v3.26.1
Income taxes - Summary of Reconciliation of Income Tax Benefit / (Expense) And The Accounting Loss (Detail) - EUR (€)
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Reconciliation of accounting profit multiplied by applicable tax rates [abstract]        
Loss before income tax € (47,240,529) € (45,277,904) € (86,168,095) € (91,316,060)
Income tax at statutory income tax rate in the Netherlands (25.8%) 12,188,056 11,681,699 22,231,369 23,559,543
Effect of tax rates in other countries (6,852,905) (6,368,484) (12,578,517) (12,922,011)
Deferred tax assets recognition effects (5,667,942) (5,236,870) (10,413,454) (10,536,949)
Temporary differences for which no deferred tax assets/liabilities have been recognized 503,571 0 821,719 0
Non-deductible expenses (226,331) (186,549) (386,955) (515,860)
Transfer Pricing adjustment 0 (43,987) 0 (43,987)
Prior period adjustments (546,649) (48,591) (549,469) (46,185)
Income tax expense € (602,200) € (202,782) € (875,307) € (505,449)