Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Depreciation [Abstract]
Depreciation expense	$ 1.5	$ 1.5	$ 1.4
Book value of property and equipment under debt agreement	$ 5.5	$ 7.1