Net Loss per Share - Summary of Potentially Dilutive Securities Excluded from Computation of Diluted Shares Outstanding (Detail) - shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Options to purchase common stock [Member] | |||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
| Potentially dilutive securities excluded from computation of diluted shares outstanding | 4,452,700 | 3,240,969 | 2,723,366 |
| Restricted stock units [Member] | |||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
| Potentially dilutive securities excluded from computation of diluted shares outstanding | 502,027 | 254,067 | 185,514 |