Income Taxes - Summary of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, Beginning balance	$ 775	$ 775	$ 775
Additions for tax positions related to prior years	0	0	0
Additions for tax positions	81	0	0
Reductions for tax positions of prior years	0	0	0
Settlements	0	0	0
Unrecognized tax benefits, Ending balance	$ 856	$ 775	$ 775