Benefit Plans (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2011
Share-Based compensation arrangement by stock option and restricted stock unit activity
Balance at December 31, 2010, Shares available for grant	10,449	7,835
Options granted, Stock Options Outstanding	(4,091)
Options Forfeited or cancelled	1,477
Stock Options [Member]
Share-Based compensation arrangement by stock option and restricted stock unit activity
Beginning Balance, Stock Options Outstanding	11,020	9,303
Beginning Balance, Weighted Average Exercise Price	6.90	7.12
Options granted, Stock Options Outstanding	(1,038)
Options granted, Weighted Average Exercise Price	8.70
Options exercised, Stock Options Outstanding	(1,794)
Options exercised, Weighted Average Exercise Price	6.17
Options Forfeited or cancelled, Stock Options Outstanding	(961)
Options Forfeited or cancelled, Weighted Average Exercise Price	8.14
Restricted Stock [Member]
Share-Based compensation arrangement by stock option and restricted stock unit activity
Balance at December 31, 2010, RSUs Outstanding	4,507
Balance at December 31, 2010, Weighted Average Fair value Per Share	6.49
Restricted stock units granted, RSUs Outstanding	2,036
Restricted stock units granted, Weighted Average Fair value Per Share	8.69
Restricted stock units released, RSUs Outstanding	(1,663)
Restricted stock units released, Weighted Average Fair Value Per Share	6.90
Restricted stock units Forfeited or cancelled, RSUs Outstanding	(1,167)
Restricted stock units Forfeited or cancelled, Weighted Average Fair value Per Share	6.48
Balance at December 31, 2011, RSUs Outstanding	3,713
Balance at December 31, 2011, Weighted Average Fair value Per Share	7.52