Property and Equipment - Depreciation and Amortization on Property and Equipment Using the Straight-Line Method (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Office furniture and fixtures	$ 927	$ 845
Software	1,640	1,312
Equipment	3,275	3,072
Leasehold improvements	1,237	1,198
Gross property and equipment	7,079	6,427
Less accumulated depreciation and amortization	(4,227)	(3,451)
Property and equipment, net	$ 2,852	$ 2,976