v3.20.1

Deferred tax - Summary of deferred tax assets and liabilities (Details) - EUR (€) € in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Deferred tax |  |  |
Deferred tax assets | € 4,205 | € 2,514 | € 1,978
Deferred tax assets unrecognized | 289,833 | 223,377 | 164,079
Deferred taxes in the consolidated statement of operations | 1,158 | 535 | 20
Tax benefit arising from previously unrecognized tax assets used to reduce deferred tax expense (+) | 1,537 | 1,973 | 414
Deferred tax expenses relating to change in tax rates |  |  | (181)
Deferred tax expenses relating to use of previously recognized deferred tax assets | € (379) | € (1,438) | € (213)

X
- Definition Represents unrecognized deferred tax assets. + References No definition available. + Details
Name: | glpg_DeferredTaxAssetsUnrecognized
Namespace Prefix: | glpg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amounts of income taxes recoverable in future periods in respect of: (a) deductible temporary differences; (b) the carryforward of unused tax losses; and (c) the carryforward of unused tax credits. [Refer: Temporary differences [member]; Unused tax credits [member]; Unused tax losses [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2019-01-01 -Paragraph 81 -Subparagraph g -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2019-en-r&anchor=para_81_g_i&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 54 -Subparagraph o -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_54_o&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 56 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_56&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_DeferredTaxAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | ifrs-full_DeferredTaxAssetsAndLiabilitiesAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of tax expense or income relating to changes in deferred tax liabilities and deferred tax assets, recognised in profit or loss. [Refer: Deferred tax assets; Deferred tax expense (income); Deferred tax liabilities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2019-01-01 -Paragraph 81 -Subparagraph g -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2019-en-r&anchor=para_81_g_ii&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_DeferredTaxExpenseIncomeRecognisedInProfitOrLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of deferred tax expense or income relating to the creation or reversal of temporary differences. [Refer: Temporary differences [member]; Deferred tax expense (income)] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 12 -IssueDate 2019-01-01 -Paragraph 80 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2019-en-r&anchor=para_80_c&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_DeferredTaxExpenseIncomeRelatingToOriginationAndReversalOfTemporaryDifferences
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of deferred tax expense or income relating to tax rate changes or the imposition of new taxes. [Refer: Deferred tax expense (income)] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 12 -IssueDate 2019-01-01 -Paragraph 80 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2019-en-r&anchor=para_80_d&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_DeferredTaxExpenseIncomeRelatingToTaxRateChangesOrImpositionOfNewTaxes
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of benefit arising from a previously unrecognised tax loss, tax credit or temporary difference of a prior period that is used to reduce deferred tax expense. [Refer: Deferred tax expense (income); Temporary differences [member]; Unused tax losses [member]; Unused tax credits [member]] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 12 -IssueDate 2019-01-01 -Paragraph 80 -Subparagraph f -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2019-en-r&anchor=para_80_f&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_TaxBenefitArisingFromPreviouslyUnrecognisedTaxLossTaxCreditOrTemporaryDifferenceOfPriorPeriodUsedToReduceDeferredTaxExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration