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Information about Stock Options Outstanding (Detail) (USD $)
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9 Months Ended |
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Sep. 30, 2012
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Outstanding, Shares |
5,951,046 |
| Outstanding, Weighted-Average Remaining Contractual Life |
4 years 6 months 7 days |
| Outstanding, Weighted-Average Exercise Price |
$ 1.06 |
| Exercisable, Total Shares |
5,838,546 |
| Exercisable, Weighted-Average Exercise Price |
$ 1.07 |
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Range One
|
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, lower range |
$ 0.30 |
| Range of Exercise Prices, upper range |
$ 0.57 |
| Outstanding, Shares |
2,936,533 |
| Outstanding, Weighted-Average Remaining Contractual Life |
3 years 5 months 9 days |
| Outstanding, Weighted-Average Exercise Price |
$ 0.38 |
| Exercisable, Total Shares |
2,824,033 |
| Exercisable, Weighted-Average Exercise Price |
$ 0.38 |
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Range Two
|
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, lower range |
$ 0.68 |
| Range of Exercise Prices, upper range |
$ 0.93 |
| Outstanding, Shares |
1,549,820 |
| Outstanding, Weighted-Average Remaining Contractual Life |
5 years 6 months 11 days |
| Outstanding, Weighted-Average Exercise Price |
$ 0.82 |
| Exercisable, Total Shares |
1,549,820 |
| Exercisable, Weighted-Average Exercise Price |
$ 0.82 |
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Range Three
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, lower range |
$ 1.14 |
| Range of Exercise Prices, upper range |
$ 2.71 |
| Outstanding, Shares |
1,104,693 |
| Outstanding, Weighted-Average Remaining Contractual Life |
5 years 11 months 1 day |
| Outstanding, Weighted-Average Exercise Price |
$ 2.05 |
| Exercisable, Total Shares |
1,104,693 |
| Exercisable, Weighted-Average Exercise Price |
$ 2.05 |
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Range Four
|
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
| Range of Exercise Prices, lower range |
$ 4.45 |
| Range of Exercise Prices, upper range |
$ 5.75 |
| Outstanding, Shares |
360,000 |
| Outstanding, Weighted-Average Remaining Contractual Life |
4 years 6 months 26 days |
| Outstanding, Weighted-Average Exercise Price |
$ 4.60 |
| Exercisable, Total Shares |
360,000 |
| Exercisable, Weighted-Average Exercise Price |
$ 4.60 |