Stock-Based Compensation - Summarizes Information Concerning Options Outstanding and Options Vested and Exercisable (Detail)
|
12 Months Ended |
|
Dec. 31, 2016
$ / shares
shares
|
|---|
| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Options outstanding, Number of Options | shares |
9,236,228
|
| Options Vested and Exercisable, Number of Options | shares |
5,968,199
|
| 1.01 - 1.91 Exercise Price [Member] |
|
| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Exercise price lower range |
$ 1.01
|
| Exercise price upper range |
$ 1.91
|
| Options outstanding, Number of Options | shares |
4,003,376
|
| Option Outstanding, Weighted Average Remaining Contractual Life |
7 years 5 months 9 days
|
| Options Outstanding, Weighted Average Exercise Price |
$ 1.58
|
| Options Vested and Exercisable, Number of Options | shares |
2,686,969
|
| Options Vested and Exercisable, Weighted Average Remaining Contractual Life |
7 years 22 days
|
| Options Vested and Exercisable, Weighted Average Exercise Price |
$ 1.59
|
| 2.09 - 3.84 Exercise Price [Member] |
|
| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Exercise price lower range |
2.09
|
| Exercise price upper range |
$ 3.84
|
| Options outstanding, Number of Options | shares |
2,499,852
|
| Option Outstanding, Weighted Average Remaining Contractual Life |
8 years 11 months 1 day
|
| Options Outstanding, Weighted Average Exercise Price |
$ 2.24
|
| Options Vested and Exercisable, Number of Options | shares |
550,230
|
| Options Vested and Exercisable, Weighted Average Remaining Contractual Life |
6 years 11 months 27 days
|
| Options Vested and Exercisable, Weighted Average Exercise Price |
$ 2.42
|
| 4.00 - 5.28 Exercise Price [Member] |
|
| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Exercise price lower range |
4.00
|
| Exercise price upper range |
$ 5.28
|
| Options outstanding, Number of Options | shares |
2,733,000
|
| Option Outstanding, Weighted Average Remaining Contractual Life |
6 months 15 days
|
| Options Outstanding, Weighted Average Exercise Price |
$ 4.98
|
| Options Vested and Exercisable, Number of Options | shares |
2,731,000
|
| Options Vested and Exercisable, Weighted Average Remaining Contractual Life |
6 months 15 days
|
| Options Vested and Exercisable, Weighted Average Exercise Price |
$ 4.98
|