Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities, Current [Abstract]
Payroll and employee-related costs	$ 2,585	$ 773
Research costs	996	910
Licensing fees	492	1,055
Professional fees	2,715	2,412
Intellectual property costs	3,372	2,592
Accrued property and equipment	5,081
Other	1,079	688
Total	$ 16,320	$ 8,430