Represents the additional milestone payment received under the license agreement.

No definition available.

Name:	incy_LicenseAgreementAdditionalMilestonePaymentsReceived
Namespace Prefix:	incy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the earning recognized and the payment received for the achievement of a predefined milestone under the license agreement.

+ References

No definition available.

+ Details

Name:	incy_LicenseAgreementAmountRecognizedAndReceivedForAchievementOfPredefinedMilestone
Namespace Prefix:	incy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the number of deliverables under the license agreement.

+ References

No definition available.

+ Details

Name:	incy_LicenseAgreementNumberOfDeliverables
Namespace Prefix:	incy_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents reimbursed costs pertaining to research and development expenses.

+ References

No definition available.

+ Details

Name:	incy_LicenseAgreementResearchAndDevelopmentReimbursedCost
Namespace Prefix:	incy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the upfront and immediate milestone payment received under the license agreement.

+ References

No definition available.

+ Details

Name:	incy_LicenseAgreementUpfrontPaymentAndImmediateMilestonePaymentToBeReceived
Namespace Prefix:	incy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the upfront payment received under the license agreement.

+ References

No definition available.

+ Details

Name:	incy_LicenseAgreementUpfrontPaymentReceived
Namespace Prefix:	incy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the percentage of associated future global development costs from the initiation of a Phase IIb trial provided the entity elects to co-develop any compounds and/or indications.

+ References

No definition available.

+ Details

Name:	incy_PercentageFundingOnCostOnPossibleElectionOfCodevelopmentOfCompounds
Namespace Prefix:	incy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents range of tiered, double-digit royalty payments on future global sales if product is successfully commercialized.

+ References

No definition available.

+ Details

Name:	incy_PercentageOfRoyaltyRatePayments
Namespace Prefix:	incy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the royalty payment receivable under the license agreement.

+ References

No definition available.

+ Details

Name:	incy_RoyaltyPaymentReceivable
Namespace Prefix:	incy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of revenue earned from products sold or services provided under the terms of a contract, including, but not limited to, government contracts and construction contracts, classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_ContractsRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 985
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128462-111756

+ Details

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

- Definition

Revenue earned during the period from the leasing or otherwise lending to a third party the entity's rights or title to certain property. Royalty revenue is derived from a percentage or stated amount of sales proceeds or revenue generated by the third party using the entity's property. Examples of property from which royalties may be derived include patents and oil and mineral rights.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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

- Details

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

- Details

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

- Details

Name:	incy_PhasesOfArrangementsAxis=incy_PhaseTwoBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	incy_AchievementOfMilestoneAxis=incy_PreSpecifiedEventsMember
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:	incy_AchievementOfMilestoneAxis=incy_DevelopmentMilestonesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	incy_PhasesOfArrangementsAxis=incy_PhaseThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	incy_PhasesOfArrangementsAxis=incy_PhaseTwoAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	incy_AchievementOfMilestoneAxis=incy_RegulatoryMilestonesMember
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_StatementGeographicalAxis=us-gaap_EuropeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	incy_AchievementOfMilestoneAxis=incy_CommercializationMilestonesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

License agreements - Lilly (Details) $ in Thousands	1 Months Ended				12 Months Ended					97 Months Ended
License agreements - Lilly (Details) $ in Thousands	Jan. 31, 2017	Mar. 31, 2016 USD ($)	Jul. 31, 2010	Dec. 31, 2009 USD ($) item	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2017 USD ($)
License agreements
Research and Development Expense					$ 1,326,361	$ 581,861	$ 479,514
Milestone and contract revenues					175,000	112,512	77,857
Product royalty revenues					$ 160,791	110,711	74,821
Eli Lilly
License agreements
Upfront payment received under license agreement				$ 90,000
Associated future global development costs from the initiation of a Phase IIb trial, if elected to co-develop (as a percentage)	30.00%				30.00%
Research and Development Expense					$ 40,800	27,300	36,000
Number of deliverables under license agreement \| item				2
Milestone and contract revenues					110,000	67,500	$ 12,900
Product royalties in accounts receivable					4,600					$ 4,600
Eli Lilly \| Non-U.S.
License agreements
Product royalty revenues					9,100
Eli Lilly \| Phase IIB
License agreements
Associated future global development costs from the initiation of a Phase IIb trial, if elected to co-develop (as a percentage)			30.00%	30.00%
Eli Lilly \| Pre-specified Events \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement				$ 665,000
Eli Lilly \| Development Milestones
License agreements
Amount recognized and received for the achievement of a predefined milestone					30,000					129,000
Eli Lilly \| Development Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement				150,000
Eli Lilly \| Development Milestones \| Phase III
License agreements
Amount recognized and received for the achievement of a predefined milestone								$ 50,000
Eli Lilly \| Development Milestones \| Phase IIA
License agreements
Amount recognized and received for the achievement of a predefined milestone									$ 30,000
Eli Lilly \| Development Milestones \| Phase IIB
License agreements
Amount recognized and received for the achievement of a predefined milestone									$ 19,000
Eli Lilly \| Regulatory Milestones
License agreements
Amount recognized and received for the achievement of a predefined milestone						35,000				$ 135,000
Eli Lilly \| Regulatory Milestones \| JAPAN
License agreements
Amount recognized and received for the achievement of a predefined milestone					15,000
Eli Lilly \| Regulatory Milestones \| Europe
License agreements
Amount recognized and received for the achievement of a predefined milestone					$ 65,000	20,000
Eli Lilly \| Regulatory Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement				365,000
Eli Lilly \| Commercialization Milestones \| Maximum
License agreements
Upfront and immediate milestone payment to be received under license agreement				$ 150,000
Royalty payments on future global net sales (as a percent)					20.00%
Eli Lilly \| GVHD
License agreements
Upfront payment received under license agreement		$ 35,000
Additional milestone payment received under license agreement		$ 40,000
Research and development expenses reimbursed						$ 35,000