Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Aug. 31, 2013	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Subsidiary, Sale of Stock [Line Items]
Deferred offering costs		$ 331,000		$ 417,000
Royalty payments received		0
Upfront payment received	$ 1,500,000
Deferred revenue recognition period	70 months
Revenue recognized from upfront payments		64,000	$ 65,000
Other receivable due from R-Pharm		648,000		$ 430,000
Sales Agreement Prospectus [Member]
Subsidiary, Sale of Stock [Line Items]
Deferred offering costs		$ 111,000