Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Dec. 31, 2020	Jun. 30, 2020
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, authorized (in shares)	100,000,000	100,000,000
Common stock, issued (in shares)	32,270,594	31,409,005
Common stock, outstanding (in shares)	31,566,285	30,704,696
Series B Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	50,000	50,000
Preferred stock, issued (in shares)	200	200
Preferred stock, outstanding (in shares)	200	200
Preferred stock, liquidation	$ 39,000	$ 38,000
Series A Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	50,000	50,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Series C Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	60,000	60,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0