REVENUE RECOGNITION - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Increase (decrease) in contract with customer, asset	$ (3,800)
Contract assets - current	11,623	$ 13,128
Contract assets - Long-term	4,596	$ 6,928
Capitalized contract costs	200
Fixed fee license revenue | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 14,400
Revenue, remaining performance obligation, period	3 years
Fixed fee license revenue | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 12,000
Revenue, remaining performance obligation, period
Fixed fee license revenue | Performance Obligation B | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 26,400
Revenue, remaining performance obligation, period