Financial Highlights Per Share Performance - Summary of Per Share Data (Details) - $ / shares	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Per Share Data:
Net asset value, beginning of year	$ 4.79	$ 2.09	$ 4.00
Net (decrease) increase in net assets from investment operations:
Net investment loss	(0.10)	(0.12)	(0.07)
Net realized and unrealized (loss) gain	(3.79)	2.82	(1.84)
Net (decrease) increase in net assets resulting from operations	(3.89)	2.70	(1.91)
Net asset value, end of year	$ 0.90	$ 4.79	$ 2.09
Total return	(81.21%)	129.19%	(47.75%)
Ratios to average net assets:
Net investment loss	(2.50%)	(2.50%)	(2.50%)
Expenses	(2.50%)	(2.50%)	(2.50%)