CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 153,244	$ 171,552
Marketable securities, current	331,192	474,791
Accounts receivable, net	79,117
Receivable from collaboration partners	68,209	57,941
Inventory	14,563
Deferred tax asset	3,416	4,047
Prepaid expenses and other current assets	38,215	23,518
Total current assets	687,956	731,849
Marketable securities, non-current	8,323	22,102
Property and equipment, net	25,933	19,734
Finite - lived intangible assets, net	257,969
Intangible assets - in-process research and development	171,500	438,800
Goodwill	193,675	193,675
Other assets	6,215	5,564
Total assets	1,351,571	1,411,724
Current liabilities:
Accounts payable	275	60
Accrued liabilities	48,252	31,168
Accrued clinical trials and related expenses	39,684	39,574
Accrued compensation	29,575	15,639
Deferred revenue	9,811
Liability for contingent consideration, current		22,174
Lease termination exit costs, current		3,177
Other current liabilities	3,772
Total current liabilities	131,369	111,792
Convertible senior notes due 2016	174,404	162,893
Liability for contingent consideration, non-current	149,163	137,816
Deferred tax liability	51,940	149,413
Other liabilities	24,576	26,397
Commitments and contingencies (Note 15)
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; none issued and outstanding
Common stock, $0.001 par value; 200,000,000 shares authorized; 67,479,518 and 63,928,082 shares issued and outstanding as of December 31, 2012 and December 31, 2011, respectively	67	64
Additional paid-in capital	1,471,585	1,289,080
Receivable from stock option exercises	(534)	(434)
Accumulated other comprehensive income (loss)	74	(2,011)
Accumulated deficit	(651,073)	(463,286)
Total stockholders' equity	820,119	823,413
Total liabilities and stockholders' equity	$ 1,351,571	$ 1,411,724