XML 17 R21.htm IDEA: XBRL DOCUMENT v3.19.3
Stockholders' Equity - Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions (Details)
9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Dividend yield 0.00% 0.00%
Risk-free interest rate, minimum 1.42% 2.68%
Risk-free interest rate, maximum 2.53% 3.05%
Expected volatility, minimum 105.20% 111.40%
Expected volatility, maximum 106.10% 137.30%
Expected life (in years) 5 years  
Minimum [Member]    
Expected life (in years)   5 years
Maximum [Member]    
Expected life (in years)   10 years