Annual report pursuant to Section 13 and 15(d)

STOCK-BASED COMPENSATION (Details)

v3.21.1
STOCK-BASED COMPENSATION (Details) - 2015 Stock Option Plan [Member] - Time Based Shares Options [Member] - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dividend yield 0.00% 0.00%
Weighted-average volatility
Expected dividends
Expected term (in years) 10 years 10 years
Minimum [Member]    
Expected volatility 62.11% 56.10%
Risk-free rate 0.63% 1.60%
Maximum [Member]    
Expected volatility 62.18% 60.30%
Risk-free rate 0.64% 2.72%