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Stock-Based Compensation - Options, Assumptions Under Black-Scholes (Details) - Board members
3 Months Ended
Mar. 31, 2021
$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected term 3 years 6 months
Expected volatility 81.10%
Risk-free interest rate 0.19%
Market value of common stock (in dollars per share) $ 12.86
Annual dividend yield 0.00%
Forfeiture rate 0.00%