Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	$ 60,564	$ 93,491	$ 140,079	$ 187,108
United States
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	24,445	35,161	57,536	71,009
EMEA
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	16,720	30,030	40,410	61,130
Other APAC
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	10,582	15,387	26,069	30,429
China
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	7,485	8,961	12,233	17,256
Other Americas
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	1,332	3,952	3,831	7,284
Product sales
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	42,259	71,045	98,784	142,622
Product sales | Product transferred to customers at a point in time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	39,209	68,202	92,764	137,176
Product sales | Product transferred to customers over time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	3,050	2,843	6,020	5,446
Service sales
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	18,305	22,446	41,295	44,486
Service sales | Product transferred to customers at a point in time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	6,649	11,609	17,644	23,290
Service sales | Product transferred to customers over time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales	$ 11,656	$ 10,837	$ 23,651	$ 21,196