Property, Plant and Equipment - Summary of property, plant and equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 25,355	$ 24,284
Less accumulated depreciation and amortization	(15,600)	(14,909)
Total property, plant and equipment	9,755	9,375
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	21	21
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	10,343	7,916
Less accumulated depreciation and amortization	(2,937)	(2,811)
Machinery, equipment and tooling
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	14,934	13,530
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 57	$ 2,817