Curis (CRIS) 10-Q 14 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 10, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	CRIS
Entity Registrant Name	CURIS INC
Entity Central Index Key	0001108205
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Emerging Growth Company	false
Small Business	true
Entity Common Stock, Shares Outstanding		33,150,780

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current Assets:
Cash and cash equivalents	$ 42,766	$ 23,636
Investments	30	634
Short term investment – restricted	153	0
Accounts receivable	1,786	2,864
Prepaid expenses and other current assets	681	827
Total current assets	45,416	27,961
Property and equipment, net	226	267
Operating lease right-of-use asset	822
Long-term investment – restricted	0	153
Goodwill	8,982	8,982
Other assets	3	2
Total assets	55,449	37,365
Current Liabilities:
Accounts payable	2,333	2,909
Accrued liabilities	1,420	3,457
Operating Lease, Liability, Current	878
Current portion of long-term debt, net	0	6,884
Total current liabilities	4,631	13,250
Long-term debt, net	0	28,600
Liability related to the sale of future royalties, net	64,547	0
Other long-term liabilities	0	11
Total liabilities	69,178	41,861
Stockholders’ Equity:
Common stock, $0.01 par value—67,500,000 shares authorized; 33,150,780 shares issued and outstanding at March 31, 2019; 33,159,253 shares issued and outstanding at December 31, 2018	332	332
Additional paid-in capital	980,663	980,012
Accumulated deficit	(994,724)	(984,840)
Total stockholders’ equity	(13,729)	(4,496)
Total liabilities and stockholders’ equity	$ 55,449	$ 37,365

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock authorized (shares)	67,500,000	67,500,000
Common stock issued (shares)	33,150,780	33,159,253
Common stock outstanding (shares)	33,150,780	33,159,253

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Total revenues	$ 1,767	$ 2,468
Costs and expenses:
Cost of royalty revenues	108	129
Research and development	4,074	8,266
General and administrative	3,143	3,981
Total costs and expenses	7,325	12,376
Loss from operations	(5,558)	(9,908)
Other (expense) income:
Loss on debt extinguishment	(3,495)	0
Interest income	108	186
Non-cash imputed interest expense related to the sale of future royalty payments	(131)	0
Interest expense	(808)	(1,025)
Total other expense, net	(4,326)	(839)
Net loss	$ (9,884)	$ (10,747)
Net loss per common share (basic and diluted) (USD per share)	$ (0.30)	$ (0.33)
Weighted average common shares (basic and diluted) (shares)	33,150,869	33,053,702
Net loss	$ (9,884)	$ (10,747)
Unrealized loss on marketable securities	0	(4)
Comprehensive loss	(9,884)	(10,751)
Royalties
Revenues:
Total revenues	2,137	2,474
Contra revenue
Revenues:
Total revenues	$ (370)	$ (6)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Deficit	Accumulated Other Comprehensive Loss
Beginning balance (shares) at Dec. 31, 2017		33,075,949
Beginning balance at Dec. 31, 2017	$ 23,993	$ 331	$ 977,453	$ (1,524)	$ (952,265)	$ (2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of common stock under grant of restricted stock awards (shares)		294,250
Issuances of common stock under grant of restricted stock awards	0	$ 3	(3)
Recognition of employee stock-based compensation	1,226		1,226
Retirement of Treasury Stock (shares)		(244,569)
Retirement of Treasury Stock	0	$ (3)	(1,521)	1,524
Other comprehensive loss	(4)					(4)
Net loss	(10,747)				(10,747)
Ending balance (shares) at Mar. 31, 2018		33,125,630
Ending balance at Mar. 31, 2018	$ 14,468	$ 331	977,155	0	(963,012)	(6)
Beginning balance (shares) at Dec. 31, 2018	33,159,253	33,159,253.2
Beginning balance at Dec. 31, 2018	$ (4,496)	$ 332	980,012	0	(984,840)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Recognition of employee stock-based compensation	651		651
Sales of restricted stock awards (shares)		(8,473)
Net loss	$ (9,884)				(9,884)
Ending balance (shares) at Mar. 31, 2019	33,150,780	33,150,780.2
Ending balance at Mar. 31, 2019	$ (13,729)	$ 332	$ 980,663	$ 0	$ (994,724)	$ 0

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (9,884)	$ (10,747)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	35	53
Non-cash lease expense	224	0
Stock-based compensation expense	651	1,226
Amortization of debt issuance costs	132	9
Non-cash imputed interest expense related to the sale of future royalties	131	0
Non-cash interest expense/(income) on investments	4	(81)
Non-cash interest expense on operating lease liability	16	0
Loss on disposal of fixed assets	5	0
Changes in operating assets and liabilities:
Accounts receivable	1,078	582
Prepaid expenses, and other assets	146	80
Accounts payable and accrued and other liabilities	(2,895)	(1,086)
Operating lease liability	(247)	0
Total adjustments	(720)	783
Net cash used in operating activities	(10,604)	(9,964)
Cash flows from investing activities:
Purchase of investments	0	(16,746)
Sales and maturities of investments	600	15,050
Expenditures for property and equipment	0	(77)
Net cash provided by (used in) investing activities	600	(1,773)
Cash flows from financing activities:
Proceeds from royalty interest purchase agreement with Oberland Capital Management, LLC	65,000	0
Payment of issuance costs on royalty interest purchase agreement	(250)	0
Payment on termination of credit agreement with HealthCare Royalty Partners, III, L.P.	(33,791)	0
Payments on Curis Royalty’s debt	(1,825)	(1,815)
Net cash provided by/(used in) financing activities	29,134	(1,815)
Net increase (decrease) in cash and cash equivalents	19,130	(13,552)
Cash and cash equivalents, beginning of period	23,636	38,288
Cash and cash equivalents, end of period	42,766	24,736
Unpaid issuance costs in accounts payable	$ 334	$ 0

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2019
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. As used throughout these consolidated financial statements, the term “the Company” refers to the business of Curis, Inc. and its wholly-owned subsidiaries, except where the context otherwise requires, and the term “Curis” refers to Curis, Inc. The Company conducts its research and development programs both internally and through strategic collaborations. The Company’s clinical stage drug candidates are fimepinostat, CA-4948, and CA-170: • Fimepinostat is currently being explored in clinical studies in patients with MYC-altered diffuse large B-cell lymphoma (DLBCL) and solid tumors and has been granted Orphan Drug Designation and Fast Track Designation for the treatment of DLBCL by the U.S. Food and Drug Administration, or FDA in April 2015 and May 2018, respectively. The Company is planning a combination study with venetoclax in DLBCL patients with alterations in both MYC and the BCL2 gene, also referred to as double-hit lymphoma, with planned enrollment commencing in the first half of 2019. The Company expects to report initial clinical data from this combination study in the second half of 2019. • CA-4948 is being tested in a dose escalating clinical trial in patients with non-Hodgkin lymphomas, including those with myeloid differentiation primary response 88, or MYD88, alterations. The Company expects to report initial clinical data from this study in mid-year 2019. • CA-170 is currently undergoing testing in a clinical study in patients with mesothelioma. The Company announced in January 2019 that it had begun enrollment of these patients and expects to report initial clinical data from this study with respect to mesothelioma in the second half of 2019. The Company’s pipeline also includes CA-327, which is a pre-Investigational New Drug ( “IND”) stage oncology drug candidate. The Company is party to a collaboration with F. Hoffmann-La Roche Ltd, or Roche, and Genentech Inc., or Genentech, a member of the Roche Group, under which Roche and Genentech are commercializing Erivedge, a first-in-class orally-administered small molecule Hedgehog signaling pathway inhibitor. Erivedge (vismodegib) is approved for the treatment of advanced basal cell carcinoma, or BCC. In January 2015, and as amended in September 2016, the Company entered into a collaboration, option and license agreement focused on immuno-oncology and selected precision oncology targets with Aurigene Discovery Technologies Limited, or "Aurigene". The collaboration with Aurigene is comprised of multiple programs, and the Company has the option to exclusively license each program, including data, intellectual property and compounds associated therewith, once a development candidate is 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, V-domain Ig suppressor of T-cell activation (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. 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. 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 advance and expand its research and development programs; the Company’s reliance on Aurigene to successfully discover and preclinically develop 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 Company’s ability to obtain adequate financing to fund its operations; the ability of the Company and its wholly-owned subsidiary, Curis Royalty, LLC, or Curis Royalty, to satisfy the terms of the royalty interest purchase agreement, or the Oberland Purchase Agreement, with entities managed by Oberland Capital Management, LLC (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, and the Company’s ability to execute on its overall business strategies. 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 successfully discover and develop preclinical programs under the Company’s collaboration with Aurigene, as well as the Company’s decision to exclusively license and 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 losses and negative cash flows from operations since its inception. As of March 31, 2019 , the Company had an accumulated deficit of approximately $994.7 million, and for the quarter ended March 31, 2019 , the Company incurred a loss of $9.9 million and used $10.6 million of cash in operations. The Company expects to continue to generate operating losses in the foreseeable future. The Company anticipates that its $42.8 million of existing cash, cash equivalents and investments at March 31, 2019 will be sufficient to fund its operating expenses and capital requirements, based upon its current operating plan, for at least the next twelve months from the issuance date of these financial statements. The Company will need to raise additional capital or incur indebtedness to continue to fund its operations in the future. 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 may 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.

