GSK-HSD License Agreement GSK-HSD License Agreement [Member] GSK-HSD License Agreement Proceeds from issuance of warrants Proceeds from Issuance of Warrants Proceeds from credit facility Proceeds from Long-Term Lines of Credit Liability related to the sale of future royalties Beginning carrying value Ending carrying value Royalties, Liability, Noncurrent Royalties, Liability, Noncurrent Enrollment related milestone payments Enrollment Related Milestone Payments Enrollment Related Milestone Payments Adjustments to reconcile net loss to net cash flow from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Statistical Measurement [Domain] Statistical Measurement [Domain] Contract assets Contract with Customer, Asset, after Allowance for Credit Loss, Current Schedule of Lease Assets and Liabilities and Lease Cost Lease, Cost [Table Text Block] Cover [Abstract] Cover [Abstract] Debt securities Debt Securities [Member] 2030 and thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Five Schedule of Maturities of Operating Lease Liabilities on an Undiscounted Basis Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Other liabilities Other Liabilities, Current Income Tax Jurisdiction [Domain] Income Tax Jurisdiction [Domain] Trading Symbol Trading Symbol Annual installments period Cash Receivable Under Collaboration Agreement, Annual Installments Period Cash Receivable Under Collaboration Agreement, Annual Installments Period Comprehensive loss Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest All Trading Arrangements All Trading Arrangements [Member] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Non-NEOs Non-NEOs [Member] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Douglass Given [Member] Douglass Given Income tax credits Tax Credit Carryforward, Amount Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Income Taxes Paid Income Taxes Paid, Net Other Commitments [Line Items] Other Commitments [Line Items] Accrued R&D expenses Accrued Research And Development Expense, Current Accrued Research And Development Expense, Current Planned area of site (in sq ft) Area of Land Pay vs Performance Disclosure [Line Items] Line of Credit Facility [Table] Line of Credit Facility [Table] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Accounts receivable Increase (Decrease) in Accounts Receivable Net Loss per Share Earnings Per Share, Policy [Policy Text Block] Operating lease, net Increase (Decrease) in Operating Lease Liability Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Proceeds from the exercises of stock options Proceeds from Stock Options Exercised Land Land [Member] Award Timing Disclosures [Line Items] Other Performance Measure, Amount Other Performance Measure, Amount 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Three Leases Lessee, Operating Leases [Text Block] Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] Operating lease cost Operating Lease, Cost Lease Cost Lease, Cost [Abstract] Christopher Anzalone September 2024 Plan [Member] James Hamilton September 2024 Plan Common stock reserved for issuance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Lease liabilities, net of current portion Operating Lease, Liability, Noncurrent Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Segment Information Segment Reporting, Policy [Policy Text Block] Tax credits Deferred Tax Assets, Tax Credit Carryforwards Deferred revenue Contract liabilities Contract with Customer, Liability, Current Plan Name Plan Name [Domain] Common stock offering price (in dollars per share) Sale of Stock, Price Per Share Operating Leased Assets [Line Items] Operating Leased Assets [Line Items] Effect of dilutive securities (in shares) Weighted Average Number of Shares Outstanding, Diluted, Adjustment Upfront payment Cash Received As Due Under Collaboration Agreement Cash received as due under collaboration agreement. Other assets Other Assets, Noncurrent Entity Tax Identification Number Entity Tax Identification Number Leases [Abstract] Leases [Abstract] Gross Carrying Amount Finite-Lived Intangible Assets, Gross Schedule Of Finite Lived Intangible Assets [Table] Intangible Asset, Finite-Lived [Table] Gross increase for prior period tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Antidilutive Securities, Name Antidilutive Securities, Name [Domain] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Foreign Deferred Foreign Income Tax Expense (Benefit) (Accretion) Amortization of note premiums/discounts Investment Income, Net, Amortization of Discount and Premium Money market instruments Money Market Funds [Member] Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Patents Patents [Member] Net proceeds Sale of Stock, Consideration Received on Transaction CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Deferred tax assets: Deferred Tax Assets, Net [Abstract] Net loss per share attributable to Arrowhead Pharmaceuticals, Inc.: Earnings Per Share Reconciliation [Abstract] Secured Debt Secured Debt [Member] Plan Name Plan Name [Axis] Prepaid expenses Prepaid Expense, Current Common Stock Equity Components [Axis] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Other current assets Other Assets, Current Award Timing Method Award Timing Method [Text Block] Common stock shares value reserved for future issuance Common Stock Capital Shares Value Reserved For Future Issuance Common stock, capital shares value reserved for future issuance. Research and Development Expenses Research and Development Expense, Policy [Policy Text Block] Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Available-for-sale securities Debt Securities, Available-for-Sale Development milestone payments Development Milestone Payments Development Milestone Payments Measurement Frequency Measurement Frequency [Axis] Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Insider Trading Policies and Procedures [Line Items] Use of Estimates Use of Estimates, Policy [Policy Text Block] Supplementary disclosure of non-cash investing activities: Cash Flow, Noncash Investing Activities Disclosure [Abstract] Cash Flow, Noncash Investing Activities Disclosure Financing Agreement Financing Agreement [Member] Financing Agreement Adjustment to Compensation, Amount Adjustment to Compensation Amount Aggregate Intrinsic Value Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Additional paid-in capital Additional Paid in Capital, Common Stock Compensation Amount Outstanding Recovery Compensation Amount Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Entity Small Business Entity Small Business Company Selected Measure Amount Company Selected Measure Amount Geographical Geographical [Axis] 2013 Plan Two Thousands Thirteen Incentive Plan [Member] Two thousands thirteen incentive plan. Payment of debt issuance costs Payments of Debt Issuance Costs Tabular List, Table Tabular List [Table Text Block] Net deferred tax assets (liabilities) Deferred Tax Assets, Net Non-deductible compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Compensation, Percent Effective Income Tax Rate Reconciliation, Nondeductible Expense, Compensation, Percent 2029 Lessee, Operating Lease, Liability, to be Paid, Year Five Interest income Investment Income, Interest and Dividend Level 3 Fair Value, Inputs, Level 3 [Member] Sales-related milestone payments Sales Related Milestone Payments Sales-related milestone payments. Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Cash paid for amounts included in the measurement of lease liabilities: Cash Flow, Operating Activities, Lessee [Abstract] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Number of securities called by warrants (in shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Office space leases (in sq ft) Land Subject to Ground Leases Lessee Lease Description [Line Items] Lessee, Lease, Description [Line Items] Contingent liabilities Loss Contingency Accrual Accrued expenses Total accrued expenses Accrued Liabilities, Current Potentially dilutive securities excluded from computation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Employee Benefit Plans Compensation and Employee Benefit Plans [Text Block] Current investments, Available-for-sale, Gross Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Current Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Current Christopher Anzalone August 22 2024 Plan [Member] Christopher Anzalone August 22 2024 Plan Asset Acquisition Asset Acquisition [Axis] Credit Facility [Domain] Credit Facility [Domain] Cash, cash equivalents and restricted cash BEGINNING OF PERIOD END OF PERIOD Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Number of distinct performance obligations Number Of Distinct Performance Obligations Number of distinct performance obligations. Percentage of commission to sales agent Percentage Of Commission On Aggregate Gross Proceeds From Sale Of Common Stock Percentage of commission on aggregate gross proceeds from sale of common stock. Additional tenant improvement allowance interest per annum Additional Tenant Improvement Allowance, Interest Per Annum Additional Tenant Improvement Allowance, Interest Per Annum Foreign Current Foreign Tax Expense (Benefit) Current assets: Assets, Current [Abstract] Commercial notes Commercial Notes [Member] Commercial Notes Proceeds from the sale of future royalties Proceeds from Sale of Future Royalties Proceeds from Sale of Future Royalties Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Debt issuance costs included in accrued expenses Debt Issuance Costs Incurred During Noncash or Partial Noncash Transaction Options Share-Based Payment Arrangement, Option [Member] Short-term lease cost Short-Term Lease, Cost Vested (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 Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] 2025 Lessee, Operating Lease, Liability, to be Paid, Year One Research Facility in San Diego Research Facility In San Diego [Member] Research Facility in San Diego. Development regulatory and sales milestones payments Development Regulatory And Sales Milestones Payments Development regulatory and sales milestones payments. Antidilutive Security, Excluded EPS Calculation [Table] Antidilutive Security, Excluded EPS Calculation [Table] Accrued R&D expenses; co-development Accrued Research And Development Co-Development Expense, Current Accrued Research And Development Co-Development Expense, Current Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Permanent and other items Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Municipal securities Municipal Bonds [Member] Security Exchange Name Security Exchange Name Non-cash interest expense on credit facility Paid-in-Kind Interest Award Type Award Type [Axis] Corporate debt securities Corporate Debt Securities [Member] Exercised (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Right-of-use assets adjusted in exchange for new/amended operating lease liabilities Right-Of-Use Asset Adjustment In Exchange For Operating Lease Liability Right-Of-Use Asset Adjustment In Exchange For Operating Lease Liability Cash, Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Supplementary disclosure of non-cash financing activities: Cash Flow, Noncash Financing Activities Disclosure [Abstract] Cash Flow, Noncash Financing Activities Disclosure Number of RSUs Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Property, plant and equipment, net Property, plant and equipment, net Property, Plant and Equipment, Net ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag State Current State and Local Tax Expense (Benefit) Schedule of Short-term, Long-term Investments and Marketable Securities Held To Maturity Securities And Marketable Securities Table [Table Text Block] Held to maturity securities and marketable securities. Noncontrolling interest Equity, Attributable to Noncontrolling Interest Additional tenant improvement allowance liability Additional Tenant Improvement Allowance Liability Additional Tenant Improvement Allowance Liability Weighted-Average Exercise Price Per Share, Exercisable (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price Other comprehensive loss, net of tax: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Foreign Currency Translation Adjustments Foreign Currency Transactions and Translations Policy [Policy Text Block] Realized loss on investments Realized Investment Gains (Losses) Expiration Date Trading Arrangement Expiration Date CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Number of new target programs Number Of New Target Programs Number Of New Target Programs Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Wisconsin WISCONSIN Lease liabilities Operating Lease, Liability, Current Total Shareholder Return Amount Total Shareholder Return Amount Common stock, shares issued (in shares) Common Stock, Shares, Issued Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Net operating loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards Research equipment Equipment [Member] Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Less: Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Subsequent Event [Line Items] Subsequent Event [Line Items] Property, plant and equipment, gross Property, Plant and Equipment, Gross Receivables included in accounts receivable