Note 10 - Stock-based Compensation - Summary of Stock Options (Details)	3 Months Ended	9 Months Ended
	Mar. 31, 2019 shares	Mar. 31, 2020 USD ($) $ / shares shares
Outstanding, shares under options (in shares)
Granted, shares under options (in shares)		100,000	[1]
Granted, weighted average exercise price (in dollars per share) | $ / shares		$ 14.50	[1]
Exercised, shares under options (in shares)	0
Forfeited, shares under options (in shares)
Outstanding, shares under options (in shares)		100,000
Aggregate intrinsic value, outstanding | $
Exercisable, end of the period (in shares)
Aggregate intrinsic value, exercisable | $
Weighted average fair value per share of options granted during the period (in dollars per share) | $ / shares		$ 7.42

[1] The fair value of each option is estimated as of the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions: (i) risk-free interest rate of 1.56%; (ii) expected life of 3.3 years; (iii) expected volatility of 74%; and (iv) expected dividend yield of 0%. The weighted average fair value per share for the options granted is $7.42