v3.26.1
Financial Highlights Per Share Performance - Summary of Per Share Data (Detail) - $ / shares
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Investment Company, Financial Highlights [Roll Forward]    
Principal Market NAV, beginning of period $ 0.76 $ 2.46
Net decrease in net assets from investment operations:    
Net investment loss (0) (0.01)
Net realized and unrealized loss (0.3) (1.7)
Net decrease in net assets resulting from operations (0.3) (1.71)
Principal Market NAV, end of period $ 0.46 $ 0.75
Total return (39.47%) (69.51%)
Ratios to average net assets:    
Net investment loss (2.50%) (2.50%)
Expenses (2.50%) (2.50%)