Accounts Receivable, after Allowance for Credit Loss Exercise of stock options (in shares) Exercised (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Weighted- Average Exercise Price Per Share Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Research and development Research and Development Expense [Member] Intangible Assets Subject to Amortization Goodwill and Intangible Assets, Policy [Policy Text Block] Lapse of statue of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Tax credit carryforward, amount, subject to expiration Tax Credit Carryforward, Amount, Subject To Expiration Tax Credit Carryforward, Amount, Subject To Expiration Common stock, shares authorized (in shares) Common Stock, Shares Authorized Schedule of Company's Current Pipeline Schedule of Current Products [Table Text Block] Schedule of Current Products Unrealized gains (losses) on available-for-sale securities OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax Diluted (in shares) Weighted-average diluted shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Intangible assets Deferred Tax Assets, Goodwill and Intangible Assets Janssen Janssen Pharmaceuticals Incorporation [Member] Janssen Pharmaceuticals, Incorporation. MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Financing Agreement, Initial Term Loan Interest Financing Agreement, Initial Term Loan Interest [Member] Financing Agreement, Initial Term Loan Interest Inducement Awards Inducement Awards [Member] Inducement Awards Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Total Arrowhead Pharmaceuticals, Inc. stockholders' equity Equity, Attributable to Parent Total gross deferred tax assets Deferred Tax Assets, Gross Entity Voluntary Filers Entity Voluntary Filers Collaboration and License Agreements Collaborative Arrangement Disclosure [Text Block] Initial transaction price Initial Transaction Price Initial transaction price. Operating lease renewal term Lessee, Operating Lease, Renewal Term Interest expense Interest Expense, Nonoperating Total deferred tax Deferred Income Tax Expense (Benefit) Inducement Plan Inducement Plan [Member] Inducement Plan Schedule Of Liability Related To The Sale Of Future Royalties Schedule Of Liability Related To The Sale Of Future Royalties [Table Text Block] Schedule Of Liability Related To The Sale Of Future Royalties Employee benefits costs Defined Contribution Plan, Cost Fair Value, Measurements, Recurring Fair Value, Recurring [Member] Audit Information [Abstract] Audit Information Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross Commercial milestone payments at first commercial sale Commercial Milestone Payments At First Commercial Sale Commercial milestone payments at first commercial sale. Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Number of shares authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized Sale of Stock [Domain] Sale of Stock [Domain] Other Increase (Decrease) in Other Operating Liabilities Net carrying amount Long-Term Debt Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Document Fiscal Period Focus Document Fiscal Period Focus 2028 Long-Term Debt, Maturity, Year Four All Executive Categories All Executive Categories [Member] Thereafter Long-Term Debt, Maturity, after Year Five Discretionary match percentage Defined Contribution Plan, Employer Matching Contribution, Percent of Match 2026 Finite-Lived Intangible Asset, Expected Amortization, Year Two Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Weighted- Average Remaining Contractual Term (Years) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term ASSETS Assets [Abstract] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Expected dividend yield Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate Document Type Document Type Common stock - restricted stock units vesting Stock Issued During Period, Value, Restricted Stock Award, Gross Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Common stock - restricted stock units vesting (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Contractual interest expense Interest Expense, Debt, Excluding Amortization Document Annual Report Document Annual Report Additional remaining development regulatory and sales milestones payments Additional Remaining Development Regulatory And Sales Milestones Payments Additional remaining development regulatory and sales milestones payments. 2021 Plan Two Thousand Twenty One Incentive Plan [Member] Two thousand twenty one incentive plan. Weighted-Average Remaining Contractual Term, Exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Financing Agreement, Initial Term Loan Financing Agreement, Initial Term Loan [Member] Financing Agreement, Initial Term Loan Schedule Of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Marketable debt securities, Adjusted Basis Debt Securities, Available-for-Sale, Amortized Cost Schedule of Receivables and Contract Liabilities Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Schedule of Intangible Assets Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Subsequent Event [Table] Subsequent Event [Table] Lease Assets and Liabilities Assets and Liabilities, Lessee [Abstract] Maximum Maximum [Member] Amortization expense Amortization of Intangible Assets Contract liabilities included in deferred revenue Contract with Customer, Liability Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Furniture Furniture and Fixtures [Member] Intangible assets, net Net Carrying Amount Finite-Lived Intangible Assets, Net Christopher Anzalone August 16 2024 Plan [Member] Christopher Anzalone August 16 2024 Plan Antidilutive Securities Antidilutive Securities [Axis] Accounts payable Accounts Payable, Current Accounting Policies [Abstract] Accounting Policies [Abstract] Leasehold improvements Leasehold Improvements [Member] Cancelled or expired (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Assumptions Used to Value Stock Options Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Current Fiscal Year End Date Current Fiscal Year End Date Less imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Total Lease, Cost Statistical Measurement [Axis] Statistical Measurement [Axis] PEO Name PEO Name Milestone payment Milestone Payment Earned Milestone payment earned. Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Loss before income tax expense and noncontrolling interest Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Award Type Award Type [Domain] Fixed assets Deferred Tax Liabilities, Property, Plant and Equipment Name Outstanding Recovery, Individual Name License Licensing Agreements [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Stock compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-Based Compensation Cost Variable lease cost Variable Lease, Cost Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Non-PEO NEO Non-PEO NEO [Member] Capital expenditures incurred Commitments, Capital Expenditures Incurred To Date Commitments, Capital Expenditures Incurred To Date Useful Lives Finite-Lived Intangible Asset, Useful Life Net (decrease) increase in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Additional Paid-In Capital Additional Paid-in Capital [Member] Award Timing Predetermined Award Timing Predetermined [Flag] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Schedule Of Held To Maturity Securities And Marketable Securities [Table] Schedule Of Held To Maturity Securities And Marketable Securities [Table] Schedule of held to maturity securities and marketable securities. Class Of Stock [Line Items] Class of Stock [Line Items] Current investments, Available-for-sale, Adjusted Basis Debt Securities, Available-for-Sale, Amortized Cost, Current Capitalized research and development Deferred Tax Assets In Process Research And Development Cost Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from in-process research and development costs. Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Forecast Forecast [Member] Operating loss carryforwards not subject to expiration Operating Loss Carryforwards, Not Subject To Expiration Operating Loss Carryforwards, Not Subject To Expiration Financing Agreement Long-Term Debt [Text Block] Diluted (in dollars per share) Diluted net loss per share (in dollars per share) Earnings Per Share, Diluted Finite-Lived Intangible Assets by Major Class Finite-Lived Intangible Assets by Major Class [Axis] Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Olpasiran Agreement Olpasiran Agreement [Member] Olpasiran agreement. Counterparty Name [Domain] Counterparty Name [Domain] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Name Measure Name State State and Local Jurisdiction [Member] Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic Entity Interactive Data Current Entity Interactive Data Current Deferred revenue Increase (Decrease) in Contract with Customer, Liability Total current tax Current Income Tax Expense (Benefit) Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Net unrealized loss on held-to-maturity securities OCI, Debt Securities, Available-for-Sale, Transfer from Held-to-Maturity, Gain (Loss), before Adjustment and Tax Retirement Benefits [Abstract] Retirement Benefits [Abstract] Percentage of compensation Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Customer [Axis] Customer [Axis] Proceeds from investment in joint venture Proceeds from Contributed Capital Foreign-derived intangible income deduction Effective Income Tax Rate Reconciliation, FDII, Percent Fair Value Measurements for Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Milestone payment receivable upon achievement of phase two and first patient dosed in phase three Milestone Payment Receivable Upon Achievement Of Phase Two And First Patient Dosed In Phase Three Milestone payment receivable upon achievement of phase two and first patient dosed in phase three. Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Computers and software Computers And Software [Member] Computers And Software Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Drug Manufacturing Facility Drug Manufacturing Facility [Member] Drug manufacturing facility. Stock-based compensation Share-Based Payment Arrangement, Noncash Expense 2004 Equity Incentive Plan, 2013 Equity Incentive Plan, 2021 Equity Incentive Plan and Inducement Grants Two Thousand Four Equity Incentive Plan Two Thousand Thirteen Equity Incentive Plan Two Thousand Twenty One Equity Incentive Plan And Inducement Grants [Member] Two thousand four equity incentive plan two thousand thirteen equity incentive plan Two thousand twenty one equity incentive plan and inducement grants. Summary of Awards Outstanding Share-Based Payment Arrangement, Activity [Table Text Block] Lease liabilities Deferred Tax Assets Right Of Use Assets Or Lease Liabilities Deferred tax assets right of use assets/ lease liabilities. Collaboration And License Agreements [Abstract] Collaboration And License Agreements [Abstract] Collaboration and license agreements. Net loss including noncontrolling interest Net loss Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Income tax (benefit) expense Income tax provision Income Tax Expense (Benefit) Other income (expense): Nonoperating Income (Expense) [Abstract] Interest rate Debt Instrument, Interest Rate, Stated Percentage Available-for-sale securities, at fair value Current investments, Available-for-sale, Fair Value Debt Securities, Available-for-Sale, Current Supplementary disclosure of cash flows: Supplemental Cash Flow Information [Abstract] Schedule Of Held To Maturity Securities And Marketable Securities [Line Items] Schedule Of Held To Maturity Securities And Marketable Securities [Line Items] Schedule of held to maturity securities and marketable securities. Weighted average period to recognize pre-tax compensation expense Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Revenue Revenue from Contract with Customer, Excluding Assessed Tax Organization And Significant Accounting Policies [Table] Organization And Significant Accounting Policies [Table] Organization and significant accounting policies. Total other (expense) income Nonoperating Income (Expense) Development and sales milestone payments Development And Sales Milestones Payments Development And Sales Milestones Payments Auditor Firm ID Auditor Firm ID Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Operating loss Operating Income (Loss) Liability, Sale Of Future Royalties [Roll Forward] Liability, Sale Of Future Royalties [Roll Forward] Liability, Sale Of Future Royalties Income Tax Jurisdiction [Axis] Income Tax Jurisdiction [Axis] Stock compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-Based Payment Arrangement, Percent Research and development Research and Development Expense (Excluding Acquired in Process Cost) Total Liabilities, Noncontrolling Interest and Stockholders' Equity Liabilities and Equity Subsequent Events Subsequent Events [Text Block] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] All Adjustments to Compensation All Adjustments to Compensation [Member] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Axis] Accrued payroll and benefits Employee-related Liabilities, Current Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Number of options to renew Number Of Options To Renew Number of options to renew. Takeda Takeda Pharmaceuticals United States Of America Incorporated [Member] Takeda Pharmaceuticals United States of America Incorporated. Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Finite-Lived Intangible Assets, Major Class Name Finite-Lived Intangible Assets, Major Class Name [Domain] Schedule of Maturities of Long-Term Debt Schedule of Maturities of Long-Term Debt [Table Text Block] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Scenario [Domain] Scenario [Domain] Individual: Individual [Axis] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Horizon Horizon Therapeutics Ireland D A C [Member] Horizon Therapeutics Ireland DAC. Expected term (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term U.S. government and agency securities US Government Agencies Debt Securities [Member] Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Entity Address, State or Province Entity Address, State or Province Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Statement [Line Items] Statement [Line Items] Liability Related to the Sale of Future Royalties Liability Related To The Sale Of Future Royalties [Text Block] Liability Related To The Sale Of Future Royalties Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] James Hamilton [Member] James Hamilton Operating expenses: Operating Expenses [Abstract] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Schedule of Useful Lives of Property Plant and Equipment Schedule of Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Financial Instruments [Domain] Financial Instruments [Domain] Beginning balance (in dollars per share) Ending balance (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value LIABILITIES, NONCONTROLLING INTEREST AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Milestone payment received Milestone Payment Received, Liability Related To Sale Of Future Royalties Milestone Payment Received, Liability Related To Sale Of Future Royalties Cash received for amounts included in the measurement of lease liabilities: Cash Flow, Operating Activities, Lessee, Cash Received For Amounts Included In Measurement Of Lease Liabilities [Abstract] Cash Flow, Operating Activities, Lessee, Cash Received For Amounts Included In Measurement Of Lease Liabilities Less: Unamortized debt discount and issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent Minimum Minimum [Member] Restatement Determination Date Restatement Determination Date Unrealized gains Deferred Tax Liabilities, Other Comprehensive Income Adoption Date Trading Arrangement Adoption Date Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Beginning balance (in dollars per share) Ending balance (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price Right-of-use assets Operating Lease, Right-of-Use Asset Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Number of options outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] U.S. federal statutory income tax Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Initial Term Loan Total Long-Term Debt, Gross Liability Related To The Sale Of Future Royalties [Abstract] Liability Related To The Sale Of Future Royalties Exercise Price Award Exercise Price California CALIFORNIA Components of the Net Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Net Loss Per Share Earnings Per Share [Text Block] Novartis Novartis [Member] Novartis. Arrangement Duration Trading Arrangement Duration Adeoye Olukotun [Member] Adeoye Olukotun Subsequent Event Subsequent Event [Member] Operating loss carryforwards Operating Loss Carryforwards Exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Annual installement Cash Receivable Under Collaboration Agreement, Annual Installments Cash Receivable Under Collaboration Agreement, Annual Installments Restricted cash Restricted Cash and Cash Equivalents, Current Granted (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Federal Domestic Tax Jurisdiction [Member] Income Taxes Income Tax, Policy [Policy Text Block] Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Net increase (decrease) in cash and investments Increase (Decrease) In Cash And Investments Increase decrease in cash and investments. License and Co-Funding Agreement License And Co Funding Agreement [Member] License and co-funding agreement. Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Debt instrument, term Debt Instrument, Term Unrecognized Tax Benefits [Roll Forward] Unrecognized Tax Benefits [Roll Forward] 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Four All Individuals All Individuals [Member] Building Building [Member] PEO PEO [Member] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Organization And Significant Accounting Policies [Line Items] Organization And Significant Accounting Policies [Line Items] Organization and significant accounting policies. Name Trading Arrangement, Individual Name ATM Agreement At The Market Agreement [Member] At-the-market agreement. Other, net Other Nonoperating Income (Expense) Corporate Headquarters In Pasadena Corporate Headquarters In Pasadena [Member] Corporate Headquarters in Pasadena Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Long-Lived Tangible Asset Long-Lived Tangible Asset [Axis] Entity Public Float Entity Public Float Number of distinct bundle Number Of Distinct Bundle Number of distinct bundle. Unrecognized pre-tax compensation expense Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Royalty payment threshold Royalty Payment Threshold Royalty Payment Threshold Schedule of Line of Credit Facilities Schedule of Line of Credit Facilities [Table Text Block] CASH, CASH EQUIVALENTS AND RESTRICTED CASH: Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations [Abstract] Property, plant and equipment, reclassification Property, Plant and Equipment, Transfers and Changes Facilities Facilities [Member] Facilities. Undistributed earnings of foreign subsidiaries Undistributed Earnings of Foreign Subsidiaries Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table] Shares reserve for issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Beginning balance (in shares) Ending balance (in shares) Shares, Outstanding Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Non-cash interest expense on liability related to the sale of future royalties Non-cash interest expense recognized Non-Cash Interest Expense, Liability Related to Sale of Future Royalties Non-Cash Interest Expense, Liability Related to Sale of Future Royalties Total long-term liabilities Liabilities, Noncurrent Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Local Phone Number Local Phone