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Organization and Significant Accounting Policies - Additional Information (Detail) (USD $)
3 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Sep. 30, 2014
Sep. 30, 2013
Schedule Of Investments [Line Items]        
Cash to fund operations $ 103,991,231us-gaap_CashAndCashEquivalentsAtCarryingValue $ 59,713,424us-gaap_CashAndCashEquivalentsAtCarryingValue $ 132,510,610us-gaap_CashAndCashEquivalentsAtCarryingValue $ 19,114,444us-gaap_CashAndCashEquivalentsAtCarryingValue
Investments 41,338,901us-gaap_MarketableSecurities   44,741,378us-gaap_MarketableSecurities  
Net increase (decrease) in cash (28,519,379)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease 40,598,980us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease    
Cash outflow related to continuing operating activities (24,200,006)us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations (7,022,332)us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations    
Other investing activities (7,000,000)us-gaap_PaymentsForProceedsFromOtherInvestingActivities       
Capital expenditures 554,945us-gaap_PaymentsToAcquirePropertyPlantAndEquipment 116,215us-gaap_PaymentsToAcquirePropertyPlantAndEquipment    
Net cash invested in fixed income investments 3,100,000arwr_NetCashInvestedInFixedIncomeInvestments      
Proceeds from the exercise of warrants and stock options 283,466arwr_ProceedsFromExerciseOfWarrantsAndStockOptions       
Restricted Cash 0us-gaap_RestrictedCashAndCashEquivalents   0us-gaap_RestrictedCashAndCashEquivalents  
Amount insured in FDIC per account 250,000us-gaap_CashFDICInsuredAmount      
Minimum        
Schedule Of Investments [Line Items]        
Property, Plant and Equipment, Useful Life 3 years      
Maximum        
Schedule Of Investments [Line Items]        
Property, Plant and Equipment, Useful Life 7 years      
Commercial bonds        
Schedule Of Investments [Line Items]        
Maturity description less than 24 months      
Investments $ 41,300,000us-gaap_MarketableSecurities
/ us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesByTypeAxis
= us-gaap_BondsMember