CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities
Net income (loss)	$ 47,474	$ (47,712)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	3,572	3,407
Recognized gain on marketable securities	(2)
Stock-based compensation	12,214	11,134
Forgiveness of notes receivable		1
Changes in operating assets and liabilities:
Receivables	129	(53)
Prepaid expenses and other current assets	127	1,717
Inventory	(4,299)
Accounts payable	(81)	813
Accrued personnel-related expenses, accrued interest on convertible subordinated notes and other current liabilities	(5,956)	(3,488)
Deferred rent	(344)	1,932
Deferred revenue	(128,530)	(11,401)
Net cash used in operating activities	(75,696)	(43,650)
Cash flows from investing activities
Purchases of property and equipment	(1,762)	(2,763)
Purchases of marketable securities	(185,456)	(176,322)
Sales of marketable securities	8,520	8,750
Maturities of marketable securities	153,921	119,476
Release of restricted cash	60
Additions to notes receivable		(140)
Payments received on notes receivable		530
Net cash used in investing activities	(24,717)	(50,469)
Cash flows from financing activities
Payments on note payable and capital lease	(69)	(113)
Proceeds from issuances of common stock, net	216,800	21,557
Net cash provided by financing activities	216,731	21,444
Net increase (decrease) in cash and cash equivalents	116,318	(72,675)
Cash and cash equivalents at beginning of period	44,778	163,333
Cash and cash equivalents at end of period	$ 161,096	$ 90,658