| Form N-CSR Cover | 12 Months Ended |
| Oct. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Perritt Funds, Inc. |
| Entity Central Index Key | 0001286087 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Oct. 31, 2024 |
| Shareholder Report | 12 Months Ended | |
| Oct. 31, 2024 USD ($) $ / shares | ||
| Shareholder Report [Line Items] | ||
| Document Type | N-CSR | |
| Amendment Flag | false | |
| Registrant Name | Perritt Funds, Inc. | |
| Entity Central Index Key | 0001286087 | |
| Entity Investment Company Type | N-1A | |
| Document Period End Date | Oct. 31, 2024 | |
| Perritt MicroCap Opportunities Fund | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Perritt MicroCap Opportunities Fund | |
| Class Name | Perritt MicroCap Opportunities Fund | |
| Trading Symbol | PRCGX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Perritt MicroCap Opportunities Fund for the period of November 1, 2023, to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://www.perrittcap.com/literature/ . You can also request this information by contacting us at 1-800-332-3133 . | |
| Additional Information Phone Number | 1-800-332-3133 | |
| Additional Information Website | https://www.perrittcap.com/literature/ | |
| Expenses [Text Block] | WHAT WERE THE FUND COSTS FOR THE PAST YEAR? (based on a hypothetical $10,000 investment) Fund Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Perritt MicroCap Opportunities Fund $188 1.73% | |
| Expenses Paid, Amount | $ 188 | |
| Expense Ratio, Percent | 1.73% | |
| Factors Affecting Performance [Text Block] | HOW DID THE FUND PERFORM LAST YEAR AND WHAT AFFECTED ITS PERFORMANCE? For the year ended October 31, 2024, the Fund’s performance relative to the Russell Microcap Index was aided by its overweight allocation to the Materials sector, and by individual holdings within the Consumer Discretionary sector. The primary detractors were the Fund’s underweightings to the Healthcare and Financial sectors, and individual holdings within the Industrial sector. During the period, the strategy continued it’s high allocation to profitable companies, as measured by those companies posting positive earnings per share. The portfolio’s allocation to profitable companies stood at approximately 70% compared to approximately 30% for the Bloomberg Microcap Index. This overweight allocation to profitable companies detracted from the fund’s relative performance during the period as investors risk appetites for unprofitable growth companies increased and drove performance of those securities following the avoidance of a US recession and easing inflationary pressures. | |
| Performance Past Does Not Indicate Future [Text] | The Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | ||
| Average Annual Return [Table Text Block] | ANNUAL AVERAGE TOTAL RETURN (%) 1 Year 5 Year 10 Year TF (without sales charge) 17.56 8.10 5.23 Bloomberg US Aggregate Equity Total Return Index 37.75 14.55 12.40 Bloomberg US Micro Cap Total Return Index 26.56 8.72 5.46 | |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares. | |
| Updated Performance Information Location [Text Block] | Visit https://www.perrittcap.com/literature/ for more recent performance information. Visit https://www.perrittcap.com/literature/ for more recent performance information. | |
| Net Assets | $ 62,093,023 | |
| Holdings Count | $ / shares | 126 | |
| Advisory Fees Paid, Amount | $ 532,465 | |
| Investment Company Portfolio Turnover | 13% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of October 31, 2024) Net Assets $62,093,023 Number of Holdings 126 Net Advisory Fee $532,465 Portfolio Turnover 13% | |
| Holdings [Text Block] | Top 10 Issuers (%) Silvercrest Asset Management Group, Inc. 4.6% Miller Industries, Inc. 4.2% Northern Technologies International Corp. 3.7% Perma-Fix Environmental Services, Inc. 3.5% Radiant Logistics, Inc. 3.4% Legacy Housing Corp. 3.1% DLH Holdings Corp. 2.3% Bel Fuse, Inc. 1.7% U.S. Global Investors, Inc. 1.6% Northwest Pipe Co. 1.6% Top Sectors ** (%) Industrials 30.2% Consumer Discretionary 14.2% Information Technology 13.2% Financials 12.5% Materials 10.1% Health Care 7.2% Energy 6.9% Communication Services 1.2% Consumer Staples 1.0% Cash & Other 3.5% | [1] |
| Material Fund Change [Text Block] | Other Material Fund Changes: During the fiscal year the Perritt Microcap Opportunities Fund was merged with the Perritt Ultra Microcap Fund. The Perritt Microcap Opportunities Fund is considered the surviving entity. | |
| Updated Prospectus Web Address | https://www.perrittcap.com/literature/ | |
