REVENUE Revenue by Type (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Revenue from Contract with Customer [Abstract]
Number of reportable segments			1
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 90,431	$ 93,461	$ 256,165	$ 295,481
Products and solutions net revenues
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	35,775		98,121
Subscription services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	17,907	10,297	48,292	29,339
Support services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	30,826	33,361	93,190	97,018
Professional services, training and other services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 5,923	$ 6,892	$ 16,562	$ 21,491