Summary of Significant Accounting Policies - Property and Equipment, Net (Details) |
12 Months Ended |
|---|---|
Dec. 31, 2016 | |
| Laboratory equipment | |
| Property and Equipment, Net | |
| Estimated Useful lives | 5 years |
| Computer equipment and purchased software | |
| Property and Equipment, Net | |
| Estimated Useful lives | 3 years |