Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2015
Business Acquisition [Line Items]
Goodwill	$ 470	$ 471	$ 446
Amortization of intangibles	3,096	2,930	$ 2,833
Alveda Acquisition
Business Acquisition [Line Items]
Goodwill				$ 400
In-process research and development (IPR&D)
Business Acquisition [Line Items]
Intangible asset impairment	1,200
Change in intangible assets		(14,700)
Product Acquisition Costs
Business Acquisition [Line Items]
Amortization of intangibles	0
Intangible asset impairment	$ 700	100
Change in product acquisition costs		$ 14,700