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Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions (Details)
6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Equity [Abstract]    
Dividend yield 0.00% 0.00%
Risk-free interest rate, minimum 0.19% 0.22%
Risk-free interest rate, maximum 0.32% 1.52%
Expected volatility, minimum 116.80% 113.80%
Expected volatility, maximum 123.80% 117.20%
Expected life (in years) 5 years 5 years