REVENUE RECOGNITION - Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) segment	Sep. 30, 2017 USD ($)
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Number of reportable segment | segment			1
Disaggregation of revenue	$ 80,092	$ 64,968	$ 236,649	$ 186,657
United States
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue	49,375		140,031
Europe
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue	29,975		94,754
Asia
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue	742		1,864
Vehicle
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue	31,717		95,071
Industrial/Electronics
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue	24,668		76,633
Medical
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue	10,732		31,214
Aerospace & Defense
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue	10,332		26,701
Other
Reconciliation of disaggregated revenue to segment revenue as well as revenue by geographical regions
Disaggregation of revenue	$ 2,643		$ 7,030