Annual report pursuant to Section 13 and 15(d)

SHARE-BASED COMPENSATION - Summary of Stock Options Pricing (Details)

v3.21.1
SHARE-BASED COMPENSATION - Summary of Stock Options Pricing (Details) - Stock Option
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Dividend yield 0.00% 0.00%
Expected volatility, minimum 70.98% 70.88%
Expected volatility, maximum 76.97% 72.11%
Risk free interest rate, minimum 0.27% 1.37%
Risk free interest rate, maximum 1.39% 2.51%
Expected life (years) 5 years 5 years