Note 11 - Stock Options - Nonvested Option (Details) - $ / shares	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Non-vested (in shares)	1,189,918	1,074,834
Non-vested, weighted average grant date fair value (in dollars per share)	$ 0.90	$ 0.96
Granted (in shares)	585,000	510,000
Granted, weighted average grant date fair value (in dollars per share)	$ 1.57	$ 0.85
Vested (in shares)	(429,334)	(394,916)
Vested, weighted average grant date fair value (in dollars per share)	$ 0.87	$ 1.01
Forfeited (in shares)	73,000
Forfeited, weighted average grant date fair value (in dollars per share)	$ 1.33
Non-vested (in shares)	1,272,584	1,189,918
Non-vested, weighted average grant date fair value (in dollars per share)	$ 1.19	$ 0.90