Property, Plant and Equipment - Summary of property, plant and equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 32,530	$ 32,473
Less accumulated depreciation and amortization	(22,181)	(21,916)
Total property, plant and equipment	10,349	10,557
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	7	7
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	11,363	11,363
Machinery, equipment and tooling
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	20,631	20,689
Construction in progress (CIP)
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 529	$ 414