Note 2 - Summary of Significant Accounting Policies - Concentration Risk (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2019
Revenue, related parties	$ 2,839,718	$ 3,939,004	$ 5,880,287	$ 8,161,988
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member]
Revenue, related parties	$ 2,839,718	$ 3,939,004	$ 5,880,287	$ 8,161,988
Concentration risk percentage	100.00%	100.00%	100.00%	100.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member] | Customers Related to the USO Fund [Member]
Revenue, related parties	$ 1,441,122	$ 1,853,481	$ 2,991,321	$ 3,838,402
Concentration risk percentage	51.00%	47.00%	51.00%	47.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member] | Customers Related to the USCI Fund [Member]
Revenue, related parties	$ 455,435	$ 1,095,830	$ 1,076,484	$ 2,349,689
Concentration risk percentage	16.00%	28.00%	18.00%	29.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member] | Customers Related to the UNG Fund [Member]
Revenue, related parties	$ 515,611	$ 572,526	$ 975,073	$ 1,077,388
Concentration risk percentage	18.00%	14.00%	17.00%	13.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member] | All Other Customers [Member]
Revenue, related parties	$ 427,550	$ 417,167	$ 837,409	$ 896,509
Concentration risk percentage	15.00%	11.00%	14.00%	11.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member]
Revenue, related parties			$ 1,002,708		$ 1,037,146
Concentration risk percentage			100.00%		100.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member] | Customers Related to the USO Fund [Member]
Revenue, related parties			$ 467,895		$ 526,981
Concentration risk percentage			47.00%		51.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member] | Customers Related to the USCI Fund [Member]
Revenue, related parties			$ 142,699		$ 236,251
Concentration risk percentage			14.00%		23.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member] | Customers Related to the UNG Fund [Member]
Revenue, related parties			$ 207,145		$ 141,413
Concentration risk percentage			21.00%		13.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member] | All Other Customers [Member]
Revenue, related parties			$ 184,969		$ 132,501
Concentration risk percentage			18.00%		13.00%