CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 323,068	$ 153,244
Marketable securities, current	427,388	331,192
Accounts receivable, net	131,311	79,117
Receivable from collaboration partners	80,190	68,209
Inventory	28,768	14,563
Deferred tax asset	3,416	3,416
Prepaid expenses and other current assets	27,584	38,215
Total current assets	1,021,725	687,956
Marketable securities, non-current	5,451	8,323
Property and equipment, net	32,331	25,933
Finite - lived intangible assets, net	247,528	257,969
Intangible assets - in-process research and development	171,500	171,500
Goodwill	193,675	193,675
Other assets	7,032	6,215
Total assets	1,679,242	1,351,571
Current liabilities:
Accounts payable	2,833	275
Accrued liabilities	44,325	48,252
Accrued clinical trials and related expenses	37,859	39,684
Accrued compensation	22,491	29,575
Deferred revenue	10,027	9,811
Other current liabilities	4,816	3,772
Total current liabilities	122,351	131,369
Convertible senior notes due 2016	180,700	174,404
Liability for contingent consideration, non-current	155,115	149,163
Deferred tax liability	51,940	51,940
Other liabilities	25,537	24,576
Commitments and contingencies (Note 12)
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; 73,056,158 and 67,479,518 shares issued and outstanding as of June 30, 2013 and December 31, 2012, respectively	73	67
Additional paid-in capital	1,882,131	1,471,585
Receivable from stock option exercises	(53)	(534)
Accumulated other comprehensive income (loss)	(640)	74
Accumulated deficit	(737,912)	(651,073)
Total stockholders' equity	1,143,599	820,119
Total liabilities and stockholders' equity	$ 1,679,242	$ 1,351,571