Non-cash stock-based compensation - Summary of Number of Shares Outstanding and Weighted Average Grant Date Fair Value (Detail) - Free Shares [member] |
6 Months Ended | |
|---|---|---|
|
Jun. 30, 2026
€ / shares
|
Jun. 30, 2025
€ / shares
|
|
| Disclosure of terms and conditions of share-based payment arrangement [line items] | ||
| Option outstanding, beginning balance | 251,946 | 509,295 |
| Option outstanding, granted | 0 | 0 |
| Option outstanding, exercised/vested | (246,749) | (231,356) |
| Option outstanding, forfeited, cancelled or expired | (5,197) | (13,894) |
| Option outstanding, ending balance | 0 | 264,045 |
| Weighted average exercise price per share, beginning balance | € 3.02 | € 2.84 |
| Weighted average exercise price per share, granted | 0 | 0 |
| Weighted average exercise price per share, Vested | 3.02 | 2.63 |
| Weighted average exercise price per share, Cancelled | 3.02 | 2.91 |
| Weighted average exercise price per share, ending balance | € 0 | € 3.01 |