Prepaid Expenses - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 1,971	$ 287
Prepaid insurance	294	92
Prepaid R&D clinical costs	1,627	177
Other prepaid costs	$ 50	$ 18