Income Taxes - Summary Of Changes In Unrecognized Tax Positions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 300	$ 300
Increases related to prior year tax positions	2,308	0
Balance at end of year	$ 2,608	$ 300