Property, Plant and Equipment, Net - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Land	$ 260	$ 260
Building and improvements	8,189	5,015
Office furniture and equipment	4,675	3,705
Tooling and equipment	21,381	13,736
Transportation equipment	560	525
Construction in progress	3,011	6,056
Property, plant and equipment, at cost	38,076	29,297
Accumulated depreciation	(12,075)	(8,405)
Property, plant and equipment, net	$ 26,001	$ 20,892