REVENUE RECOGNITION - Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Number of reportable segment | segment									1
Disaggregation of revenue	$ 87,925	$ 96,633	$ 92,630	$ 93,896	$ 73,962	$ 80,092	$ 79,981	$ 76,576	$ 371,084	$ 310,611	$ 252,012
United States
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue									244,347	184,507
Europe
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue									124,914	123,771
Other
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue									1,823	2,333
Vehicle
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue									126,811	121,864
Industrial
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue									124,196	101,332
Medical
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue									51,586	43,239
Aerospace & Defense
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue									47,748	35,927
Other
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue									$ 20,743	$ 8,249