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of the Company have been prepared in accordance with the instructions to Form 10-Q and Article 10 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., or 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, 2018 as filed with the Securities and Exchange Commission, or the SEC, on March 26, 2019 . 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 March 31, 2019 ; the results of operations for the three -month periods ended March 31, 2019 and 2018 ; stockholder's equity for the three -month periods ended March 31, 2019 and 2018 and the cash flows for the three -month periods ended March 31, 2019 and 2018 . The condensed consolidated balance sheet at December 31, 2018 was derived from audited annual financial statements but does not contain all of the footnote disclosures from the annual financial statements. 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 intangible assets; 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.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
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, up-front 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 obligation to determine whether the combined performance obligation is 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, up-front 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 inconsequential or perfunctory and that are determined to be 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 Under the Financial Accounting Standards Board, or FASB, Codification Topic 606, Revenue from Contracts with Customers , or ASC 606, there is a constraint on 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, a company will estimate the amount of consideration in exchange for transfer of promised goods or services. The consideration also can vary if a 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 4). However, a portion of Erivedge royalties will be paid to the Purchasers under the Oberland Purchase Agreement (see Note 9). Contra revenue includes amounts related to the reimbursement of patent related research and development costs and amounts related to potential adjustments in countries where the Company's royalties are subject to reductions. Summary During the three months ended March 31, 2019 and 2018 , total gross revenues were 100% from the Company’s collaboration with Genentech. Deferred Revenue Amounts received prior to satisfying the above revenue recognition criteria are recorded as deferred revenue in the accompanying consolidated balance sheets. Significant judgments are required in the application of revenue recognition guidance. Short-term deferred revenue would consist of amounts that are expected to be recognized as revenue, or applied against future co-development costs, within the next fiscal year. Amounts that the Company expects will not be recognized in the next fiscal year would be classified as long-term deferred revenue. However, this estimate would be based on the Company's operating plan as of the balance sheet date and on its estimated performance periods under the collaboration in which the Company has recorded deferred revenues. If the Company's operating plan or its estimated performance period would change, the Company could recognize a different amount of deferred revenue over the reporting period. 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 the Company's initial judgments, its revenue recognition with respect to such transactions would change accordingly and any such change could affect its reported financial results.

Research and Development Collab

Research and Development Collaborations	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 . 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. In March 2017, the Company and Curis Royalty entered into a new credit agreement with HealthCare Royalty Partners III, L.P., or HealthCare Royalty, for the purpose of refinancing and terminating its prior loan from BioPharma Secured Debt Fund II. Accordingly, HealthCare Royalty made a $45.0 million loan at an annual interest rate of 9.95% to Curis Royalty, which was used in part to pay off $18.4 million in remaining loan obligations to BioPharma-II under the prior loan, with the residual proceeds of $26.6 million distributed to the Company as sole equity member of Curis Royalty. The final maturity date of the loan was the earlier of such date that the principal is paid in full, or Curis Royalty's right to receive royalties under the collaboration agreement with Genentech is terminated. On March 22, 2019, in connection with entering into the Oberland Purchase Agreement, the Company and Curis Royalty terminated, and repaid in full all amounts outstanding under, the loan with HealthCare Royalty. The Company has identified the following performance obligations related to the Genentech collaboration: 1. To grant the license for its Hedgehog antagonist programs and to provide service on both a steering committee and co-development committee. This performance obligation has been satisfied and only contingent royalty revenue remains to be recognized in the future. 2. To provide reimbursable research and development services. This performance obligation has been satisfied and no revenue remains to be recognized in the future. The Company recognized $2.1 million and $2.5 million in royalty revenue under the Genentech collaboration during the three months ended March 31, 2019 and 2018 , respectively. The Company also recorded $0.1 million and $0.1 million, respectively, as cost of royalty revenues within the costs and expenses section of its condensed consolidated statements of operations and comprehensive loss during these same periods. Cost of royalty revenues is comprised of 5% of the royalties earned by Curis Royalty with respect to Erivedge outside Australia, and 2% direct net sales in Australia (subject to decrease on expiration of the patent in April 2019 to 5% of the royalty payments that Curis Royalty receives from Genentech, through February 2022), that the Company is obligated to pay to university licensors. As further discussed in Note 9, 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. The Company recorded immaterial research and development revenue during the three months ended March 31, 2019 and 2018 , related to expenses incurred by the Company on behalf of Genentech that were paid by the Company and for which Genentech is obligated to reimburse the Company. Genentech incurred expenses of an immaterial amount during the three months ended March 31, 2019 and 2018 , under this collaboration for which the Company is obligated to reimburse to Genentech, and which the Company has recorded as contra-revenues which have been net against research and development revenues in its 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 the ASC 606 are met. The Company has recorded as amounts receivable from Genentech under this collaboration, comprised primarily of Erivedge royalties earned in the first quarters of 2019 and 2018 of $1.8 million and $2.5 million as of March 31, 2019 and 2018 , respectively, in "accounts receivable" in the Company's current assets section of its consolidated balance sheets. (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. As of March 31, 2019 , the Company has exercised its option to license the following four programs under the collaboration: 1. IRAK4 Program - a precision oncology program of small molecule inhibitors of IRAK4. The development candidate is 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. Subject to specified exceptions, Aurigene and the Company agreed to collaborate exclusively with each other on the discovery, research, development and commercialization of programs and compounds within immuno-oncology for an initial period of approximately two years from the effective date of the collaboration agreement. At the Company's option, and subject to specified conditions, it may extend such exclusivity for up to three additional one year periods by paying to Aurigene additional exclusivity option fees on an annual basis. The Company exercised the first one-year exclusivity option in the first quarter of 2017. The fee for this exclusivity option exercise was $7.5 million, which the Company paid in two equal installments in the first and third quarters of 2017 . The Company elected not to further exercise its exclusivity option and thus did not make the $10.0 million payment required for this additional exclusivity in 2018. As a result of the Company’s election to not further exercise its exclusivity option, Curis is no longer operating under broad immuno-oncology exclusivity with Aurigene. The Company has, however, as provided in the agreement, elected to exercise its option to extend exclusivity on a program-by-program, year-by-year, basis for the IRAK4 Program and the PD1/VISTA Program, both of the licensed programs currently in clinical trials. 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 did no t make any cash payments to Aurigene for the three months ended March 31, 2019 and made payments of an immaterial amount for the three months ended March 31, 2018 .

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2019
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 provides a framework for measuring fair value under GAAP and requires expanded disclosures regarding fair value measurements. GAAP defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. GAAP requires the use of valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets and liabilities. The income approach uses valuation techniques to convert future amounts, such as cash flows or earnings, to a single present amount on a discounted basis. The cost approach is based on the amount that currently would be required to replace the service capacity of an asset (replacement cost). Valuation techniques should be consistently applied. GAAP also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair value. The standard describes three levels of inputs that may be used to measure fair value: 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 March 31, 2019 and December 31, 2018 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 March 31, 2019 and 2018 . Quoted Prices in Active Markets (Level 1) Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Fair Value As of March 31, 2019: Cash equivalents: Money market funds $ 13,596 $ — $ — $ 13,596 Corporate commercial paper, stock, bonds and notes — 120 — 120 Municipal and government securities — — — — Short-term investments: Corporate commercial paper, bonds and notes — 30 — 30 Total assets at fair value $ 13,596 $ 150 $ — $ 13,746 Quoted Prices in Active Markets (Level 1) Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Fair Value As of December 31, 2018: Cash equivalents: Money market funds $ 18,180 $ — $ — $ 18,180 Corporate commercial paper, stock, bonds and notes — 2,199 — 2,199 Municipal bonds — 135 — 135 Short-term investments: Corporate commercial paper, stock, bonds and notes — 634 — 634 Total assets at fair value $ 18,180 $ 2,968 $ — $ 21,148 No investments held at March 31, 2019 were transferred between levels. Fair Value of Financial Liabilities As of March 31, 2019 the fair value of the liability related to the sale of future royalties is based on the Company's current estimates of future royalties expected to be paid to the Purchasers over the life of the agreement, which are considered Level 3 (See Note 9, "Liability related to the Sale of Future Royalties").

