Prepaid Expenses - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 3,398	$ 1,729
Prepaid insurance	460	98
Prepaid R&D clinical costs	2,874	1,500
Other prepaid costs	$ 64	35
Prepaid rent		$ 96