Note 7 - Stockholders' Equity - Nonvested Share Activity (Details)	6 Months Ended
	Dec. 31, 2020 $ / shares shares
Nonvested (in shares) | shares
Nonvested, weighted-average grant-date fair value (in dollars per share) | $ / shares
Granted, options (in shares) | shares
Granted, weighted-average grant-date fair value (in dollars per share) | $ / shares
Vested (in shares) | shares
Vested, weighted-average grant-date fair value (in dollars per share) | $ / shares
Nonvested (in shares) | shares
Nonvested, weighted-average grant-date fair value (in dollars per share) | $ / shares