Stock-Based Compensation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
Jun. 30, 2012
Summary of related activity under Incentive Plan
Awards Available, Beginning balance	2,010
Plan amendment, Awards Available	1,700
Restricted stock awards granted, Awards Available	(415)
Restricted stock awards cancelled, Awards Available	13
Stock option awards granted, Awards Available	(1,563)
Stock option awards exercised, Awards Available
Stock option awards cancelled, Awards Available	419
Awards Available, Ending balance	2,164
Options Outstanding, Beginning balance	7,858
Plan amendment, Options Outstanding
Restricted stock awards granted, Options Outstanding
Restricted stock awards cancelled, Options Outstanding
Stock option awards granted, Options Outstanding	1,563
Stock option awards exercised, Options Outstanding	(303)
Stock option awards cancelled, Options Outstanding	(419)
Options Outstanding, Ending balance	8,699
Weighted Average Exercise Price, Beginning balance	$ 6.21
Plan amendment, Weighted Average Exercise Price
Restricted stock awards granted, Weighted Average Exercise Price
Restricted stock awards cancelled, Weighted Average Exercise Price
Stock option awards granted, Weighted Average Exercise Price	$ 4.66
Stock option awards exercised, Weighted Average Exercise Price	$ 1.66
Stock option awards cancelled, Weighted Average Exercise Price	$ 8.32
Weighted Average Exercise Price, Ending balance	$ 5.99

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Share based compensation arrangement by share based payment award plan amendment.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target 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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Other than shares newly issued, the number of additional shares issued (for example, a stock split) or canceled (for example, to correct a share issuance), during the period under the 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 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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