Segment Reporting and Geographic Information - Segment (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) segment item	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Revenue reporting by end-market and geographic region
Number of operating segments | segment									1
Number of reportable segments | segment									1
Number of key markets | item									4
Net sales	$ 138,946	$ 112,078	$ 98,637	$ 104,502	$ 113,202	$ 108,954	$ 97,822	$ 99,371	$ 454,163	$ 419,349	$ 542,082
Semiconductor
Revenue reporting by end-market and geographic region
Net sales									165,909	175,608	137,797
Compound Semiconductor
Revenue reporting by end-market and geographic region
Net sales									107,922	85,877	260,323
Data Storage
Revenue reporting by end-market and geographic region
Net sales									123,288	84,075	69,141
Scientific & Other
Revenue reporting by end-market and geographic region
Net sales									$ 57,044	$ 73,789	$ 74,821