Shareholder Report, Line Graph (Details) 462680_Jacob Small Cap Growth Fund_Institutional Class_TSR Annual {Institutional 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 |
|
| Institutional Class | |||||||||||
| Account Value [Line Items] | |||||||||||
| Accumulated Value | $ 230,955 | $ 159,322 | $ 137,585 | $ 142,361 | $ 307,752 | $ 189,925 | $ 143,679 | $ 171,386 | $ 110,173 | $ 100,000 | $ 206,007 |
| S&P 500 TR [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | S&P 500 TR | ||||||||||
| Accumulated Value | 347,177 | 299,601 | 235,655 | 203,248 | 228,955 | 174,554 | 143,151 | 139,088 | 116,234 | 100,000 | $ 417,931 |
| Bloomberg US 2000 Growth Total Return Index [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg US 2000 Growth Total Return Index | ||||||||||
| Accumulated Value | $ 227,862 | $ 206,652 | $ 175,900 | $ 169,549 | $ 225,943 | $ 155,504 | $ 135,256 | $ 151,286 | $ 115,191 | $ 100,000 | $ 283,684 |