v3.26.3
Convertible Preferred Stock, Convertible Preferred Stock Warrant Liability and Common Stock - Schedule of Shares Authorized, Issued, Outstanding, Par Value and Liquidation Preference of Convertible Preferred Stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
Sep. 30, 2026
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Sep. 20, 2017
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01     $ 0.01          
Convertible preferred stock, authorized (in shares) 444,760,848     444,760,848         444,760,848
Convertible preferred stock, issued (in shares) 421,983,987     261,227,694          
Convertible preferred stock, outstanding (in shares) 421,983,987     261,227,694          
Liquidation Preference, Outstanding Shares $ 549,861     $ 414,019          
Convertible Preferred Stock Held by Consolidated VIE                  
Class of Stock [Line Items]                  
Convertible preferred stock, outstanding (in shares) 51,361,475 51,361,475 51,247,915 51,247,915 51,247,915 51,247,915 51,247,915 51,247,915  
Series A                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 68,558,220                
Convertible preferred stock, issued (in shares) 66,138,625                
Convertible preferred stock, outstanding (in shares) 66,138,625                
Liquidation Preference, Outstanding Shares $ 19,076                
Series A | Convertible Preferred Stock Held by Consolidated VIE                  
Class of Stock [Line Items]                  
Convertible preferred stock, issued (in shares) 34,725,815                
Convertible preferred stock, outstanding (in shares) 34,725,815                
Series A-1                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 24,760,915                
Convertible preferred stock, issued (in shares) 22,515,315                
Convertible preferred stock, outstanding (in shares) 22,515,315                
Liquidation Preference, Outstanding Shares $ 45,031                
Series A-1 | Convertible Preferred Stock Held by Consolidated VIE                  
Class of Stock [Line Items]                  
Convertible preferred stock, issued (in shares) 58,165                
Convertible preferred stock, outstanding (in shares) 58,165                
Series B                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 35,775,880                
Convertible preferred stock, issued (in shares) 35,127,160                
Convertible preferred stock, outstanding (in shares) 35,127,160                
Liquidation Preference, Outstanding Shares $ 21,190                
Series B | Convertible Preferred Stock Held by Consolidated VIE                  
Class of Stock [Line Items]                  
Convertible preferred stock, issued (in shares) 16,577,495                
Convertible preferred stock, outstanding (in shares) 16,577,495                
Series C                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 24,404,770                
Convertible preferred stock, issued (in shares) 24,404,770                
Convertible preferred stock, outstanding (in shares) 24,404,770                
Liquidation Preference, Outstanding Shares $ 70,075                
Series D                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 23,888,640                
Convertible preferred stock, issued (in shares) 23,888,640                
Convertible preferred stock, outstanding (in shares) 23,888,640                
Liquidation Preference, Outstanding Shares $ 165,000                
Series E-1                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 35,544,141                
Convertible preferred stock, issued (in shares) 35,544,141                
Convertible preferred stock, outstanding (in shares) 35,544,141                
Liquidation Preference, Outstanding Shares $ 30,000                
Series E-2                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 16,858,078                
Convertible preferred stock, issued (in shares) 0                
Convertible preferred stock, outstanding (in shares) 0                
Liquidation Preference, Outstanding Shares $ 0                
Series F                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 177,720,707                
Convertible preferred stock, issued (in shares) 177,115,839                
Convertible preferred stock, outstanding (in shares) 177,115,839                
Liquidation Preference, Outstanding Shares $ 149,489                
Series G                  
Class of Stock [Line Items]                  
Convertible preferred stock, par value (in dollars per share) $ 0.01                
Convertible preferred stock, authorized (in shares) 37,249,497                
Convertible preferred stock, issued (in shares) 37,249,497                
Convertible preferred stock, outstanding (in shares) 37,249,497                
Liquidation Preference, Outstanding Shares $ 50,000