Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Fair value of stock-based compensation (Details)

v3.21.2
Stock-Based Compensation - Fair value of stock-based compensation (Details) - $ / shares
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share Price $ 0.17 $ 0.37
Expected volatility , minimum 57.09% 49.15%
Expected volatility , maximum 57.81% 52.41%
Risk-free interest rate , mininum 0.50% 0.37%
Risk-free interest rate , maximum 0.57% 1.46%
Dividend yield 0.00% 0.00%
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected term (in years) 6 years 18 days 6 years 14 days
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected term (in years) 5 years 6 months 18 days 5 years