CONSOLIDATED BALANCE SHEETS - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 11,781,549	$ 4,823,544
Short-term investment securities	20,053,019	29,399,146
Interest receivable	226,135	329,711
Accounts receivable	564,672	558,530
Income tax receivable	500,616	250,308
Prepaid expenses and other current assets	599,514	277,999
Total current assets	33,725,505	35,639,238
Non-current assets:
Long-term investment securities	0	1,511,636
Long-term income tax receivable	0	250,308
Other assets	6,116	51,314
Total assets	33,731,621	37,452,496
Current liabilities:
Accounts payable	1,143,961	943,378
Accrued expenses	378,124	566,003
Provision for contract losses	74,955	0
Deferred research and development obligations	41,376	78,644
Total current liabilities	1,638,416	1,588,025
Commitments and contingencies (Note 4)
Stockholders’ equity:
Preferred stock	0	0
Common stock	39,736	39,613
Additional paid-in capital	97,200,023	96,105,851
Treasury stock, shares held at cost	(18,929,915)	(18,929,915)
Accumulated deficit	(46,216,639)	(41,351,078)
Total stockholders’ equity	32,093,205	35,864,471
Total liabilities and stockholders’ equity	$ 33,731,621	$ 37,452,496