PRODUCT AND GEOGRAPHIC INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues	$ 104,301	$ 90,431	$ 79,281	$ 86,453	$ 116,306	$ 93,461	$ 98,701	$ 103,319	$ 360,466	$ 411,788	$ 413,282
United States [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									143,518	152,012	150,877
Other Americas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									24,026	32,783	27,494
Europe, Middle East and Africa [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									142,370	161,764	172,238
Asia-Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									50,552	65,229	62,673
Product [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									140,762	207,445	205,107
Video products and solutions net revenues [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									77,232	131,225	132,276
Audio products and solutions net revenues [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									63,530	76,220	72,831
Service [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									219,704	204,343	208,175
Subscription services
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									72,831	45,181	35,888
Support services
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									124,175	130,443	139,205
Professional Services, Training, And Other Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues									$ 22,698	$ 28,719	$ 33,082