Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	$ 79,515	$ 93,617
United States
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	33,091	35,848
EMEA
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	23,690	31,100
Other APAC
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	15,487	15,042
China
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	4,748	8,295
Other Americas
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	2,499	3,332
Product sales
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	56,525	71,578
Product sales | Product transferred to customers at a point in time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	53,554	68,975
Product sales | Product transferred to customers over time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	2,971	2,603
Service sales
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	22,990	22,039
Service sales | Product transferred to customers at a point in time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	10,996	11,680
Service sales | Product transferred to customers over time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	$ 11,994	$ 10,359