INCOME TAXES - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 114	$ (4)	$ (1,192)
State	930	752	739
Foreign	3,099	2,224	1,987
Total current provision for income taxes	4,143	2,972	1,534
Deferred:
Federal	(777)	(404)	(1,169)
State	(399)	35	57
Foreign	(200)	(277)	(273)
Total deferred provision for income taxes	(1,376)	(646)	(1,385)
Total provision for income taxes	$ 2,767	$ 2,326	$ 149