Entity Central Index Key Document Document and Entity Information [Abstract] Document Document And Entity Information [Abstract] Document Document And Entity Information [Abstract] Statement [Table] Statement [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Document Document And Entity Information [Line Items] Document Document And Entity Information [Line Items] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Research equipment. Statement Of Financial Position [Abstract] Statement Of Financial Position [Abstract] Statement Consolidated Balance Sheets [Line Items] Statement Consolidated Balance Sheets [Line Items] CURRENT ASSETS Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Trade receivable Accounts Receivable Net Current Other receivables Other Receivables Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Short term investments Marketable Securities Current TOTAL CURRENT ASSETS Assets Current PROPERTY AND EQUIPMENT Property Plant And Equipment Net [Abstract] Computers, office equipment and furniture Furniture And Fixtures Gross Research equipment Research Equipment Software Capitalized Computer Software Gross Leasehold improvements Leasehold Improvements Gross Property, Plant and Equipment, Gross, Total Property Plant And Equipment Gross Less: Accumulated depreciation and amortization Accumulated Depreciation Depletion And Amortization Property Plant And Equipment PROPERTY AND EQUIPMENT, NET Property Plant And Equipment Net OTHER ASSETS Other Assets [Abstract] Patents and other intangible assets, net Finite Lived Intangible Assets Gross Investments Investment Owned At Cost TOTAL OTHER ASSETS Other Assets Noncurrent TOTAL ASSETS Assets CURRENT LIABILITIES Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued expenses Accrued Liabilities Current Accrued payroll and benefits Employee Related Liabilities Current Deferred revenue Deferred Revenue Current Derivative liabilities Derivative Liabilities Current Capital lease obligation Capital Lease Obligations Current Notes payable Notes Payable Current Other current liabilities Other Liabilities Current TOTAL CURRENT LIABILITIES Liabilities Current LONG-TERM LIABILITIES Liabilities Noncurrent [Abstract] Notes payable, net of current portion Long Term Notes Payable Capital lease obligation, net of current portion Capital Lease Obligations Noncurrent Other non-current liabilities Other Liabilities Noncurrent TOTAL LONG-TERM LIABILITIES Liabilities Noncurrent Commitments and contingencies Commitments And Contingencies STOCKHOLDERS’ EQUITY Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract] Preferred stock, $0.001 par value; 5,000,000 shares authorized; 51,291 and 9,900 shares issued and outstanding as of December 31, 2013 and September 30, 2013, respectively Preferred Stock Value Common stock, $0.001 par value; 145,000,000 shares authorized; 39,002,152 and 32,489,444 shares issued and outstanding as of December 31, 2013 and September 30, 2013, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated deficit during the development stage Retained Earnings Accumulated Deficit Total Arrowhead Research Corporation stockholders' equity Stockholders Equity Noncontrolling interest Minority Interest TOTAL STOCKHOLDERS’ EQUITY Stockholders Equity Including Portion Attributable To Noncontrolling Interest TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities And Stockholders Equity Statement Consolidated Balance Sheets Parenthetical [Line Items] Statement Consolidated Balance Sheets Parenthetical [Line Items] Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares issued Preferred Stock Shares Issued Preferred stock, shares outstanding Preferred Stock Shares Outstanding Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Impairment of intangible assets. Gain on Acquisition. Gain (loss) on entity's disposition of equity in securities of subsidiaries. Reflects the difference in the parent company's carrying amount of the equity interest in the subsidiary immediately before and after all stock transactions. Income Statement [Abstract] Income Statement [Abstract] Statement Consolidated Statements Of Operations [Line Items] Statement Consolidated Statements Of Operations [Line Items] REVENUE Revenues OPERATING EXPENSES Operating Expenses [Abstract] Salaries and payroll-related costs Labor And Related Expense General and administrative expenses General And Administrative Expense Research and development Research And Development Expense Stock-based compensation Share Based Compensation Depreciation and amortization Depreciation Depletion And Amortization Impairment expense