v3.19.3
Convertible Preferred Stock and Stockholders’ Equity (Deficit) - Summary of Stock Option Activity Under 2018 Plan and 2006 Plan (Details) - 2018 Employee Stock Purchase Plan - 2018 Plan and 2006 Plan
9 Months Ended 12 Months Ended
Sep. 30, 2019
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Shares    
Beginning balance (shares) | shares 1,282,847  
Granted (shares) | shares 706,640  
Exercised (shares) | shares (50,047)  
Canceled (shares) | shares (95,379)  
Ending balance (shares) | shares 1,844,061 1,282,847
Vested and exercisable (shares) | shares 682,462  
Weighted- Average Exercise Price    
Beginning balance (USD per share) | $ / shares $ 6.90  
Granted (USD per share) | $ / shares 3.82  
Exercised (USD per share) | $ / shares 1.30  
Canceled (USD per share) | $ / shares 9.83  
Ending balance (USD per share) | $ / shares 5.71 $ 6.90
Vested and exercisable (USD per share) | $ / shares $ 6.51  
Weighted- Average Remaining Contractual Term    
Outstanding 8 years 9 months 18 days 9 years 2 months 12 days
Vested and exercisable 8 years 4 months 24 days  
Aggregate Intrinsic Value    
Beginning balance | $  
Exercised | $  
Ending balance | $ 0
Vested and exercisable | $ $ 0