Selected Quarterly Financial Data (Unaudited) - Impact of adoption (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 |
|
| Operating expenses: | |||||||||||
| Research and development | $ 51,769 | $ 21,226 | $ 8,403 | ||||||||
| General and administrative | 39,894 | 22,038 | 2,449 | ||||||||
| Total operating expenses | $ 29,122 | $ 27,554 | $ 20,384 | $ 14,603 | $ 17,473 | $ 11,975 | $ 9,033 | $ 4,783 | 91,663 | 43,264 | 10,852 |
| Loss from operations | (29,122) | (27,554) | (20,384) | (14,603) | (17,473) | (11,975) | (9,033) | (4,783) | (91,663) | (43,264) | (10,852) |
| 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) |
| 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) |
| Comprehensive loss: | |||||||||||
| Net loss | $ (89,195) | $ (43,847) | $ (11,016) | ||||||||
| Other comprehensive loss: | |||||||||||
| Unrealized losses on investments, net of tax of $0 | (29) | ||||||||||
| Comprehensive loss | $ (89,224) | $ (43,847) | $ (11,016) | ||||||||
| ASU 2018-07 | |||||||||||
| Operating expenses: | |||||||||||
| Research and development | $ 11,361 | $ 9,506 | |||||||||
| General and administrative | 9,023 | 5,097 | |||||||||
| Total operating expenses | 20,384 | 14,603 | |||||||||
| Loss from operations | (20,384) | (14,603) | |||||||||
| Net loss attributable to common stockholders | $ (21,239) | $ (14,411) | |||||||||
| Net loss per share attributable to common stockholders, basic and diluted | $ (2.43) | $ (1.72) | |||||||||
| As previously reported | ASU 2018-07 | |||||||||||
| Operating expenses: | |||||||||||
| Research and development | $ 11,965 | $ 9,650 | |||||||||
| General and administrative | 16,279 | 5,797 | |||||||||
| Total operating expenses | 28,244 | 15,447 | |||||||||
| Loss from operations | (28,244) | (15,447) | |||||||||
| Net loss attributable to common stockholders | $ (29,099) | $ (15,255) | |||||||||
| Net loss per share attributable to common stockholders, basic and diluted | $ (3.33) | $ (1.83) | |||||||||