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in Operating Capital [Abstract] Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Issuance of common stock under employee stock purchase plan Stock Issued During Period, Value, Employee Stock Purchase Plan Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Vested, Weighted average grant date fair value per share (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value General, administrative, and other General and Administrative Expense [Member] Basis of Consolidation Consolidation, Policy [Policy Text Block] Expected term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Class of Stock [Domain] Class of Stock [Domain] ESPP Employee Stock [Member] Taxes paid related to net share settlement of equity awards Payment, Tax Withholding, Share-based Payment Arrangement Cash paid to common and preferred stockholders, warrant holders, and vested option holders Payments to Acquire Businesses, Gross Stock-based compensation expense APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Loss Contingencies [Table] Loss Contingencies [Table] Cash Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Underwriting discount Payments for Underwriting Expense Intangible Assets Acquired Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Options vested and expected to vest, Aggregate intrinsic value (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Entity Address, Postal Zip Code Entity Address, Postal Zip Code Prepayment rate Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Prepayment Speed Accounts payable Accounts Payable Outstanding principal balance Financing Receivable, before Allowance for Credit Loss Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Title of 12(b) Security Title of 12(b) Security Statement [Table] Statement [Table] Purchase of loans held-for-sale Payments to Purchase Loans Held-for-sale Stock Appreciation Rights Activity Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] Loans held-for-sale Loans Held-for-sale, Fair Value Disclosure Recently Adopted And Issued Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Statistical Measurement [Axis] Statistical Measurement [Axis] Capitalized software costs Payments for Software Period of payment deferral Loan Payment Deferral Period, CARES Act Loan Payment Deferral Period, CARES Act Cover [Abstract] Net fair value and accrued interest adjustments Financing Receivable, Allowance for Credit Loss Schedule of Other Assets Schedule of Other Assets [Table Text Block] Net Carrying Amount Finite-Lived Intangible Assets, Net Goodwill Beginning balance Ending balance Goodwill Initial conversion price (in dollars per share) Debt Instrument, Convertible, Capped Calls Initial Strike Price Debt Instrument, Convertible, Capped Calls Initial Strike Price Initial cap price (in dollars per share) Debt Instrument, Convertible, Capped Calls Initial Cap Price Debt Instrument, Convertible, Capped Calls Initial Cap Price Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Significant Unobservable Inputs Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Goodwill Rollforward Schedule of Goodwill [Table Text Block] Adjustments to reconcile net income to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Developed technology Developed Technology Rights [Member] Rent expense Operating Lease, Cost Aggregate outstanding principal of loans pledged as collateral Loans Pledged as Collateral Computer equipment Computer Equipment [Member] Derecognition of payable to securitization note holders and residual certificate holders Derecognition Of Payable To Securitization Note Holders And Residual Certificate Holders Derecognition Of Payable To Securitization Note Holders And Residual Certificate Holders Related Party Transactions Related Party Transactions Disclosure [Text Block] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Unamortized debt discount Debt Instrument, Unamortized Discount Purchases of loans Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Employee Stock Purchase Plan Fair Value Assumptions Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block] Options vested and expected to vest, Weighted average remaining contractual term Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term