Net Income (Loss) per Share (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Numerator
Net income (loss) - basic	$ (34,692)	$ (30,626)	$ 12,782	$ (78,337)
Add: interest and issuance costs related to convertible notes			4,503
Net income (loss) - diluted	$ (34,692)	$ (30,626)	$ 17,285	$ (78,337)
Denominator
Weighted-average common shares outstanding	97,590	84,951	91,834	84,238
Less: unvested RSAs (in shares)	(2,563)	(2,461)	(2,563)	(2,461)
Weighted-average shares used in computing basic net income (loss) per share	95,027	82,490	89,271	81,777
Effect of dilutive equity incentive plans and ESPP (in shares)			2,442
Effect of dilutive convertible subordinated notes (in shares)			6,668
Weighted-average common shares outstanding - diluted	95,027	82,490	98,381	81,777
Securities that could potentially dilute basic EPS in the future
Anti-dilutive securities (in shares)	11,766	13,412	2,915	12,873
Equity Incentive Plans and ESPP
Securities that could potentially dilute basic EPS in the future
Anti-dilutive securities (in shares)	5,098	6,744	2,915	6,205
Convertible subordinated notes
Securities that could potentially dilute basic EPS in the future
Anti-dilutive securities (in shares)	6,668	6,668		6,668