Annual report pursuant to Section 13 and 15(d)

Stock and Employee Benefit Plans - Fair Value Assumptions (Details)

v3.21.1
Stock and Employee Benefit Plans - Fair Value Assumptions (Details)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk free interest rate, minimum (as a percent) 0.10%  
Risk free interest rate, maximum (as a percent) 0.18%  
Expected volatility, minimum (as a percent) 74.36%  
Expected volatility, maximum (as a percent) 120.89%  
Stock Options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk free interest rate, minimum (as a percent) 0.33% 1.41%
Risk free interest rate, maximum (as a percent) 1.53% 2.60%
Dividend yield (as a percent) 0.00% 0.00%
Expected volatility, minimum (as a percent) 70.00% 81.70%
Expected volatility, maximum (as a percent) 75.80% 81.80%
Stock Options | Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected term (in years) 5 years 5 years
Stock Options | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected term (in years) 5 years 8 months 23 days 5 years 8 months 23 days
Employee Stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk free interest rate (as a percent)   2.48%
Expected term (in years) 6 months 6 months
Dividend yield (as a percent) 0.00% 0.00%
Expected volatility (as a percent)   57.57%