CONSOLIDATED BALANCE SHEETS - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 3,975,761	$ 2,386,314
Short-term investment securities	35,778,093	38,816,441
Interest receivable	290,259	294,240
Accounts receivable	425,951	318,744
Income tax receivable	500,617	506,866
Prepaid research and development	170,334	253,446
Prepaid expenses and other current assets	166,944	172,001
Total current assets	41,307,959	42,748,052
Non-current assets:
Long-term income tax receivable	500,616	500,616
Other assets	50,951	52,139
Total assets	41,859,526	43,300,807
Current liabilities:
Accounts payable	948,058	309,060
Accrued expenses	302,970	399,576
Deferred research and development obligations	23,024	141,002
Total current liabilities	1,274,052	849,638
Commitments and contingencies (See Note 4)
Stockholders' equity:
Preferred stock	0	0
Common stock	38,967	38,967
Additional paid-in capital	94,694,793	94,385,230
Treasury stock, shares held at cost	(18,929,915)	(18,929,915)
Accumulated deficit	(35,218,371)	(33,043,113)
Total stockholders’ equity	40,585,474	42,451,169
Total liabilities and stockholders’ equity	$ 41,859,526	$ 43,300,807