CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Jun. 30, 2013	Dec. 31, 2012
Assets
Cash and cash equivalents	$ 22,012,466	$ 28,424,631
Prepaid contract research and manufacturing	84,793	175,192
Other prepaid expenses and other current assets	384,798	176,181
Total current assets	22,482,057	28,776,004
Property and equipment, net	92,169	151,544
Total Assets	22,574,226	28,927,548
Liabilities and Stockholders' Equity
Accounts payable	811,304	788,073
Accrued compensation and related expenses	208,320	199,935
Accrued restructuring	519,479	841,184
Accrued contract research and manufacturing	503,764	496,901
Other accrued expenses	757,326	685,305
Total current liabilities	2,800,193	3,011,398
Commitments
Stockholders' equity:
Preferred stock, $0.0001 par value, 5,000,000 shares authorized, no shares issued and outstanding	0	0
Common stock, $0.0001 par value, 200,000,000 and 100,000,000 shares authorized, respectively; 67,120,154 and 67,075,779 shares issued and outstanding, respectively	6,712	6,708
Additional paid-in capital	242,081,834	240,970,852
Deficit accumulated during the development stage	(222,314,513)	(215,061,410)
Total stockholders' equity	19,774,033	25,916,150
Total liabilities and stockholders' equity	$ 22,574,226	$ 28,927,548