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Stock-Based Compensation - Valuation (Details) - Employee Stock Option
3 Months Ended 9 Months Ended
Sep. 30, 2023
Sep. 30, 2022
Sep. 30, 2023
Sep. 30, 2022
Black-Scholes option with following assumptions:        
Expected stock price volatility (as a percent) 92.00% 91.00% 92.00%  
Expected stock price volatility, minimum (as a percent)       90.00%
Expected stock price volatility, maximum (as a percent)       97.00%
Expected option term 6 years 6 years 6 years 6 years
Risk-free interest rate (as a percent) 4.10%      
Risk-free interest rate, minimum (as a percent)   2.90% 3.50% 1.70%
Risk-free interest rate, maximum (as a percent)   3.50% 4.10% 3.60%
Expected dividend yield (as a percent) 0.00% 0.00% 0.00% 0.00%