v3.21.1
STOCKHOLDERS' EQUITY - RSU, PSU and SPSU activity (Details) - RSU, PSU and SPSU
3 Months Ended
Mar. 31, 2021
$ / shares
shares
Shares of RSU PSU and SPSU  
Balance at the beginning of the period (in shares) | shares 4,159,261
Granted (in shares) | shares 3,583,764
Forfeited (in shares) | shares (17,167)
Nonvested at the end of the period (in shares) | shares 7,725,858
Weighted Average Grant Date Fair Value  
Balance at the beginning of the period (in dollars per share) | $ / shares $ 6.27
Granted (in dollars per share) | $ / shares 7.70
Forfeited (in dollars per share) | $ / shares 5.22
Unvested at the end of the period (in dollars per share) | $ / shares $ 6.94