Note 2 - Principal Contracts and Agreements - Summary of Expenses - Hashdex Bitcoin Futures ETF (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022		Jun. 30, 2023	Jun. 30, 2022
Amount Recognized for Custody Services	$ 97,437	$ 97,970	[1]	$ 217,997	$ 129,490	[1]
Amount Recognized for Distribution Services	976,404	1,127,864	[1]	1,904,116	1,887,941	[1]
Related Party [Member]
Amount Waived	44,857	358,002	[1]	68,722	479,081	[1]
Hashdex Bitcoin Futures ETF [Member]
Amount Recognized for Custody Services	858			1,117
Amount Recognized for Distribution Services	3,379			4,741
Custody Services [Member] | Related Party [Member]
Amount Recognized for Custody Services	97,438	97,970	[1]	217,997	129,490	[1]
Amount Waived	9,187	27,908	[1]	16,516	28,101	[1]
Custody Services [Member] | Hashdex Bitcoin Futures ETF [Member] | Related Party [Member]
Amount Recognized for Custody Services	858	0		1,117	0
Amount Waived	858	0		1,117	0
Distribution Services [Member] | Related Party [Member]
Amount Waived	2,614	22,981	[1]	4,936	42,994	[1]
Amount Recognized for Distribution Services	37,728	55,129	[1]	76,493	94,055	[1]
Distribution Services [Member] | Hashdex Bitcoin Futures ETF [Member] | Related Party [Member]
Amount Waived	224	0		284	0
Amount Recognized for Distribution Services	$ 224	$ 0		$ 284	$ 0

[1] The Hashdex Bitcoin Futures ETF commenced operations on September 15, 2022.