Number Valuation allowance Valuation allowance Deferred Tax Assets, Valuation Allowance Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Royalty Pharma Agreement Royalty Pharma Agreement [Member] Royalty Pharma Agreement Total operating expenses Operating Expenses Expected volatility Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Risk-free interest rate, maximum Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum Summary of Share Activity Related to RSUs Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Schedule of Interest Expense Recognized Related to Credit Facility Summary Of Interest Expense Recognized Related To Credit Facility [Table Text Block] Summary Of Interest Expense Recognized Related To Credit Facility Upfront payment received Upfront Payment Received, Liability Related To Sale Of Future Royalties Upfront Payment Received, Liability Related To Sale Of Future Royalties Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Operating cash flows from operating leases Operating Lease, Cash Received For Amounts Included In Measurement Of Lease Liabilities Operating Lease, Cash Received For Amounts Included In Measurement Of Lease Liabilities Long-term liabilities: Liabilities, Noncurrent [Abstract] PEO Total Compensation Amount PEO Total Compensation Amount Federal Deferred Federal Income Tax Expense (Benefit) Long-Lived Tangible Asset Long-Lived Tangible Asset [Domain] Schedule of Accrued Liabilities Schedule of Accrued Liabilities [Table Text Block] Statement of Income Location, Balance [Axis] Statement of Income Location, Balance [Axis] Amount insured in FDIC per account Cash, FDIC Insured Amount Intangible assets subject to amortization, impairment Impairment of Intangible Assets, Finite-Lived Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Thereafter Finite-Lived Intangible Asset, Expected Amortization, after Year Five Debt Disclosure [Abstract] Common Stock Common Stock [Member] Measure: Measure [Axis] Gross increase for current period tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Amgen Amgen Incorporated [Member] Amgen Incorporated. Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Common stock issued, net of offering costs (in shares) Stock Issued During Period, Shares, New Issues Line of Credit Line of Credit [Member] Entity Emerging Growth Company Entity Emerging Growth Company Market capitalization threshold Debt Instrument, Covenant, Market Capitalization, Threshold Debt Instrument, Covenant, Market Capitalization, Threshold Entity Central Index Key Entity Central Index Key Principal repayment schedule for fifth year 2029 Long-Term Debt, Maturity, Year Five Scenario [Axis] Scenario [Axis] General and administrative expense General and Administrative Expense [Member] Lessee Lease Description [Table] Lessee, Lease, Description [Table] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Clinical Accrual Clinical Accrual Policy [Policy Text Block] Clinical Accrual Policy Stockholders' Equity Equity [Text Block] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Equity Component Equity Component [Domain] Financial Instrument [Axis] Financial Instrument [Axis] Operating loss carryforwards subject to expiration Operating Loss Carryforwards, Subject To Expiration Operating Loss Carryforwards, Subject To Expiration Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Stock-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Entity Shell Company Entity Shell Company Number of collaboration programs Number Of Collaboration Programs Number Of Collaboration Programs Deferred tax liabilities: Deferred Tax Liabilities, Net [Abstract] Entity Incorporation State Country Code Entity Incorporation, State or Country Code Title Trading Arrangement, Individual Title Statement [Table] Statement [Table] Total interest expense Interest Expense, Debt Milestone payment receivable upon FDA approval Milestone Payment Receivable Upon FDA Approval Milestone Payment Receivable Upon FDA Approval Measurement Frequency Measurement Frequency [Domain] Counterparty Name [Axis] Counterparty Name [Axis] Schedule of Components of Loss Before Income Tax Expense and Noncontrolling Interest Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Beginning balance of unrecognized tax benefits Ending balance of unrecognized tax benefits Unrecognized Tax Benefits Numerator: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Variable Interest Entity Consolidation, Variable Interest Entity, Policy [Policy Text Block] City Area Code City Area Code Current liabilities: Liabilities, Current [Abstract] Auditor Location Auditor Location Milestone payment receivable upon achievement of enrollment in phase 3 clinical trial Milestone Payment Receivable Upon Achievement of Enrollment in Phase 3 Clinical Trial Milestone Payment Receivable Upon Achievement of Enrollment in Phase 3 Clinical Trial Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Level 1 Fair Value, Inputs, Level 1 [Member] Impairment Finite-Lived Intangible Assets, Impairment Finite-Lived Intangible Assets, Impairment Foreign currency translation adjustments Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Accrued compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Total current assets Assets, Current Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Aggregate purchase price by investors Sale Of Stock, Aggregate Purchase Price Sale Of Stock, Aggregate Purchase Price Accrued expenses Increase (Decrease) in Accrued Liabilities Line of credit facility, remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Number of Options Outstanding, Exercisable (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number 2027 Long-Term Debt, Maturity, Year Three Milestone payments Milestone Payment Received Milestone payment received. Weighted- Average Grant Date Fair Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted-average grant date fair value per share Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Subsequent Event Type [Axis] Subsequent Event Type [Axis] Percentage of eligible to receive tiered royalties on net sales Percentage Of Eligible To Receive Tiered Royalties On Net Sales Percentage of eligible to receive tiered royalties on net sales. Income Taxes Income Tax Disclosure [Text Block] Organization and Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] 2028 Lessee, Operating Lease, Liability, to be Paid, Year Four Earnings Per Share [Abstract] Employee Contributions up to 3% Employee Contributions Up To Three Percent [Member] Employee contributions up to three percent. Equity [Abstract] Equity [Abstract] Accumulated deficit Retained Earnings (Accumulated Deficit) Employee