BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 32,218,905	$ 11,483,112
Short-term investments	45,621,593	27,084,980
Receivables	2,019,293us-gaap_ReceivablesNetCurrent	117,527us-gaap_ReceivablesNetCurrent
Interest receivable	104,627us-gaap_InterestReceivable	8,464us-gaap_InterestReceivable
Prepaid expenses and other current assets	3,250,355	2,329,742
Total current assets	83,214,773us-gaap_AssetsCurrent	41,023,825us-gaap_AssetsCurrent
Equipment and furnishings, net	970,873us-gaap_PropertyPlantAndEquipmentNet	175,452us-gaap_PropertyPlantAndEquipmentNet
Goodwill	183,780us-gaap_Goodwill	183,780us-gaap_Goodwill
Other assets	1,323,156us-gaap_OtherAssetsNoncurrent	116,998us-gaap_OtherAssetsNoncurrent
Total assets	85,692,582us-gaap_Assets	41,500,055us-gaap_Assets
Current liabilities:
Accounts payable	6,655,962us-gaap_AccountsPayableCurrent	3,853,531us-gaap_AccountsPayableCurrent
Accrued expenses and other current liabilities	5,994,072	2,802,833
Warrant liabilities	5,131,085us-gaap_DerivativeLiabilitiesCurrent	24,182,324us-gaap_DerivativeLiabilitiesCurrent
Total current liabilities	17,781,119us-gaap_LiabilitiesCurrent	30,838,688us-gaap_LiabilitiesCurrent
Commitment and contingencies
Stockholders' equity:
Preferred Stock, $.01 par value, 5,000,000 shares authorized, including 25,000 shares of Series A Junior Participating Preferred Stock; no shares issued and outstanding	0us-gaap_PreferredStockValue	0us-gaap_PreferredStockValue
Common stock, $.001 par value, 250,000,000 shares authorized; 55,921,986 and 42,116,964 shares issued and outstanding at December 31, 2014 and 2013, respectively	55,924us-gaap_CommonStockValue	42,118us-gaap_CommonStockValue
Additional paid-in capital	376,975,984us-gaap_AdditionalPaidInCapital	289,426,100us-gaap_AdditionalPaidInCapital
Treasury stock, at cost (199,275 and 143,796 shares at December 31, 2014 and 2013, respectively)	(2,612,861)us-gaap_TreasuryStockValue	(2,417,247)us-gaap_TreasuryStockValue
Accumulated deficit	(306,507,584)	(276,389,604)
Total stockholders' equity	67,911,463us-gaap_StockholdersEquity	10,661,367us-gaap_StockholdersEquity
Total liabilities and stockholders' equity	$ 85,692,582	$ 41,500,055

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, and other costs not separately disclosed in the balance sheet that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered.

No definition available.