Note 10 - Stock-based Compensation - Summary of Stock Options (Details) - USD ($)	3 Months Ended	9 Months Ended
Mar. 31, 2021	Mar. 31, 2021	Mar. 31, 2020
Outstanding (in shares)		100,000
Outstanding (in shares)	100,000	100,000
The 2010 Plan [Member]
Outstanding (in shares)		100,000
Outstanding, weighted average exercise price (in dollars per share)		$ 14.50
Granted (in shares)
Granted, weighted average exercise price (in dollars per share)
Exercised (in shares)	0	0	0
Exercised, weighted average exercise price (in dollars per share)
Forfeited (in shares)
Forfeited, weighted average exercise price (in dollars per share)
Outstanding (in shares)	100,000	100,000
Outstanding, weighted average exercise price (in dollars per share)	$ 14.50	$ 14.50
Aggregate intrinsic value, outstanding	$ 443,000	$ 443,000
Exercisable, end of the period (in shares)	50,000	50,000
Aggregate intrinsic value, exercisable	$ 221,500	$ 221,500
Available for grant, end of period (in shares)	260,927	260,927
Weighted average fair value per share of options granted during the period (in dollars per share)

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Number of share options (or share units) exercised during the current period.

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