License Agreements	3 Months Ended
Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
License Agreements	5.License Agreements Merck License In December 2012, the Company entered into an exclusive worldwide royalty free license agreement with Merck Sharp & Dohme Corp. (“Merck”) for exclusive worldwide rights for the development and commercialization of serlopitant and two other NK₁‑receptor antagonists in all human diseases, disorders or conditions, except for the treatment and prevention of nausea or vomiting. The Company paid Merck an upfront non‑refundable non‑creditable licensing fee of $1.0 million dollars and issued to Merck shares of its common stock. In addition, the Company agreed to make aggregate payments of up to $25.0 million dollars upon the achievement of specified development and regulatory milestones. In May 2018, the Company paid a $3.0 million milestone payment associated with the initiation of the Company’s Phase 3 clinical program for pruritus associated with prurigo nodularis. Future milestone payments are considered a form of variable consideration and accrued for when the Company determines that it is probable that there will not be a significant reversal of the accrual in future periods. JT Torii Collaboration Agreement In August 2016, the Company entered into a license and collaboration agreement (the “Collaboration Agreement”) with Japan Tobacco Inc. and Torii Pharmaceutical Co. Ltd. (together referred to as “JT Torii”). Under the Collaboration Agreement, the Company granted to JT Torii the rights to develop and commercialize products containing serlopitant in Japan, for the treatment of diseases and conditions other than nausea or vomiting. In exchange, JT Torii paid the Company an upfront, non‑refundable payment of $11.0 million. In addition, the Company was entitled to receive aggregate payments of up to $28.0 million upon the achievement of specified development and regulatory milestones, and $15.0 million upon the achievement of a commercial milestone, as well as tiered royalties from the mid-single digits up to the mid‑teens on sales of licensed products in Japan. The Company’s performance obligations under the license agreement included the transfer of intellectual property rights in the form of licenses, obligations to participate on certain development and/or commercialization committees with the collaboration partners and supply manufactured drug product for clinical trials. In the second quarter of 2018, JT Torii informed the Company that they decided to halt the Japanese Phase 2 clinical trial of serlopitant, following which the Company and JT Torii agreed to terminate the Collaboration Agreement. As a result, the Company has reacquired full ownership of the development and commercialization rights to serlopitant in Japan and accelerated recognition of the remaining deferred revenue of $8.1 million during the quarter. In the second quarter of 2018, the Company also earned and recognized a $2.0 million milestone payment related to JT Torii’s receipt of investigational new drug application (“IND”) enabling past clinical study reports delivered by the Company under the Collaboration Agreement. Under the Collaboration Agreement, the Company was reimbursed by JT Torii for the non-commercial supplies of serlopitant at the same rate it was charged by the third-party manufacturer for such supplies, which price did not include a significant or incremental discount for JT Torii. The assessment of performance obligations required judgment in order to determine the allocation of revenue to each deliverable and the appropriate period of time over which the revenue should be recognized. Under the Collaboration Agreement, the Company determined that the license was not distinct from the research and development services because JT Torii could not use the license with its available resources to obtain any economic value without the Company’s participation. The license and the services were combined as one unit of accounting and upfront payments were recorded initially as deferred revenue in the balance sheet. Revenue was then recognized over an estimated performance period as performance of services was being completed. The Company recognized the upfront fee based on performance of the obligation using input method over the period of performance, which represented the estimated development period in the territories based on the initial development plan managed by the joint steering committee. The original term of the agreement was through the expiration of the patents associated with serlopitant. Under the Collaboration Agreement, two of the milestones, which amount to $2.0 million each, related to the preparation of an IND for submission to regulatory authorities in the territory were considered substantive given that they are triggered by the Company’s performance relative to the achievement of pre-specified, “at risk” milestone events, including the submission of all completed trials clinical data packages and the validation of the manufacturing process. On September 1, 2017, the Company entered into a new services agreement with JT Torii to provide research and development services, including regulatory, chemistry and manufacturing support and related materials that is distinct from the original Collaboration Agreement. The Company evaluated the new services agreement and determined that the research and materials delivered to JT Torii represented another contract that provides distinct goods and services to JT Torii. The fees received under the services agreement were recognized as and when such services were performed by the Company and JT Torii consumed the benefits of those services. During the three months ended March 31, 2019 and 2018, the Company recognized revenue of zero and $0.5 million, respectively, in the condensed statements of operations and comprehensive loss related to the services and collaboration agreement. The services agreement terminated upon the termination of the Collaboration Agreement.

