Stockholders' Equity - Stock Option Activity Related to Shares of Common Stock (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands |
12 Months Ended |
Dec. 31, 2016 |
Dec. 31, 2015 |
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |
|
|
| Number of stock options outstanding, Outstanding, Beginning Balance (in shares) |
2,168
|
|
| Number of stock options outstanding, Granted (in shares) |
1,010
|
|
| Number of stock options outstanding, Exercised (in shares) |
(2)
|
|
| Number of stock options outstanding, Forfeited (in shares) |
(1,029)
|
|
| Number of stock options outstanding, Outstanding, Ending Balance (in shares) |
2,147
|
2,168
|
| Number of stock options outstanding, Options vested and expected to vest, Ending Balance (in shares) |
1,418
|
|
| Number of stock options outstanding, Options exercisable, Ending Balance (in shares) |
773
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] |
|
|
| Weighted-average exercise price, Outstanding, Beginning Balance (in dollars per share) |
$ 6.48
|
|
| Weighted-average exercise price, Granted (in dollars per share) |
3.47
|
|
| Weighted-average exercise price, Exercised (in dollars per share) |
3.20
|
|
| Weighted-average exercise price, Forfeited (in dollars per share) |
7.07
|
|
| Weighted-average exercise price, Outstanding, Ending Balance (in dollars per share) |
4.79
|
$ 6.48
|
| Weighted-average exercise price, Options vested and expected to vest, Ending Balance (in dollars per share) |
5.32
|
|
| Weighted-average exercise price, Options exercisable, Ending Balance (in dollars per share) |
$ 6.39
|
|
| Weighted-average remaining contractual life (years), Outstanding |
6 years 4 months 6 days
|
5 years 2 months 12 days
|
| Weighted-average remaining contractual life (years), Options vested and expected to vest, Ending Balance |
5 years 3 months 26 days
|
|
| Weighted-average remaining contractual life (years), Options exercisable, Ending Balance |
3 years 5 months 9 days
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] |
|
|
| Aggregate intrinsic value, Outstanding |
$ 8
|
$ 118
|
| Aggregate intrinsic value, Options vested and expected to vest |
7
|
|
| Aggregate Intrinsic Value, Options exercisable |
$ 4
|
|