CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities
Net income (loss)	$ 12,782	$ (78,337)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	5,462	5,459
Gain on sales of available-for-sale securities	(8)
Stock-based compensation	18,044	18,706
Forgiveness of notes receivable		16
Changes in operating assets and liabilities:
Receivables	152	113
Prepaid expenses and other current assets	(247)	1,983
Inventory	(4,567)
Accounts payable	(452)	1,446
Accrued personnel-related expenses, accrued interest on convertible subordinated notes and other current liabilities	(3,902)	(679)
Deferred rent	(546)	2,336
Deferred revenue	(129,979)	(14,025)
Net cash used in operating activities	(103,261)	(62,982)
Cash flows from investing activities
Purchases of property and equipment	(2,329)	(2,723)
Purchases of short-term investments and marketable securities	(276,425)	(231,284)
Sales of short-term investments and marketable securities	181,495	8,750
Maturities of short-term investments and marketable securities	38,670	164,401
Release of restricted cash	60
Issuances of notes receivable	(140)	(140)
Payments received on notes receivable	240	630
Net cash used in investing activities	(58,429)	(60,366)
Cash flows from financing activities
Payments on note payable and capital lease	(69)	(166)
Proceeds from issuances of common stock, net	229,216	22,917
Net cash provided by financing activities	229,147	22,751
Net increase (decrease) in cash and cash equivalents	67,457	(100,597)
Cash and cash equivalents at beginning of period	44,778	163,333
Cash and cash equivalents at end of period	$ 112,235	$ 62,736