Entity Central Index Key Document and entity information. Document And Entity Information [Abstract] 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 Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Public Float Entity Public Float Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] CURRENT ASSETS Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Prepaid expenses Prepaid Expense Current Other current assets Other Assets Current Short term investments Held To Maturity Securities Current TOTAL CURRENT ASSETS Assets Current Property and equipment, net Property Plant And Equipment Net Intangible assets, net Intangible Assets Net Excluding Goodwill Investments Held To Maturity Securities Noncurrent Other assets Other Assets Miscellaneous Noncurrent TOTAL ASSETS Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities And Stockholders Equity [Abstract] 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] Capital lease obligation, net of current portion Capital Lease Obligations Noncurrent Contingent consideration obligations Business Combination Contingent Consideration Liability 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] Arrowhead Research Corporation stockholders' equity: Stockholders Equity [Abstract] Preferred stock, $0.001 par value; 5,000,000 shares authorized; 15,652 and 18,300 shares issued and outstanding as of September 30, 2015 and September 30, 2014, respectively Preferred Stock Value Common stock, $0.001 par value; 145,000,000 shares authorized; 59,544,677 and 54,656,936 shares issued and outstanding as of September 30, 2015 and September 30, 2014, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit 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 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 The amount of purchased research and development assets that are acquired in asset acquisition have no alternative future use and are therefore written off in the period of acquisition. Income Statement [Abstract] REVENUE Revenues OPERATING EXPENSES Operating Expenses [Abstract] Research and development Research And Development Expense Acquired in-process research and development Acquired In Process Research And Development Salaries and payroll-related costs Labor And Related Expense General and administrative expenses General And Administrative Expense Stock-based compensation Allocated Share Based Compensation Expense Depreciation and amortization Depreciation And Amortization Impairment expense Impairment Of Intangible Assets Excluding Goodwill 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 Gain (loss) on sale of fixed assets, net Gain Loss On Sale Of Property Plant Equipment Interest income (expense), net Interest Income Expense Nonoperating Net Change in value of derivatives Unrealized Gain Loss On Derivatives Other income (expense) Other Nonoperating Income Expense TOTAL OTHER INCOME (EXPENSE) Nonoperating Income Expense LOSS 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 Loss from discontinued operations Discontinued Operation Income Loss From Discontinued Operation Before Income Tax NET LOSS FROM DISCONTINUED OPERATIONS Income Loss From Discontinued Operations Net Of Tax NET LOSS Profit Loss Net loss attributable to non-controlling 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 OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX Comprehensive Income Net Of Tax [Abstract] Foreign Currency Translation Adjustments Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax COMPREHENSIVE LOSS ATTRIBUTABLE TO ARROWHEAD Comprehensive Income Net Of Tax Stock issued during period value exercise of warrants. Stock issued during period shares exercise of warrants. Exchange rights exercised during period value. Exchange rights exercised during period shares. Subscription receivable. Cancellation of subscription receivables. Cancellation of shares related to subscription receivables. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Statement Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Preferred Stock Preferred Stock [Member] Common Stock Common Stock [Member] Additional Paid In Capital Additional Paid In Capital [Member] Subscription receivable. Subscriptions Receivable Subscription Receivable [Member] Accumulated Other Comprehensive Income (loss) Accumulated Other Comprehensive Income [Member] Accumulated Deficit Retained Earnings [Member] Noncontrolling Interest Noncontrolling Interest [Member] Asset acquisition. Asset Acquisition Asset Acquisition [Axis] Asset acquisition. Asset Acquisition Asset Acquisition [Domain] Novartis. Novartis Novartis [Member] Statement Class Of Stock Statement Class Of Stock [Axis] Class Of Stock Class Of Stock [Domain] Issued at four dollars and forty nine cents per share. Common stock issued @ $4.49 Issued At Four Dollars And Forty Nine Cents Per Share [Member] Issued at two dollars and twenty six cents per share. Common stock issued @ $2.26 Issued At Two Dollars And Twenty Six Cents Per Share [Member] Issued at two dollars and twelve cents per share. Common stock issued @ $2.12 Issued At Two Dollars And Twelve Cents Per Share [Member] Issued at one dollar and eighty three cents per share. Common stock issued @ $1.83 Issued At One Dollar And Eighty Three Cents Per Share [Member] Preferred stock issued at thousand dollar per share. Preferred stock issued at $1,000 per share Preferred Stock Issued At Thousand Dollar Per Share [Member] Issued at five dollar and eighty six cents per share. Common stock issued @ $5.86 Issued At Five Dollar And Eighty Six Cents Per Share [Member] Issued at eighteen dollar and ninety five cents per share. Common stock issued @ $18.95 Issued At Eighteen Dollar And Ninety Five Cents Per Share [Member] Issued to Galloway. Common Stock Issued to Galloway Issued To Galloway [Member] Statement [Line Items] Statement [Line Items] Beginning Balance Amount Beginning Balance Shares Shares Issued Exercise of warrants, Amount Stock Issued During Period Value Exercise Of Warrants Exercise of warrants Stock Issued