Summary of Stock Option Activity (Detail) (USD $)	6 Months Ended
Jun. 30, 2012
Number of Shares
Beginning Balance	546,001
Granted
Exercised
Forfeited	(110,000)
Ending Balance	436,001
Weighted Average Exercise Price
Beginning Balance	$ 4.54
Granted
Exercised
Forfeited	$ 8.30
Ending Balance	$ 3.59
Weighted-Average Remaining Contractual Term
Outstanding, end of period	2 years 3 months 18 days
Aggregate Intrinsic Value
Outstanding, end of period	$ 174,267

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Net number of share options (or share units) granted during the period.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded.

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Number of share options (or share units) exercised during the current period.

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