Strategic Agreements - Agreement with Impax Laboratories, Inc. - Additional Information (Detail) - Agreement with Impax Laboratories, Inc. [Member] - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2014	Dec. 31, 2016	Jan. 03, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable upfront fee	$ 2,000,000
Future milestone payments			$ 61,000,000
Cumulative aggregate payments received by the Company		$ 2,100,000
Development-Based Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone payments			31,000,000
Sales-Based Milestones [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone payments			$ 30,000,000
Revenue recognition milestone achieved		$ 0