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Employee Stock Options (Details) - Employee Stock Option [Member]
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Summary of assumptions used to estimate fair value of stock options granted    
Expected dividend yield 0.00% 0.00%
Expected volatility 90.00%  
Risk-free interest rate   2.49%
Expected life of options 4 years  
Minimum [Member]    
Summary of assumptions used to estimate fair value of stock options granted    
Expected volatility   83.00%
Risk-free interest rate 2.40%  
Expected life of options   2 years 6 months
Maximum [Member]    
Summary of assumptions used to estimate fair value of stock options granted    
Expected volatility   86.00%
Risk-free interest rate 2.47%  
Expected life of options   3 years