Note 2 - Significant Accounting Policies (Details Textual) - USD ($)		Mar. 31, 2020	Dec. 31, 2019
Deposits with Clearing Organizations and Others, Securities	[1]	$ 59,285,472	$ 29,438,936

[1] Cost of short-term investments held at the broker (restricted): $59,252,215 and $29,427,850, respectively.