Redeemable Convertible Preferred Stock - Schedule of Warrants Outstanding and Exercisable (Details) - USD ($) $ / shares in Units, $ in Thousands |
9 Months Ended | 12 Months Ended | |||
---|---|---|---|---|---|
Sep. 30, 2018 |
Dec. 31, 2017 |
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Class Of Warrant Or Right [Line Items] | |||||
Shares | 3,603,019 | 3,331,972 | |||
Estimated fair value | $ 867 | $ 1,708 | |||
Series B Redeemable Convertible Preferred Stock | |||||
Class Of Warrant Or Right [Line Items] | |||||
Expiration date | 2018-06 | 2018-06 | |||
Exercise price per share | $ 0.8822 | $ 0.8822 | |||
Shares | 170,030 | ||||
Estimated fair value | $ 0 | $ 116 | |||
Series C Redeemable Convertible Preferred Stock | |||||
Class Of Warrant Or Right [Line Items] | |||||
Exercise price per share | [1] | $ 0.4797 | $ 0.4797 | ||
Shares | [1] | 1,920,148 | 2,479,712 | ||
Estimated fair value | [1] | $ 336 | $ 1,263 | ||
Series C Redeemable Convertible Preferred Stock | Minimum | |||||
Class Of Warrant Or Right [Line Items] | |||||
Expiration date | [1] | 2020-07 | |||
Series C Redeemable Convertible Preferred Stock | Maximum | |||||
Class Of Warrant Or Right [Line Items] | |||||
Expiration date | [1] | 2021-11 | |||
Series D-2 Redeemable Convertible Preferred Stock | |||||
Class Of Warrant Or Right [Line Items] | |||||
Expiration date | 2027-08 | 2027-08 | |||
Exercise price per share | $ 0.6596 | $ 0.6596 | |||
Shares | 682,230 | ||||
Estimated fair value | $ 0 | $ 329 | |||
Series E Redeemable Convertible Preferred Stock | |||||
Class Of Warrant Or Right [Line Items] | |||||
Expiration date | 2027-08 | 2027-08 | |||
Exercise price per share | $ 0.2674 | $ 0.2674 | |||
Shares | 1,682,871 | 0 | |||
Estimated fair value | $ 531 | ||||
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