Purdue Collaboration	3 Months Ended
Mar. 31, 2018
Research and Development [Abstract]
Purdue Collaboration	Purdue Collaboration On December 2, 2016, the Company entered into a research collaboration, option and license agreement with Purdue Pharma, L.P. (“Purdue”) and referred to herein as the “Purdue Collaboration.” Purdue has the option to obtain from us the full worldwide development and commercial rights to AST-005 (the Company’s lead therapeutic candidate that targets tumor necrosis factor), an option to obtain three additional collaboration targets and a further option to obtain from us the full worldwide development and commercial rights to any therapeutic candidates developed targeting the three additional collaboration targets. Additionally, Purdue has rights of first offer to some potential collaboration targets. These rights of first offer are subject to limitations in time and scope. In connection with the Purdue Collaboration, the Company received a non-refundable development fee of $10,000. In addition, the Company is eligible to receive up to $776,500 upon successful completion of certain research, regulatory and commercial sales milestones. The research milestones are payable upon target identification and IND-enabling pre-clinical development, per program, with an aggregate total of up to $16,500. The regulatory milestones are payable upon the initiation or completion of clinical trials, and regulatory approval in the United States and outside the United States, per program, with an aggregate total of up to $410,000. The commercial sales milestones are payable upon achievement of specified aggregate product sales thresholds and total up to $350,000. In the event a therapeutic candidate subject to the collaboration results in commercial sales, the Company is eligible to receive royalties ranging from the low single digits to a maximum of 10% on future net sales of such commercialized therapeutic candidates. Additionally, Purdue had an obligation to invest in a qualified equity financing of the Company if such financing was completed before June 2, 2017. The Company did not complete such qualified equity financing before June 2, 2017. See Note 13, Subsequent Events, for recent developments related to the Purdue Collaboration. Prior to the adoption of ASC 606, the upfront payment of $10,000 was accounted for pursuant to ASC 605 and was recorded as deferred revenue and recognized on a ratable basis over the estimated performance period of the relevant research and development activities. On January 1, 2018, in connection with the adoption of ASC 606, the Company recorded the unamortized deferred revenue of $1,034 as an adjustment to the beginning balance of retained deficit at January 1, 2018. See Note 2, Significant Accounting Policies, for more information related to the adoption of ASC 606. The Company identified multiple performance obligations as part of the Purdue Collaboration agreement, including the upfront payment of $10,000, discussed above, and the research and development services. The Company determined that the performance obligations should not be combined, the license should be recognized at the time the license is granted and the research and development services at the time the service is performed. The Purdue Collaboration agreement includes contingent promises related to specified research, development and regulatory milestones and sale-based milestones. Each contingent promise related to contingent and milestone payment is evaluated to determine whether it represents a material right. The Company recognizes any payment that is contingent upon the achievement of a substantive milestone entirely in the period in which it is determined that the revenue is not subject to a significant reversal. To date, the Company has not recognized any contingent payments in connection with the Purdue Collaboration agreement as revenue. During the three months ended March 31, 2018, the Company recognized collaboration revenue of $36, which consisted entirely of research and development activities that will be reimbursed by Purdue and is presented on a gross basis in the accompanying statement of operations. During the three months ended March 31, 2017, the Company recognized collaboration revenue of $2,432, which included $363 of research and development activities that was reimbursed by Purdue and is presented on a gross basis in the accompanying statement of operations.

Purdue Collaboration

On December 2, 2016, the Company entered into a research collaboration, option and license agreement with Purdue Pharma, L.P. (“Purdue”) and referred to herein as the “Purdue Collaboration.” Purdue has the option to obtain from us the full worldwide development and commercial rights to AST-005 (the Company’s lead therapeutic candidate that targets tumor necrosis factor), an option to obtain three additional collaboration targets and a further option to obtain from us the full worldwide development and commercial rights to any therapeutic candidates developed targeting the three additional collaboration targets. Additionally, Purdue has rights of first offer to some potential collaboration targets. These rights of first offer are subject to limitations in time and scope. In connection with the Purdue Collaboration, the Company received a non-refundable development fee of $10,000. In addition, the Company is eligible to receive up to $776,500 upon successful completion of certain research, regulatory and commercial sales milestones. The research milestones are payable upon target identification and IND-enabling pre-clinical development, per program, with an aggregate total of up to $16,500. The regulatory milestones are payable upon the initiation or completion of clinical trials, and regulatory approval in the United States and outside the United States, per program, with an aggregate total of up to $410,000. The commercial sales milestones are payable upon achievement of specified aggregate product sales thresholds and total up to $350,000. In the event a therapeutic candidate subject to the collaboration results in commercial sales, the Company is eligible to receive royalties ranging from the low single digits to a maximum of 10% on future net sales of such commercialized therapeutic candidates. Additionally, Purdue had an obligation to invest in a qualified equity financing of the Company if such financing was completed before June 2, 2017. The Company did not complete such qualified equity financing before June 2, 2017.

See Note 13, Subsequent Events, for recent developments related to the Purdue Collaboration.

Prior to the adoption of ASC 606, the upfront payment of $10,000 was accounted for pursuant to ASC 605 and was recorded as deferred revenue and recognized on a ratable basis over the estimated performance period of the relevant research and development activities. On January 1, 2018, in connection with the adoption of ASC 606, the Company recorded the unamortized deferred revenue of $1,034 as an adjustment to the beginning balance of retained deficit at January 1, 2018. See Note 2, Significant Accounting Policies, for more information related to the adoption of ASC 606.

The Company identified multiple performance obligations as part of the Purdue Collaboration agreement, including the upfront payment of $10,000, discussed above, and the research and development services. The Company determined that the performance obligations should not be combined, the license should be recognized at the time the license is granted and the research and development services at the time the service is performed. The Purdue Collaboration agreement includes contingent promises related to specified research, development and regulatory milestones and sale-based milestones. Each contingent promise related to contingent and milestone payment is evaluated to determine whether it represents a material right. The Company recognizes any payment that is contingent upon the achievement of a substantive milestone entirely in the period in which it is determined that the revenue is not subject to a significant reversal. To date, the Company has not recognized any contingent payments in connection with the Purdue Collaboration agreement as revenue.

During the three months ended March 31, 2018, the Company recognized collaboration revenue of $36, which consisted entirely of research and development activities that will be reimbursed by Purdue and is presented on a gross basis in the accompanying statement of operations. During the three months ended March 31, 2017, the Company recognized collaboration revenue of $2,432, which included $363 of research and development activities that was reimbursed by Purdue and is presented on a gross basis in the accompanying statement of operations.