Note 2 - Cash, Cash Equivalents, and Investments - Major Security Type (Details) - USD ($)		Sep. 30, 2021	Dec. 31, 2020
Cash and cash equivalent, fair value		$ 13,660,611	$ 20,637,045
Cash, adjusted cost		1,486,993	149,015
Money Market Funds, adjusted cost		12,173,618	20,488,030
Cash and cash equivalents, adjusted cost		13,660,611	20,637,045
Gross Unrealized Holding Gains		0	22,473
Gross Unrealized Holding Losses		(7,789)	(6,463)
Short-term investment securities		9,087,199	8,457,452
Total, fair value		22,740,021	29,110,506
Total, adjusted		22,747,810	29,094,496
Corporate Bond Securities [Member]
Short-term investment securities	[1],[2]	9,087,199	8,457,451
Fair Value, Inputs, Level 2 [Member] | Short-term Corporate Bonds [Member]
Gross Unrealized Holding Gains	[1],[2]	0	22,473
Cash [Member]
Cash and cash equivalent, fair value		1,486,993	149,015
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalent, fair value		12,173,618	20,488,030
Short-term Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Corporate Bonds, fair value	[1],[2]	9,079,410	8,473,461
Gross Unrealized Holding Losses	[1],[2]	$ (7,789)	$ (6,463)

[1] For the three months ended September 30, 2021 and 2020, there was no premium paid to purchase held-to-maturity investment securities. The premium paid to purchase held-to-maturity investment securities was $283,940 and $221,156 for the nine months ended September 30, 2021, and 2020, respectively. The premium paid to purchase held-to-maturity investment securities was $282,946 for the year ended December 31, 2020.

[2] Short-term investment securities will mature within 12 months or less, from the applicable reporting date.