Note 9 - Equity Compensation - Stock Options (Details) - USD ($)	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Outstanding, shares (in shares)	2,749,626
Outstanding, weighted average exercise price (in dollars per share)	$ 7.23
Outstanding, weighted average remaining contractual term (Year)	7 years 36 days	6 years 292 days
Outstanding, aggregate intrinsic value	$ 2,731,949	$ 23,500
Granted, shares (in shares)	735,429
Granted, weighted average exercise price (in dollars per share)	$ 4.51
Exercised, shares (in shares)	(143,766)
Exercised, weighted average exercise price (in dollars per share)	$ 5.57
Forfeited, shares (in shares)	(889,351)
Forfeited, weighted average exercise price (in dollars per share)	$ 7.69
Expired, shares (in shares)	(169,000)
Expired, weighted average exercise price (in dollars per share)	$ 8.24
Outstanding, shares (in shares)	2,282,938	2,749,626
Outstanding, weighted average exercise price (in dollars per share)	$ 6.20	$ 7.23
Exercisable, shares (in shares)	1,017,148
Exercisable, weighted average exercise price (in dollars per share)	$ 8.35
Exercisable, weighted average remaining contractual term (Year)	5 years 36 days
Exercisable, aggregate intrinsic value	$ 100,719
Vested and expected to vest at June 30, 2020 (in shares)	2,206,744
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 6.26
Vested and expected to vest, weighted average remaining contractual term (Year)	7 years
Vested and expected to vest, aggregate intrinsic value	$ 2,574,232