Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 25,515	$ 14,902	[1]
Marketable securities		2,001	[1]
Restricted cash	6,469
Receivables		10,000	[1]
Prepaid expenses and other current assets	766	649	[1]
Total current assets	32,750	27,552	[1]
Property and equipment, net	17,156	20,425	[1]
Other assets	409	628	[1]
Total assets	50,315	48,605	[1]
Current liabilities:
Accounts payable	1,832	3,603	[1]
Accrued clinical trial expenses	96	134	[1]
Other accrued expenses	2,319	2,872	[1]
Current portion of contingent consideration liability	7,000	12,300	[1]
Financing obligations	7,994	12,280	[1]
Current portion of deferred revenue	2,915	3,759	[1]
Total current liabilities	22,156	34,948	[1]
Deferred rent	8,574	12,274	[1]
Noncurrent portion of contingent consideration liability	3,500	4,200	[1]
Noncurrent portion of deferred revenues	5,829	6,875	[1]
Stockholders' equity:
Preferred stock			[1]
Common stock	2	1	[1]
Additional paid-in-capital	334,594	296,942	[1]
Deficit accumulated during development stage	(324,340)	(306,635)	[1]
Total stockholders' equity (deficit)	10,256	(9,692)	[1]
Total liabilities and stockholders' equity	$ 50,315	$ 48,605	[1]

[1] The condensed consolidated balance sheet at December 31, 2011 has been derived from audited consolidated financial statements at that date.