Note 8 - Stockholders' Equity - Stock Options Activity (Details) - USD ($)	9 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jun. 30, 2017
Outstanding, beginning balance (in shares)	4,545,037
Outstanding, weighted-average exercise price, beginning balance (in dollars per share)	$ 1.42
Outstanding, weighted-average remaining contractual life (Year)	4 years		2 years 328 days
Outstanding, aggregate intrinsic value			$ 176,575
Granted, options (in shares)	2,647,500	294,500
Granted, weighted-average exercise price (in dollars per share)	$ 0.76
Expired, options (in shares)	(365,312)
Expired, weighted-average exercise price (in dollars per share)
Outstanding, ending balance (in shares)	6,827,225		4,545,037
Outstanding, weighted-average exercise price, ending balance (in dollars per share)	$ 1.11		$ 1.42
Exercisable, options (in shares)	6,827,225
Exercisable, weighted-average exercise price (in dollars per share)	$ 1.11
Exercisable, weighted-average remaining contractual life (Year)	4 years
Exercisable, aggregate intrinsic value