XML 247 R227.htm IDEA: XBRL DOCUMENT v3.21.1
STOCK-BASED COMPENSATION - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options granted, weighted-average grant date fair value (in dollars per share) $ 2.24   $ 0.82 $ 0.34  
Options granted (in shares) 18,335 0 10,932,615    
Options exercised, intrinsic value $ 30.2 $ 0.1 $ 1.1 $ 0.1  
Remaining unrecognized stock-based compensation expense $ 3.5   $ 8.0    
Weighted average period for recognition of stock-based compensation expense 2 years 2 months 12 days   3 years 2 months 12 days    
2009 Stock Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares reserved for issuance (in shares)     55,305,506   55,305,506
Exercise price as a percentage of fair value     100.00%    
Significant shareholder threshold used for determining exercise price         10.00%
Exercise period 10 years   10 years    
2009 Stock Plan | Minimum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Exercise price as a percentage of fair value         100.00%
Exercise price as a percentage of fair value for shareholders owning specified minimum amount         110.00%
2009 Stock Plan | Share-based Payment Arrangement, Tranche One          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period         1 year
Vesting percentage         25.00%
2009 Stock Plan | Share-based Payment Arrangement, Tranche Two          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period         3 years
Vesting percentage         2.083%