Consolidated Balance Sheets - USD ($)	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 4,035,578	$ 5,525,094	$ 5,856,242
Contracts and grants receivable	733,565	794,767	867,086
Prepaid expenses	243,538	$ 172,928	135,391
Taxes receivable			750,356
Total current assets	5,012,681	$ 6,492,789	7,609,075
Office furniture and equipment, net	52,919	51,510	23,868
Intangible assets, net	300,589	409,949	632,512
Total assets	5,366,189	6,954,248	8,265,455
Current liabilities:
Accounts payable	2,636,447	3,003,545	1,520,290
Warrant liability	6,201,555	3,789,562	8,281,247
Accrued compensation	48,087	315,030	233,739
Total current liabilities	$ 8,886,089	$ 7,108,137	$ 10,035,276
Commitments and contingencies
Shareholders' deficiency:
Preferred stock: 350,000 shares authorized: none issued or outstanding
Common stock, $.001 par value; 50,000,000 shares authorized; 26,374,833 shares , 23,936,568 shares and 19,626,439 shares issued and outstanding at June 30, 2015, December 31, 2014 and December 31, 2013, respectively	$ 26,375	$ 23,937	$ 19,626
Additional paid-in capital	144,047,090	138,868,523	130,549,930
Accumulated deficit	(147,593,365)	(139,046,349)	(132,339,377)
Total shareholders' deficiency	(3,519,900)	(153,889)	(1,769,821)
Total liabilities and shareholders' deficiency	$ 5,366,189	$ 6,954,248	$ 8,265,455

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.