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Days notice required by Fennec to terminate OHSU agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	fenc_DaysNoticeRequiredByFennecToTerminateOhsuAgreement
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Days notice required to terminate OHSU agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	fenc_DaysNoticeToTerminateOhsuAgreement
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Duration of FDA's ability to give final approval to proposed products that reference PEDMARK subsequent to the filing of a patent infringement suit, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

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Data Type:	xbrli:durationItemType
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Licensing term under OHSU agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	fenc_LicensingTermOhsuAgreement
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Data Type:	xbrli:durationItemType
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Represents number of severance payments following executive's termination.

No definition available.

Name:	fenc_NumberOfSeverancePayments
Namespace Prefix:	fenc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Days notice required to terminate lease agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	fenc_OperatingLeaseDaysNoticeRequiredToTerminateAgreement
Namespace Prefix:	fenc_
Data Type:	xbrli:durationItemType
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Represents number of scheduled payment increases over the duration of the lease agreement.

No definition available.

Name:	fenc_OperatingLeaseNumberOfScheduledPaymentIncreases
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Amount of operating lease penalties and contingent payments due.

No definition available.

Name:	fenc_OperatingLeasePenaltiesAndContingentPaymentsPayable
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Data Type:	xbrli:monetaryItemType
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Duration of PEDMARK's exclusivity period under the European Market Exclusivity for Pediatric Use (PUMA) program, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	fenc_PedmarkSExclusivityPeriodUnderPuma
Namespace Prefix:	fenc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Duration of PEDMARK's exclusivity period due to Orphan Drug Exclusivity status, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	fenc_PedmarkSOrphanDrugExclusivityPeriod
Namespace Prefix:	fenc_
Data Type:	xbrli:durationItemType
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Period Type:	duration

Represents the percentage of royalties to be received as consideration.

No definition available.

Name:	fenc_RoyaltiesPercentage
Namespace Prefix:	fenc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The variable rate of interest (added to the current prime interest rate) used in determining the Company's incremental borrowing rate.

No definition available.

Name:	fenc_VariableInterestRateOverPrime
Namespace Prefix:	fenc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Amount of operating lease expense. Excludes sublease income.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479041/842-20-45-4

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Data Type:	xbrli:monetaryItemType
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Describes the maximum potential amount of consideration, undiscounted, that could be transferred under the registration payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 825
-SubTopic 20
-Section 50
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Describes the term of the registration payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 825
-SubTopic 20
-Section 50
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482804/825-20-50-1

Name:	us-gaap_RegistrationPaymentArrangementTerm
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Data Type:	xbrli:stringItemType
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Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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This element represents money paid in advance to protect the provider of a product or service, such as a lessor, against damage or nonpayment by the buyer or tenant (lessee) during the term of the agreement. Such damages may include physical damage to the property, theft of property, and other contractual breaches. Security deposits held may be interest or noninterest bearing.

No definition available.

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

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Name:	srt_StatementGeographicalAxis=country_IE
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Name:	us-gaap_OtherCommitmentsAxis=fenc_LitigationCiplaAndaMember
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Data Type:	na
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