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Plant and Equipment, Net Loss on loan purchase commitment Loss On Financing Receivable Commitments To Purchase Loss On Financing Receivable Commitments To Purchase Entity Tax Identification Number Entity Tax Identification Number Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Equity Incentive Plans Share-based Payment Arrangement [Text Block] Net Loss Net Loss Net Loss Net Income (Loss) Attributable to Parent Accrued expenses and other liabilities Accrued Liabilities And Other Liabilities, Fair Value Disclosure Accrued Liabilities And Other Liabilities, Fair Value Disclosure LIBOR London Interbank Offered Rate (LIBOR) [Member] Provision for credit losses Provision for credit losses Financing Receivable, Credit Loss, Expense (Reversal) Merchant relationships Merchant Relationships [Member] Merchant Relationships Total net assets Net Assets Net Assets Current Fiscal Year End Date Current Fiscal Year End Date Operating Expenses Operating Expenses [Abstract] Equity securities, at cost Debt Securities, Held-to-maturity Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Shares purchased by warrants (in shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Developed technology Developed Technology Rights [Member] Number of Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Financing Receivable, Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] 2022 Financing Receivable, Year One, Originated, Current Fiscal Year Performance fee liability Performance Fee Liability, Fair Value Disclosure Performance Fee Liability, Fair Value Disclosure Supplemental Disclosures of Cash Flow Information Supplemental Cash Flow Information [Abstract] Certificates of deposit, corporate bonds, and commercial paper classified as cash and cash equivalents 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Point Increase (Decrease) In Measurement Input Remaining amount available of credit facility Line of Credit Facility, Remaining Borrowing Capacity Gross Finite-Lived Intangible Assets, Gross Less than 12 months, unrealized losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Related Party Transactions [Abstract] Schedule of Maturities of Lease Liabilities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] 2021 Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year Basic (in shares) Basic weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Actual performance Fair Value, 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[Domain] Plan Name [Domain] 2012 Stock Plan Amended And Restated 2012 Stock Plan [Member] Amended And Restated 2012 Stock Plan Income Tax Expense Income Tax Expense (Benefit) Cash and cash equivalents and restricted cash, beginning of period Cash and Cash Equivalents and Restricted Cash, end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] Schedule of Funding Debt and Aggregate Future Maturities Schedule of Maturities of Long-term Debt [Table Text Block] Temporary Equity [Line Items] Temporary Equity [Line Items] Variable Rate Component [Axis] Variable Rate Component [Axis] Variable Rate Component Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Local Phone Number Local Phone Number Commercial agreement, profit share liability, measurement input Commercial Agreement, Profit Share Liability, 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Activity for Liabilities With Significant Unobservable Inputs for Fair Value Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Schedule of Indefinite-Lived Intangible Assets Schedule of Indefinite-Lived Intangible Assets [Table Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Borrowings outstanding Funding debt Long-term Debt, Gross Other assets Increase (Decrease) in Other Operating Assets Issuance of common stock Stock Issued During Period, Value, Stock Options Exercised Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Less: Fair value adjustment on loans acquired through business combination Financing Receivable, Acquired In Business Combination, Fair Value Adjustment Financing 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Measurement Basis [Axis] Measurement Basis [Axis] Charge-offs Financing Receivable, Allowance for Credit Loss, Writeoff Net Cash Used in Investing Activities Net Cash Provided by (Used in) Investing Activities First Warrant Shares First Warrant Shares [Member] First Warrant Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Award Type [Domain] Award Type [Domain] Schedule of Loans Held for Investment and Allowance for Credit Loss Financing Receivable, Allowance for Credit Loss [Table Text Block] Schedule of Other Assets Schedule of Other Assets [Table Text Block] Schedule of Servicing Assets at Fair Value Schedule of Servicing Assets at Fair Value [Table Text Block] 60 – 89 calendar days past due Financial Asset, 60 to 89 Days Past Due [Member] Vested and exercisable (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price 2021-A Affirm Asset Securitization Trust 2021-A Notes [Member] Affirm Asset Securitization Trust 2021-A Notes Percentage of residual certificates retained Securitized Assets, Percentage Of Residual Certificates Retained Securitized Assets, Percentage Of Residual Certificates Retained Net Loss per Share Attributable to Common Stockholders Earnings Per Share [Text Block] Recently Adopted Accounting Standards and Recent Accounting Pronouncements Not Yet Adopted New Accounting Pronouncements, Policy [Policy Text Block] Discount rate Measurement Input, Discount Rate [Member] Statement of Financial Position [Abstract] Program profitability Measurement Input, Program Profitability [Member] Measurement Input, Program Profitability