Income Taxes - The Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ 2,451	$ 4,409	$ 3,218
State	292	393	333
Foreign	886	710	499
Current, Total	3,629	5,512	4,050
Deferred:
Federal	(268)	197	(12)
State	390	166	(466)
Foreign	178	(223)	94
Deferred, Total	300	140	(384)
Provision for income taxes	$ 3,929	$ 5,652	$ 3,666