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Stockholders' Equity (Schedule of Fair Value of Employee Stock Options) (Details) - Stock Options [Member]
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Expected term in years 5 years 1 month 6 days   5 years 1 month 6 days  
Expected volatility 71.00%  
Risk-free interest rate 0.30%  
Risk-free interest rate, minimum     0.30%  
Risk-free interest rate, maximum     1.20%  
Dividend yield
Minimum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Expected volatility     57.00%  
Maximum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Expected volatility     71.00%