Debt	9 Months Ended
Sep. 30, 2016
Debt Disclosure [Abstract]
Debt	Debt In December 2012, Curis’ wholly owned subsidiary, Curis Royalty, received a $30.0 million loan at an annual interest rate of 12.25% pursuant to a credit agreement between Curis Royalty and BioPharma-II. In connection with the loan, Curis transferred to Curis Royalty its right to receive royalty and royalty-related payments on the commercial sales of Erivedge that it receives from Genentech (see Note 4(a)). The loan and accrued interest is being repaid by Curis Royalty using such royalty and royalty-related payments. To secure repayment of the loan, Curis Royalty granted a first priority lien and security interest (subject only to permitted liens) to BioPharma-II in all of its assets and all real, intangible and personal property, including all of its right, title and interest in and to the royalty and royalty-related payments. The loan constitutes an obligation of Curis Royalty, and is non-recourse to Curis. Under the terms of the loan, quarterly royalty payments received by Curis Royalty from Genentech will first be applied to pay (i) escrow fees payable by Curis pursuant to an escrow agreement between Curis, Curis Royalty, BioPharma-II and Boston Private Bank and Trust Company, (ii) Curis’ royalty obligations to university licensors, (iii) certain expenses incurred by BioPharma-II 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 Curis enforcing its right to indemnification under the collaboration agreement with Genentech. Remaining amounts are applied first to pay interest and second, principal on the loan. Curis remains entitled to receive any contingent payments upon achievement of clinical development objectives. Curis Royalty retains its right to royalty payments related to sales of Erivedge following repayment of the loan. The final maturity date of the loan will be the earlier of the date when the principal is paid in full or the termination of Curis Royalty’s right to receive royalties under the collaboration agreement with Genentech. Because the repayment of the term loan is contingent upon the level of Erivedge royalties received, the short- and long-term classification of the debt is based on the Company’s estimate of the timing of amounts to be repaid. The Company cannot estimate when the loan will be repaid as repayment is impacted by numerous factors, all of which are beyond the Company’s control. The repayment term may be shortened or extended depending on the actual level of Erivedge royalties received. In addition, if Erivedge royalties are insufficient to pay the accrued interest on the outstanding loan, any unpaid interest outstanding will be added to the principal on a quarterly basis. The length of the actual repayment period could vary materially to the extent that royalty payments Curis Royalty receives are lower than the Company’s current estimates, which could arise due to factors beyond the Company’s control, such as the sale of competing products that result in a lowering of the royalty rates that Curis Royalty is entitled to receive, decreased market acceptance or a failure by Genentech and/or Roche to successfully commercialize Erivedge in territories where it has received regulatory approval. At any time after January 1, 2017, Curis Royalty may, subject to certain limitations, prepay the outstanding principal of the loan in whole or in part, at a price equal to 105% of the outstanding principal on the loan, plus accrued but unpaid interest. The obligations of Curis Royalty under the credit agreement to repay the loan may be accelerated upon the occurrence of an event of default as defined in the credit agreement. During the nine months ended September 30, 2016 and 2015, Curis Royalty made payments totaling $5.3 million and $5.3 million, respectively, of which $3.2 million and $2.8 million have been applied to the principal, respectively, with the remainder applied to accrued interest. As of September 30, 2016, the Company recorded short- and long-term debt of $5.1 million and $15.8 million, respectively, and at December 31, 2015, the Company recorded short- and long-term debt of $4.6 million and $19.6 million, respectively, related to the loan, with such amounts recorded within the Company’s condensed consolidated balance sheets. In the three months ended March 31, 2016, the Company adopted ASU No. 2015-3, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. In accordance with the updated standard, the Company reclassified certain of its debt issuance costs, related to the loan, from assets to a direct deduction from the carrying amount of the related debt liability. The adoption of this guidance did not impact the consolidated statement of operations and comprehensive loss and the impact to the balance sheet was not material. In addition, the Company recorded related accrued interest on the debt of $0.2 million and $0.3 million as of September 30, 2016 and December 31, 2015, respectively, with such amounts included in the Company’s accrued liabilities section of its condensed consolidated balance sheets. For the three months ended September 30, 2016 and 2015, the Company recognized interest expense related to the loan with BioPharma-II of $0.7 million and $0.8 million, respectively, in the condensed consolidated statement of operations and comprehensive loss. For the nine months ended September 30, 2016 and 2015, the Company recognized interest expense related to the loan with BioPharma-II of $2.1 million and $2.5 million, respectively, in the condensed consolidated statement of operations and comprehensive loss. At September 30, 2016, the fair value of the debt approximates its carrying value due to the expected repayment period and because the interest rate yield is near current market rate yields. Due to the assumptions required in estimating future Erivedge royalties, the expected repayment period and weighting of various royalty projection scenarios, the fair value of the debt is measured using Level 3 inputs.

