Income Taxes - Changes in Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, Beginning Balance	$ 1,410	$ 1,093
Decrease in prior year unrecognized tax benefits	(447)
Increase in prior year unrecognized tax benefits		195
Increase in current year unrecognized tax benefits	109	122
Unrecognized tax benefits, Ending Balance	$ 1,072	$ 1,410