Investments

Investments	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Cash equivalents are 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 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 the Company's long-term investments are marketable securities with original maturities of greater than twelve months from the balance sheet date. 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 with any unrealized holding gains or losses included as a component of stockholders’ equity and any realized gains and losses recorded in the statement of operations in the period during which the securities are sold. 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). Any premium or discount arising at purchase is amortized and/or accreted to interest income. The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of March 31, 2019 are as follows: Amortized Cost Unrealized Gain Unrealized Loss Fair Value Corporate commercial paper, bonds and notes – short-term $ 30 $ — $ — $ 30 Total investments $ 30 $ — $ — $ 30 Short-term investments have maturities ranging from one to twelve months with a weighted-average maturity of 0.1 years at March 31, 2019 . The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of December 31, 2018 are as follows: Amortized Cost Unrealized Gain Unrealized Loss Fair Value Corporate bonds and notes – short-term $ 634 $ — $ — $ 634 Total investments $ 634 $ — $ — $ 634 Short-term investments have maturities ranging from one to twelve months with a weighted-average maturity of 0.1 years at December 31, 2018 . As of March 31, 2019 , the Company did not have any debt securities in an unrealized loss position.

Debt

Debt	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt (a) HealthCare Royalty Partners III On March 6, 2017, the Company and Curis Royalty entered into a credit agreement, referred to herein as the credit agreement, with HealthCare Royalty for the purpose of refinancing Curis Royalty’s financing arrangement with BioPharma-II, referred to herein as the prior loan. On March 22, 2017, the Company's prior credit agreement with BioPharma-II was terminated in its entirety. Pursuant to the credit agreement, HealthCare Royalty made a $45.0 million loan at an interest rate of 9.95% to Curis Royalty, which was used to pay off $18.4 million in remaining loan obligations to BioPharma-II under the prior loan. The remaining proceeds of $26.6 million were distributed to Curis as sole equity holder of Curis Royalty. Under the terms of the credit agreement with HealthCare Royalty, quarterly Erivedge royalty and royalty-related payments from Genentech were to be first applied to pay, collectively: (i) escrow fees payable by the Company pursuant to an escrow agreement, (ii) the Company’s royalty obligations to academic institutions, (iii) certain expenses incurred by HealthCare Royalty in connection with the credit agreement and related transaction documents, including enforcement of its rights in the case of an event of default under the credit agreement and (iv) expenses incurred by the Company enforcing its right to indemnification under the collaboration agreement. Subsequently, remaining amounts were to be applied first, to pay interest and second, to pay principal on the loan. If royalties owed under the Genentech collaboration agreement were insufficient to pay the accrued interest on the outstanding loan, the unpaid interest outstanding would be added to the loan principal on a quarterly basis. On March 22, 2019, the Company and Curis Royalty terminated, and repaid all amounts outstanding under, the credit agreement, consisting of approximately $33.8 million in remaining loan principal and approximately $3.4 million in accrued and unpaid interest and prepayment fees. The $3.4 million in accrued and unpaid interest and prepayment fees along with the remaining deferred issuance costs of $0.1 million were recorded as a loss on debt extinguishment. (b) Debt Payments to HealthCare Royalty Partners III During the three months ended March 31, 2019 and 2018 , Curis Royalty made payments totaling $36.6 million and $2.9 million, respectively, of which $35.6 million and $1.8 million were applied to the principal, respectively, with the remainder applied to accrued interest and the prepayment fee made in extinguishing the Company's debt to HealthCare Royalty. As of March 31, 2019 , the Company has repaid all outstanding debt and related accrued interest. At December 31, 2018 , the Company recorded short- and long-term debt of $6.9 million and $28.6 million, respectively, and accrued interest of $0.2 million in the Company’s condensed consolidated balance sheets. For the three months ended March 31, 2019 and 2018 , the Company recognized interest expense related to its debt of $0.8 million and $1.0 million, respectively, in the condensed consolidated statement of operations and comprehensive loss.

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2019
Other Liabilities Disclosure [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consist of the following: March 31, December 31, Accrued compensation $ 930 $ 2,774 Professional fees 262 233 Accrued interest on debt (Note 7) — 165 Other 228 285 Total $ 1,420 $ 3,457

Liability Related to the Sale o

Liability Related to the Sale of Future Royalties	3 Months Ended
	Mar. 31, 2019
Nonmonetary Transactions [Abstract]
Liability Related to the Sale of Future Royalties	es On March 22, 2019 , the Company and Curis Royalty entered into the Oberland Purchase Agreement 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 the 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, referred to as the Purchased Receivables, at a price, referred to as 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 our obligation to pay future royalties to Oberland, we recorded the proceeds from this transaction as a liability on our consolidated balance sheet that will be accounted for using the interest method over the estimated life of the Oberland Purchase Agreement. As a result, we impute interest on the transaction and record non-cash imputed interest expense at the estimated interest rate. Our 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. We periodically assess 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 our initial estimates or the timing of such payments is materially different than our original estimates, we 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 an effective annual non-cash imputed interest rate of 8.1% . The Company incurred $0.6 million of transaction costs in connection with the agreement. These transaction costs will be amortized to non-cash 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 three months ended March 31, 2019 . Liability related to the sale of future royalties at March 22, 2019 $ 65,000 Non-cash imputed interest expense recognized 129 Liability related to the sale of future royalties at March 31, 2019 65,129 Less: Unamortized transaction costs (582 ) Carrying value of liability related to the sale of future royalties at March 31, 2019 $ 64,547

Lease

Lease	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Lease	Lease Leased assets represent the Company's right to use an underlying asset for the expected lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. These assets and related lease liabilities are recognized at the commencement date based on the present value of lease payments over the expected lease term, including any contractually specified annual rent increases. When determinable, the Company uses the rate implicit in the lease to determine the present value of lease payments. If a lease agreement does not contain an implicit rate in the agreement, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The Company is party to a lease agreement with the Trustees of Lexington Office Realty Trust pursuant to which the Company leases 24,529 square feet of property that is used for office, research and laboratory space located at 4 Maguire Road in Lexington, Massachusetts. The term of the 4 Maguire Road lease agreement commenced on December 1, 2010 , and was set to expire in February 2018 . The Company had the option to extend the term for one additional five -year period upon the Company’s written notice to the lessor at least one year and no more than 18 months in advance of the extension. On November 1, 2017 , the Company entered into a second amendment to the lease agreement pursuant to which the Company agreed to extend the lease for an additional two -year period. The term of the lease amendment commenced on March 1, 2018 , and expires on February 29, 2020 . The amendment provides for no option to extend the term beyond the two -year period, nor does it provide an option for early termination of the lease. The total cash obligations for the base rent over the initial term of the lease agreement and the extended term of the lease agreement were approximately $4.4 million and $2.0 million, respectively. In addition to the base rent, the Company is also responsible for its share of operating expenses and real estate taxes, in accordance with the terms of the lease agreement. The Company has provided a security deposit to the lessor in the form of an irrevocable letter of credit in the original amount of $0.3 million. The original deposit has been reduced throughout the lease term since its inception to $0.2 million during each of 2019 and 2018 , respectively, in accordance with the terms of the lease. These amounts have been classified as restricted investments in the Company’s Consolidated Balance Sheets as of March 31, 2019 and December 31, 2018 . The Company’s remaining lease commitments for all leased facilities with an initial or remaining term of at least one year are as follows as of March 31, 2019 . Year Ending December 31, 2019 $ 754 2020 168 Total minimum payments 922 Less: Present value adjustments (44 ) Total operating lease liability $ 878 The Company’s remaining lease commitments for all leased facilities with an initial or remaining term of at least one year were as follows as of December 31, 2018 . Year Ending December 31, 2019 $ 1,002 2020 168 Total minimum payments $ 1,170 Operating cost for all leases was $0.2 million for the periods ended March 31, 2019 and 2018 . The Company recorded non-cash lease expense related to the operating lease right-of-use asset of $0.2 million for the period ended March 31, 2019 .

