v3.20.1

Significant accounting policies - Property, Plant and Equipment (Details) | 12 Months Ended
--- | ---
Dec. 31, 2019
Minimum | Installation and machinery |
Disclosure of detailed information about property, plant and equipment |
Useful lives | 3 years
Minimum | Furniture, fixtures & vehicles |
Disclosure of detailed information about property, plant and equipment |
Useful lives | 4 years
Maximum | Installation and machinery |
Disclosure of detailed information about property, plant and equipment |
Useful lives | 15 years
Maximum | Furniture, fixtures & vehicles |
Disclosure of detailed information about property, plant and equipment |
Useful lives | 10 years

X
- Definition The useful lives used for property, plant and equipment, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | glpg_UsefulLivesPropertyPlantAndEquipment
Namespace Prefix: | glpg_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=glpg_InstallationAndMachineryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=glpg_FurnitureFixturesAndVehiclesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |