Net Loss Per Share - Weighted Average Shares (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Numerator: | |||||||||||
| Net loss | $ (89,195) | $ (43,847) | $ (11,016) | ||||||||
| Accretion of Series A redeemable convertible preferred stock to redemption value | (656) | (748) | |||||||||
| Net loss attributable to common stockholders | $ (27,183) | $ (26,362) | $ (21,239) | $ (14,411) | $ (17,517) | $ (11,919) | $ (9,834) | $ (5,233) | $ (89,195) | $ (44,503) | $ (11,764) |
| Denominator: | |||||||||||
| Weighted average common shares outstanding basic and diluted | 39,285,468 | 8,023,785 | 7,200,581 | ||||||||
| Net loss per share attributable to common stockholders, basic and diluted | $ (0.35) | $ (0.42) | $ (2.43) | $ (1.72) | $ (2.07) | $ (1.48) | $ (1.25) | $ (0.68) | $ (2.27) | $ (5.55) | $ (1.63) |