Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of Stock Option Activity (Details)

v3.19.3
Stock-Based Compensation - Summary of Stock Option Activity (Details) - $ / shares
9 Months Ended 12 Months Ended
Sep. 30, 2019
Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Number of shares, beginning balance 3,092,606  
Number of shares, Granted 1,094,756  
Number of shares, Exercised (408,170)  
Number of shares, Expired/forfeited/cancelled (678,645)  
Number of shares, ending balance 3,100,547 3,092,606
Number of shares, Vested 1,973,108  
Number of shares, Vested and expected to vest 3,100,547  
Weighted average exercise price, beginning balance $ 7.32  
Weighted average exercise price, Granted 7.95  
Weighted average exercise price, Exercised 5.94  
Weighted average exercise price, Expired/forfeited/cancelled 7.84  
Weighted average exercise price, ending balance 7.61 $ 7.32
Weighted average exercise price, Vested 7.31  
Weighted average exercise price, Vested and expected to vest $ 7.61  
Weighted average remaining contractual life 6 years 10 months 24 days 7 years 3 months 18 days
Weighted average remaining contractual life, Vested 5 years 10 months 24 days  
Weighted average remaining contractual life, Vested and expected to vest 6 years 10 months 24 days