| [1] ** The Global Industry Classification Standard (“GICS®”) was developed by and/or is the exclusive property of MSCI, Inc. (“MSCI”) and Standard & Poor’s Financial Services LLC (“S&P”). GICS® is a service mark of MSCI and S&P and has been licensed for use by U.S. Bank Global Fund Services. | ||
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | ||||||||||
| Oct. 31, 2024 | Oct. 31, 2023 | Oct. 31, 2022 | Oct. 31, 2021 | Oct. 31, 2020 | Oct. 31, 2019 | Oct. 31, 2018 | Oct. 31, 2017 | Oct. 31, 2016 | Oct. 31, 2015 | Oct. 31, 2014 | |
| Perritt MicroCap Opportunities Fund | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 16,655 | $ 14,167 | $ 13,786 | $ 16,210 | $ 9,877 | $ 11,282 | $ 12,105 | $ 12,863 | $ 10,356 | $ 9,693 | $ 10,000 |
| Bloomberg US Aggregate Equity Total Return Index [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg US Aggregate Equity Total Return Index | ||||||||||
| Account Value | $ 32,181 | 23,362 | 21,565 | 26,003 | 18,001 | 16,315 | 14,372 | 13,498 | 10,890 | 10,436 | 10,000 |
| Bloomberg US Micro Cap Total Return Index [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg US Micro Cap Total Return Index | ||||||||||
| Account Value | $ 17,024 | $ 13,451 | $ 16,834 | $ 23,550 | $ 12,736 | $ 11,206 | $ 12,426 | $ 12,175 | $ 9,596 | $ 9,587 | $ 10,000 |
| Shareholder Report, Average Annual Return (Details) | 12 Months Ended | 60 Months Ended | 120 Months Ended |
| Oct. 31, 2024 | Oct. 31, 2024 | Oct. 31, 2024 | |
| Without Sales Load [Member] | Perritt MicroCap Opportunities Fund | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | TF (without sales charge) | ||
| Average Annual Return, Percent | 17.56% | 8.10% | 5.23% |
| Bloomberg US Aggregate Equity Total Return Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg US Aggregate Equity Total Return Index | ||
| Average Annual Return, Percent | 37.75% | 14.55% | 12.40% |
| Bloomberg US Micro Cap Total Return Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg US Micro Cap Total Return Index | ||
| Average Annual Return, Percent | 26.56% | 8.72% | 5.46% |
| Label | Element | Value |
| Perritt MicroCap Opportunities Fund | Silvercrest Asset Management Group, Inc. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 4.60% |
| Perritt MicroCap Opportunities Fund | Miller Industries, Inc. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 4.20% |
| Perritt MicroCap Opportunities Fund | Northern Technologies International Corp. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 3.70% |
| Perritt MicroCap Opportunities Fund | Perma-Fix Environmental Services, Inc. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 3.50% |
| Perritt MicroCap Opportunities Fund | Radiant Logistics, Inc. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 3.40% |
| Perritt MicroCap Opportunities Fund | Legacy Housing Corp. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 3.10% |
| Perritt MicroCap Opportunities Fund | DLH Holdings Corp. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 2.30% |
| Perritt MicroCap Opportunities Fund | Bel Fuse, Inc. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 1.70% |
| Perritt MicroCap Opportunities Fund | U.S. Global Investors, Inc. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 1.60% |
| Perritt MicroCap Opportunities Fund | Northwest Pipe Co. [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 1.60% |
| Perritt MicroCap Opportunities Fund | Industrials [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 30.20% |
| Perritt MicroCap Opportunities Fund | Consumer Discretionary [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 14.20% |
| Perritt MicroCap Opportunities Fund | Information Technology [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 13.20% |
| Perritt MicroCap Opportunities Fund | Financials [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 12.50% |
| Perritt MicroCap Opportunities Fund | Materials [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 10.10% |
| Perritt MicroCap Opportunities Fund | Health Care [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 7.20% |
| Perritt MicroCap Opportunities Fund | Energy [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 6.90% |
| Perritt MicroCap Opportunities Fund | Communication Services [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 1.20% |
| Perritt MicroCap Opportunities Fund | Consumer Staples [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 1% |
| Perritt MicroCap Opportunities Fund | Cash & Other [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 3.50% |
