CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income (loss)	$ (33,671)	$ (56,212)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,989	1,274
Stock-based compensation	8,848	7,257
Amortization of convertible senior notes discount and debt issuance costs	3,103	2,749
Amortization of finite-lived intangible assets	5,220
Changes in fair value of liability for contingent consideration	2,930	3,178
Changes in operating assets and liabilities:
Accounts receivable	(53,520)
Receivable from collaboration partners	(22,742)	3,403
Inventory	(9,124)
Prepaid expenses and other current assets	4,486	(2,733)
Other assets	130	(401)
Accounts payable	2,449	(60)
Accrued liabilities	(11,464)	(9,292)
Accrued clinical trials and related expenses	1,315	10,829
Accrued compensation	(9,539)	(8,044)
Deferred revenue	(489)
Lease termination exit costs liability		(1,847)
Other current liabilities	(503)
Other liabilities	(591)	5,536
Net cash (used in) provided by operating activities	(111,173)	(44,363)
Cash flows from investing activities:
Purchases of marketable securities	(52,782)	(102,353)
Sales of marketable securities	546	45,755
Maturities of marketable securities	89,384	64,889
Capital expenditures	(6,090)	(8,880)
Net cash (used in) provided by investing activities	31,058	(589)
Cash flows from financing activities:
Repurchases of restricted stock awards	(417)	(124)
Net proceeds from issuances of common stock	363,817	6,547
Payment for redemption of convertible senior notes	(9)
Net cash provided by financing activities	363,391	6,423
Net increase (decrease) in cash and cash equivalents	283,276	(38,529)
Cash and cash equivalents at beginning of period	153,244	171,552
Cash and cash equivalents at end of period	436,520	133,023
Supplemental cash flow data
Cash paid during the period for income taxes	1	32
Cash paid during the period for interest	$ 4,600	$ 4,600