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Stock-Based Compensation - Assumptions Used to Estimate Fair Value of Stock Options (Details)
9 Months Ended
Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Risk-free interest rate, minimum 0.30%
Risk-free interest rate, maximum 1.70%
Volatility, minimum 69.80%
Volatility, maximum 82.30%
Dividend yield 0.00%
Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected life (years) 5 years 3 months 18 days
Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected life (years) 6 years 3 months 18 days