Stock Plans and Stock Based Com

Stock Plans and Stock Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Plans and Stock Based Compensation	Stock Plans and Stock Based Compensation As of March 31, 2019 , the Company had two shareholder-approved, share-based compensation plans: (i) the Amended and Restated 2010 Employee Stock Purchase Plan, or the 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, or the 2010 Plan. 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. The Company can issue up to 6,190,000 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 10 years from the date of grant. The 2010 Plan uses a “fungible share” concept under which each share of stock subject to awards granted as options and stock appreciation rights, will cause one share per share under the award to be removed from the available share pool, while each share of stock subject to awards granted as restricted stock, restricted stock units, other stock-based awards or performance awards where the price charged for the award is less than 100% of the fair market value of the Company’s common stock will cause 1.3 shares per share under the award to be removed from the available share pool. As of March 31, 2019 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 March 31, 2019 , 1,018,998 shares remained available for grant under the 2010 Plan. During the three months ended March 31, 2019 , the Company’s board of directors granted options to purchase a total of 1,859,998 shares of the Company’s common stock to employees and directors 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 1,139,988 shares were granted to employees and vest as to 25% of the shares underlying the award after the first year and as to an additional 6.25% of the shares underlying the award in each subsequent quarter, based upon continued employment over a four -year period, and are exercisable at a price equal to the closing price of the Company’s common stock on the Nasdaq Global Market on the grant dates. Additionally, the Company’s board of directors authorized a grant of options to purchase 1,502,867 shares of the Company’s common stock to its officers in January 2019. Such stock options have an exercise price equal to $1.16 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 after the first year and as to an additional 6.25% of the shares underlying the award in each subsequent quarter, based upon continued employment over a four -year period; provided that such awards would terminate and be forfeited if the Company’s stockholders did not approve an amendment to the 2010 Plan to increase the number of shares authorized for issuance thereunder within 12 months of the grant date; and further provided that such options would not be exercisable and no common stock would be issued thereunder, before the approval of such stock incentive plan amendment by the Company’s stockholders. During the three months ended March 31, 2019 , the Company’s board of directors also 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 in one year from the date of grant. These options were granted at an exercise price of $1.16 per share, which equals the closing market price of the Company’s common stock on the Nasdaq Global Market on the grant date. 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 on each successive three-month period thereafter. During the quarter ended March 31, 2019 , the Company’s board of directors granted options to purchase 30,000 shares of common stock as inducement equity awards. These options were granted at a weighted average exercise price of $0.82 which is based on the closing market price of the Company’s common stock on the Nasdaq Global Market on the grant date. 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 three months ended March 31, 2019 and 2018 based on the assumptions noted in the following table: Three Months Ended 2019 2018 Expected term (years) - employees 5.5 5.5 Expected term (years) - officers 5.5 5.5 Expected term (years) – directors 5.5 6.25 Risk-free interest rate 2.5%-2.6% 2.5 % Expected Volatility 76 % 66 % 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 is summarized as follows: Number of Shares Weighted Average Exercise Price per Share Weighted Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding, December 31, 2018 3,714,394 $ 7.68 Granted 1,859,998 1.15 Exercised — — Canceled (304,312 ) 8.70 Outstanding, March 31, 2019 5,270,080 $ 5.32 7.44 $ 1,766,878 Exercisable at March 31, 2019 1,760,626 $ 11.25 4.01 $ — Vested and unvested expected to vest at March 31, 2019 4,621,232 $ 5.82 7.18 $ 1,411,312 The weighted average grant-date fair values of these stock options granted during the three months ended March 31, 2019 and 2018 were $0.76 and $2.04 , respectively. As of March 31, 2019 , 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 2.71 years. There were no options exercised during the three months ended March 31, 2019 and March 31, 2018 . The following table presents a summary of outstanding RSAs under the 2010 Plan as of March 31, 2019 : Number of Shares Weighted Average Grant Date Fair Value Outstanding, December 31, 2018 226,250 $ 3.45 Awarded — — Vested (195,313 ) 3.45 Forfeited — — Outstanding, March 31, 2019 30,937 $ 3.45 As of March 31, 2019 , there were 30,937 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 March 31, 2019 , 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 2.81 years. Second Amended and Restated 2010 Employee Stock Purchase Plan (ESPP) The Company has reserved 2,000,000 of its 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 any purchase period within a two -year enrollment period, as defined. The Company has four six -month purchase periods per each two -year enrollment period. If, within any one of the four purchase periods in an enrollment period, the purchase period ending stock price is lower than the stock price at the beginning of the enrollment period, the two -year enrollment resets at the new lower stock price. This aspect of the plan was amended in 2017. Prior to 2017, the plan included two six -month purchase periods per year with no defined enrollment period. As of March 31, 2019 , 231,053 shares were issued under the ESPP, of which none were issued during the quarter ended March 31, 2019 . As of March 31, 2019 , there were 1,768,947 shares available for future purchase under the ESPP. The Company recorded an immaterial amount in compensation expense for the three months ended March 31, 2019 and $0.1 million for the three months ended March 31, 2018 related to its ESPP. Stock-Based Compensation Expense The Company recorded $0.7 million in compensation expense for the three months ended March 31, 2019 and $1.2 million for the three months ended March 31, 2018 related to employee and director stock option grants. The total fair values of vested stock options for each of the three months ended March 31, 2019 and 2018 was $0.5 million and $1.8 million, respectively. Total Stock-Based Compensation Expense For the three months ended March 31, 2019 and 2018 , 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 2019 2018 Research and development expenses $ 176 $ 413 General and administrative expenses 475 813 Total stock-based compensation expense $ 651 $ 1,226

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The Company had an immaterial balance of accumulated other comprehensive income as of March 31, 2019 and December 31, 2018 . The following table summarizes the changes in accumulated other comprehensive income (loss) as of March 31, 2018 . Unrealized Losses and Gain on Securities Available-for-Sale Balance, as of December 31, 2017 $ (2 ) Unrealized loss on marketable securities (4 ) Net current period other comprehensive income (4 ) Balance, as of March 31, 2018 $ (6 )

Common Stock

Common Stock	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Common Stock	Common Stock (a) Reverse Stock Split On May 29, 2018 (the “Effective Date”), the Company filed a Certificate of Amendment to the Company’s Restated Certificate of Incorporation with the Secretary of State of the State of Delaware (the “Certificate of Amendment”), which effected, as of 5:00 p.m. Eastern Time on the Effective Date, a 1 -for- 5 reverse stock split (the “Reverse Stock Split”) of the Company’s issued and outstanding common stock, $0.01 par value per share (the “Common Stock”). As a result of the Reverse Stock Split, every five shares of Common Stock issued and outstanding was converted into one share of Common Stock. No fractional shares were issued in connection with the Reverse Stock Split. Stockholders who would have otherwise been entitled to a fractional share of Common Stock were instead entitled to receive a proportional cash payment. The Reverse Stock Split proportionately reduced the number of authorized shares of Common Stock. The Reverse Stock Split did not change the par value of the Common Stock or the authorized number of shares of preferred stock of the Company. All outstanding stock options were adjusted as a result of the Reverse Stock Split, as required by the terms of such stock options (b) 2015 Sales Agreement with Cowen On July 2, 2015, the Company entered into a sales agreement with Cowen, pursuant to which the Company may 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 will act as sales agent. Subject to the terms and conditions of the sales agreement, Cowen may 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 may also sell the common stock by any other method permitted by law, including in negotiated transactions. Cowen will use its commercially reasonable efforts consistent with its normal trading and sales practices and applicable state and federal laws, rules and regulations and the rules of the Nasdaq Global Market to sell on the Company’s behalf all of the shares requested to be sold by the Company. The Company has no obligation to sell any of the common stock under the sales agreement. Either the Company or Cowen may at any time suspend solicitations and offers under the sales agreement upon notice to the other party. The sales agreement may be terminated at any time by either the Company or Cowen upon written notice to the other party as specified in the sales agreement. The aggregate compensation payable to Cowen shall be 3% of the gross sales price of the common stock sold by Cowen pursuant to the sales agreement. Each party has 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 shares sold under the sales agreement, have been issued and sold pursuant to the universal shelf registration statement on Form S-3, filed with the Securities and Exchange Commission on July 2, 2015. The remaining shares that may be sold under the sales agreement are expected to be issued and sold, if at all, pursuant to the currently effective universal shelf registration statement on Form S-3, filed with the Securities and Exchange Commission on May 3, 2018. The Company did no t sell shares of common stock under this sales agreement during the quarter ended March 31, 2019 . The shares sold under the sales agreement have been issued and sold pursuant to the universal shelf registration statement on Form S-3, filed with the Securities and Exchange Commission on July 2, 2015. The remaining shares that may be sold under the sales agreement are expected to be issued and sold, if at all, pursuant to the currently effective universal shelf registration statement on Form S-3, filed with the Securities and Exchange Commission on May 3, 2018. As of March 31, 2019 , the Company has sold an aggregate of 420,796 shares of common stock pursuant to this sales agreement, for net proceeds of $6.2 million. (c) Treasury Stock Retirement Since 2002, the Company has repurchased 244,569 shares of common stock at a total cost of $1.5 million. The shares were repurchased through a combination of a repurchase program of up to $3.0 million approved by the Board of Directors in 2002 and through employee purchases of common stock upon the exercise of stock options by remittance of shares of Company stock. The Company accounts for its common stock repurchases as treasury stock under the cost method. In March 2018, the Company retired all 244,569 shares of common stock at a total cost of $1.5 million. This was a non-cash transaction and thus only affected the classifications within the stockholders' equity section of the Company's consolidated balance sheet. (d) 2018 Charter Amendment On May 15, 2018, the Company's stockholders approved an increase to the number of authorized shares of its common stock from 45,000,000 shares to 67,500,000 shares.

