Strategic Agreements - Summary of Collaborative Research and Development and Other Revenues Associated with Company's Collaborators or Counterparties (Detail) - USD ($)		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue		$ 2,212,000	$ 1,595,000
Collaborative Research and Development and Other Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue		574,000	(30,000)
Agreement with Gilead [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue		0	(465,000)
Agreement with Gilead [Member] | Collaborative Research and Development and Other Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue	[1]		(268,000)
Agreements With Other Collaborators or Counterparties [Member] | Collaborative Research and Development and Other Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total collaborative research and development and other revenue	[2]	$ 574,000	$ 238,000

[1] Amounts related to recognition of a license upfront fee and milestone payment were zero and $(465,000) for the three months ended March 31, 2021 and 2020, respectively. The Company signed a license agreement with Gilead on July 19, 2019 and received a nonrefundable upfront license fee and a milestone payment totaling $35.0 million in 2019 which was being recognized as revenue as its obligation was being satisfied using the cost-to-cost input method. The Company recorded a net revenue reversal of $465,000 related to the upfront license fee and milestone payment in the three months ended March 31, 2020 due to a change in the Company’s estimated costs to complete its obligations under the license agreement, which was partially offset by $197,000 of reimbursable collaborative research and development services with Gilead earned during the quarter. In June 2020, the Company received notice that Gilead was terminating the License Agreement and a related R&D agreement between Gilead and the Company and as a result, the Company recognized all its remaining deferred revenue as there were no remaining substantive performance obligations to be provided to Gilead by the Company as of the date when the termination notice was received.

[2] Includes: (a) amounts related to earn-out revenue from Indivior UK Limited (Indivior) with respect to PERSERIS net sales; (b) feasibility programs; (c) research and development activities funded by Santen Pharmaceutical Co. Ltd. (Santen); and (d) royalty revenue from OP Pharma with respect to Methydur net sales. Note that in January 2018, the Company was notified by Santen that due to a shift in priorities, Santen had elected to reallocate research and development resources and put the Company’s program on pause until further notice. While the main program is on pause, the parties are working together on a limited set of research and development activities funded by Santen.