CONDENSED BALANCE SHEETS (Unaudited) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 6,036,220	$ 14,344,088
Short-term investments	17,000,000	24,000,000
Receivables	2,451	109,802
Interest receivable	77,960	26,517
Prepaid expenses and other current assets	875,093	1,212,041
Total current assets	23,991,724	39,692,448
Equipment and furnishings, net	188,235	253,277
Goodwill	183,780	183,780
Other assets	103,271	102,271
Total assets	24,467,010	40,231,776
Current liabilities:
Accounts payable	2,865,616	3,060,516
Accrued expenses and other current liabilities	3,314,859	3,033,189
Warrant liabilities	7,144,554	3,972,230
Total current liabilities	13,325,029	10,065,935
Commitments and contingencies
Stockholders' equity
Preferred Stock, $0.01 par value, 5,000,000 shares authorized, including 25,000 shares of Series A Junior Participating Preferred Stock; no shares issued and outstanding	0	0
Common stock, $0.001 par value, 250,000,000 shares authorized; 30,608,392 shares issued and outstanding at September 30, 2013; 30,607,916 shares issued and outstanding at December 31, 2012	30,609	30,608
Additional paid-in capital	262,656,237	261,318,638
Treasury stock, at cost (132,980 shares at September 30, 2013 and 90,546 shares at December 31, 2012)	(2,373,442)	(2,279,238)
Accumulated deficit	(249,171,423)	(228,904,167)
Total stockholders' equity	11,141,981	30,165,841
Total liabilities and stockholders' equity	$ 24,467,010	$ 40,231,776