Loss Per Common Share

Loss Per Common Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Loss Per Common Share	Loss Per Common Share Basic and diluted loss per common share is computed by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per common share is the same as basic net loss per common share for the three months ended March 31, 2019 and 2018 , 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 5,270,080 and 3,486,744 as of March 31, 2019 and 2018 , respectively.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2019
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 has agreed to pay Epi-Cure an upfront payment of $0.1 million for legal and consulting costs incurred by Epi-Cure in connection with the transaction. Under the terms of the agreement, Epi-Cure will have primary responsibility for conducting research and development activities and Curis will be 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 initial research and development period, Curis has sixty days to elect to exercise its option to license the program compounds. If the Company makes this election it will make a $2.0 million license fee payment and will be responsible for the development and commercialization of products that may result from the collaboration. Curis will also make cash payments to Epi-Cure subject to successful achievement of certain patent, development, regulatory, and commercial milestones, up to $63.0 million and will also pay Epi-Cure mid-single digit royalties on net product sales if product candidates derived from this collaboration are successfully developed. Epi-Cure has retained the right to opt in to co-develop and share in profits upon initiation of a Phase 2 clinical study, in which event Curis will share in any development costs and profits on a 50/50 basis. Epi-Cure also has the right to opt-out of co-development/co-profit in which case they will receive royalty payments in lieu of profit-sharing. Each party has the right to terminate the agreement for uncured material breach by the other party. Curis has the right to terminate the agreement for its convenience upon 60 days prior written notice. The agreement also sets forth customary terms regarding each party’s intellectual property ownership rights, representations and warranties, indemnification obligations, confidentiality rights and obligations, patent prosecution, and maintenance and defense rights and obligations. For the period ended March 31, 2019 , Curis has paid and expensed an immaterial amount of fees related to this agreement. (b) Agreement with David Tuck, M.D. On May 24, 2018 , the Company announced that David Tuck, M.D., Chief Medical Officer, provided notice of his intention to retire from the Company, effective as of August 31, 2018 . Dr. Tuck subsequently determined to retire on August 3, 2018. The Company and Dr. Tuck entered into a letter agreement on August 1, 2018 (the “Letter Agreement”) pursuant to which Dr. Tuck agreed to provide the Company with specified advisory services commencing on August 4, 2018 and extending until May 3, 2019 , subject to earlier termination (the “Advisory Period”). In consideration for Dr. Tuck’s advisory services, the Company has agreed to (i) pay him a monthly retainer of $35,000 during the Advisory Period and (ii) reimburse him for any pre-approved reasonable, documented out-of-pocket expenses relating to his advisory services. In addition, the Company and Dr. Tuck have agreed to amend his stock option agreements such that his outstanding options will cease to vest as of his date of resignation on August 3, 2018 . The Letter Agreement may be terminated (i) at any time upon the mutual written consent of the parties, (ii) at any time by the Company immediately upon Dr. Tuck’s breach or threatened breach of the terms of his Invention, Non-Disclosure and Non-Competition Agreement with the Company, or (iii) by the Company at any time upon Dr. Tuck’s material breach of the terms of the Letter Agreement and failure to cure such breach within five days after written notice from the Company. In the event of termination of the Letter Agreement, Dr. Tuck will be entitled to payment for services performed and expenses paid or incurred prior to the effective date of termination that have not previously been paid. The Letter Agreement also contains other customary terms and conditions relating to his advisory service. While the Company may utilize Dr. Tuck's consulting services in the future, the Company deemed the services to be a reduced level of service and not substantive. Under ASC 450, Contingencies , when an employee terminates and enters into a consulting agreement and the services to be provided are not deemed substantive, the transaction should be accounted for as a severance arrangement with no future service requirement. Based on this guidance, the Company recognized $0.3 million of expense during 2018, which represented the total obligation under the Letter Agreement.

New Accounting Pronouncements

New Accounting Pronouncements	3 Months Ended
	Mar. 31, 2019
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements	New Accounting Pronouncements Recently Issued and Adopted In February 2016, the FASB issued ASU 2016-02, Leases . In addition, the FASB recently issued ASUs 2018-10 and 2018-11, all of which are further clarifying amendments to ASU 2016-02. The standard requires organizations that lease assets to recognize on the balance sheet assets or liabilities, as applicable, for the rights and obligations created by those leases. Additionally, the guidance modifies current guidance for lessor accounting and leveraged leases. This new standard was effective for the Company as of January 1, 2019. The Company elected to adopt the new standard using the modified retrospective method and, accordingly, has not recast comparative periods presented in its unaudited consolidated financial statements. The Company has elected the package of transition practical expedients for its existing leases and therefore it has not reassessed the following: lease classification for existing leases, whether any existing contracts contained leases, if any initial direct costs were incurred and whether any existing land easements should be accounted for as leases. As permitted by the new standard the Company has elected as accounting policy elections to not recognize assets and related lease liabilities for leases with terms of twelve months or less. The Company elected the available practical expedients and updated internal controls to enable the preparation of financial information on adoption. The Company adopted this standard as of January 1, 2019 which had an impact on its Condensed Consolidated Balance Sheets as of January 1, 2019 and March 31, 2019, with the recognition of an operating lease right-of-use asset in the amount of $1.0 million and $0.8 million, respectively, and the recognition of operating lease liabilities of $1.1 million and $0.9 million, respectively. The new standard did not have a significant impact on the Company's Condensed Consolidated Statements of Operations for any period. Recently Issued, Not Yet Adopted In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement, which modified the disclosure requirements for fair value measurement under ASC 820. The standard will be effective for annual reporting periods and interim periods within those annual periods, beginning after December 15, 2019, and early adoption is permitted. 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.

