Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation and Employee Benefit Plans - ESPP (Details)

v3.20.4
Stock-Based Compensation and Employee Benefit Plans - ESPP (Details) - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
ESPP [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock Issued During Period, Shares, Employee Stock Purchase Plans 285,633    
Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased $ 13.29    
Employee Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Dividend yield 0.00% 0.00% 0.00%
Expected life (in years) 6 months 6 months 6 months
Minimum [Member] | Employee Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted-average grant date fair value per share $ 6.41 $ 5.48 $ 5.01
Risk-free interest rate 0.12% 1.59% 2.09%
Volatility 59.72% 40.47% 38.82%
Maximum [Member] | Employee Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted-average grant date fair value per share $ 8.66 $ 6.61 $ 5.37
Risk-free interest rate 0.15% 2.43% 2.51%
Volatility 93.25% 43.14% 46.17%