Name:	glpg_DeferredCharges
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of trade payables and other payables and other current assets.

No definition available.

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Namespace Prefix:	glpg_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Trade And Other Receivables And Other Current Assets [Abstract]

No definition available.

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

The amount of current accrued income. [Refer: Accrued income]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 112
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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of current prepayments. [Refer: Prepayments]

Name:	ifrs-full_CurrentPrepayments
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of current trade receivables. [Refer: Trade receivables]

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
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Name:	ifrs-full_CurrentTradeReceivables
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of current inventories. [Refer: Inventories]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 2
-IssueDate 2019-01-01
-Paragraph 36
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-URIDate 2019-03-27

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
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Name:	ifrs-full_Inventories
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of current assets that the entity does not separately disclose in the same statement or note. [Refer: Current assets]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
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Name:	ifrs-full_OtherCurrentAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of current other receivables. [Refer: Other receivables]

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of current trade receivables and current other receivables. [Refer: Current trade receivables; Other current receivables]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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