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Stockholders' Equity - Summary of Fair Value of Stock Option Grants (Details)
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Risk-free interest rate, minimum 0.60% 0.40%
Risk-free interest rate. maximum 1.10% 0.70%
Expected volatility, minimum 86.20% 82.40%
Expected volatility, maximum 89.50% 94.80%
Expected dividend yield 0.00% 0.00%
Minimum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Expected term (in years) 5 years 6 months 5 years 9 months 18 days
Maximum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Expected term (in years) 6 years 25 days 10 years