REVENUE Revenue by Type (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Number of reportable segments			1
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 101,640	$ 90,431	$ 290,880	$ 256,165
Products and solutions net revenues
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	36,850		107,295
Subscription services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	28,008	17,907	74,384	48,292
Maintenance
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	30,702	30,826	90,997	93,190
Professional services, training and other services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 6,080	$ 5,923	$ 18,204	$ 16,562