Financial Highlights Per Share Performance - Summary of Per Share Data (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Per Share Data:
Net asset value, beginning of period	$ 4.55	$ 2.11	$ 4.79	$ 2.09
Net (decrease) increase in net assets from investment operations:
Net investment loss	(0.03)	(0.02)	(0.06)	(0.03)
Net realized and unrealized (loss) gain	(0.70)	1.10	(0.91)	1.13
Net (decrease) increase in net assets resulting from operations	(0.73)	1.08	(0.97)	1.10
Net asset value, end of period	$ 3.82	$ 3.19	$ 3.82	$ 3.19
Total return	(50.03%)	417.76%	(36.17%)	131.90%
Ratios to average net assets:
Net investment loss	(2.50%)	(2.50%)	(2.50%)	(2.50%)
Expenses	(2.50%)	(2.50%)	(2.50%)	(2.50%)