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Stock Compensation (Schedule of Share Based Compensation Arrangement By Share Based Payment Award Grants in Period Fair Value Assumptions) (Details) - Stock Options [Member]
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Volatility, minimum 61.90% 87.00%
Volatility, maximum 87.10% 87.20%
Expected term (in years) 6 years 6 years
Risk-free interest rate, minimum 0.90% 2.50%
Risk-free interest rate, maximum 1.70% 2.90%