Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Research and Development	$ 1,140	$ 1,606
Payroll and other employee-related expenses	1,495	3,393
Professional services fees	2,146	926
Other	877	159
Interest expense	157	161
Total accrued expenses and other current liabilities	$ 5,815	$ 6,245