No definition available.

Name:	arwr_ApplicableOutLicenseTerm
Namespace Prefix:	arwr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

Business acquisition equity interests issued number of shares issuable.

No definition available.

Name:	arwr_BusinessAcquisitionEquityInterestsIssuedNumberOfSharesIssuable
Namespace Prefix:	arwr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Business acquisition equity interests issued number of shares issued.

No definition available.

Name:	arwr_BusinessAcquisitionEquityInterestsIssuedNumberOfSharesIssued
Namespace Prefix:	arwr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Business combination consideration promissory note issued.

No definition available.

Name:	arwr_BusinessCombinationConsiderationPromissoryNoteIssued
Namespace Prefix:	arwr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Gross offering proceeds.

No definition available.

Name:	arwr_GrossOfferingProceeds
Namespace Prefix:	arwr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Obligation to pay royalties.

No definition available.

Name:	arwr_ObligationToPayRoyalties
Namespace Prefix:	arwr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of common stock to be issued as additional consideration.

No definition available.

Name:	arwr_PercentageOfCommonStockToBeIssuedAsAdditionalConsideration
Namespace Prefix:	arwr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of royalty liability.

No definition available.

Name:	arwr_PercentageOfRoyaltyLiability
Namespace Prefix:	arwr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 99-12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)(3)

-URI http://asc.fasb.org/extlink&oid=7488404&loc=d3e6927-128479

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph g

-Clause 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

For contingent consideration arrangements and indemnification assets recognized in connection with a business combination, this element represents an estimate of the low-end of the potential range (undiscounted) of the consideration which may be paid.