Note 2 - Summary of Significant Accounting Policies (Tables)

6 Months Ended

Dec. 31, 2019

Notes Tables

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	For the Three Months Ended December 31, 2019				For the Three Months Ended December 31, 2018
	Revenue				Revenue
Fund
USO	$	1,441,122	51	%	$	1,853,481	47	%
USCI		455,435	16	%		1,095,830	28	%
UNG		515,611	18	%		572,526	14	%
All Others		427,550	15	%		417,167	11	%
Total	$	2,839,718	100	%	$	3,939,004	100	%

	For the Six Months Ended December 31, 2019				For the Six Months Ended December 31, 2018
	Revenue				Revenue
Fund
USO	$	2,991,321	51	%	$	3,838,402	47	%
USCI		1,076,484	18	%		2,349,689	29	%
UNG		975,073	17	%		1,077,388	13	%
All Others		837,409	14	%		896,509	11	%
Total	$	5,880,287	100	%	$	8,161,988	100	%

	As of December 31, 2019				As of June 30, 2019
	Accounts Receivable				Accounts Receivable
Fund
USO	$	467,895	47	%	$	526,981	51	%
USCI		142,699	14	%		236,251	23	%
UNG		207,145	21	%		141,413	13	%
All Others		184,969	18	%		132,501	13	%
Total	$	1,002,708	100	%	$	1,037,146	100	%

Property, Plant and Equipment, Estimated Useful Life [Table Text Block]

Category	Estimated Useful Life (in years)
Plant and equipment:		5 to 10
Furniture and office equipment:		3 to 5
Vehicles		3 to 5
Buildings		10 to 39

Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

	ASC 842
Increase (decrease):
Assets	$	1,113,840
Current portion operating lease liabilities	$	370,697
Long-term operating lease liabilities	$	780,219
Accumulated other comprehensive income	$	-
Retained earnings	$	-