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Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions (Details)
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Risk-free interest rate range, lower range 0.22% 0.48%
Risk-free interest rate range, upper range 0.73% 1.65%
Expected stock price volatility, minimum 107.00% 110.80%
Expected stock price volatility, maximum 125.00% 128.00%
Expected dividend yield
Minimum [Member]    
Expected life of option-years 5 years 3 months 18 days 5 years 2 months 12 days
Maximum [Member]    
Expected life of option-years 6 years 6 months 5 years 9 months 7 days