Strategic Agreements - Summary of Collaborative Research and Development Revenue Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total collaborative research and development revenue	$ 1,880	$ 7,832	$ 8,256
Agreement with Zogenix, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Ratable recognition of upfront payment	208	255	255
Research and development expenses reimbursable by the Company	347	4,643	4,176
Total collaborative research and development revenue	555	4,898	4,431
Agreement with Impax Laboratories, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Ratable recognition of upfront payment	0	0	2,000
Research and development expenses reimbursable by the Company			106
Total collaborative research and development revenue			2,106
Agreement with Santen Pharmaceutical Co., Ltd. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Ratable recognition of upfront payment	228	274	15
Research and development expenses reimbursable by the Company	286	550	1
Total collaborative research and development revenue	$ 514	$ 824	$ 16