Significant Contracts (Detail Textuals) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Supply Commitment [Line Items]
Collaboration and research and development revenue	$ 0	$ 0
Daiichi Sankyo
Supply Commitment [Line Items]
Future milestone payments payable	$ 10,000,000
Period for which royalties will be paid following first commercial sale of licensed products	10 years
Notice period for termination of license by the entity for technical, scientific, efficacy, safety, or commercial reasons	6 months
Notice period for termination of license after launch of a sapacitabine-based product by the entity, or by either party for material default	12 months
ManRos Therapeutics SA ("ManRos") \| Collaboration, Supply and Licensing Agreements
Supply Commitment [Line Items]
Payment received from achieving a clinical milestone	$ 150,000

Represent amount of collaboration and research and development revenue.

No definition available.

Name:	cycc_CollaborationAndResearchAndDevelopmentRevenue
Namespace Prefix:	cycc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the notice period for the termination of license after a launch of a sapacitabine-based product, or by either party for material default.

+ References

No definition available.

+ Details

Name:	cycc_LicenseAgreementNoticePeriodForTerminationOfAgreementAfterLaunchOfSapacitabineBasedProductOrInCaseOfMaterialDefault
Namespace Prefix:	cycc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the period for which royalties will be paid following the first commercial sale of licensed products in the country.

+ References

No definition available.

+ Details

Name:	cycc_LicenseAgreementPeriodForRoyaltiesPaymentAfterFirstCommercialSaleOfLicensedProductsInCountry
Namespace Prefix:	cycc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The potential future milestone payments required to be made under certain contractual agreements.

+ References

No definition available.

+ Details

Name:	cycc_LicenseAgreementPotentialFutureMilestonePayments
Namespace Prefix:	cycc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the notice period for the termination of license by the reporting entity for technical, scientific, efficacy, safety, or commercial reasons.

+ References

No definition available.

+ Details

Name:	cycc_LicensingAgreementNoticePeriodForTerminationOfAgreementDueToTechnicalScientificEfficacySafetyOrCommercialReason
Namespace Prefix:	cycc_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

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

- Details

Name:	dei_LegalEntityAxis=cycc_DaiichiSankyoCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cycc_ManrosTherapeuticsSaManrosMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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