Stock-Based Compensation (Details 1) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013
Summary of Company's stock option plan activity
Number of Shares, Options outstanding, Beginning balance	887
Weighted Average Price Per Share, Options outstanding, Beginning balance	$ 8.66
Number of Shares, Granted	100
Weighted Average Price Per Share, Granted	$ 16.73
Number of Shares, Exercised	98
Weighted Average Price Per Share, Exercised	$ 5.46
Number of Shares, Forfeited	0
Weighted Average Price Per Share, Forfeited	$ 0.00
Number of Shares, Options outstanding, Ending balance	889
Weighted Average Price Per Share, Options outstanding, Ending balance	$ 9.92
Weighted Average Remaining Contractual Life (Years), Option outstanding	6 years 2 months 12 days
Aggregate Intrinsic Value, Option outstanding	$ 9,136
Number of Shares, Options exercisable	561
Weighted Average Price Per Share, Option exercisable	$ 6.64
Weighted Average Remaining Contractual Life (Years), Option exercisable	4 years 4 months 24 days
Aggregate Intrinsic Value, Option exercisable	$ 7,604
Number of Shares, Available for grant	988

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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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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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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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 remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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