Goodwill and Intangible Assets - Intangible Assets Activity Summary (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortized intangible assets	$ 14,985	$ 14,132
Accumulated amortization, amortized intangible assets	(7,781)	(6,748)
Net carrying amount, amortized intangible assets	7,204	7,384
Intangible assets, gross carrying value	17,389	16,781
Net	9,608	10,033	$ 23,258
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	1,396	1,641
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortized intangible assets	1,414	1,009
Accumulated amortization, amortized intangible assets	(1,066)	(1,009)
Net carrying amount, amortized intangible assets	348	0
Patents and know how
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortized intangible assets	9,180	8,732
Accumulated amortization, amortized intangible assets	(4,475)	(3,840)
Net carrying amount, amortized intangible assets	4,705	4,892
Customer and supplier relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortized intangible assets	4,271	4,271
Accumulated amortization, amortized intangible assets	(2,202)	(1,891)
Net carrying amount, amortized intangible assets	2,069	2,380
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortized intangible assets	120	120
Accumulated amortization, amortized intangible assets	(38)	(8)
Net carrying amount, amortized intangible assets	$ 82	$ 112