Consolidated Balance Sheets - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 43,489,935	$ 27,092,928
Prepaid expenses and other	322,493	355,891
Total current assets	43,812,428	27,448,819
Property and equipment, net	1,046,514	229,591
Other assets	242,023	34,485
Total assets	45,100,965	27,712,895
Current liabilities:
Accounts payable	2,087,770	1,064,626
Payable to related party	2,228,366	0
Accrued liabilities	745,961	250,950
Total current liabilities	5,062,097	1,315,576
Note payable, net of discount	1,498,754	1,491,278
Contingent rights derivative liability	0	4,122,266
Total liabilities	6,560,851	6,929,120
Commitments and contingencies
Stockholders’ equity:
Convertible preferred stock, $1.00 par value; 5,000,000 shares authorized and 0 shares issued and outstanding at December 31, 2017 and 2016	0	0
Common stock, $.01 par value: 170,000,000 shares authorized at December 31, 2017 and 2016; 69,901,625 shares and 60,276,119 shares issued at December 31, 2017 and 2016, respectively	699,015	602,760
Additional paid-in capital	498,577,372	470,147,086
Treasury stock, at cost: 79,545 shares held at December 31, 2017 and 2016	(8,034,244)	(8,034,244)
Accumulated deficit	(452,702,029)	(441,931,827)
Total stockholders’ equity	38,540,114	20,783,775
Total liabilities and stockholders’ equity	$ 45,100,965	$ 27,712,895