Other current and non-current assets - Additional Information (Detail) - EUR (€) € in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Other Current And Non-Current Asset [Abstract] | ||
| Prepaid maintenance expenses | € 1.5 | € 1.0 |
| Prepaid expense for supply of clinical materials | 1.1 | 2.7 |
| Upfront payment for commercial supply | 0.9 | |
| Prepaid expenses for clinical research organizations insurance and other services | 3.6 | 5.8 |
| Prepaid expenses of licenses and software | 4.4 | 3.4 |
| Capitalized capital gains tax and tax research allowance included in other assets | € 15.6 | € 13.0 |