License Agreements	3 Months Ended
Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License Agreements	License Agreements Merck License In December 2012, the Company entered into an exclusive worldwide royalty free license agreement with Merck Sharp & Dohme Corp., or “Merck” for exclusive worldwide rights for the development and commercialization of serlopitant and two other NK₁‑R 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 has agreed to make aggregate payments of up to $25.0 million dollars upon the achievement of specified development and regulatory milestones. 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. Through March 31, 2018, no milestones have been achieved under the license agreement with Merck. JT Torii Collaboration Agreement On August 10, 2016, the Company entered into a license and collaboration agreement with Japan Tobacco Inc. and Torii Pharmaceutical Co. Ltd., together referred to as “JT Torii”, which is referred to as the “Collaboration Agreement”. 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 is 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 include 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. The Company is reimbursed by JT Torii for the non-commercial supplies of serlopitant at the same rate it is charged by the third-party manufacturer for such supplies, which price does not include a significant or incremental discount for JT Torii. The assessment of performance obligations also requires 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 has determined that the license is not distinct from the research and development services because JT Torii cannot use the license with its available resources to obtain any economic value without the Company’s participation. The license and the services are combined as one unit of accounting and upfront payments are recorded initially as deferred revenue in the balance sheet. Revenue is then recognized over an estimated performance period as performance of services is being completed. The Company is recognizing the upfront fee based on performance of the obligation using input method over the period of performance of six years, which represents the estimated development period in the territories based on the initial development plan managed by the joint steering committee. The term of the agreement is through the expiration of the patents associated with serlopitant. The Company periodically reviews its estimated periods of performance based on the progress under each arrangement and accounts for the impact of any changes in estimated periods of performance on a prospective basis. Under the Collaboration Agreement, the Company is 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. Two of the milestones, which amount to $2.0 million each, relate to the preparation of an investigational new drug application (“IND”) for submission to regulatory authorities in the territory are 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. All other milestones, which amount to an aggregate of $24.0 million, are included in the transaction price when the Company determines that it is probable that there will not be a significant reversal of cumulative revenue recognized in future periods. 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 represents another contract that provides distinct goods and services to JT Torii. The fees received under the services agreement will be recognized as and when such services are performed by the Company and JT Torii consumes the benefits of those services. The Company has no obligation to provide services unless requested by JT Torii and agreed to by the Company. The Company is eligible to receive reimbursement of estimated costs incurred and payment for research services performed directly by the Company at agreed upon rates. During the quarter ended March 31, 2018, the Company recognized revenue of $48,000 in the statement of operations related to the services agreement. The services agreement terminates upon the termination of the Collaboration Agreement or by mutual agreement of the parties. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, current portion. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Expenses related to the collaboration agreement are recorded as a component of research and development in the statement of operations as incurred, and to date have been immaterial. In April 2018, JT Torii informed the Company that they have decided to halt the recently initiated Japanese Phase 2 clinical trial of serlopitant. JT Torii has indicated that they are reevaluating their serlopitant development program based upon evolving commercial considerations in Japan. Based upon communication with JT Torii, the Company expects that the Collaboration Agreement for serlopitant will ultimately be terminated. If the Collaboration Agreement is terminated, the Company will accelerate recognition of deferred revenue under the agreement. In the second quarter of 2018, the Company expects to earn and recognize a $2.0 million milestone payment related to JT Torii’s receipt of IND-enabling past clinical study reports delivered by the Company under the agreement.

License Agreements

Merck License

In December 2012, the Company entered into an exclusive worldwide royalty free license agreement with Merck Sharp & Dohme Corp., or “Merck” for exclusive worldwide rights for the development and commercialization of serlopitant and two other NK₁‑R 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 has agreed to make aggregate payments of up to $25.0 million dollars upon the achievement of specified development and regulatory milestones.

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. Through March 31, 2018, no milestones have been achieved under the license agreement with Merck.

JT Torii Collaboration Agreement

On August 10, 2016, the Company entered into a license and collaboration agreement with Japan Tobacco Inc. and Torii Pharmaceutical Co. Ltd., together referred to as “JT Torii”, which is referred to as the “Collaboration Agreement”. 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 is 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 include 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.

The Company is reimbursed by JT Torii for the non-commercial supplies of serlopitant at the same rate it is charged by the third-party manufacturer for such supplies, which price does not include a significant or incremental discount for JT Torii. The assessment of performance obligations also requires 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 has determined that the license is not distinct from the research and development services because JT Torii cannot use the license with its available resources to obtain any economic value without the Company’s participation. The license and the services are combined as one unit of accounting and upfront payments are recorded initially as deferred revenue in the balance sheet. Revenue is then recognized over an estimated performance period as performance of services is being completed. The Company is recognizing the upfront fee based on performance of the obligation using input method over the period of performance of six years, which represents the estimated development period in the territories based on the initial development plan managed by the joint steering committee. The term of the agreement is through the expiration of the patents associated with serlopitant. The Company periodically reviews its estimated periods of performance based on the progress under each arrangement and accounts for the impact of any changes in estimated periods of performance on a prospective basis.

Under the Collaboration Agreement, the Company is 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. Two of the milestones, which amount to $2.0 million each, relate to the preparation of an investigational new drug application (“IND”) for submission to regulatory authorities in the territory are 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. All other milestones, which amount to an aggregate of $24.0 million, are included in the transaction price when the Company determines that it is probable that there will not be a significant reversal of cumulative revenue recognized in future periods.

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 represents another contract that provides distinct goods and services to JT Torii. The fees received under the services agreement will be recognized as and when such services are performed by the Company and JT Torii consumes the benefits of those services. The Company has no obligation to provide services unless requested by JT Torii and agreed to by the Company. The Company is eligible to receive reimbursement of estimated costs incurred and payment for research services performed directly by the Company at agreed upon rates. During the quarter ended March 31, 2018, the Company recognized revenue of $48,000 in the statement of operations related to the services agreement. The services agreement terminates upon the termination of the Collaboration Agreement or by mutual agreement of the parties.

Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, current portion. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Expenses related to the collaboration agreement are recorded as a component of research and development in the statement of operations as incurred, and to date have been immaterial.

In April 2018, JT Torii informed the Company that they have decided to halt the recently initiated Japanese Phase 2 clinical trial of serlopitant. JT Torii has indicated that they are reevaluating their serlopitant development program based upon evolving commercial considerations in Japan. Based upon communication with JT Torii, the Company expects that the Collaboration Agreement for serlopitant will ultimately be terminated. If the Collaboration Agreement is terminated, the Company will accelerate recognition of deferred revenue under the agreement. In the second quarter of 2018, the Company expects to earn and recognize a $2.0 million milestone payment related to JT Torii’s receipt of IND-enabling past clinical study reports delivered by the Company under the agreement.