v3.26.1
Leases - Additional Information (Detail) - EUR (€)
6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Disclosure Of Lease Liabilities [Line Items]      
Lease agreement term 3 years    
Average incremental borrowing rate applied to the lease liabilities 7.77%   7.77%
Depreciation expense € 107,162 € 100,000 € 229,203
Total expense related to short-term and low-value leases 100,000  
Cash outflow for leases € 100,000 € 100,000  
United States      
Disclosure Of Lease Liabilities [Line Items]      
Average incremental borrowing rate applied to the lease liabilities 6.39%   6.39%