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Warrants (Details) - Stock options [Member] - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Warrants [Line Items]      
Market price per share (USD/share) $ 0.39 $ 1.13 $ 1.73
Exercise price (USD/share) $ 2.20 $ 2.20 $ 2.20
Risk free rate 1.81% 2.60% 2.36%
Dividend yield 0.00% 0.00% 0.00%
Expected term/Contractual life (years) 6 years 3 months 19 days 7 years 3 months 19 days 8 years 3 months 19 days
Expected volatility 279.93% 256.20% 241.20%