Trade and other receivables - Schedule of Trade And Other Receivables (Detail) - EUR (€) € in Thousands  | 
Jun. 30, 2022  | 
Dec. 31, 2021  | 
Dec. 31, 2020  | 
|---|---|---|---|
| Schedule of Trade and other receivables [Line Items] | |||
| Trade receivables – gross | € 39,563 | € 23,193 | |
| Loss allowance | (1) | (2) | |
| Trade receivables – net | 39,562 | 23,191 | |
| VAT receivables | 1,015 | 709 | |
| Other receivables | 232 | 95 | |
| Receivables from related parties | 142 | 8 | |
| Government grants receivables | 1,126 | 1,073 | |
| Total | € 33,693 | € 42,077 | € 25,076 | 
| X | ||||||||||
- Definition Current Trade Receivables, Gross. No definition available. 
  | 
| X | ||||||||||
- Definition Government grants receivables. No definition available. 
  | 
| X | ||||||||||
- Definition Schedule of Trade and other receivables. No definition available. 
  | 
| X | ||||||||||
- Definition The amount of an allowance account used to record impairments to financial assets due to credit losses. [Refer: Financial assets] Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Definition The amount of current trade receivables. [Refer: Trade receivables] Reference 1: http://www.xbrl.org/2003/role/exampleRef 
  | 
| X | ||||||||||
- Definition The amount of current value added tax receivables. [Refer: Value added tax receivables] Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
  | 
| X | ||||||||||
- Definition The amount of current other receivables. [Refer: Other receivables] Reference 1: http://www.xbrl.org/2003/role/exampleRef 
  | 
| X | ||||||||||
- Definition 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 
  | 
| X | ||||||||||
- Definition The amount of current receivables due from related parties. [Refer: Related parties [member]] Reference 1: http://www.xbrl.org/2003/role/exampleRef 
  |