Impairment Of Intangible Assets Contingent consideration - fair value adjustments Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 TOTAL OPERATING EXPENSES Operating Expenses OPERATING LOSS Operating Income Loss OTHER INCOME (EXPENSE) Nonoperating Income Expense [Abstract] Equity in income (loss) of unconsolidated affiliates Income Loss From Equity Method Investments Impairment of investment in unconsolidated affiliates Impairment Of Investments Gain on purchase of Roche Madison Gain On Acquisition Gain (loss) on sale of fixed assets, net Gain Loss On Sale Of Property Plant Equipment Realized and unrealized gain (loss) in marketable securities Marketable Securities Gain Loss Interest income (expense), net Interest Income Expense Net Change in value of derivatives Unrealized Gain Loss On Derivatives Gain on sale of stock in subsidiary Gain Loss On Sale Of Stock In Subsidiary Other income (expense) Other Nonoperating Income Expense TOTAL OTHER INCOME (EXPENSE) Nonoperating Income Expense LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Provision for income taxes Income Tax Expense Benefit LOSS FROM CONTINUING OPERATIONS Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest Income (loss) from discontinued operations Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Net Of Tax Gain on disposal of discontinued operations Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax NET INCOME (LOSS) FROM DISCONTINUED OPERATIONS Income Loss From Discontinued Operations Net Of Tax NET LOSS Profit Loss Net loss attributable to noncontrolling interests Net Income Loss Attributable To Noncontrolling Interest NET LOSS ATTRIBUTABLE TO ARROWHEAD Net Income Loss NET LOSS PER SHARE ATTRIBUTABLE TO ARROWHEAD SHAREHOLDERS - BASIC AND DILUTED: Earnings Per Share Basic And Diluted Weighted average shares outstanding - basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Statement Of Stockholders Equity [Abstract] Statement Of Stockholders Equity [Abstract] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Issued for cash at zero point zero one dollars per unit. Issued For Cash At Zero Point Zero One Dollars Per Unit Issued For Cash At Zero Point Zero One Dollars Per Unit [Member] Issued for cash at ten dollar per unit. Issued For Cash At Ten Dollar Per Unit Issued For Cash At Ten Dollar Per Unit [Member] Stock Issuance Cost Charged To Additional Paid In Capital Member Stock Issuance Cost Charged To Additional Paid In Capital Stock Issuance Cost Charged To Additional Paid In Capital [Member] Issued for marketable securities at ten dollar per unit. Issued For Marketable Securities At Ten Dollar Per Unit Issued For Marketable Securities At Ten Dollar Per Unit [Member] Issued for cash at fifteen dollar per unit. Issued For Cash At Fifteen Dollar Per Unit Issued For Cash At Fifteen Dollar Per Unit [Member] Equity Issued in Business Combination Equity Issued In Business Combination [Member] Issued as a gift for ten dollar and ninety cents per share. Issued As Gift For Ten Dollar And Ninety Cents Per Share Issued As Gift For Ten Dollar And Ninety Cents Per Share [Member] Issued as stock issuance cost at fifteen dollar per unit. Issued As Stock Issuance Cost At Fifteen Dollar Per Unit Issued As Stock Issuance Cost At Fifteen Dollar Per Unit [Member] Exercised at two dollar per share. Exercised At Two Dollar Per Share Exercised At Two Dollar Per Share [Member] Exercised at ten dollar per share. Exercised At Ten Dollar Per Share Exercised At Ten Dollar Per Share [Member] Exercised at fifteen dollar per share. Exercised At Fifteen Dollar Per Share Exercised At Fifteen Dollar Per Share [Member] Issued to purchase insert therapeutics share at thirty nine dollars and eighty cents per share. Issued To Purchase Insert Therapeutics Share At Thirty Nine Dollars And Eighty Cents Per Share Issued To Purchase Insert Therapeutics Share At Thirty Nine Dollars And Eighty Cents Per Share [Member] Issued at forty eight dollars and eighty cents per share. Issued At Forty Eight Dollars And Eighty Cents Per Share Issued At Forty Eight Dollars And Eighty Cents Per Share [Member] Issued at thirty eight dollars and forty cents per share. Issued At Thirty Eight Dollars And Forty Cents Per Share Issued At Thirty Eight Dollars And Forty Cents Per Share [Member] Issued at thirty five dollars per share. Issued At Thirty Five Dollars Per Share Issued At Thirty Five Dollars Per Share [Member] Issued at fifty nine dollars and ten cents per share. Issued At Fifty Nine Dollars And Ten Cents Per Share Issued At Fifty Nine Dollars And Ten Cents Per Share [Member] Issued to