Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation - Valuation Assumptions (Details)

v3.19.3
Stock-based Compensation - Valuation Assumptions (Details) - shares
shares in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Dividend yield   0.00% 0.00% 0.00%
Risk-free interest rate     2.12%  
Expected term (in years)     6 years  
Volatility   106.00% 102.00% 104.00%
Minimum        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Risk-free interest rate   2.75%   2.70%
Expected term (in years)   5 years   5 years
Maximum        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Risk-free interest rate   2.99%   2.99%
Expected term (in years)   6 years   10 years
2014 Plan        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Options granted (in shares) 0   674