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Stock-Based Compensation - Schedule of Assumptions Used to Determine Fair Value of Options Granted (Details)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Risk-free interest rate, minimum 1.64%  
Risk-free interest rate, maximum 1.74%  
Risk-free interest rate   1.33%
Expected volatility, minimum 106.80%  
Expected volatility, maximum 112.50%  
Expected volatility   102.70%
Expected life (in years)   8 years 6 months
Expected dividend yield 0.00% 0.00%
Minimum [Member]    
Expected life (in years) 7 years 6 months  
Maximum [Member]    
Expected life (in years) 10 years