New Accounting Pronouncements (

New Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Changes and Error Corrections [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of the Company have been prepared in accordance with the instructions to Form 10-Q and Article 10 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., or 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, 2018 as filed with the Securities and Exchange Commission, or the SEC, on March 26, 2019 . 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 March 31, 2019 ; the results of operations for the three -month periods ended March 31, 2019 and 2018 ; stockholder's equity for the three -month periods ended March 31, 2019 and 2018 and the cash flows for the three -month periods ended March 31, 2019 and 2018 . The condensed consolidated balance sheet at December 31, 2018 was derived from audited annual financial statements but does not contain all of the footnote disclosures from the annual financial statements. 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 intangible assets; 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.
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, up-front 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 obligation to determine whether the combined performance obligation is 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, up-front 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 inconsequential or perfunctory and that are determined to be 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 Under the Financial Accounting Standards Board, or FASB, Codification Topic 606, Revenue from Contracts with Customers , or ASC 606, there is a constraint on 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, a company will estimate the amount of consideration in exchange for transfer of promised goods or services. The consideration also can vary if a 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 4). However, a portion of Erivedge royalties will be paid to the Purchasers under the Oberland Purchase Agreement (see Note 9) Deferred Revenue Amounts received prior to satisfying the above revenue recognition criteria are recorded as deferred revenue in the accompanying consolidated balance sheets. Significant judgments are required in the application of revenue recognition guidance. Short-term deferred revenue would consist of amounts that are expected to be recognized as revenue, or applied against future co-development costs, within the next fiscal year. Amounts that the Company expects will not be recognized in the next fiscal year would be classified as long-term deferred revenue. However, this estimate would be based on the Company's operating plan as of the balance sheet date and on its estimated performance periods under the collaboration in which the Company has recorded deferred revenues. If the Company's operating plan or its estimated performance period would change, the Company could recognize a different amount of deferred revenue over the reporting period. 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 the Company's initial judgments, its revenue recognition with respect to such transactions would change accordingly and any such change could affect its reported financial results.
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 provides a framework for measuring fair value under GAAP and requires expanded disclosures regarding fair value measurements. GAAP defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. GAAP requires the use of valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets and liabilities. The income approach uses valuation techniques to convert future amounts, such as cash flows or earnings, to a single present amount on a discounted basis. The cost approach is based on the amount that currently would be required to replace the service capacity of an asset (replacement cost). Valuation techniques should be consistently applied. GAAP also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair value. The standard describes three levels of inputs that may be used to measure fair value: 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.
Loss Per Common Share	Loss Per Common Share Basic and diluted loss per common share is computed by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per common share is the same as basic net loss per common share for the three months ended March 31, 2019 and 2018 , because the effect of the potential common stock equivalents would be antidilutive due to the Company’s net loss position for these periods.
New Accounting Pronouncements	New Accounting Pronouncements Recently Issued and Adopted In February 2016, the FASB issued ASU 2016-02, Leases . In addition, the FASB recently issued ASUs 2018-10 and 2018-11, all of which are further clarifying amendments to ASU 2016-02. The standard requires organizations that lease assets to recognize on the balance sheet assets or liabilities, as applicable, for the rights and obligations created by those leases. Additionally, the guidance modifies current guidance for lessor accounting and leveraged leases. This new standard was effective for the Company as of January 1, 2019. The Company elected to adopt the new standard using the modified retrospective method and, accordingly, has not recast comparative periods presented in its unaudited consolidated financial statements. The Company has elected the package of transition practical expedients for its existing leases and therefore it has not reassessed the following: lease classification for existing leases, whether any existing contracts contained leases, if any initial direct costs were incurred and whether any existing land easements should be accounted for as leases. As permitted by the new standard the Company has elected as accounting policy elections to not recognize assets and related lease liabilities for leases with terms of twelve months or less. The Company elected the available practical expedients and updated internal controls to enable the preparation of financial information on adoption. The Company adopted this standard as of January 1, 2019 which had an impact on its Condensed Consolidated Balance Sheets as of January 1, 2019 and March 31, 2019, with the recognition of an operating lease right-of-use asset in the amount of $1.0 million and $0.8 million, respectively, and the recognition of operating lease liabilities of $1.1 million and $0.9 million, respectively. The new standard did not have a significant impact on the Company's Condensed Consolidated Statements of Operations for any period. Recently Issued, Not Yet Adopted In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement, which modified the disclosure requirements for fair value measurement under ASC 820. The standard will be effective for annual reporting periods and interim periods within those annual periods, beginning after December 15, 2019, and early adoption is permitted. 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 Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 and December 31, 2018 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 March 31, 2019 and 2018 . Quoted Prices in Active Markets (Level 1) Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Fair Value As of March 31, 2019: Cash equivalents: Money market funds $ 13,596 $ — $ — $ 13,596 Corporate commercial paper, stock, bonds and notes — 120 — 120 Municipal and government securities — — — — Short-term investments: Corporate commercial paper, bonds and notes — 30 — 30 Total assets at fair value $ 13,596 $ 150 $ — $ 13,746 Quoted Prices in Active Markets (Level 1) Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Fair Value As of December 31, 2018: Cash equivalents: Money market funds $ 18,180 $ — $ — $ 18,180 Corporate commercial paper, stock, bonds and notes — 2,199 — 2,199 Municipal bonds — 135 — 135 Short-term investments: Corporate commercial paper, stock, bonds and notes — 634 — 634 Total assets at fair value $ 18,180 $ 2,968 $ — $ 21,148

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2019
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 December 31, 2018 are as follows: Amortized Cost Unrealized Gain Unrealized Loss Fair Value Corporate bonds and notes – short-term $ 634 $ — $ — $ 634 Total investments $ 634 $ — $ — $ 634 The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of March 31, 2019 are as follows: Amortized Cost Unrealized Gain Unrealized Loss Fair Value Corporate commercial paper, bonds and notes – short-term $ 30 $ — $ — $ 30 Total investments $ 30 $ — $ — $ 30

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
Other Liabilities Disclosure [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consist of the following: March 31, December 31, Accrued compensation $ 930 $ 2,774 Professional fees 262 233 Accrued interest on debt (Note 7) — 165 Other 228 285 Total $ 1,420 $ 3,457

Liability Related to the Sale_2

Liability Related to the Sale of Future Royalties (Tables)	3 Months Ended
	Mar. 31, 2019
Nonmonetary Transactions [Abstract]
Schedule of Liability Due to Non-Cash Transaction	he following table shows the activity with respect to the liability related to the sale of future royalties during the three months ended March 31, 2019 . Liability related to the sale of future royalties at March 22, 2019 $ 65,000 Non-cash imputed interest expense recognized 129 Liability related to the sale of future royalties at March 31, 2019 65,129 Less: Unamortized transaction costs (582 ) Carrying value of liability related to the sale of future royalties at March 31, 2019 $ 64,547

Lease (Tables)

Lease (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Remaining Lease Commitments	The Company’s remaining lease commitments for all leased facilities with an initial or remaining term of at least one year are as follows as of March 31, 2019 . Year Ending December 31, 2019 $ 754 2020 168 Total minimum payments 922 Less: Present value adjustments (44 ) Total operating lease liability $ 878
Remaining Lease Commitments as of Prior Year End	The Company’s remaining lease commitments for all leased facilities with an initial or remaining term of at least one year were as follows as of December 31, 2018 . Year Ending December 31, 2019 $ 1,002 2020 168 Total minimum payments $ 1,170

Stock Plans and Stock Based C_2

Stock Plans and Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [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 three months ended March 31, 2019 and 2018 based on the assumptions noted in the following table: Three Months Ended 2019 2018 Expected term (years) - employees 5.5 5.5 Expected term (years) - officers 5.5 5.5 Expected term (years) – directors 5.5 6.25 Risk-free interest rate 2.5%-2.6% 2.5 % Expected Volatility 76 % 66 % 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 is summarized as follows: Number of Shares Weighted Average Exercise Price per Share Weighted Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding, December 31, 2018 3,714,394 $ 7.68 Granted 1,859,998 1.15 Exercised — — Canceled (304,312 ) 8.70 Outstanding, March 31, 2019 5,270,080 $ 5.32 7.44 $ 1,766,878 Exercisable at March 31, 2019 1,760,626 $ 11.25 4.01 $ — Vested and unvested expected to vest at March 31, 2019 4,621,232 $ 5.82 7.18 $ 1,411,312
Schedule of Restricted Stock Award Activity	The following table presents a summary of outstanding RSAs under the 2010 Plan as of March 31, 2019 : Number of Shares Weighted Average Grant Date Fair Value Outstanding, December 31, 2018 226,250 $ 3.45 Awarded — — Vested (195,313 ) 3.45 Forfeited — — Outstanding, March 31, 2019 30,937 $ 3.45
Schedule of Stock-Based Compensation Expense	For the three months ended March 31, 2019 and 2018 , 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 2019 2018 Research and development expenses $ 176 $ 413 General and administrative expenses 475 813 Total stock-based compensation expense $ 651 $ 1,226

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Schedule of Changes in Accumulated Other Comprehensive Income (Loss)	The Company had an immaterial balance of accumulated other comprehensive income as of March 31, 2019 and December 31, 2018 . The following table summarizes the changes in accumulated other comprehensive income (loss) as of March 31, 2018 . Unrealized Losses and Gain on Securities Available-for-Sale Balance, as of December 31, 2017 $ (2 ) Unrealized loss on marketable securities (4 ) Net current period other comprehensive income (4 ) Balance, as of March 31, 2018 $ (6 )

Nature of Business - Narrative

Nature of Business - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Oct. 31, 2016program	Oct. 31, 2015program
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Retained earnings (accumulated deficit)	$ (994,724)		$ (984,840)
Net loss	9,884	$ 10,747
Cash used in operations	10,604	$ 9,964
Cash, cash equivalents and investments	$ 42,800
Aurigene
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of programs licensed in collaboration agreement | program					2

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Genentech, Inc. | Customer Concentration Risk
Concentration Risk [Line Items]
Total gross revenues (as a percent)	100.00%	100.00%

