Note 11 - Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Jun. 30, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 17,920	$ 17,202
Tax credit carryforwards	1,530	1,330
Lease liability - current and non-current	128	113
Unrealized loss on securities	305	0
IRC Section 174 R&D Expense Capitalization	1,061
Accrued expenses and other timing	143	180
Stock-based compensation	111	579
Property and equipment, principally due to differences in depreciation	0	0
Total gross deferred tax assets	21,198	19,404
Less — valuation allowance	(21,064)	(19,348)
Net deferred tax assets	134	56
Deferred tax liabilities:
Right-of-use assets	(55)	(34)
Property and equipment, principally due to differences in depreciation	(79)	(22)
Total gross deferred tax liabilities	(134)	(56)
Net deferred tax assets	$ 0	$ 0