Net Loss per Common Share - Summary of Potentially Dilutive Securities Excluded from Computation of Diluted Per Share (Details) - shares
|
3 Months Ended |
Mar. 31, 2018 |
Mar. 31, 2017 |
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |
|
|
| Anti-dilutive securities excluded from computation of diluted net loss per share |
38,727,221
|
29,671,866
|
| Convertible Preferred Stock |
|
|
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |
|
|
| Anti-dilutive securities excluded from computation of diluted net loss per share |
31,750,297
|
25,280,436
|
| Options to Purchase Common Stock |
|
|
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |
|
|
| Anti-dilutive securities excluded from computation of diluted net loss per share |
4,433,459
|
2,332,221
|
| Early Exercised Common Stock Subject to Future Vesting |
|
|
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |
|
|
| Anti-dilutive securities excluded from computation of diluted net loss per share |
1,058,270
|
1,199,098
|
| Restricted Stock Accounted For as Options |
|
|
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |
|
|
| Anti-dilutive securities excluded from computation of diluted net loss per share |
625,084
|
|
| Warrants to Purchase Convertible Preferred Stock |
|
|
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |
|
|
| Anti-dilutive securities excluded from computation of diluted net loss per share |
763,501
|
763,501
|
| Warrants to Purchase Common Stock |
|
|
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] |
|
|
| Anti-dilutive securities excluded from computation of diluted net loss per share |
96,610
|
96,610
|