43
Granted (USD per share) | $ / shares	1.27
Exercised (USD per share) | $ / shares	1.17
Canceled (USD per share) | $ / shares	2.89
Ending balance (USD per share) | $ / shares	2.66	$ 3.43
Exercisable at end of period (USD per share) | $ / shares	4.78
Vested and unvested expected to vest at end of period (USD per share) | $ / shares	$ 2.83
Weighted Average Remaining Contractual Life
Outstanding at end of period	8 years 5 months 19 days	8 years 3 months 29 days
Exercisable at end of period	7 years 3 months 7 days
Vested and unvested expected to vest at end of period	8 years 4 months 13 days
Aggregate Intrinsic Value
Outstanding at end of period | $	$ 0
Exercisable at end of period | $	0
Vested and unvested expected to vest at end of period | $	$ 0

Stock Plans and Stock Based C_6

Stock Plans and Stock Based Compensation - Restricted Stock Award Activity (Details)	6 Months Ended
	Jun. 30, 2020$ / sharesshares
Number of Shares
Awarded (shares) | shares	250,000
Weighted Average Grant Date Fair Value
Awarded (USD per share) | $ / shares	$ 1.33
Restricted Stock
Number of Shares
Beginning balance (shares) | shares	30,937
Awarded (shares) | shares	0
Vested (shares) | shares	(10,313)
Forfeited (shares) | shares	0
Ending balance (shares) | shares	20,624
Weighted Average Grant Date Fair Value
Beginning balance (USD per share) | $ / shares	$ 3.45
Vested (USD per share) | $ / shares	3.45
Awarded (USD per share) | $ / shares	0
Forfeited (USD per share) | $ / shares	0
Ending balance (USD per share) | $ / shares	$ 3.45

Stock Plans and Stock Based C_7

Stock Plans and Stock Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock based compensation expense	$ 585	$ 631	$ 1,210	$ 1,282
Research and development expenses
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock based compensation expense	185	123	355	299
General and administrative expenses
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock based compensation expense	$ 400	$ 508	$ 855	$ 983

Loss Per Common Share - Narrati

Loss Per Common Share - Narrative (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Stock options outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	9,162,208	5,940,813

Related Party Transactions - Na

Related Party Transactions - Narrative (Details)	Oct. 17, 2018USD ($)	Aug. 01, 2018USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)day	Jun. 30, 2019USD ($)
Related Party Transaction [Line Items]
Monthly retainer for advisory services		$ 35,000
Epi-Cure Pharmaceuticals, Inc. | Affiliated Entity
Related Party Transaction [Line Items]
Amount paid for transaction				$ 100,000	$ 200,000	$ 100,000
Epi-Cure Pharmaceuticals, Inc. | Affiliated Entity | Minimum
Related Party Transaction [Line Items]
Amount paid for transaction			$ 100,000
Epi-Cure Pharmaceuticals, Inc. | Affiliated Entity | Agreement With Head of Research and Development
Related Party Transaction [Line Items]
Purchases from related party	$ 100,000
Maximum funding amount					$ 500,000
Minimum days notice to terminate prior to written notice (days) | day					60
Epi-Cure Pharmaceuticals, Inc. | Affiliated Entity | Development Costs and Profits
Related Party Transaction [Line Items]
Cost and revenue split (percent)					50.00%