Stock Options And Employee Stock Purchase Plan (Tables)

12 Months Ended

Dec. 31, 2012

Stock Options And Employee Stock Purchase Plan [Abstract]

Summary Of Stock Option Activity And Weighted Average Exercise Prices

	Options			Weighted Average Exercise Price
Options outstanding at December 31, 2009		8,711,808		$	3.82
Options granted		3,809,380			7.13
Options exercised		(2,843,547	)		4.10
Options cancelled		(860,881	)		5.09
Options outstanding at December 31, 2010		8,816,760			5.04
Options granted		3,642,600			12.24
Options exercised		(2,278,451	)		4.28
Options cancelled		(1,337,496	)		7.03
Options outstanding at December 31, 2011		8,843,413			7.91
Options granted		3,463,500			16.20
Options exercised		(1,634,658	)		5.10
Options cancelled		(830,776	)		10.78
Options outstanding at December 31, 2012		9,841,479		$	11.06
Options exercisable at December 31, 2010		3,097,748		$	3.93
Options exercisable at December 31, 2011		2,805,399		$	4.63
Options exercisable at December 31, 2012		3,220,228		$	6.61

Summary Of The Status Of Nonvested Options

	Shares			Weighted Average Grant-Date Fair Value
Nonvested Shares at January 1, 2011		5,719,012		$	3.13
Granted		3,642,600			6.47
Vested		(1,967,639	)		3.00
Cancelled		(1,355,959	)		3.83
Nonvested Shares at December 31, 2011		6,038,014		$	5.04
Nonvested Shares at January 1, 2012		6,038,014		$	5.04
Granted		3,463,500			8.20
Vested		(2,060,707	)		4.46
Cancelled		(819,556	)		5.69
Nonvested Shares at December 31, 2012		6,621,251		$	6.84