CONSOLIDATED BALANCE SHEETS - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 4,696,831	$ 4,823,544
Short-term investment securities	26,587,752	29,399,146
Interest receivable	227,146	329,711
Accounts receivable	518,601	558,530
Income tax receivable	500,616	250,308
Prepaid expenses and other current assets	288,495	277,999
Total current assets	32,819,441	35,639,238
Non-current assets:
Long-term investment securities	2,518,160	1,511,636
Long-term income tax receivable	0	250,308
Other assets	50,489	51,314
Total assets	35,388,090	37,452,496
Current liabilities:
Accounts payable	653,373	943,378
Accrued expenses	240,003	566,003
Deferred research and development obligations	242,443	78,644
Total current liabilities	1,135,819	1,588,025
Commitments and contingencies (Note 4)
Stockholders’ equity:
Preferred stock	0	0
Common stock	39,713	39,613
Additional paid-in capital	96,707,690	96,105,851
Treasury stock, shares held at cost	(18,929,915)	(18,929,915)
Accumulated deficit	(43,565,217)	(41,351,078)
Total stockholders’ equity	34,252,271	35,864,471
Total liabilities and stockholders’ equity	$ 35,388,090	$ 37,452,496