Note 11 - Income Taxes (Tables)

12 Months Ended

Jun. 30, 2021

Notes Tables

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	As of June 30,
	2021			2020
Fixed assets	$	55		$	124
Share-based compensation		563			682
Other accruals		49			37
Asset retirement obligation		128			121
Research credit carryforwards		277			218
Other		6			6
Net operating loss carryforwards		16,568			15,799
Total deferred tax assets		17,646			16,987
Valuation allowance		(17,646	)		(16,987	)
Total	$	-		$	-

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	For the year ended June 30,
	2021			2020			2019
U.S. federal statutory income tax rate		21	%		21	%		21	%
Expected income tax benefit	$	(711	)	$	(724	)	$	(1,080	)
Meals and entertainment		6			8			12
Non-deductible penalties		22			24			18
Change in estimate		28			(58	)		(178	)
Incentive stock options		48
Research credit		(52	)		11			-
Change in valuation allowance		659			739			1,228
Income tax expense (benefit)	$	-		$	-		$	-