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SHARE-BASED PAYMENTS - Schedule of Valuation Assumptions (Details) - Compensation Plan - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.27% 2.62% 2.84%
Expected life 4 years 7 months 6 days 5 years 5 years
Expected volatility 61.81% 59.38% 59.00%
Expected dividend yield 0.00% 0.00% 0.00%
Weighted average grant date fair value $ 0.82 $ 1.54 $ 0.96