v3.20.1

General information (Details)	Dec. 31, 2019 employee
General information.
Number of employees	1,003

X

- Definition

NA.

+ References

No definition available.

+ Details

Name:	glpg_DisclosureOfGeneralInformationAboutFinancialStatementAbstract
Namespace Prefix:	glpg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of personnel employed by the entity at a date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_NumberOfEmployees
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant