Net Income (Loss) Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net Income (Loss) Per Share
Income (loss)	$ (471)	$ 4,227	$ (10,499)	$ 6,039
Weighted average common shares outstanding used in computing basic net income (loss) per share	107,639	106,097	107,353	106,017
Incremental shares		2,814		3,706
Weighted average common shares outstanding used in computing diluted net income (loss) per share	107,639	108,911	107,353	109,723
Net income (loss) per share:
Basic (in dollars per share)		$ 0.04	$ (0.10)	$ 0.06
Diluted (in dollars per share)		$ 0.04	$ (0.10)	$ 0.06