Stock-Based Compensation - Summary of Share-Based Option Activity (Detail) (USD $)	3 Months Ended
Mar. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares Outstanding, Begginning of Period	8,478,148
Shares Granted	13,728
Shares Canceled	(189,933)
Shares Outstanding, End of Period	8,301,943
Shares Vested and expected to vest at March 31, 2013	6,345,379
Shares Exercisable at March 31, 2013	1,393,852
Weighted Average Exercise Price Outstanding, Beginning of Period	$ 12.22
Weighted Average Exercise Price Granted	$ 11.18
Weighted Average Exercise Price Canceled	$ 13.31
Weighted Average Exercise Price Outstanding, End of Period	$ 12.20
Weighted Average Exercise Price Vested and expected to vest at March 31, 2013	$ 12.24
Weighted Average Exercise Price Exercisable at March 31, 2013	$ 11.60

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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.

+ References

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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.

+ References

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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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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 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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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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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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