Property and Equipment - Depreciation and Amortization on Property and Equipment Using the Straight-Line Method (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Office furniture and fixtures	$ 1,052	$ 1,068
Software	1,957	1,748
Equipment	3,990	3,416
Leasehold improvements	1,589	1,276
Gross property and equipment	8,588	7,508
Less accumulated depreciation and amortization	(5,145)	(4,498)
Property and equipment, net	$ 3,443	$ 3,010