Financial Highlights Per Share Performance (Tables)

12 Months Ended

Sep. 30, 2025

Investment Company, Financial Highlights [Abstract]

Summary of Per Share Data

	Years Ended September 30,
	2025			2024			2023
Per Share Data:
Principal Market NAV, beginning of year	$	0.70		$	0.68		$	1.27
Net (decrease) increase in net assets from investment operations:
Net investment loss		(0.02	)		(0.02	)		(0.02	)
Net realized and unrealized (loss) gain		(0.03	)		0.04			(0.57	)
Net (decrease) increase in net assets resulting from operations		(0.05	)		0.02			(0.59	)
Principal Market NAV, end of year	$	0.65		$	0.70		$	0.68
Total return		-7.14	%		2.94	%		-46.46	%
Ratios to average net assets:
Net investment loss		-2.50	%		-2.50	%		-2.50	%
Expenses		-2.50	%		-2.50	%		-2.50	%