Share-Based Compensation (Details 2) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012
Option activity under the equity incentive plans
Options outstanding at December 31, 2011, Number of Shares		7,578,612
Options outstanding at December 31,2011, Weighted Average Exercise Price per Share		$ 6.25
Granted, Number of Shares	0	1,605,325
Granted, Weighted Average Exercise Price per Share		$ 11.71
Cancelled, Number of Shares		(238,318)
Cancelled, Weighted Average Exercise Price per Share		$ 11.27
Exercised, Number of Shares		(1,279,343)
Exercised, Weighted Average Exercise Price per Share		$ 4.02
Options outstanding at September 30, 2012, Number of Shares	7,666,276	7,666,276
Options outstanding at September 30,2012, Weighted Average Exercise Price per Share	$ 7.61	$ 7.61
Options exercisable at September 30, 2012, Number of Shares	5,297,324	5,297,324
Options exercisable at September 30, 2012, Weighted Average Exercise Price per Share	$ 7.44	$ 7.44