Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation - Schedule of Share Based Payment Assumptions (Details)

v3.19.2
Stock-based Compensation - Schedule of Share Based Payment Assumptions (Details)
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Share-based Payment Arrangement [Abstract]        
Volatility 108.78%      
Volatility, minimum   105.85% 108.78% 105.85%
Volatility, maximum   108.46% 111.34% 108.46%
Risk-free interest rate 1.90%      
Risk-free interest rate, minimum   2.77% 1.90% 2.29%
Risk-free interest rate, maximum   2.89% 2.65% 2.89%
Dividend yield 0.00% 0.00% 0.00% 0.00%
Expected life 6 years 6 years 6 years 6 years