Income Taxes - Schedule of Unrecognized Tax Benefits Roll Forward (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 404	$ 99	$ 97
Additions based on tax positions related to prior year	19	46
Additions based on tax positions related to current year	1,408	259	2
Balance at end of year	$ 1,831	$ 404	$ 99