REVENUE RECOGNITION AND RELATED ALLOWANCES - Timing (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Revenue recognition	$ 48,625	$ 48,470	$ 103,146	$ 98,244
Performance obligations satisfied in prior periods			10,300	(5,700)
Deferred revenue	62		62		$ 80
Revenue recognized	100	300	100	200
Performance obligations transferred at a point in time [Member]
Revenue recognition	48,528	47,585	102,891	96,782
Performance obligations transferred over time [Member]
Revenue recognition	$ 97	$ 885	$ 255	$ 1,462