Shareholder Report, Line Graph (Details) 557750_Jacob Internet Fund_Investor Class_TSR Annual {Investor Class} - USD ($) |
12 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Aug. 31, 2025 |
Aug. 31, 2024 |
Aug. 31, 2023 |
Aug. 31, 2022 |
Aug. 31, 2021 |
Aug. 31, 2020 |
Aug. 31, 2019 |
Aug. 31, 2018 |
Aug. 31, 2017 |
Aug. 31, 2016 |
Aug. 31, 2026 |
|
| Investor Class | |||||||||||
| Account Value [Line Items] | |||||||||||
| Accumulated Value | $ 29,580 | $ 18,384 | $ 16,892 | $ 19,013 | $ 40,569 | $ 23,678 | $ 15,232 | $ 14,560 | $ 11,365 | $ 10,000 | $ 23,286 |
| S&P 500 TR [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | S&P 500 TR | ||||||||||
| Accumulated Value | 34,718 | 29,960 | 23,566 | 20,325 | 22,895 | 17,455 | 14,315 | 13,909 | 11,623 | 10,000 | $ 41,793 |
| NASDAQ Composite Total Return Index [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | NASDAQ Composite Total Return Index | ||||||||||
| Accumulated Value | $ 44,583 | $ 36,558 | $ 28,753 | $ 23,992 | $ 30,755 | $ 23,569 | $ 15,783 | $ 15,897 | $ 12,473 | $ 10,000 | $ 55,121 |