Stock-Based Awards - Summary of Stock Option Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands |
12 Months Ended |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
| Shares Issuable Under Options |
|
|
|
| Outstanding as of December 31, 2014 |
2,146,927
|
|
|
| Granted |
996,845
|
1,039,155
|
786,537
|
| Exercised |
(201,153)
|
|
|
| Forfeited |
(81,608)
|
|
|
| Outstanding as of December 31, 2015 |
2,861,011
|
2,146,927
|
|
| Options vested and expected to vest as of December 31, 2015 |
2,822,786
|
|
|
| Options exercisable as of December 31, 2015 |
1,199,676
|
|
|
| Weighted Average Exercise Price |
|
|
|
| Outstanding as of December 31, 2014 |
$ 5.54
|
|
|
| Granted |
10.60
|
|
|
| Exercised |
2.31
|
|
|
| Forfeited |
4.27
|
|
|
| Outstanding as of December 31, 2015 |
7.57
|
$ 5.54
|
|
| Options vested and expected to vest as of December 31, 2015 |
7.52
|
|
|
| Options exercisable as of December 31, 2015 |
$ 4.10
|
|
|
| Weighted Average Remaining Contractual Term (In years) |
|
|
|
| Outstanding as of December 31, 2014 |
8 years 3 months 18 days
|
8 years 7 months 6 days
|
|
| Options vested and expected to vest as of December 31, 2015 |
8 years 2 months 12 days
|
|
|
| Options exercisable as of December 31, 2015 |
7 years
|
|
|
| Aggregate Intrinsic Value |
|
|
|
| Aggregate intrinsic value, Outstanding |
$ 7,906
|
$ 19,802
|
|
| Options vested and expected to vest as of December 31, 2015 |
7,896
|
|
|
| Options exercisable as of December 31, 2015 |
$ 6,455
|
|
|