CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current Assets
Cash and cash equivalents	$ 87,697	$ 24,212
Prepaid expenses and other current assets	304	406
Total current assets	88,001	24,618
Fixed assets, net	93	53
Other assets, net	2,546	2,161
Total assets	90,640	26,832
Current Liabilities
Accounts payable	3,561	3,240
Accrued expenses	377	558
Total current liabilities	3,938	3,798
Commitments and contingencies (note 5)
Stockholders' Equity
Undesignated Preferred Stock, $.001 par value, 5,000,000 shares authorized, none issued and outstanding	0	0
Common Stock, $.001 par value, 75,000,000 shares authorized, 23,117,187 and 17,272,505 shares issued, respectively and 23,004,837 and 17,160,155 shares outstanding, respectively	23	17
Additional paid-in capital	312,542	234,299
Cost of treasury stock, 112,350 shares	(1,380)	(1,380)
Deficit accumulated during the development stage	(224,483)	(209,902)
Total stockholders' equity	86,702	23,034
Total liabilities and stockholders' equity	$ 90,640	$ 26,832