Common Stock - Summary of Reserved Shares of Common Stock for Future Issuances (Detail) - shares |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Class Of Stock [Line Items] | ||
| Common Stock, Capital Shares Reserved for Future Issuance | 5,998,840 | 4,845,579 |
| Stock Compensation Plan [Member] | ||
| Class Of Stock [Line Items] | ||
| Common Stock, Capital Shares Reserved for Future Issuance | 1,044,113 | 1,350,543 |
| Options to purchase common stock [Member] | ||
| Class Of Stock [Line Items] | ||
| Common Stock, Capital Shares Reserved for Future Issuance | 4,452,700 | 3,240,969 |
| Restricted stock units [Member] | ||
| Class Of Stock [Line Items] | ||
| Common Stock, Capital Shares Reserved for Future Issuance | 502,027 | 254,067 |