Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	$ 14,262	$ 14,985
Accumulated amortization	(8,215)	(7,781)
Net carrying amount	6,047	7,204
Intangible assets, gross carrying value	16,319	17,389
Net	8,104	9,608
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Gross carrying value, indefinite lived	1,008	1,008
Patents in process
Finite-Lived Intangible Assets [Line Items]
Gross carrying value, indefinite lived	1,049	1,396
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	1,414	1,414
Accumulated amortization	(1,133)	(1,066)
Net carrying amount	281	348
Patents and know-how
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	8,967	9,180
Accumulated amortization	(4,746)	(4,475)
Net carrying amount	4,221	4,705
Customer and supplier relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	3,761	4,271
Accumulated amortization	(2,283)	(2,202)
Net carrying amount	1,478	2,069
Non compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying value	120	120
Accumulated amortization	(53)	(38)
Net carrying amount	$ 67	$ 82