CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income (loss)	$ (187,787)	$ 76,110	$ (84,847)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Deferred income taxes	(96,769)	136	(11,860)
Depreciation	5,175	5,463	3,641
Stock-based compensation	38,340	27,081	22,797
Amortization of convertible senior notes discount and debt issuance costs	11,511	10,192	9,655
Amortization of finite-lived intangible assets	9,331
Changes in fair value of liability for contingent consideration	69,173	(93,468)	92,930
Property and equipment write-off		732
Impairment of equity investment	500	3,750
Accretion of lease exit costs liability		345
Realized gains on sales of current marketable securities	(14)	(642)	(90)
Changes in operating assets and liabilities:
Restricted cash			(310)
Accounts receivable	(79,117)
Receivable from collaboration partners	(10,268)	(6,529)	6
Inventory	(14,563)
Prepaid expenses and other current assets	(14,697)	(14,955)	(3,013)
Other assets	(1,151)	18,472	(15,527)
Accounts payable	142	44	(1,347)
Accrued liabilities	17,084	14,302	5,014
Accrued clinical trials and related expenses	110	24,481	1,278
Accrued compensation	13,936	6,388	(3,897)
Deferred revenue	9,811
Escrow liability		(31,634)	34
Lease termination exit costs liability	(3,177)	2,832
Other current liabilities	3,772
Other liabilities	(1,821)	7,445	13,893
Net cash (used in) provided by operating activities	(230,479)	50,545	28,357
Cash flows from investing activities:
Purchases of marketable securities	(264,936)	(614,511)	(508,508)
Sales of marketable securities	149,668	169,660	277,891
Maturities of marketable securities	274,745	299,347	359,525
Transfers from restricted cash		31,910	(4,000)
Payment for liability for contingent consideration, current	(17,065)		(36,000)
Capital expenditures	(11,374)	(15,107)	(6,990)
Net cash (used in) provided by investing activities	131,038	(128,701)	81,918
Cash flows from financing activities:
Repurchases of restricted stock awards	(124)	(181)	(78)
Net proceeds from issuances of common stock	81,257	23,549	8,475
Net cash provided by financing activities	81,133	23,368	8,397
Net increase (decrease) in cash and cash equivalents	(18,308)	(54,788)	118,672
Cash and cash equivalents at beginning of period	171,552	226,340	107,668
Cash and cash equivalents at end of period	153,244	171,552	226,340
Supplemental cash flow data
Cash paid during the period for income taxes	299	94	537
Cash paid during the period for interest	9,200	9,200	9,277
Equity issued in lieu of cash payment of contingent consideration liability	$ 62,935