Note 7 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($)	Jun. 30, 2020	Jun. 30, 2019		Jun. 30, 2018
Deferred compensation	$ 614,018	$ 642,424
Stock-based compensation	249,313	228,981
Accrued expenses and reserves	479,112	503,726
Deferred revenue	146,841	202,102
Federal and state net operating loss carryforwards	606,730	558,117
Credit carryforwards	216,484	139,504
Equipment and leasehold improvements	134,045	122,714
Valuation allowance	(2,444,035)	(2,382,087)		$ (2,710,628)
Total deferred income tax assets	2,508	15,481
Other	(2,508)	(2,205)
Net deferred income tax assets		$ 13,276	[1]

[1] Excludes approximately 2,786,225 and 2,523,513 stock options for the years ended June 30, 2020 and 2019, respectively, as the impact of such awards was anti-dilutive.