REVENUE RECOGNITION AND RELATED ALLOWANCES - Timing (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Revenue recognition	$ 54,521	$ 49,774
Performance obligations satisfied in prior periods	10,700	(2,400)
Deferred revenue	62		$ 80
Revenue recognized	100	100
Performance obligations transferred at a point in time [Member]
Revenue recognition	54,363	49,197
Performance obligations transferred over time [Member]
Revenue recognition	$ 158	$ 577