Contributions Next 2% Employee Contribution Next Two Percent [Member] Employee contribution next two percent. General and administrative General and Administrative Expense 2026 Long-Term Debt, Maturity, Year Two Organization, Consolidation and Presentation of Financial Statements [Abstract] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Equity Awards Adjustments Equity Awards Adjustments [Member] Weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Total operating lease liabilities Operating Lease, Liability Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Underlying Securities Award Underlying Securities Amount Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Total (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Options And Equity Instruments Other Than Options, Outstanding Share-Based Compensation Arrangement By Share-Based Payment Award, Options And Equity Instruments Other Than Options, Outstanding Debt instrument, covenant, minimum liquidity cash, cash equivalents and investments Debt Instrument, Covenant, Minimum Liquidity If Capitalization Is Above Threshold Debt Instrument, Covenant, Minimum Liquidity If Capitalization Is Above Threshold Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Credit Facility [Axis] Credit Facility [Axis] Amendment Flag Amendment Flag Entity Registrant Name Entity Registrant Name Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Depreciation and amortization expense for property and equipment Depreciation, Depletion and Amortization Intangible Assets Intangible Assets Disclosure [Text Block] State Deferred State and Local Income Tax Expense (Benefit) Fair Value as of Grant Date Award Grant Date Fair Value Subsequent Events [Abstract] Subsequent Events [Abstract] Level 2 Fair Value, Inputs, Level 2 [Member] Shares of common stock issued (in shares) Sale of Stock, Number of Shares Issued in Transaction Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Domain] Noncontrolling interest and stockholders' equity: Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Geographical Geographical [Domain] GSK Glaxosmithkline Intellectual Property Limited [Member] Glaxosmithkline Intellectual Property Limited. Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Schedule of Revenue Disaggregation of Revenue [Table Text Block] Common stock issued, net of offering costs Stock Issued During Period, Value, New Issues Collaborative Arrangements Collaborative Arrangement, Accounting Policy [Policy Text Block] Colorado Owner, LLC Colorado Owner L L C [Member] Colorado Owner, LLC. Entity Address, Postal Zip Code Entity Address, Postal Zip Code Current investments, Available-for-sale, Gross Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, Current Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, Current Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Schedule of Share-Based Payment Arrangement, Expensed Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Restatement Determination Date: Restatement Determination Date [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Number of agreements Number Of Agreements Number of agreements. Security12b Title Title of 12(b) Security Common stock, $0.001 par value: Authorized 290,000 shares; issued and outstanding 124,376 and 107,312 shares Common Stock, Value, Issued Document Financial Statement Error Correction [Flag] Document Financial Statement Error Correction [Flag] Sarepta Collaboration Agreement Sarepta Collaboration Agreement [Member] Sarepta Collaboration Agreement Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] U.S. government bonds US Government Debt Securities [Member] Total Income (Loss) Attributable to Parent, before Tax State income taxes, net of federal tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Maximum additional tenant improvement allowance Maximum Additional Tenant Improvement Allowance Maximum Additional Tenant Improvement Allowance Auditor Name Auditor Name Other Deferred Tax Assets, Other Finite Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Forfeited (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Credit facility Long-Term Line of Credit, Noncurrent Proceeds from sales and maturities of investments Proceeds from Sale, Maturity and Collection of Investments Estimated Useful Lives Property, Plant and Equipment, Useful Life Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward] Total gross deferred tax liability Deferred Tax Liabilities, Gross Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Basic (in dollars per share) Basic net loss per share (in dollars per share) Earnings Per Share, Basic Accounts payable Increase (Decrease) in Accounts Payable Proceeds from the issuance of common stock, net of offering costs Proceeds from Issuance of Common Stock Operating cash flows from operating leases Operating Lease, Payments Cash receivable under collaboration agreement Cash Receivable Under Collaboration Agreement Cash receivable as upfront payment due under collaboration agreement. Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Amount intends to invest for buildout of the facilities Amount Intends To Invest For Buildout Of Facilities Amount intends to invest for buildout of facilities. Visirna ESOP Visirna ESOP [Member] Visirna ESOP Deferred revenue Deferred Tax Assets, Deferred Income Capital expenditures included in accounts payable and accrued expenses Capital Expenditures Incurred but Not yet Paid Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Proceeds from debt, net of issuance costs Proceeds from Debt, Net of Issuance Costs Milestone payment receivable upon receipt of royalty payments Milestone Payment Receivable, Upon Receipt Of Royalty Payments Milestone Payment Receivable, Upon Receipt Of Royalty Payments Property, Plant and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Schedule Of Stock By Class [Table] Stock, Class of Stock [Table] Total current liabilities Liabilities, Current Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Unrecognized pre-tax compensation expense Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Total Assets Assets Concentration of Credit Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] 2025 Finite-Lived Intangible Asset, Expected Amortization, Year One Long-term line of credit Long-Term Line of Credit Christopher Anzalone [Member] Christopher Anzalone Liability related to the sale of future royalties, interest rate Liability, Sale Of Future Royalties, Interest Rate Liability, Sale Of Future Royalties, Interest Rate Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Interest in joint venture Noncontrolling Interest, Increase from Subsidiary Equity