Provisions - Summary of Jubilee Provisions (Detail) - EUR (€) € in Thousands  | 
Dec. 31, 2021  | 
Dec. 31, 2020  | 
Dec. 31, 2019  | 
|---|---|---|---|
| Disclosure of other provisions [line items] | |||
| Current | € 248 | € 364 | |
| Non-current | 133 | 207 | |
| Total | 381 | 571 | |
| Jubilee Provisions [Member] | |||
| Disclosure of other provisions [line items] | |||
| Non-current | 73 | 78 | |
| Total | 73 | 78 | |
| Restructuring provision [member] | |||
| Disclosure of other provisions [line items] | |||
| Current | 248 | 364 | € 0 | 
| Non-current | 0 | 59 | 0 | 
| Total | 248 | 423 | € 0 | 
| Miscellaneous other provisions [member] | |||
| Disclosure of other provisions [line items] | |||
| Non-current | 60 | 70 | |
| Total | € 60 | € 70 | 
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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table. No definition available. 
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- Definition The amount of non-current provisions other than provisions for employee benefits. [Refer: Non-current provisions] Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition The amount of provisions other than provisions for employee benefits. [Refer: Provisions] Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition The amount of current provisions other than provisions for employee benefits. [Refer: Provisions] Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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