Note 9 - Share-based Compensation - Assumptions (Details) - $ / shares	12 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Weighted average fair value (in dollars per share)	$ 0.55	$ 0.86	$ 0.39
Options issued (in shares)	3,269,100	400,000	1,330,000
Expected term (in years) (Year)	5 years	5 years	5 years
Minimum [Member]
Exercise price (in dollars per share)	$ 0.28	$ 0.64	$ 0.32
Risk-free rate	0.73%	0.22%	33.00%
Volatility	99.00%	83.00%	83.00%
Maximum [Member]
Exercise price (in dollars per share)	$ 0.79	$ 1.66	$ 0.61
Risk-free rate	3.24%	0.94%	1.80%
Volatility	100.00%	100.00%	89.00%

Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

Number of shares issued under share-based payment arrangement.

+ References

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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