Note 8 - Stockholders' Equity (Tables)

9 Months Ended

Mar. 31, 2020

Notes Tables

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Weighted Average, March 31, 2020			Range, March 31, 2020			Weighted Average, March 31, 2019			Range, March 31, 2019
Volatility		68	%	68	-	70%		69	%	58%	-	76%
Dividend yield		—			—			—			—
Risk-free interest rate		1.75	%	1.74	–	1.75%		2.71	%	2.52%	-	2.78%
Expected term (years)		5.0		5.0	to	5.2		3.8		1.9	to	4.3

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life		Aggregate Intrinsic Value
Outstanding at July 1, 2019		7,411,600		$	1.08		3.1	$	20,375
Granted		390,000			0.60
Exercised		-			-
Forfeited		-			-
Expired		(85,000	)		0.60
Outstanding at March 31, 2020		7,716,600		$	1.06		2.5	$	-
Exercisable at March 31, 2020		7,716,600		$	1.06		2.5	$	-

Schedule of Nonvested Share Activity [Table Text Block]

	Options			Weighted Average Grant-Date Fair Value
Nonvested at July 1, 2019		-		$	-
Granted		390,000			0.26
Vested		(390,000	)		0.26
Nonvested at March 31, 2020		—		$	—

Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Three months ended March 31, 2020		Three months ended March 31, 2019		Nine months ended March 31, 2020		Nine months ended March 31, 2019
General and administrative:
Change in fair value from modification of option terms	$	-	$	-	$	-	$	211,185
Change in fair value from modification of warrant terms		-		-		-		118,233
Fair value of stock options expensed		-		5,250		92,000		97,375
Total	$	-	$	5,250	$	92,000	$	426,793
Research and development:
Change in fair value from modification of option terms	$	-	$	-	$	-		11,115
Change in fair value from modification of warrant terms		-		-		-		44,793
Fair value of stock options expensed		-		-		7,500		25,875
Total	$	-	$	-	$	7,500	$	81,783