purchase calando pharmaceuticals inc at fifty one dollars and seventy cents per share. Issued To Purchase Calando Pharmaceuticals Inc At Fifty One Dollars And Seventy Cents Per Share Issued To Purchase Calando Pharmaceuticals Inc At Fifty One Dollars And Seventy Cents Per Share [Member] Issued at fifty seven dollars and eighty cents per share. Issued At Fifty Seven Dollars And Eighty Cents Per Share Issued At Fifty Seven Dollars And Eighty Cents Per Share [Member] Issued for purchase of carbon nanotechnologies inc at thirty seven dollars and seventy cents per share. Issued For Purchase Of Carbon Nanotechnologies Inc At Thirty Seven Dollars And Seventy Cents Per Share Issued For Purchase Of Carbon Nanotechnologies Inc At Thirty Seven Dollars And Seventy Cents Per Share [Member] Issued at approximately eighteen dollar per share net. Issued At Approximately Eighteen Dollar Per Share Net Issued At Approximately Eighteen Dollar Per Share Net [Member] Issued at twenty seven dollars and twenty cents per share to rice university. Issued At Twenty Seven Dollars And Twenty Cents Per Share To Rice University Issued At Twenty Seven Dollars And Twenty Cents Per Share To Rice University [Member] Issued at twenty eight dollars and thirty cents per share to purchase shares of unidym inc. Issued At Twenty Eight Dollars And Thirty Cents Per Share To Purchase Shares Of Unidym Inc Issued At Twenty Eight Dollars And Thirty Cents Per Share To Purchase Shares Of Unidym Inc [Member] Issued at twenty nine dollars and fifty cents per share to purchase MASA energy LLC. Issued At Twenty Nine Dollars And Fifty Cents Per Share To Purchase Masa Energy Llc Issued At Twenty Nine Dollars And Fifty Cents Per Share To Purchase Masa Energy Llc [Member] Issued at twenty one dollars and ninety cents per share to unidym for the acquisition of nanoconduction. Issued At Twenty One Dollars And Ninety Cents Per Share To Unidym For Acquisition Of Nanoconduction Issued At Twenty One Dollars And Ninety Cents Per Share To Unidym For Acquisition Of Nanoconduction [Member] Issued at twenty one dollars and eighty cents per share. Issued At Twenty One Dollars And Eighty Cents Per Share Issued At Twenty One Dollars And Eighty Cents Per Share [Member] Issued at five dollars and fifty cents per share to unidym stockholder in exchange for unidym's shares. Issued At Five Dollars And Fifty Cents Per Share To Unidym Stockholder In Exchange For Unidym S Shares Issued At Five Dollars And Fifty Cents Per Share To Unidym Stockholder In Exchange For Unidym S Shares [Member] Issued at five dollars and twenty cents per share to TEL ventures in exchange for unidym's shares. Issued At Five Dollars And Twenty Cents Per Share To Tel Ventures In Exchange For Unidym S Shares Issued At Five Dollars And Twenty Cents Per Share To Tel Ventures In Exchange For Unidym S Shares [Member] Arrowheads Increase In Proportionate Share Of Calandos Equity Member Arrowheads Increase In Proportionate Share Of Calandos Equity Arrowheads Increase In Proportionate Share Of Calandos Equity [Member] Issued at three dollars per share. Issued At Three Dollars Per Share Issued At Three Dollars Per Share [Member] Issued To Unidym Stockholders In Exchange For Unidym's Shares [Member] Issued To Unidym Stockholders In Exchange For Unidyms Shares Issued To Unidym Stockholders In Exchange For Unidyms Shares [Member] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Preferred Stock Preferred Stock [Member] Additional Paid-in Capital Additional Paid In Capital [Member] Subscriptions Receivable [Member] Subscriptions Receivable Subscriptions Receivable [Member] Accumulated Deficit during Development Stage Accumulated Deficit During Development Stage [Member] Noncontrolling Interest Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Beginning Balance Amount Issuance and sold of Common Stock Stock Issued During Period Shares New Issues Stock issuances Stock Issued During Period Value New Issues Stock issuance cost charged to additional paid-in capital Adjustments To Additional Paid In Capital Stock Issued Issuance Costs Net loss Ending Balance Amount Ending Balance Shares Shares Issued Stock options exercised Stock Issued During Period Shares Stock Options Exercised Stock options exercised, Amount Stock Issued During Period Value Stock Options Exercised Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Adjustments to additional paid in capital, reallocation of noncontrolling interest Noncontrolling Interest Increase From Subsidiary Equity Issuance Reclassification of former Unidym mezzanine debt to equity Adjustments To Additional