General form of registration statement for all companies including face-amount certificate companies

Stock-Based Compensation - Schedule of Share-based Payment Award, Stock Options, Valuation Assumption (Details)

v3.21.2
Stock-Based Compensation - Schedule of Share-based Payment Award, Stock Options, Valuation Assumption (Details) - $ / shares
9 Months Ended 12 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Dec. 31, 2019
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]      
Fair value per common share $ 0.0121    
Weighted-average grant date fair value     $ 0.99
Weighted-average risk-free interest rate 0.83% 0.81% 2.10%
Volatility 65.00% 65.00% 65.00%
Expected term (in years) 2 days 12 hours 2 years 6 months 4 years
Dividend rate 0.00% 0.00% 0.00%