Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued employee related costs	$ 7,358	$ 6,520
Accrued development costs	7,359	1,706
Other accrued liabilities	4,317	3,282
Accrued Liabilities, Current	$ 19,034	$ 11,508