Net Income (Loss) per Share (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Numerator
Net income (loss) - basic	$ (37,120)	$ (25,045)	$ 47,474	$ (47,712)
Add: interest and issuance costs related to convertible notes			3,002
Net income (loss) - diluted	$ (37,120)	$ (25,045)	$ 50,476	$ (47,712)
Denominator
Weighted-average common shares outstanding	91,809	84,263	89,019	83,867
Less: unvested RSAs (in shares)	(2,640)	(2,452)	(2,640)	(2,452)
Weighted-average shares used in computing basic net income (loss) per share	89,169	81,811	86,379	81,415
Effect of dilutive equity incentive plans and ESPP (in shares)			1,997
Effect of dilutive convertible subordinated notes			6,668
Weighted-average common shares outstanding - diluted	89,169	81,811	95,044	81,415
Securities that could potentially dilute basic EPS in the future
Anti-dilutive securities (in shares)	13,016	12,140	3,801	12,284
Equity Incentive Plans and ESPP
Securities that could potentially dilute basic EPS in the future
Anti-dilutive securities (in shares)	6,348	5,472	3,801	5,616
Convertible debt
Securities that could potentially dilute basic EPS in the future
Anti-dilutive securities (in shares)	6,668	6,668		6,668