Share-Based Compensation (Details) (USD $)	3 Months Ended
Mar. 31, 2013
Schedule of stock option activity
Number of Share options Outstanding, Beginning Balance	1,538,713
Number of Share options, Granted	399,600
Number of Share options, Exercised	(25,258)
Number of Share options, Cancelled	(25,041)
Number of Share options Outstanding, Ending Balance	1,888,014
Weighted average exercise price Outstanding, Beginning Balance	$ 5.42
Weighted average exercise price, Granted	$ 10.96
Weighted average exercise price, Exercised	$ 4.47
Weighted average exercise price, Cancelled	$ 5.17
Weighted average exercise price Outstanding, Ending Balance	$ 6.61
Number of Share options, Exercisable	854,209
Weighted average exercise price, Exercisable	$ 5.61

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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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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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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