Collaborative arrangements revenue.

No definition available.

Name:	irwd_CollaborativeArrangementsRevenue
Namespace Prefix:	irwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount to be received by the company upon completion of milestone.

+ References

No definition available.

+ Details

Name:	irwd_MilestonePaymentToBeReceivedByCompanyUponMilestoneAchievement
Namespace Prefix:	irwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the total number of milestone payments to be received once all milestones have been achieved.

+ References

No definition available.

+ Details

Name:	irwd_NumberOfMilestonePayments
Namespace Prefix:	irwd_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents deferred revenue recognized as up-front license fees in the current period.

+ References

No definition available.

+ Details

Name:	irwd_RevenueRecognizedUpFrontLicenseFee
Namespace Prefix:	irwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the total payments to be received once all milestones have been achieved.

+ References

No definition available.

+ Details

Name:	irwd_TotalMilestonePaymentsToBeReceived
Namespace Prefix:	irwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash received from licensees for license fees during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

+ Details

Name:	us-gaap_ProceedsFromLicenseFeesReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_CounterpartyNameAxis=irwd_AstellasPharmaIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=us-gaap_CollaborativeArrangementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=country_JP
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=us-gaap_CollaborativeArrangementProductAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	irwd_AchievementOfMilestoneAxis=irwd_AdditionalDevelopmentMilestonesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	irwd_AchievementOfMilestoneAxis=irwd_Phase3MilestonesMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	irwd_AchievementOfMilestoneAxis=irwd_ApprovalOfJapaneseNDAEquivalentFilingMilestoneMember
Namespace Prefix:
Data Type:	na
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Collaboration, License, Co-Promotion and Other Commercial Agreements - Japan (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Nov. 30, 2009 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) item	Jun. 30, 2016 USD ($)
Collaboration, License and Co-Promotion Agreements
Collaborative arrangements revenue		$ 64,612	$ 54,350	$ 116,489	$ 120,392
Astellas \| Collaborative arrangement
Collaboration, License and Co-Promotion Agreements
Collaborative arrangements revenue		$ 6,000	2,300	$ 6,000	17,000
Astellas \| Japan \| Product related collaborative arrangements
Collaboration, License and Co-Promotion Agreements
Up-front fee received	$ 30,000
Up-front license fee revenue recognized			$ 1,300		$ 2,600
Astellas \| Japan \| Product related collaborative arrangements \| Additional development milestones
Collaboration, License and Co-Promotion Agreements
Number of milestone payments to be received (in payments) \| item				3
Astellas \| Japan \| Product related collaborative arrangements \| Additional development milestones \| Maximum
Collaboration, License and Co-Promotion Agreements
Total milestone payments to be received				$ 45,000
Astellas \| Japan \| Product related collaborative arrangements \| Phase 3 milestones
Collaboration, License and Co-Promotion Agreements
Milestone payment to be received by company upon milestone achievement				15,000
Astellas \| Japan \| Product related collaborative arrangements \| Approval of Japanese NDA equivalent filing milestone
Collaboration, License and Co-Promotion Agreements
Milestone payment to be received by company upon milestone achievement				$ 15,000