Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Schedule of Fair Values of Stock Options Granted Using Black-scholes Valuation Model Assumptions (Details)

v3.19.2
Stock-Based Compensation - Schedule of Fair Values of Stock Options Granted Using Black-scholes Valuation Model Assumptions (Details)
6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
2014 Long Term Incentive Equity Plan [Member] | Non Employee Stock Option [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate 2.30% 2.60%
Expected term of stock options (in years) 8 years 8 months 12 days 9 years
Expected stock price volatility 60.00% 60.00%
Expected dividend yield 0.00% 0.00%
2014 Long Term Incentive Equity Plan [Member] | Employee Stock Option [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate 2.30%  
Expected term of stock options (in years) 5 years 9 months 18 days  
Expected stock price volatility 63.00%  
Expected dividend yield 0.00%  
2018 Long-Term Incentive Equity Plan [Member] | Non Employee Stock Option [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate 2.20% 2.90%
Expected term of stock options (in years) 9 years 1 month 6 days 9 years 10 months 25 days
Expected stock price volatility 62.00% 63.00%
Expected dividend yield 0.00% 0.00%