Paid In Capital Equity Component Of Convertible Debt Issuance of preferred stock in subsidiary Proceeds From Issuance Of Preferred Stock And Preference Stock Amortization of discount on Unidym Series D Preferred Stock Adjustments To Additional Paid In Capital Convertible Debt With Conversion Feature Common stock and warrants issued for cash, price per unit Exercise of stock options, price per share Common Stock Issuance Value Per Share Preferred stock issuance value per share. Issued At Six Dollars And Thirty Four Cents Per Share [Member] Issued at $6.34 per share Issued At Six Dollars And Thirty Four Cents Per Share [Member] Issued at thirteen dollars and twelve cents per share. Issued at $13.12 per share Issued At Thirteen Dollars And Twelve Cents Per Share [Member] Issued at three dollars and eighty cents per share. Issued at $3.80 per share Issued At Three Dollars And Eighty Cents Per Share [Member] Issued at three dollars and seventy cents per share. Issued at $3.70 per share Issued At Three Dollars And Seventy Cents Per Share [Member] Issued at four dollars per share. Issued at $4.00 per share Issued At Four Dollars Per Share [Member] Issued at six dollars and twenty three cents per share. Issued at $6.23 per share Issued At Six Dollars And Twenty Three Cents Per Share [Member] Issued at five dollars and eleven cents per share. Issued at $5.11 per share Issued At Five Dollars And Eleven Cents Per Share [Member] Issued At Two Dollars And Seventy Six Cents Per Share [Member] Issued at $2.76 per share Issued At Two Dollars And Seventy Six Cents Per Share [Member] Preferred stock issued at thousand dollars per share. Preferred Stock Issued At Thousand Dollars Per Share Preferred Stock Issued At Thousand Dollars Per Share [Member] Issued At Four Dollars And Forty Nine Cents Per Share [Member] Issued at $4.49 per share Issued At Four Dollars And Forty Nine Cents Per Share [Member] Issued At Two Dollars And Twenty Six Cents Per Share [Member] Issued at $2.26 per share Issued At Two Dollars And Twenty Six Cents Per Share [Member] Issued At Two Dollars And Twelve Cents Per Share [Member] Issued at $2.12 per share Issued At Two Dollars And Twelve Cents Per Share [Member] Issued At One Dollar And Eighty Three Cents Per Share [Member] Issued at $1.83 per share Issued At One Dollar And Eighty Three Cents Per Share [Member] Issued at five dollars and eighty six cents per share. Issued at $5.86 per share Issued At Five Dollars And Eighty Six Cents Per Share [Member] Common stock & warrants issued for cash, price per unit Common Stock And Warrants Issued For Cash Price Per Unit Exercise of stock options, price per share Exercise Of Stock Options Price Per Share Common stock issued, par value per share Common Stock Issuance Value Per Share Preferred stock issued, par value per share Preferred Stock Issuance Value Per Share Subscription Receivable Cancellation Of Shares Related To Subscription Receivables Cancellation Of Subscription Receivables Issued to Calando stockholders in exchange for Calando's shares [Member] Issued To Calando Stockholders In Exchange For Calando S Shares Issued To Calando Stockholders In Exchange For Calando S Shares [Member] Issuance of common stock for subscription. Issuance Of Common Stock For Subscription Issuance Of Common Stock For Subscription [Member] Common stock issued under committed capital agreement. Issued Under Committed Capital Agreement Issued Under Committed Capital Agreement [Member] Issued At Five Dollar And Eighty Six Cents Per Share [Member] Issued At Five Dollar And Eighty Six Cents Per Share Issued At Five Dollar And Eighty Six Cents Per Share [Member] Divestiture of Unidym Noncontrolling Interest Increase From Sale Of Parent Equity Interest Establish derivative liability Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax Fractional shares redeemed in reverse stock split Stock Issued During Period Shares Reverse Stock Splits Preferred stock converted to common stock, shares Stock Issued During Period Shares Conversion Of Units Preferred stock converted to common stock Stock Issued During Period Value Conversion Of Units Subscription payment Subscription Receivable Subscription reversal, Shares Cancellation Of Shares Related To Subscription Receivables Subscription reversal Cancellation Of Subscription Receivables Establish and settlements related to derivative liability Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax Provision For Allowance For Bad Debts And Sales Related Allowances Gain (loss) from sale of subsidiary. Non cash impairment charges. Non controlling interest.