License Agreements

3 Months Ended

Mar. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

5.License Agreements

Merck License

In December 2012, the Company entered into an exclusive worldwide royalty free license agreement with Merck Sharp & Dohme Corp. (“Merck”) for exclusive worldwide rights for the development and commercialization of serlopitant and two other NK₁‑receptor antagonists in all human diseases, disorders or conditions, except for the treatment and prevention of nausea or vomiting. The Company paid Merck an upfront non‑refundable non‑creditable licensing fee of $1.0 million dollars and issued to Merck shares of its common stock. In addition, the Company agreed to make aggregate payments of up to $25.0 million dollars upon the achievement of specified development and regulatory milestones.

In May 2018, the Company paid a $3.0 million milestone payment associated with the initiation of the Company’s Phase 3 clinical program for pruritus associated with prurigo nodularis. Future milestone payments are considered a form of variable consideration and accrued for when the Company determines that it is probable that there will not be a significant reversal of the accrual in future periods.

JT Torii Collaboration Agreement

In August 2016, the Company entered into a license and collaboration agreement (the “Collaboration Agreement”) with Japan Tobacco Inc. and Torii Pharmaceutical Co. Ltd. (together referred to as “JT Torii”). Under the Collaboration Agreement, the Company granted to JT Torii the rights to develop and commercialize products containing serlopitant in Japan, for the treatment of diseases and conditions other than nausea or vomiting. In exchange, JT Torii paid the Company an upfront, non‑refundable payment of $11.0 million. In addition, the Company was entitled to receive aggregate payments of up to $28.0 million upon the achievement of specified development and regulatory milestones, and $15.0 million upon the achievement of a commercial milestone, as well as tiered royalties from the mid-single digits up to the mid‑teens on sales of licensed products in Japan. The Company’s performance obligations under the license agreement included the transfer of intellectual property rights in the form of licenses, obligations to participate on certain development and/or commercialization committees with the collaboration partners and supply manufactured drug product for clinical trials.

In the second quarter of 2018, JT Torii informed the Company that they decided to halt the Japanese Phase 2 clinical trial of serlopitant, following which the Company and JT Torii agreed to terminate the Collaboration Agreement. As a result, the Company has reacquired full ownership of the development and commercialization rights to serlopitant in Japan and accelerated recognition of the remaining deferred revenue of $8.1 million during the quarter. In the second quarter of 2018, the Company also earned and recognized a $2.0 million milestone payment related to JT Torii’s receipt of investigational new drug application (“IND”) enabling past clinical study reports delivered by the Company under the Collaboration Agreement.

Under the Collaboration Agreement, the Company was reimbursed by JT Torii for the non-commercial supplies of serlopitant at the same rate it was charged by the third-party manufacturer for such supplies, which price did not include a significant or incremental discount for JT Torii. The assessment of performance obligations required judgment in order to determine the allocation of revenue to each deliverable and the appropriate period of time over which the revenue should be recognized.

Under the Collaboration Agreement, the Company determined that the license was not distinct from the research and development services because JT Torii could not use the license with its available resources to obtain any economic value without the Company’s participation. The license and the services were combined as one unit of accounting and upfront payments were recorded initially as deferred revenue in the balance sheet. Revenue was then recognized over an estimated performance period as performance of services was being completed. The Company recognized the upfront fee based on performance of the obligation using input method over the period of performance, which represented the estimated development period in the territories based on the initial development plan managed by the joint steering committee. The original term of the agreement was through the expiration of the patents associated with serlopitant.

Under the Collaboration Agreement, two of the milestones, which amount to $2.0 million each, related to the preparation of an IND for submission to regulatory authorities in the territory were considered substantive given that they are triggered by the Company’s performance relative to the achievement of pre-specified, “at risk” milestone events, including the submission of all completed trials clinical data packages and the validation of the manufacturing process.

On September 1, 2017, the Company entered into a new services agreement with JT Torii to provide research and development services, including regulatory, chemistry and manufacturing support and related materials that is distinct from the original Collaboration Agreement. The Company evaluated the new services agreement and determined that the research and materials delivered to JT Torii represented another contract that provides distinct goods and services to JT Torii. The fees received under the services agreement were recognized as and when such services were performed by the Company and JT Torii consumed the benefits of those services. During the three months ended March 31, 2019 and 2018, the Company recognized revenue of zero and $0.5 million, respectively, in the condensed statements of operations and comprehensive loss related to the services and collaboration agreement. The services agreement terminated upon the termination of the Collaboration Agreement.