Schedule of Share-based Compensation, Stock Options, Activity (Detail) (USD $)	12 Months Ended
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding beginning balance	8,704,289
Options granted	0
Options exercised	0
Options forfeited	(391,520)
Options outstanding ending balance	8,312,769
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	3,722,963
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	1,342,986
Weighted Average Exercise Price of Options Outstanding beginning balance	$ 5.61
Weighted Average Exercise Price of Options granted	$ 0
Weighted Average Exercise Price of Options Exercised	$ 0
Weighted Average Exercise Price of Options forfeited	$ 5.40
Weighted Average Exercise Price of Exercisable options ending balance	$ 5.62
Weighted Average Exercise Price of options expected to vest at December 31, 2011	$ 5.89
Expected to vest at December 31, 2012	$ 5.03

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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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For presentations that combine terminations, 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 or that expired.

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

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No definition available.

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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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As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the 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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