Note 2 - Summary of Significant Accounting Policies - Concentration Risk (Details) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Revenue, related parties	$ 2,986,503	$ 3,567,702	$ 8,866,790	$ 11,729,689
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member]
Revenue, related parties			$ 1,062,166	$ 1,207,361
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			$ 629,310	$ 598,810
Concentration risk percentage			59.00%	49.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member] | Customers Related to the UNG Fund [Member]
Revenue, related parties			$ 193,400	$ 309,916
Concentration risk percentage			18.00%	26.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member] | Customers Related to the USCI Fund [Member]
Revenue, related parties			$ 90,707	$ 142,351
Concentration risk percentage			9.00%	12.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Wainwright [Member] | All Other Customers [Member]
Revenue, related parties			$ 148,749	$ 156,284
Concentration risk percentage			14.00%	13.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member]
Revenue, related parties	$ 2,986,503	$ 3,567,702	$ 8,866,790	$ 11,729,689
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	$ 1,659,435	$ 1,803,427	$ 4,650,756	$ 5,641,829
Concentration risk percentage	55.00%	51.00%	52.00%	48.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member] | Customers Related to the UNG Fund [Member]
Revenue, related parties	$ 688,156	$ 432,915	$ 1,663,229	$ 1,510,303
Concentration risk percentage	23.00%	12.00%	19.00%	13.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member] | Customers Related to the USCI Fund [Member]
Revenue, related parties	$ 322,162	$ 912,419	$ 1,398,646	$ 3,262,108
Concentration risk percentage	11.00%	25.00%	16.00%	28.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Wainwright [Member] | All Other Customers [Member]
Revenue, related parties	$ 316,750	$ 418,941	$ 1,154,159	$ 1,315,449
Concentration risk percentage	11.00%	12.00%	13.00%	11.00%