Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating activities
Net loss	$ (152,030)	$ (66,265)	$ (81,683)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Share-based compensation expense	19,984	14,330	11,849
Depreciation and amortization	4,170	3,562	3,260
Amortization of discounts, accretion of premiums and loss on investments	12,474	3,429	3,622
Deferred rent and other long-term liabilities	2,247	198	1,248
Changes in operating assets and liabilities
Interest receivable	141	568	538
Accounts receivable	(35,676)	60,843	(71,936)
Inventories	(9,469)	0	0
Prepaid expenses and other current assets	(1,574)	4,056	(839)
Accounts payable and accrued liabilities	27,265	6,287	3,617
Deferred revenue	8,437	(20,200)	68,569
Net cash provided by (used in) operating activities	(124,031)	6,808	(61,755)
Investing activities
Purchases of securities available for sale	(479,389)	(453,599)	(396,840)
Proceeds from maturities of securities available for sale	498,959	443,256	251,919
Proceeds from sales of securities available for sale	0	2,321	2,092
Purchases of property and equipment	(11,252)	(3,548)	(4,589)
Change in other non-current assets	(5,764)	26	(28)
Net cash provided by (used in) investing activities	2,554	(11,544)	(147,446)
Financing activities
Net proceeds from issuance of common stock	168,053	0	192,141
Proceeds from exercise of stock options, warrants and employee stock purchase plan	19,931	7,377	4,746
Net cash provided by financing activities	187,984	7,377	196,887
Net increase (decrease) in cash and cash equivalents	66,507	2,641	(12,314)
Cash and cash equivalents at beginning of year	21,127	18,486	30,800
Cash and cash equivalents at end of year	$ 87,634	$ 21,127	$ 18,486