v3.25.1

Summary of significant transactions - Clinical collaboration agreement with Adaptimmune (Details) - Adaptimmune Collaboration [member] - USD ($) |  | 12 Months Ended
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May 30, 2024 | Dec. 31, 2024
Summary Of Significant Transaction [line items] |  |
Upfront Exclusivity Payment | $ 70,000,000 |
Research And Development Payment | $ 15,000,000 |
Upfront Exclusive Research And Development Payable |  | $ 15,000,000
Intangible assets capitalised |  | 70,000,000
Deferred Expenses |  | 15,000,000
First Payment [member] |  |
Summary Of Significant Transaction [line items] |  |
Upfront Exclusivity Payment |  | 70,000,000
Second Payment [member] |  |
Summary Of Significant Transaction [line items] |  |
Research And Development Payment |  | $ 15,000,000

X
- Definition The amount of R&D deferred expenses + References No definition available. + Details
Name: | glpg_DeferredExpenses
Namespace Prefix: | glpg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of research and development payment made. + References No definition available. + Details
Name: | glpg_ResearchAndDevelopmentPayment
Namespace Prefix: | glpg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent summary of significant transaction. + References No definition available. + Details
Name: | glpg_SummaryOfSignificantTransactionLineItems
Namespace Prefix: | glpg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of upfront exclusivity payment payable subject to the start of dosing in the proof-of-concept trial. + References No definition available. + Details
Name: | glpg_UpfrontExclusiveResearchAndDevelopmentPayable
Namespace Prefix: | glpg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of upfront exclusivity payment made. + References No definition available. + Details
Name: | glpg_UpfrontExclusivityPayment
Namespace Prefix: | glpg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of additions to intangible assets other than goodwill, other than those acquired through business combinations. [Refer: Total for all business combinations [member]; Intangible assets other than goodwill] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 38 -IssueDate 2024-01-01 -Paragraph 118 -Subparagraph e -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2024-en-r&anchor=para_118_e_i&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | glpg_IfrsTypeOfArrangementAxis=glpg_AdaptimmuneCollaborationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | glpg_IfrsScenarioAxis=glpg_FirstPaymentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | glpg_IfrsScenarioAxis=glpg_SecondPaymentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |