v3.26.3
Significant events for the year ended December 31, 2025 and the six-month period ended June 30, 2026 and subsequent events - For the year ended December 31, 2025 (Details)
€ / shares in Units, $ / shares in Units, € in Thousands, $ in Millions
1 Months Ended 6 Months Ended 10 Months Ended 12 Months Ended 115 Months Ended
Jul. 06, 2026
USD ($)
shares
Jul. 06, 2026
EUR (€)
€ / shares
shares
Dec. 23, 2025
EUR (€)
Nov. 28, 2025
EUR (€)
Nov. 25, 2025
shares
Aug. 28, 2025
shares
Aug. 08, 2025
shares
Jul. 30, 2025
EUR (€)
note
€ / shares
shares
Jul. 30, 2025
EUR (€)
note
€ / shares
shares
Jul. 28, 2025
USD ($)
shares
Jul. 28, 2025
EUR (€)
€ / shares
shares
Feb. 28, 2026
shares
Apr. 30, 2025
shares
Jan. 31, 2025
shares
Jun. 30, 2026
shares
Nov. 30, 2025
shares
plan
Dec. 31, 2025
EUR (€)
Jun. 30, 2026
shares
Jul. 06, 2026
$ / shares
May 07, 2026
€ / shares
May 07, 2026
$ / shares
Apr. 30, 2026
Jul. 28, 2025
$ / shares
Jul. 23, 2025
note
Jun. 30, 2025
€ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of free shares plans issued | plan                               8                  
Par value per share (in euro per share) | € / shares                     € 57.00                           € 6.64
Number of ordinary shares issued (in shares)                             877,310                    
Closing foreign exchange rate                             1.1394     1.1394       1.1702   1.1726  
Proceeds from issue of ordinary shares                   $ 747.5 € 637,500                            
Net proceeds from issuance of ordinary shares                   $ 700.3 € 597,200                            
Proceeds from issuing other equity instruments | €                                 € 608,100                
Completion of a public offering                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Proceeds from issue of ordinary shares $ 920.0 € 807,400                                              
Net proceeds from issuance of ordinary shares $ 874.1 € 767,100                                              
Heights convertible notes                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of ordinary shares issued (in shares)               920,377                                  
Number of convertible notes converted | note               200 200                             150  
Notional amount | €               € 21,900 € 21,900                                
Kreos/Claret Financing B And C                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Repayments of borrowings, classified as financing activities | €     € 33,823 € 33,823                                          
ADS                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of ordinary shares issued (in shares)                   11,679,400 11,679,400                            
Issue of equity, offering price per share (in dollar/euro per share) | $ / shares                                         $ 111.57   $ 64.00    
ADS | Completion of a public offering                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of ordinary shares issued (in shares) 7,360,000 7,360,000                                              
Issue of equity, offering price per share (in dollar/euro per share) | $ / shares                                     $ 125.00            
Ordinary shares                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Issue of equity, offering price per share (in dollar/euro per share) | € / shares                     € 54.58                 € 95.34          
Ordinary shares | Completion of a public offering                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Issue of equity, offering price per share (in dollar/euro per share) | € / shares   € 109.71                                              
Ordinary shares | Heights convertible notes                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Borrowings, fixed conversion price (euro per share) | € / shares               € 23.7674 € 23.7674                                
Ordinary shares | Kreos & Claret convertible notes (OCABSA)                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of ordinary shares issued (in shares)         392,695   785,389                                    
Ordinary shares | Kreos A & B & C BSA                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of ordinary shares issued (in shares)           206,662     319,251                                
BSAs                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of instruments issued (in shares)                       23,477 39,370 125,000 23,477     314,867              
Number of ordinary shares issued (in shares)                             16,400                    
BSAs | Board member                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Vesting period                       4 years 4 years 4 years                      
Vesting percentage                       25.00% 25.00% 25.00%                      
AGA-2025                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of instruments issued (in shares)                               6,280,727                  
AGA-2025 | Tranche 1                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Vesting period                               2 years                  
Vesting percentage                               50.00%                  
AGA-2025 | Tranche 2                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Vesting period                               3 years                  
Vesting percentage                               25.00%                  
AGA-2025 | Tranche 3                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Vesting period                               4 years                  
Vesting percentage                               25.00%                  
AGA-2025-2                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of instruments issued (in shares)                               123,102                  
Vesting period                               2 years                  
AGA-2025-5                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of instruments issued (in shares)                               50,000                  
AGA-2025-1                                                  
Disclosure of terms and conditions of share-based payment arrangement [line items]                                                  
Number of instruments issued (in shares)                               4,319,500