Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 251,874	$ 118,271
Restricted cash	1,353	411
Receivables from related party	1,376	1,157
Other current assets	3,204	3,999
Total current assets	257,807	123,838
Intangible asset, net		8,708
Property and equipment, net	3,908	4,696
Restricted cash	750	750
Receivables from related party, net of current portion	6,460
Other assets	3,962	3,052
Total assets	272,887	141,044
Current liabilities:
Accounts payable	2,681	2,886
Accrued expenses	10,661	8,413
Deferred revenue		36,068
Deferred revenue, related party	714	2,897
Other current liabilities	713	261
Total current liabilities	14,769	50,525
Other long-term liabilities	9,639	10,640
Deferred revenue, net of current portion	4,272	4,272
Deferred revenue, related party, net of current portion	4,167	24,382
Total liabilities	32,847	89,819
Commitments and contingencies (Note 9)
Stockholders' equity:
Common stock, $0.001 par value; 200,000,000 shares authorized at September 30, 2012 and December 31, 2011; 133,882,699 and 107,218,463 shares issued and outstanding at September 30, 2012 and December 31, 2011, respectively	134	107
Additional paid-in capital	925,019	726,468
Accumulated other comprehensive income	276	365
Accumulated deficit	(685,389)	(675,715)
Total stockholders' equity	240,040	51,225
Total liabilities and stockholders' equity	$ 272,887	$ 141,044