CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 171,892	$ 94,849
Short-term investments	334,261	153,640
Accounts receivable	450
Receivables from collaborative arrangements (including amounts from a related party of $517 at September 30, 2013 and $123 at December 31, 2012)	2,489	1,064
Notes receivable	140	100
Prepaid expenses and other current assets	4,071	3,966
Inventories	9,038	7,514
Total current assets	522,341	261,133
Marketable securities	88,333	95,194
Restricted cash	833	833
Property and equipment, net	8,563	9,154
Intangible assets	40,000
Other assets	5,946	2,268
Total assets	666,016	368,582
Current liabilities:
Accounts payable	5,733	5,377
Accrued personnel-related expenses	8,362	9,002
Accrued clinical and development expenses	10,599	6,550
Other accrued liabilities	3,093	2,072
Accrued interest on convertible subordinated notes	1,273	2,372
Deferred revenue, current	9,601	4,593
Total current liabilities	38,661	29,966
Convertible subordinated notes	287,500	172,500
Deferred rent	4,658	5,074
Deferred revenue, non-current	5,148	6,014
Commitments and contingencies (Notes 3, 9 and 11)
Stockholders' equity:
Common stock, $0.01 par value; authorized: 200,000 shares; outstanding: 110,543 at September 30, 2013 and 98,379 at December 31, 2012	1,105	984
Additional paid-in capital	1,784,016	1,488,447
Accumulated other comprehensive income	202	99
Accumulated deficit	(1,455,274)	(1,334,502)
Total stockholders' equity	330,049	155,028
Total liabilities and stockholders' equity	$ 666,016	$ 368,582