Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 61,840	$ 2,681
State research and development credit exchange receivable - current	450
Prepaid expenses and other current assets	4,520	3,140
Total current assets	66,810	5,821
Property and equipment - net	183,961	193,029
State research and development credit exchange receivable - net of current portion	313	473
Other assets	230	230
Total	251,314	199,553
Current liabilities:
Accounts payable	4,555	4,624
Accrued expenses and other current liabilities	25,777	20,736
Senior convertible notes	114,443
Total current liabilities	144,775	25,360
Senior convertible notes	97,583	210,642
Note payable to related party	119,635	277,203
Total liabilities	361,993	513,205
Commitments and contingencies
Stockholders' deficit:
Undesignated preferred stock, $0.01 par value - 10,000,000 shares authorized; no shares issued or outstanding at December 31, 2011 and 2012
Common stock, $0.01 par value - 250,000,000 and 550,000,000 shares authorized at December 31, 2011 and 2012, respectively; 131,522,945 and 286,035,082 shares issued and outstanding at December 31, 2011 and 2012, respectively	2,860	1,315
Additional paid-in capital	1,991,379	1,620,535
Accumulated other comprehensive income (loss)	(6)	44
Deficit accumulated during the development stage	(2,104,912)	(1,935,546)
Total stockholders' deficit	(110,679)	(313,652)
Total	$ 251,314	$ 199,553