Accrued and Other Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Commercial related	$ 2,663	$ 1,694
Legal and accounting fees	329	256
Deferred rent	899	879
Product revenue provision	53
Other	1,697	723
Total accrued liabilities	$ 5,641	$ 3,552