Financial Highlights Per Share Performance - Summary of Per Share Data (Details) - $ / shares	12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Per Share Data:
Net asset value, beginning of year	$ 4.61	$ 13.03	$ 3.88
Net increase (decrease) in net assets from investment operations:
Net investment loss	(0.16)	(0.31)	(0.38)
Net realized and unrealized gain (loss)	4.77	(8.11)	9.53
Net increase (decrease) in net assets resulting from operations	4.61	(8.42)	9.15
Net asset value, end of year	$ 9.22	$ 4.61	$ 13.03
Total return	100.00%	(64.62%)	235.82%
Ratios to average net assets:
Net investment loss	(2.50%)	(2.50%)	(2.50%)
Expenses	(2.50%)	(2.50%)	(2.50%)