v3.26.3
Stockholders' equity - Common Stock (Details)
 1 Months Ended 9 Months Ended
Sep. 17, 2026
$ / shares
shares
Jun. 06, 2025
$ / shares
shares
Aug. 31, 2025
$ / shares
shares
Jun. 30, 2025
$ / shares
shares
Sep. 30, 2026
vote
class
$ / shares
shares
Dec. 31, 2025
$ / shares
shares
Class of Stock            
Preferred stock, shares authorized (in shares)   500,000,000.0        
Number of classes of common stock | class         3  
ESPP            
Class of Stock            
Common stock reserved for future issuance (in shares)         8,000,000.0  
Common Stock Issuable Under Stock Award Plan            
Class of Stock            
Common stock reserved for future issuance (in shares)         19,400,000  
Shares issued (in shares)         700,000  
Common Stock Available For Future Issuance Under Stock Award Plan            
Class of Stock            
Common stock reserved for future issuance (in shares)         38,700,000  
Class A common stock            
Class of Stock            
Common stock, shares authorized (in shares)   2,500,000,000     2,500,000,000 2,500,000,000
Common stock, par or stated value per share (in dollars per share) | $ / shares   $ 0.0001     $ 0.0001 $ 0.0001
Preferred stock par value (in dollars per share) | $ / shares   $ 0.0001        
Common stock, shares, issued (in shares)         237,100,000 223,600,000
Conversion of stock, shares issued (in shares)   139,800,000        
Number of votes for each share of common stock held | vote         1  
Class A common stock | IPO            
Class of Stock            
Number of shares issued (in shares)       19,900,000    
Purchase price per share (in dollars per share) | $ / shares       $ 31.00    
Class A common stock | Follow-on Public Offering            
Class of Stock            
Number of shares issued (in shares)     3,500,000      
Purchase price per share (in dollars per share) | $ / shares     $ 130.00      
Class A common stock | Private Placement            
Class of Stock            
Number of shares issued (in shares) 1,200,000     19,200,000    
Purchase price per share (in dollars per share) | $ / shares $ 80.84          
Class B common stock            
Class of Stock            
Common stock, shares authorized (in shares)   500,000,000.0     500,000,000.0 500,000,000.0
Common stock, par or stated value per share (in dollars per share) | $ / shares   $ 0.0001     $ 0.0001 $ 0.0001
Common stock, shares, issued (in shares)         19,100,000 19,100,000
Number of votes for each share of common stock held | vote         5  
Common stock aggregate voting power maximum percentage (in percent)         30.00%  
Class B common stock | Co-Founder            
Class of Stock            
Conversion of stock, shares issued (in shares)   19,600,000        
Class C common stock            
Class of Stock            
Common stock, shares authorized (in shares)         500,000,000.0 500,000,000.0
Common stock, par or stated value per share (in dollars per share) | $ / shares   $ 0.0001     $ 0.0001 $ 0.0001
Common stock, shares, issued (in shares)   500,000,000.0     0 0