Income Taxes - Changes in Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance of unrecognized tax benefits	$ 1,853	$ 1,092	$ 569
(Decrease) increase for prior year tax positions	(250)	(73)	137
Increase for current year tax positions	695	834	386
Total	$ 2,298	$ 1,853	$ 1,092