The company's share of the net profit (loss) from the commercial sale of a product under a collaboration agreement.

No definition available.

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

- Definition

Represents the percentage of net loss from commercialization.

+ References

No definition available.

+ Details

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

- Definition

Represents the percentage of net profit from commercialization.

+ References

No definition available.

+ Details

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

- Definition

Amount represents 50% of product net sales as well as cost of revenue and selling and marketing cost-sharing settlement payments to the company from its collaboration partner.

+ References

No definition available.

+ Details

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

- Definition

Represents the revenue recognized from the sale of linaclotide API.

+ References

No definition available.

+ Details

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

- Definition

Represents the revenue recognized in royalty payments.

+ References

No definition available.

+ Details

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

- Definition

The royalty percentages to be applied per license agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	irwd_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the cumulative amount of license fees and milestone payments received to date.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Represents net cost sharing offset amounts related to collaborative arrangement where a cost sharing agreement exists for research and development expenses. Amounts may net to either a reduction of expense, or may net to increased expense.

+ References

No definition available.

+ Details

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Namespace Prefix:	irwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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Namespace Prefix:	irwd_
Data Type:	xbrli:integerItemType
Balance Type:	na
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

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Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

Proceeds from issuance of capital stock which provides for a specific dividend that is paid to the shareholders before any dividends to common stockholders and which takes precedence over common stockholders in the event of liquidation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3255-108585

+ Details

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

- Definition

The amount of consideration recognized during the period for the milestone or milestones.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 28
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=68058744&loc=SL6892177-166501

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate total amount of expenses directly related to the marketing or selling of products or services.

+ References

No definition available.

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_StatementScenarioAxis=irwd_FuturePaymentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

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

- Details

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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=irwd_CanadaAndMexicoMember
Namespace Prefix:
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Collaboration, License, Co-Promotion and Other Commercial Agreements - North America (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Sep. 30, 2007	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) item	Jun. 30, 2016 USD ($)
AstraZeneca \| Licensing agreement
Collaboration, License and Co-Promotion Agreements
Royalty percentage per agreement				single digits
North America \| Allergan \| Product related collaborative arrangements
Collaboration, License and Co-Promotion Agreements
Equity investment in the entity's capital stock				$ 25,000
Net cost sharing offset or incremental expense related to research and development expense		$ 500	$ 3,200	500	$ 5,200
North America \| Allergan \| Product related collaborative arrangements \| Development milestones
Collaboration, License and Co-Promotion Agreements
Cumulative license fees and development milestone payments received				$ 205,000
Number of milestone payments \| item				6
North America \| Allergan \| Product related collaborative arrangements \| Commercialization milestone
Collaboration, License and Co-Promotion Agreements
Percentage of net profit from commercialization				50.00%
Percentage of net loss from commercialization				50.00%
North America \| Future payments \| Product related collaborative arrangements \| Maximum \| Sales milestones
Collaboration, License and Co-Promotion Agreements
Milestone payment to be received by company upon milestone achievement				$ 100,000
U.S. \| Allergan \| Collaborative arrangement
Collaboration, License and Co-Promotion Agreements
Collaborative arrangements revenue related to sales of LINZESS in the U.S.		56,307	48,333	105,759	94,980
Revenue recognized from sale of API			1,465		4,482
Royalty revenue		435	238	934	547
Total collaborative arrangements revenue		56,742	50,036	106,693	100,009
U.S. \| Allergan \| Product related collaborative arrangements
Collaboration, License and Co-Promotion Agreements
Collaborative arrangements revenue related to sales of LINZESS in the U.S.		56,307	48,333	105,759	94,980
Selling, general and administrative costs incurred by the Company		(12,496)	(8,879)	(23,605)	(18,032)
The Company's share of net profit (loss)		43,811	39,454	82,154	76,948
Canada and Mexico \| Allergan \| Product related collaborative arrangements
Collaboration, License and Co-Promotion Agreements
Royalty percentage per agreement	mid-teens
Royalty revenue		$ 400	$ 200	$ 900	$ 500