Warrants to Purchase Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions |
1 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Jul. 31, 2018 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2015 |
|
| Warrants to purchase convertible preferred stock | ||||
| Other expenses | $ 2.2 | $ 0.8 | ||
| IPO | ||||
| Warrants to purchase convertible preferred stock | ||||
| Warrants to purchase aggregate | 135,567 | |||
| Issuance of warrants exercise | 131,273 | |||
| Shares withheld to pay exercise price | 4,294 | |||
| Series A redeemable convertible preferred stock | ||||
| Warrants to purchase convertible preferred stock | ||||
| Maximum number of preferred shares can purchase from outstanding warrants | 133,333 | |||
| Warrants exercisable price | $ 0.60 | |||
| Warrants contractual term (in years) | 10 years | |||
| Series B convertible preferred stock | ||||
| Warrants to purchase convertible preferred stock | ||||
| Maximum number of preferred shares can purchase from outstanding warrants | 2,234 | |||
| Warrants exercisable price | $ 8.39 | |||
| Warrants contractual term (in years) | 10 years | |||