Stock Option Activity (Detail) (USD $)	9 Months Ended
Sep. 30, 2012
Number of shares
Outstanding January 1, 2012	5,886,261
Granted during the period	300,000
Exercised during the period	0
Cancelled during the period	(426,136)
Outstanding September 30, 2012	5,760,125
Exercisable at September 30, 2012	3,503,567
Weighted-average exercise price
Outstanding January 1, 2012	$ 1.11
Granted during the period	$ 0.72
Exercised during the period	$ 0
Cancelled during the period	$ 1.11
Outstanding September 30, 2012	$ 1.11
Exercisable at September 30, 2012	$ 1.04

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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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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