During Period Shares Exercise Of Warrants Stock options exercised, Amount Stock Issued During Period Value Stock Options Exercised Stock options exercised Stock Issued During Period Shares Stock Options Exercised Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Exercise of exchange rights, Amount Exchange Rights Exercised During Period Value Exercise of exchange rights, Shares Exchange Rights Exercised During Period Shares Subscription payment Subscription Receivable Subscription reversal, Amount Cancellation Of Subscription Receivables Subscription reversal Cancellation Of Shares Related To Subscription Receivables Stock issuances Stock Issued During Period Value New Issues Stock issuances, Shares Stock Issued During Period Shares New Issues Establish and settlements related to derivative liability Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax Preferred stock converted to common stock, Amount Stock Issued During Period Value Conversion Of Convertible Securities Preferred stock converted to common stock, Shares Stock Issued During Period Shares Conversion Of Convertible Securities Deconsolidation of Calando Pharmaceuticals, Inc. Noncontrolling Interest Decrease From Deconsolidation Common stock-RSU vesting, Amount Stock Issued During Period Value Restricted Stock Award Gross Common stock-RSU vesting, Shares Stock Issued During Period Shares Restricted Stock Award Gross Stock issuances Stock Issued During Period Value Acquisitions Stock issuances, Shares Stock Issued During Period Shares Acquisitions Net loss Ending Balance Amount Ending Balance Shares Common stock issued, price per share Shares Issued Price Per Share Non-cash gain in equity investment. Non cash impairment charges. Proceeds from exercise of warrants and stock options. Common stock issued to Novartis for asset acquisition. value of stock issue in settlement of services agreement. Value of common stock issued for the acquisition. Statement Of Cash Flows [Abstract] Business Acquisition Business Acquisition [Axis] Business Acquisition Acquiree Business Acquisition Acquiree [Domain] Roche Madison. Roche Madison Inc Roche Madison [Member] Service agreement settlement. Service Agreement Settlement Service Agreement Settlement [Axis] Service agreement settlement. Service Agreement Settlement Service Agreement Settlement [Domain] Galloway limited. Galloway Limited Galloway Limited [Member] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided By Used In Operating Activities Continuing Operations [Abstract] Loss from discontinued operations (Gain) loss on disposal of fixed assets Change in value of derivatives Stock-based compensation Share Based Compensation Amortization of note premiums Investment Income Amortization Of Premium Gain on debt extinguishment Gains Losses On Extinguishment Of Debt Noncash gain in equity investment Non Cash Gain In Equity Investment Noncash impairment expense Non Cash Impairment Charges Non-controlling interest Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Receivables Increase Decrease In Receivables Other receivables Increase Decrease In Other Receivables Prepaid expenses Increase Decrease In Prepaid Expense Other current assets Increase Decrease In Other Current Assets Accounts payable Increase Decrease In Accounts Payable Accrued expenses Increase Decrease In Accrued Liabilities Other Increase Decrease In Other Operating Liabilities NET CASH USED IN OPERATING ACTIVITIES Net Cash Provided By Used In Operating Activities Continuing Operations CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Cash paid for acquisitions Payments To Acquire Assets Investing Activities Purchases of property and equipment Payments To Acquire Property Plant And Equipment Proceeds from sale of fixed assets Proceeds From Sale Of Property Plant And Equipment Purchase of marketable securities Payments To Acquire Marketable Securities Proceeds from sale of marketable securities Proceeds From Sale And Maturity Of Marketable Securities NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES Net Cash Provided By Used In Investing Activities Continuing Operations CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Principal payments on capital leases Repayments Of Long Term Capital Lease Obligations Proceeds from issuance of common stock and preferred stock, net Proceeds From Issuance Or Sale Of Equity Proceeds from the exercise of warrants and stock options Proceeds From Exercise Of Warrants And Stock Options NET CASH PROVIDED BY FINANCING ACTIVITIES Net Cash Provided By Used In Financing Activities Continuing Operations Cash flows from discontinued operations: Net Cash Provided By Used In Discontinued Operations [Abstract] Operating cash flows Cash Provided By Used In Operating Activities Discontinued Operations Investing cash flows Cash Provided By Used In Investing Activities Discontinued Operations Financing cash flows Cash Provided By Used In Financing Activities Discontinued Operations Net cash used in discontinued operations: Net Cash Provided By Used In Discontinued Operations NET INCREASE (DECREASE) IN CASH Cash And Cash Equivalents Period Increase Decrease CASH AT BEGINNING OF PERIOD CASH AT END OF PERIOD Supplementary disclosures: Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid 3,321,383 shares of Common stock issued to Novartis for asset acquisition Common Stock Issued For Asset Acquisition 131,579 shares of Common stock issued to Galloway Limited in settlement of services agreement Common Stock Issued For Settlement Of Service Agreement 239,894 shares of Common stock issued to Roche for stock and asset acquisition Common Stock Issued For Stock And Asset Acquisition Accounting Policies [Abstract] Organization and Significant Accounting Policies Organization Consolidation And Presentation Of Financial Statements Disclosure And Significant Accounting Policies [Text Block] Asset acquisition. Asset acquisition. Asset Acquisition [Abstract] Acquisitions Asset Acquisition Disclosure [Text Block] Property Plant And Equipment [Abstract]