Research and Development Coll_2

Research and Development Collaborations - Narrative (Details)	Mar. 06, 2017USD ($)	Sep. 07, 2016USD ($)shares	Apr. 30, 2019	Mar. 31, 2017USD ($)	Sep. 30, 2016program	Jun. 30, 2003USD ($)	Mar. 31, 2019USD ($)productpaymenttermprogram	Mar. 31, 2018USD ($)	Dec. 31, 2015USD ($)shares	Dec. 31, 2018USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Distribution of remaining loan proceeds	$ 26,600,000			$ 26,600,000
Total revenues							$ 1,767,000	$ 2,468,000
Cost of royalty revenues							108,000	129,000
Accounts receivable							1,786,000			$ 2,864,000
Value of common stock issued							$ 332,000			$ 332,000
Number of program licensed | program					4		4
Collaboration agreement, number of optional additional terms | term							3
Collaboration agreement, optional additional term							1 year
Option fees							$ 7,500,000
Number of payments | payment							2
Exclusivity payment							$ 10,000,000
Royalties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenues							2,137,000	2,474,000
Genentech, Inc.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amount received for specified clinical development and regulatory objectives							59,000,000
Percentage of royalty rate decrease						2.00%
Cost of royalty revenues							$ 100,000	100,000
Percentage of royalties earned							5.00%
Accounts receivable							$ 1,800,000	2,500,000
Genentech, Inc. | Royalties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenues							$ 2,100,000	$ 2,500,000
Genentech, Inc. | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [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 Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales						5.00%
HealthCare Royalty Partners III, L.P. | Curis Royalty, LLC
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Principal loan amount to Curis Royalty given by BioPharma under credit agreement				$ 45,000,000
Interest rate on loan to Curis Royalty given by BioPharma under credit agreement				9.95%
BioPharma-II | Curis Royalty, LLC
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Remaining loan obligations				$ 18,400,000
Aurigene
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Issued shares of common stock (in shares) | shares									3,424,026.2
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
Collaboration agreement, number of products required to commercialize (at least) | product							1
Collaboration agreement period							2 years
Milestone payments waived to date							$ 19,500,000
Aurigene | Programs three and four
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Agreement to provide additional funding, if options are exercised (up to)		$ 2,000,000
Payments made under collaboration arrangements							14,500,000
Aurigene | IRAK4, PD1/VISTA,PD1/TIM3 Program
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Waived payment of milestone and other payments (up to)							$ 42,500,000
Forecast | Genentech, Inc.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty payments			5.00%
Australia | Genentech, Inc.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of direct net sales							2.00%

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Short-term investments:
Corporate commercial paper, bonds and notes	$ 30	$ 634
Corporate commercial paper, bonds and notes
Short-term investments:
Corporate commercial paper, bonds and notes	30	634
Fair Value, Measurements, Recurring
Short-term investments:
Total assets at fair value	13,746	21,148
Fair Value, Measurements, Recurring | Corporate commercial paper, bonds and notes
Short-term investments:
Corporate commercial paper, bonds and notes	30	634
Fair Value, Measurements, Recurring | Money market funds
Cash equivalents:
Cash equivalents	13,596	18,180
Fair Value, Measurements, Recurring | Corporate Commercial Paper, Stock, Bonds And Notes | Corporate commercial paper, bonds and notes
Cash equivalents:
Cash equivalents	120	2,199
Fair Value, Measurements, Recurring | Municipal and government securities
Cash equivalents:
Cash equivalents	0	135
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1)
Short-term investments:
Total assets at fair value	13,596	18,180
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	13,596	18,180
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Corporate Commercial Paper, Stock, Bonds And Notes | Corporate commercial paper, bonds and notes
Cash equivalents:
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Municipal and government securities
Cash equivalents:
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2)
Short-term investments:
Total assets at fair value	150	2,968
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2) | Corporate commercial paper, bonds and notes
Short-term investments:
Corporate commercial paper, bonds and notes	30	634
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) | Corporate Commercial Paper, Stock, Bonds And Notes | Corporate commercial paper, bonds and notes
Cash equivalents:
Cash equivalents	120	2,199
Fair Value, Measurements, Recurring | Other Observable Inputs (Level 2) | Municipal and government securities
Cash equivalents:
Cash equivalents	0	135
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) | Corporate Commercial Paper, Stock, Bonds And Notes | Corporate commercial paper, bonds and notes
Cash equivalents:
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) | Municipal and government securities
Cash equivalents:
Cash equivalents	$ 0	$ 0

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
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	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 30	$ 634
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	30	634
Corporate commercial paper, bonds and notes – short-term
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	30	634
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	$ 30	$ 634

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	Mar. 22, 2019	Mar. 06, 2017	Mar. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Distribution of remaining loan proceeds		$ 26,600,000	$ 26,600,000
Loss on debt extinguishment				$ 3,495,000	$ 0
Payment towards debt obligations				1,825,000	1,815,000
Short-term debt				0		$ 6,884,000
Long-term debt				0		28,600,000
Interest expense recognized related to loan				808,000	1,025,000
HealthCare Royalty Partners III, L.P.
Debt Instrument [Line Items]
Repayment of debt, principal	$ 33,800,000
Accrued and unpaid interest and prepayment fees	3,400,000
Loss on debt extinguishment	100,000
Payment towards debt obligations	$ 37,200,000
Curis Inc and Curis Royalty, LLC | HealthCare Royalty Partners III, L.P.
Debt Instrument [Line Items]
Loan received		$ 45,000,000
Annual interest rate		9.95%
Remaining loan obligations		$ 18,400,000
Curis Royalty, LLC | HealthCare Royalty Partners III, L.P.
Debt Instrument [Line Items]
Loan received			$ 45,000,000
Annual interest rate			9.95%
Curis Royalty, LLC | BioPharma-II
Debt Instrument [Line Items]
Remaining loan obligations			$ 18,400,000
BioPharma II and HealthCare Royalty Partners III
Debt Instrument [Line Items]
Short-term debt						6,900,000
Long-term debt				0		28,600,000
Accrued interest on loan amount to Curis Royalty given by BioPharma under credit agreement						$ 200,000
BioPharma II and HealthCare Royalty Partners III | BioPharma-II
Debt Instrument [Line Items]
Interest expense recognized related to loan				800,000	1,000,000
BioPharma II and HealthCare Royalty Partners III | Curis Royalty, LLC
Debt Instrument [Line Items]
Payment towards debt obligations				36,600,000	2,900,000
BioPharma II and HealthCare Royalty Partners III | Curis Royalty, LLC | Principal portion
Debt Instrument [Line Items]
Payment towards debt obligations				$ 35,600,000	$ 1,800,000

Accrued Liabilities - Summary (

Accrued Liabilities - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Other Liabilities Disclosure [Abstract]
Accrued compensation	$ 930	$ 2,774
Professional fees	262	233
Accrued interest on debt (Note 7)	0	165
Other	228	285
Total	$ 1,420	$ 3,457

Liability Related to the Sale_3

Liability Related to the Sale of Future Royalties (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 22, 2019	Mar. 31, 2019	Mar. 31, 2018
Nonmonetary Transaction [Line Items]
Proceeds from royalty interest purchase agreement with Oberland Capital Management, LLC			$ 65,000	$ 0
Payment towards debt obligations			1,825	$ 1,815
Transaction fees		$ 600
Non-cash interest rate (percent)		8.10%
Nonmonetary Transaction [Roll Forward]
Non-cash imputed interest expense recognized	$ 129
Liability related to the sale of future royalties at March 31, 2019	65,129	$ 65,000	65,129
Less: Unamortized transaction costs	(582)		(582)
Carrying value of liability related to the sale of future royalties at March 31, 2019	$ 64,547		$ 64,547
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

Lease (Details)

Lease (Details) $ in Millions	Dec. 01, 2010ft²period	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Nov. 01, 2017USD ($)
Lessee, Lease, Description [Line Items]
Area of property (square feet) | ft²	24,529
Number of extension periods available | period	1
Additional lease period (years)	5 years				2 years
Operating lease cash obligation					$ 4.4
Operating lease cash obligation, extended term					$ 2
Restricted investments		$ 0.2		$ 0.2
Operating lease cost		0.2
Operating lease cost			$ 0.2
Non-cash lease expense related to operating lease right-of-use asset		0.2
Minimum
Lessee, Lease, Description [Line Items]
Extension period (years)	1 year
Maximum
Lessee, Lease, Description [Line Items]
Extension period (years)	18 months
Financial Standby Letter of Credit
Lessee, Lease, Description [Line Items]
Security deposit		$ 0.3

