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Note 9 - Debt (Details Textual) - USD ($) $ in Thousands		9 Months Ended
Note 9 - Debt (Details Textual) - USD ($) $ in Thousands	Sep. 03, 2021	Mar. 31, 2022	Mar. 21, 2021	Feb. 13, 2020	Sep. 05, 2019
Interest Paid, Excluding Capitalized Interest, Operating Activities		$ 8	$ 2
Secured Promissory Note (2019 Note) [Member]
Repayments of Debt	$ 1,000
Interest Paid, Excluding Capitalized Interest, Operating Activities	330
Notes Payable, Total		$ 500
Secured Promissory Note (2019 Note) [Member] \| Chief Executive Officer and Board of Directors Chairman, Thomas B. Pickens III [Member]
Debt Instrument, Face Amount					$ 1,500
Secured Promissory Note, (2020 Note) [Member]
Repayments of Debt	1,000
Interest Paid, Excluding Capitalized Interest, Operating Activities	$ 172
Secured Promissory Note, (2020 Note) [Member] \| Chief Executive Officer and Board of Directors Chairman, Thomas B. Pickens III [Member]
Debt Instrument, Face Amount				$ 1,000
Secured Promissory Notes, "Original Notes" [Member] \| Chief Executive Officer and Board of Directors Chairman, Thomas B. Pickens III [Member]
Debt Instrument, Interest Rate, Stated Percentage				11.00%