Annual report pursuant to Section 13 and 15(d)

Stock Options - Valuation Assumptions (Details)

v3.21.1
Stock Options - Valuation Assumptions (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life of option grants 5 years 7 years
Expected volatility of underlying stock 34.43%  
Dividends assumption $ 0 $ 0
Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate 0.33% 1.77%
Expected volatility of underlying stock   49.48%
Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate 0.35% 2.66%
Expected volatility of underlying stock   106.16%