Property, Plant and Equipment, Net - Components of Property, Plant and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Property Plant And Equipment [Abstract]
Land	$ 260	$ 260
Building and improvements	4,125	3,882
Office furniture and equipment	2,723	2,172
Tooling and equipment	7,595	5,505
Transportation equipment	203	223
Construction in progress	4,844	594
Property, plant and equipment, at cost	19,750	12,636
Accumulated depreciation	(6,646)	(5,491)
Property, plant and equipment, net	$ 13,104	$ 7,145