Commitments and Contingencies - Summary of Rental Expense Charged to Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Leases, Rent Expense, Net [Abstract]
Rental expense	$ 3,167	$ 2,732	$ 2,304
Sublease rental income	(195)	(238)	(278)
Net rental expense	$ 2,972	$ 2,494	$ 2,026