Note 7 - Commitments and Contingencies (Details Textual) $ in Millions		3 Months Ended		9 Months Ended	42 Months Ended
	Jul. 01, 2023	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2024	Jun. 30, 2023	Jan. 01, 2021	Dec. 31, 2020
Number of Operating Leases							1
Lessee, Operating Lease, Term of Contract (Year)						4 years 5 months 1 day
Lessee, Operating Lease, Discount Rate						6.25%
Lessee, Operating Lease, Remaining Lease Term (Year)		1 year 7 months 28 days		1 year 7 months 28 days
Operating Lease, Payments		$ 0.3	$ 0.3
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%				4.00%
Defined Contribution Plan, Cost		$ 0.1	$ 0.1
Maximum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay				6.00%