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Warrants (Details) - Warrant [Member]
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Summary of assumptions used to estimate fair value of stock warrants granted    
Expected dividend yield 0.00% 0.00%
Expected volatility 91.00% 80.00%
Risk-free interest rate 2.93% 2.62%
Expected life of warrants 4 years  
Minimum [Member]    
Summary of assumptions used to estimate fair value of stock warrants granted    
Expected life of warrants   4 years
Maximum [Member]    
Summary of assumptions used to estimate fair value of stock warrants granted    
Expected life of warrants   5 years