Debt

In December 2012, Curis’ wholly owned subsidiary, Curis Royalty, received a $30.0 million loan at an annual interest rate of 12.25% pursuant to a credit agreement between Curis Royalty and BioPharma-II. In connection with the loan, Curis transferred to Curis Royalty its right to receive royalty and royalty-related payments on the commercial sales of Erivedge that it receives from Genentech (see Note 4(a)). The loan and accrued interest is being repaid by Curis Royalty using such royalty and royalty-related payments. To secure repayment of the loan, Curis Royalty granted a first priority lien and security interest (subject only to permitted liens) to BioPharma-II in all of its assets and all real, intangible and personal property, including all of its right, title and interest in and to the royalty and royalty-related payments. The loan constitutes an obligation of Curis Royalty, and is non-recourse to Curis. Under the terms of the loan, quarterly royalty payments received by Curis Royalty from Genentech will first be applied to pay (i) escrow fees payable by Curis pursuant to an escrow agreement between Curis, Curis Royalty, BioPharma-II and Boston Private Bank and Trust Company, (ii) Curis’ royalty obligations to university licensors, (iii) certain expenses incurred by BioPharma-II 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 Curis enforcing its right to indemnification under the collaboration agreement with Genentech. Remaining amounts are applied first to pay interest and second, principal on the loan. Curis remains entitled to receive any contingent payments upon achievement of clinical development objectives. Curis Royalty retains its right to royalty payments related to sales of Erivedge following repayment of the loan.

The final maturity date of the loan will be the earlier of the date when the principal is paid in full or the termination of Curis Royalty’s right to receive royalties under the collaboration agreement with Genentech. Because the repayment of the term loan is contingent upon the level of Erivedge royalties received, the short- and long-term classification of the debt is based on the Company’s estimate of the timing of amounts to be repaid. The Company cannot estimate when the loan will be repaid as repayment is impacted by numerous factors, all of which are beyond the Company’s control. The repayment term may be shortened or extended depending on the actual level of Erivedge royalties received. In addition, if Erivedge royalties are insufficient to pay the accrued interest on the outstanding loan, any unpaid interest outstanding will be added to the principal on a quarterly basis. The length of the actual repayment period could vary materially to the extent that royalty payments Curis Royalty receives are lower than the Company’s current estimates, which could arise due to factors beyond the Company’s control, such as the sale of competing products that result in a lowering of the royalty rates that Curis Royalty is entitled to receive, decreased market acceptance or a failure by Genentech and/or Roche to successfully commercialize Erivedge in territories where it has received regulatory approval. At any time after January 1, 2017, Curis Royalty may, subject to certain limitations, prepay the outstanding principal of the loan in whole or in part, at a price equal to 105% of the outstanding principal on the loan, plus accrued but unpaid interest. The obligations of Curis Royalty under the credit agreement to repay the loan may be accelerated upon the occurrence of an event of default as defined in the credit agreement.

During the nine months ended September 30, 2016 and 2015, Curis Royalty made payments totaling $5.3 million and $5.3 million, respectively, of which $3.2 million and $2.8 million have been applied to the principal, respectively, with the remainder applied to accrued interest. As of September 30, 2016, the Company recorded short- and long-term debt of $5.1 million and $15.8 million, respectively, and at December 31, 2015, the Company recorded short- and long-term debt of $4.6 million and $19.6 million, respectively, related to the loan, with such amounts recorded within the Company’s condensed consolidated balance sheets. In the three months ended March 31, 2016, the Company adopted ASU No. 2015-3, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. In accordance with the updated standard, the Company reclassified certain of its debt issuance costs, related to the loan, from assets to a direct deduction from the carrying amount of the related debt liability. The adoption of this guidance did not impact the consolidated statement of operations and comprehensive loss and the impact to the balance sheet was not material.

In addition, the Company recorded related accrued interest on the debt of $0.2 million and $0.3 million as of September 30, 2016 and December 31, 2015, respectively, with such amounts included in the Company’s accrued liabilities section of its condensed consolidated balance sheets. For the three months ended September 30, 2016 and 2015, the Company recognized interest expense related to the loan with BioPharma-II of $0.7 million and $0.8 million, respectively, in the condensed consolidated statement of operations and comprehensive loss. For the nine months ended September 30, 2016 and 2015, the Company recognized interest expense related to the loan with BioPharma-II of $2.1 million and $2.5 million, respectively, in the condensed consolidated statement of operations and comprehensive loss.

At September 30, 2016, the fair value of the debt approximates its carrying value due to the expected repayment period and because the interest rate yield is near current market rate yields. Due to the assumptions required in estimating future Erivedge royalties, the expected repayment period and weighting of various royalty projection scenarios, the fair value of the debt is measured using Level 3 inputs.