Intangible Assets - Activity Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 11,291	$ 11,285
Accumulated amortization	(7,549)	(7,334)
Net carrying amount	3,742	3,951
Indefinite-lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	13,467	13,338
Intangible assets, net carrying amount	5,918	6,004
Trade names and trademarks
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, indefinite lived	1,008	1,008
Patents in process
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value, indefinite lived	1,168	1,045
Patents and know how
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	9,516	9,510
Accumulated amortization	(5,899)	(5,730)
Net carrying amount	3,617	3,780
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,414	1,414
Accumulated amortization	(1,369)	(1,334)
Net carrying amount	45	80
Customer and supplier relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	241	241
Accumulated amortization	(176)	(172)
Net carrying amount	65	69
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	120	120
Accumulated amortization	(105)	(98)
Net carrying amount	$ 15	$ 22