Issuance Purchases of property, plant and equipment Payments to Acquire Property, Plant, and Equipment Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Commitments and contingencies (Note 7) Commitments and Contingencies Stock-Based Compensation Share-Based Payment Arrangement [Policy Text Block] Risk-free interest rate, minimum Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum Summary of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Termination Date Trading Arrangement Termination Date Warrant exercise price (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] 2026 Lessee, Operating Lease, Liability, to be Paid, Year Two 2025 Long-Term Debt, Maturity, Year One Stock-Based Compensation Share-Based Payment Arrangement [Text Block] Entity Address, City or Town Entity Address, City or Town Sarepta Sarepta [Member] Sarepta Leases Lessee, Leases [Policy Text Block] Debt Instrument [Axis] Debt Instrument [Axis] Summarized Information about Stock Options Share-Based Payment Arrangement, Option, Activity [Table Text Block] Intrinsic value of options exercised Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value Stock-based compensation expense Share-Based Payment Arrangement, Expense Net loss attributable to Arrowhead Pharmaceuticals, Inc. Net loss attributable to Arrowhead Pharmaceuticals, Inc. Net Income (Loss) Attributable to Parent Trading Arrangement: Trading Arrangement [Axis] Investments, Debt and Equity Securities [Abstract] Income tax expense (benefit) related to uncertain tax positions Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense Granted (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Other Commitments [Table] Other Commitments [Table] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Schedule of Finite-Lived Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Warrants purchase price (in dollars per share) Class of Warrant or Right, Purchase Price of Warrants or Rights Class of Warrant or Right, Purchase Price of Warrants or Rights Foreign Foreign Tax Jurisdiction [Member] Accrued capital expenditures Accrued Capital Expenditure, Current Accrued Capital Expenditure, Current Milestone payment receivable Milestone Payment Receivable Milestone Payment Receivable Entity File Number Entity File Number Right-of-use assets Deferred Tax Liabilities, Leasing Arrangements Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Document Fiscal Year Focus Document Fiscal Year Focus Non- controlling Interest Noncontrolling Interest [Member] Income Statement [Abstract] Income Statement [Abstract] Entity Address, Address Line One Entity Address, Address Line One Underwriting Agreement Underwriting Agreement [Member] Underwriting Agreement Federal Current Federal Tax Expense (Benefit) Weighted-average shares used in calculating Denominator: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Entity Address, Address Line Two Entity Address, Address Line Two Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Effect of exchange rate on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations Total financial assets Assets, Fair Value Disclosure Lease term Lessee, Operating Lease, Term of Contract Other Other Accrued Liabilities, Current Name Forgone Recovery, Individual Name Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Aggregate Intrinsic Value, Exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Intrinsic Value Weighted-average remaining lease term (in years) Operating Lease, Weighted Average Remaining Lease Term 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Five Document Period End Date Document Period End Date Sale of Stock [Axis] Sale of Stock [Axis] Investments Investment, Policy [Policy Text Block] Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Total Lessee, Operating Lease, Liability, to be Paid Horizon License Agreement Horizon License Agreement [Member] Horizon License Agreement Share-based payment award (in shares) Beginning of period (in shares) End of period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Cancelled or expired (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Expirations in Period Insider Trading Arrangements [Line Items] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Balance Sheet Accounts Supplemental Balance Sheet Disclosures [Text Block] Gross decrease for prior period tax positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Schedule of Shares of Common Stock and Preferred Stock Schedule of Stock by Class [Table Text Block] 2027 Lessee, Operating Lease, Liability, to be Paid, Year Three PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Adjustment to Compensation: Adjustment to Compensation [Axis] GSK-HBV Agreement GSK-HBV Agreement [Member] GSK-HBV Agreement Net loss attributable to noncontrolling interest, net of tax Net Income (Loss) Attributable to Noncontrolling Interest Document Transition Report Document Transition Report Schedule of Gross Unrecognized Tax Benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Percent Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Customer [Domain] Customer [Domain] Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Current Reporting Status Entity Current Reporting Status Laboratory And Office Facility Laboratory And Office Facility [Member] Laboratory and office facility. Accumulated Deficit Retained Earnings [Member] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Asset Acquisition Asset Acquisition [Domain] Basic (in shares) Weighted-average basic shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Research Facility in Madison Research Facility In Madison [Member] Research facility in Madison. Total noncontrolling interest and stockholders' equity Beginning balance Ending balance Equity, Including Portion Attributable to Noncontrolling Interest Amortization of debt discount and issuance costs Amortization of Debt Issuance Costs and Discounts Restricted stock units Restricted Stock Units (RSUs) [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Executive Category: Executive Category [Axis] Purchases of investments Payments to Acquire Investments Name Awards Close in Time to MNPI Disclosures, Individual Name Construction in progress Construction in Progress [Member] Number of shares forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period Provisions for Income Taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Entity Filer Category Entity Filer Category Shares issued Shares, Issued Statement of Income Location, Balance [Domain] Statement of Income Location, Balance [Domain] Company Selected Measure Name Company Selected Measure Name Private Placement Private Placement [Member]