Lease - Current Lease Maturitie

Lease - Current Lease Maturities (Details) $ in Thousands	Mar. 31, 2019USD ($)
Leases [Abstract]
2019	$ 754
2020	168
Total minimum payments	922
Less: Present value adjustments	(44)
Total operating lease liability	$ 878

Lease - Prior Period Lease Matu

Lease - Prior Period Lease Maturities (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 1,002
2020	168
Total minimum payments	$ 1,170

Stock Plans and Stock Based C_3

Stock Plans and Stock Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	May 29, 2018	Jan. 31, 2019$ / sharesshares	Mar. 31, 2019USD ($)purchase_periodplan$ / sharesshares	Mar. 31, 2018USD ($)$ / shares	Dec. 31, 2016purchase_period	Dec. 31, 2018$ / sharesshares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shareholder-approved, share-based compensation plans | plan			2
Reverse stock split ratio	0.2
Number of options granted (shares)			1,859,998
Awarded (shares)			30,000
Exercise price (USD per share) | $ / shares			$ 0.82
Weighted average grant-date fair values of stock options (USD per share) | $ / shares			$ 0.76	$ 2.04
Unrecognized compensation cost, net of estimated forfeitures | $			$ 3,900
Unrecognized compensation cost, weighted average period for recognition			2 years 8 months 15 days
Intrinsic values of employee stock options exercised | $			$ 0	$ 0
Compensation expense related to employee and director stock option grants | $			$ 651	1,226
Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Awarded (shares)			0
Exercise price (USD per share) | $ / shares			$ 0
Outstanding shares (shares)			30,937			226,250
Weighted average fair value (USD per share) | $ / shares			$ 3.45			$ 3.45
Fair value | $			$ 100
Employee Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Compensation expense related to employee and director stock option grants | $			700	1,200
Fair values of vested stock options | $			$ 500	1,800
Officers | Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period of options			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
Unrecognized compensation cost, weighted average period for recognition			2 years 9 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 Two Thousand Ten Stock Incentive Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares authorized (shares)			6,190,000
Expiration period (years)			10 years
Shares awarded under plan (shares)			1,018,998
Amended And Restated Two Thousand Ten Stock Incentive Plan | Stock Options, or Stock Appreciation Rights
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares removed from pool (shares per share)			1
Amended And Restated Two Thousand Ten 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
2010 Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted (shares)			1,859,998
2010 Plan | Officers
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted (shares)		1,502,867
Vesting period of options		4 years
Exercise price (USD per share) | $ / shares		$ 1.16
2010 Plan | Non-employee directors
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted (shares)			720,000
Vesting period of options		1 year
Exercise price (USD per share) | $ / shares			$ 1.16
2010 Plan | Tranche one
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Options granted to employees (shares)			1,139,988
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]
Purchase price of common stock (percentage of fair market value)			85.00%
Additional shares added to 2010 plan (shares)			2,000,000
Enrollment period (years)			2 years
Number of purchase periods per year | purchase_period			4		2
Stock plan offering period (months)			6 months		6 months
Stock issued under ESPPs (shares)			231,053
Stock issued under ESPPs in current period (shares)			0
Stock available under ESPPs (shares)			1,768,947
Compensation expense related to employee and director stock option grants | $			$ 0	$ 100
Maximum | Amended And Restated Two Thousand Ten Stock Incentive Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Purchase price of common stock (percentage of fair market value)			100.00%

Stock Plans and Stock Based C_4

Stock Plans and Stock Based Compensation - Key Assumptions (Details)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Risk-free interest rate (minimum) (as a percent)	2.50%
Risk-free interest rate (maximum) (as a percent)	2.60%
Risk-free interest rate (as a percent)		2.50%
Expected volatility (as a percent)	76.00%	66.00%
Expected dividends (as a percent)	0.00%	0.00%
Employees
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Expected term (years)	5 years 6 months	5 years 6 months
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	6 years 3 months

Stock Plans and Stock Based C_5

Stock Plans and Stock Based Compensation - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)$ / sharesshares
Number of Shares
Beginning balance (shares) | shares	3,714,394
Granted (shares) | shares	1,859,998
Exercised (shares) | shares	0
Canceled (shares) | shares	(304,312)
Ending balance (shares) | shares	5,270,080
Exercisable at end of period (shares) | shares	1,760,626
Vested and unvested expected to vest at end of period (shares) | shares	4,621,232
Weighted Average Exercise Price per Share
Beginning balance (USD per share) | $ / shares	$ 7.68
Granted (USD per share) | $ / shares	1.15
Exercised (USD per share) | $ / shares	0
Canceled (USD per share) | $ / shares	8.70
Ending balance (USD per share) | $ / shares	5.32
Exercisable at end of period (USD per share) | $ / shares	11.25
Vested and unvested expected to vest at end of period (USD per share) | $ / shares	$ 5.82
Weighted Average Remaining Contractual Life
Outstanding at end of period	7 years 5 months 8 days
Exercisable at end of period	4 years 3 days
Vested and unvested expected to vest at end of period	7 years 2 months 4 days
Aggregate Intrinsic Value
Outstanding at end of period | $	$ 1,766,878
Exercisable at end of period | $	0
Vested and unvested expected to vest at end of period | $	$ 1,411,312

Stock Plans and Stock Based C_6

Stock Plans and Stock Based Compensation - Restricted Stock Award Activity (Details)	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Number of Shares
Awarded (shares) | shares	30,000
Weighted Average Grant Date Fair Value
Awarded (USD per share) | $ / shares	$ 0.82
Restricted Stock
Number of Shares
Beginning balance (shares) | shares	226,250
Awarded (shares) | shares	0
Vested (shares) | shares	(195,313)
Forfeited (shares) | shares	0
Ending balance (shares) | shares	30,937
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
	Mar. 31, 2019	Mar. 31, 2018
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock-based compensation expense	$ 651	$ 1,226
Research and development expenses
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock-based compensation expense	176	413
General and administrative expenses
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Total stock-based compensation expense	$ 475	$ 813

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Summary (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 23,993
Net current period other comprehensive income	(4)
Ending balance	14,468
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2)
Unrealized loss on marketable securities	(4)
Net current period other comprehensive income	(4)
Ending balance	$ (6)

Common Stock - Narrative (Detai

Common Stock - Narrative (Details)	May 29, 2018$ / shares	Jul. 02, 2015USD ($)	Mar. 31, 2018USD ($)shares	Mar. 31, 2019$ / sharesshares	Mar. 31, 2018USD ($)	Mar. 31, 2019USD ($)$ / sharesshares	Mar. 31, 2018USD ($)shares	Dec. 31, 2018$ / sharesshares	May 15, 2018shares	May 14, 2018shares
Class of Stock [Line Items]
Reverse stock split ratio	0.2
Common stock, par value (USD per share) | $ / shares	$ 0.01			$ 0.01		$ 0.01		$ 0.01
Treasury stock acquired (shares) | shares							244,569
Treasury stock acquired, cost							$ 1,500,000
Authorized amount of shares for repurchase (up to)			$ 3,000,000		$ 3,000,000		$ 3,000,000
Common stock retired (shares) | shares			244,569
Value of common stock retired			$ 1,500,000		$ 0
Common stock authorized (shares) | shares				67,500,000		67,500,000		67,500,000	67,500,000	45,000,000
Cowen | At-the-market sale facility
Class of Stock [Line Items]
Compensation payable, percentage of gross sales price		3.00%
Shares of common stock sold (shares) | shares				0		420,796.2
Proceeds from issuance of common stock associated with offerings, net of issuance costs						$ 6,200,000
Maximum | Cowen | At-the-market sale facility
Class of Stock [Line Items]
Planned proceeds from sale of stock (up to)		$ 30,000,000

Loss Per Common Share - Narrati

Loss Per Common Share - Narrative (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stock options outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	5,270,080	3,486,744

Related Party Transactions - Na

Related Party Transactions - Narrative (Details)	Oct. 17, 2018USD ($)	Aug. 01, 2018USD ($)	Mar. 31, 2019USD ($)day	Dec. 31, 2018USD ($)
Related Party Transaction [Line Items]
Monthly retainer for advisory services		$ 35,000
Severance expense				$ 300,000
Epi-Cure Pharmaceuticals, Inc. | Affiliated Entity
Related Party Transaction [Line Items]
Amount paid for transaction			$ 0
Expenses from transactions with related party			0
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
License payment if option is exercised			2,000,000
Milestone payments			$ 63,000,000
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%

New Accounting Pronouncements -

New Accounting Pronouncements - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use asset	$ 822
Total operating lease liability	878
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use asset	800	$ 1,000
Total operating lease liability	$ 900	$ 1,100