Stockholders' Equity (Details 1) (Stock Options [Member], USD $)	9 Months Ended
Sep. 30, 2012
Stock Options [Member]
Activity For Stock Options Under 2007 Plan
Number of Shares, Balances, at December 31, 2011	4,378,053
Number of Shares, Options granted	914,750
Number of Shares, Options exercised	(122,622)
Number of Shares, Options forfeited	(150,332)
Number of Shares, Options expired	(39,653)
Number of Shares, Balances, at September 30, 2012	4,980,196
Weighted Average Exercise Price, Balances, at December 31, 2011	$ 10.86
Weighted Average Exercise Price, Options granted	$ 14.21
Weighted Average Exercise Price, Options exercised	$ 6.91
Weighted Average Exercise Price, Options forfeited	$ 14.11
Weighted Average Exercise Price, Options expired	$ 15.21
Weighted Average Exercise Price, Balances, at September 30, 2012	$ 11.44

Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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

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