Options Outstanding and Exercisable (Detail) - 2002 Stock Incentive Plan
|
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 Shares | shares |
6,611,563
|
| Options Outstanding Weighted Average Exercise Price |
$ 2.06
|
| Options Outstanding Weighted Average Remaining Life (Years) |
7 years 8 months 12 days
|
| Options Exercisable Number of Shares | shares |
3,352,355
|
| Options Exercisable Weighted Average Exercise Price |
$ 2.50
|
| Range One |
|
| Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, Lower Limit |
0.82
|
| Range of Exercise Prices, Upper Limit |
$ 1.43
|
| Options Outstanding Number of Shares | shares |
1,207,757
|
| Options Outstanding Weighted Average Exercise Price |
$ 1.26
|
| Options Outstanding Weighted Average Remaining Life (Years) |
8 years 9 months 7 days
|
| Options Exercisable Number of Shares | shares |
504,736
|
| Options Exercisable Weighted Average Exercise Price |
$ 1.28
|
| Range Two |
|
| Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, Lower Limit |
1.44
|
| Range of Exercise Prices, Upper Limit |
$ 1.55
|
| Options Outstanding Number of Shares | shares |
1,410,000
|
| Options Outstanding Weighted Average Exercise Price |
$ 1.45
|
| Options Outstanding Weighted Average Remaining Life (Years) |
9 years 9 months 18 days
|
| Options Exercisable Number of Shares | shares |
33,332
|
| Options Exercisable Weighted Average Exercise Price |
$ 1.44
|
| Range Three |
|
| Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, Lower Limit |
1.56
|
| Range of Exercise Prices, Upper Limit |
$ 2.10
|
| Options Outstanding Number of Shares | shares |
1,470,510
|
| Options Outstanding Weighted Average Exercise Price |
$ 1.87
|
| Options Outstanding Weighted Average Remaining Life (Years) |
8 years 5 months 19 days
|
| Options Exercisable Number of Shares | shares |
547,171
|
| Options Exercisable Weighted Average Exercise Price |
$ 1.94
|
| Range Four |
|
| Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, Lower Limit |
2.11
|
| Range of Exercise Prices, Upper Limit |
$ 2.50
|
| Options Outstanding Number of Shares | shares |
976,947
|
| Options Outstanding Weighted Average Exercise Price |
$ 2.28
|
| Options Outstanding Weighted Average Remaining Life (Years) |
7 years 2 months 19 days
|
| Options Exercisable Number of Shares | shares |
975,155
|
| Options Exercisable Weighted Average Exercise Price |
$ 2.28
|
| Range Five |
|
| Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, Lower Limit |
2.51
|
| Range of Exercise Prices, Upper Limit |
$ 3.50
|
| Options Outstanding Number of Shares | shares |
1,054,499
|
| Options Outstanding Weighted Average Exercise Price |
$ 2.70
|
| Options Outstanding Weighted Average Remaining Life (Years) |
5 years 11 months 5 days
|
| Options Exercisable Number of Shares | shares |
805,528
|
| Options Exercisable Weighted Average Exercise Price |
$ 2.70
|
| Range Six |
|
| Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, Lower Limit |
3.51
|
| Range of Exercise Prices, Upper Limit |
$ 8.75
|
| Options Outstanding Number of Shares | shares |
491,850
|
| Options Outstanding Weighted Average Exercise Price |
$ 4.59
|
| Options Outstanding Weighted Average Remaining Life (Years) |
1 year 6 months 11 days
|
| Options Exercisable Number of Shares | shares |
486,433
|
| Options Exercisable Weighted Average Exercise Price |
$ 4.59
|