REVENUE - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Unearned revenue associated with outstanding contracts	$ 536	$ 515
Estimated revenue to be recognized in 2021	136
Estimated revenue to be recognized after 2021	$ 400
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, period