CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities
Net income (loss)	$ (120,772)	$ 12,782
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	5,684	5,462
Stock-based compensation	19,704	18,044
Gain on marketable securities	(3)	(8)
Loss on disposal of assets	20
Change in capped-call option valuation	1,422
Changes in operating assets and liabilities:
Receivables from collaborative arrangements	(1,425)	152
Prepaid expenses and other current assets	(35)	(247)
Inventories	(2,912)	(4,567)
Accounts payable	2,040	(452)
Accrued personnel-related expenses, accrued clinical and development expenses, and other accrued liabilities	4,472	(3,902)
Accrued interest on convertible subordinated notes	(1,099)
Deferred rent expense	(416)	(546)
Deferred revenue	3,692	(129,979)
Net cash used in operating activities	(89,628)	(103,261)
Cash flows from investing activities
Purchases of property and equipment	(1,667)	(2,329)
Purchases of available-for-sale securities	(354,583)	(276,425)
Maturities of available-for-sale securities	155,396	38,670
Sales of available-for-sale securities	22,600	181,495
Increase in intangible assets	(40,000)
Release of restricted cash		60
Issuances of notes receivable		(140)
Payments received on notes receivable	100	240
Net cash used in investing activities	(218,154)	(58,429)
Cash flows from financing activities
Payments on note payable and capital lease		(69)
Proceeds from issuances of common stock, net	140,003	229,216
Payment for capped calls	(36,800)
Proceeds from issuances of convertible subordinated notes, net	281,622
Net cash provided by financing activities	384,825	229,147
Net increase in cash and cash equivalents	77,043	67,457
Cash and cash equivalents at beginning of period	94,849	44,778
Cash and cash equivalents at end of period	171,892	112,235
Supplemental non-cash financing activities:
Conversion of convertible subordinated notes into common stock	$ 172,499