Statements of Assets and Liabilities (Unaudited) (Parenthetical) - USD ($)	Sep. 30, 2017	Jun. 30, 2017
SIT RISING RATE ETF [Member]
Investment in short-term securities, fair value	$ 25,951,275	$ 20,283,172
Options written, premiums received	24,407	16,688
ETF MANAGERS GROUP COMMODITY TRUST I [Member]
Investment in short-term securities, fair value	25,951,275	20,283,172
Options written, premiums received	$ 24,407	$ 16,688