Document and Entity Information	3 Months Ended
	Dec. 31, 2013	Jan. 31, 2014
Document Document And Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2013
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q1
Trading Symbol	ARWR
Entity Registrant Name	ARROWHEAD RESEARCH CORP
Entity Central Index Key	0000879407
Current Fiscal Year End Date	--09-30
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		39,687,033