v3.26.1
Financial Highlights Per Share Performance - Summary of Per Share Data (Detail) - $ / shares
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Investment Company, Financial Highlights [Roll Forward]        
Principal Market NAV, beginning of period $ 0.46 $ 0.75 $ 0.76 $ 2.46
Net decrease in net assets from investment operations:        
Net investment loss 0 0 (0.01) (0.01)
Net realized and unrealized loss (0.13) (0.13) (0.42) (1.83)
Net decrease in net assets resulting from operations (0.13) (0.13) (0.43) (1.84)
Principal Market NAV, end of period $ 0.33 $ 0.62 $ 0.33 $ 0.62
Total return (28.26%) (17.33%) (56.58%) (74.80%)
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%)