Cash and cash equivalents - Narrative (Details) - EUR (€) € in Thousands |
3 Months Ended | 9 Months Ended | 12 Months Ended | |
|---|---|---|---|---|
Sep. 30, 2025 |
Sep. 30, 2025 |
Sep. 30, 2024 |
Dec. 31, 2024 |
|
| Disclosure Of Cash And Cash Equivalents [Line Items] | ||||
| Notice accounts | € 15,169 | € 15,169 | € 44,239 | |
| Effect of movements in exchange rates on cash held | (8,940) | € (171) | ||
| United States of America, Dollars | ||||
| Disclosure Of Cash And Cash Equivalents [Line Items] | ||||
| Effect of movements in exchange rates on cash held | € (8,297) | € (8,297) | € 2,035 | |