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

Represents the amount of arrangement consideration for clinical trial material supply services and research, development and regulatory activities, which are a part of the initial development plan.

No definition available.

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

Represents the total amount of non-contingent arrangement consideration.

No definition available.

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

Represents the amount of collaborative arrangement consideration allocated to the clinical trial material supply services.

No definition available.

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

Represents the amount of collaborative arrangement consideration allocated to the co-promotion deliverable in the relative selling price model.

No definition available.

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

Represents the amount of collaborative arrangement consideration allocated to the joint development committee services.

No definition available.

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

Represents the amount of collaborative arrangement consideration allocated to the license deliverable.

No definition available.

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

Represents the amount of collaborative arrangement consideration allocated to the research and development services.

No definition available.

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

Represents the percentage of the costs allocated to the reporting entity for clinical trial material supply services and research, development and regulatory activities which are included in the arrangement consideration.

No definition available.

Name:	irwd_CollaborativeArrangementPercentOfCostsAllocatedToReportingEntityIncludedInConsideration
Namespace Prefix:	irwd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of net loss from commercialization.

No definition available.

Name:	irwd_CollaborativeArrangementPercentageOfNetLoss
Namespace Prefix:	irwd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of net profit from commercialization.

No definition available.

Name:	irwd_CollaborativeArrangementPercentageOfNetProfit
Namespace Prefix:	irwd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the period of time for which written notice is required to be given prior to termination of the collaborative agreement.

No definition available.

Name:	irwd_CollaborativeArrangementPeriodOfPriorNoticeToTerminateAgreement
Namespace Prefix:	irwd_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Collaborative arrangements revenue.

No definition available.

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

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

No definition available.

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

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.

No definition available.

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

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

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=66902209&loc=d3e3536-108585

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

Name:	us-gaap_ProductOrServiceAxis=irwd_LinaclotideMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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

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

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

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