Taxation - Summary of Income Tax Expense Recognized in The Consolidated Statement of Profit or Loss (Detail) - EUR (€) € in Thousands  | 
6 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2022  | 
Jun. 30, 2021  | 
Dec. 31, 2021  | 
Dec. 31, 2020  | 
Dec. 31, 2019  | 
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| Current income tax expense | |||||
| Current income tax expense for the year | € (200) | € (33) | € (276) | ||
| Total current tax expense | (200) | (33) | (276) | ||
| Deferred tax expense | |||||
| (De)recognition of deferred tax assets | (152) | 722 | 0 | ||
| Total deferred tax expense | (152) | 722 | 0 | ||
| Income tax expense | € (161) | € (597) | € (352) | € 689 | € (276) | 
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- Definition The amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
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- Definition The amount of current tax expense (income) and adjustments for the current tax of prior periods. [Refer: Current tax expense (income); Adjustments for current tax of prior periods] Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- References No definition available. 
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- Definition The amount of deferred tax expense arising from the write-down, or reversal of a previous write-down, of a deferred tax asset. [Refer: Deferred tax assets] Reference 1: http://www.xbrl.org/2003/role/exampleRef 
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- Definition The amount of tax expense (income) relating to changes in deferred tax liabilities and deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities] Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- References No definition available. 
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- Definition The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax. [Refer: Current tax expense (income); Deferred tax expense (income)] Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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