CONDENSED BALANCE SHEETS (Unaudited) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 51,866,891	$ 11,483,112
Short-term investments	50,601,506	27,084,980
Receivables	1,597,594	117,527
Interest receivable	57,393	8,464
Prepaid expenses and other current assets	913,949	2,329,742
Total current assets	105,037,333	41,023,825
Equipment and furnishings, net	238,835	175,452
Goodwill	183,780	183,780
Other assets	121,898	116,998
Total assets	105,581,846	41,500,055
Current liabilities:
Accounts payable	3,801,005	3,853,531
Accrued expenses and other current liabilities	6,750,958	2,802,833
Warrant liabilities	11,948,023	24,182,324
Total current liabilities	22,499,986	30,838,688
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; 55,920,319 shares issued and outstanding at June 30, 2014; 42,116,964 shares issued and outstanding at December 31, 2013	55,922	42,118
Additional paid-in capital	373,003,698	289,426,100
Treasury stock, at cost (171,536 shares at June 30, 2014 and 143,796 shares at December 31, 2013)	(2,533,201)	(2,417,247)
Accumulated deficit	(287,444,559)	(276,389,604)
Total stockholders' equity	83,081,860	10,661,367
Total liabilities and stockholders' equity	$ 105,581,846	$ 41,500,055