v3.26.1
Convertible Preferred Stock, Convertible Preferred Stock Warrant Liability and Common Stock - Additional Information (Details)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
Jul. 30, 2026
USD ($)
shares
Jun. 30, 2026
$ / shares
shares
Jun. 15, 2026
USD ($)
shares
May 15, 2026
USD ($)
shares
May 05, 2026
shares
Apr. 26, 2026
shares
Mar. 31, 2026
USD ($)
$ / shares
shares
Mar. 19, 2026
USD ($)
shares
Jul. 21, 2020
shares
Dec. 23, 2019
shares
Feb. 27, 2017
$ / shares
shares
Feb. 16, 2016
Jun. 30, 2026
USD ($)
$ / shares
shares
Jun. 30, 2025
USD ($)
shares
Jun. 30, 2026
USD ($)
time
$ / shares
shares
Jun. 30, 2025
USD ($)
shares
Dec. 31, 2025
vote
$ / shares
shares
Mar. 31, 2025
shares
Dec. 31, 2024
shares
Sep. 20, 2017
$ / shares
shares
Dec. 16, 2016
shares
Class of Stock [Line Items]                                          
Purchase of stock by consolidated VIE (in shares)   244,130                                      
Proceeds from Exercises of Series E-1 and Series F Convertible Preferred Stock Warrants (Note 13) | $                             $ 1,611 $ 0          
Aggregate fair value of warrants | $                             $ (58,008) $ 2,133          
Common and preferred stock, shares authorized (in shares)                                       1,069,760,848  
Common stock, authorized (in shares)   625,000,000                     625,000,000   625,000,000   625,000,000     625,000,000  
Common stock, par value (in dollars per share) | $ / shares   $ 0.01                     $ 0.01   $ 0.01   $ 0.01     $ 0.01  
Convertible preferred stock, authorized (in shares)   444,760,848                     444,760,848   444,760,848   444,760,848     444,760,848  
Preferred stock, par value (in dollars per share) | $ / shares                                       $ 0.01  
Common stock, issued (in shares)   80,871,884                     80,871,884   80,871,884   79,138,710        
Common stock, outstanding (in shares)   79,935,949                     79,935,949   79,935,949   78,202,775        
Number of votes per share | vote                                 1        
Common stock transferred (in shares)   244,130                                      
Cashless exercise of common stock warrants (in shares)           503,821                              
Common Stock                                          
Class of Stock [Line Items]                                          
Stock split conversion ratio                       5                  
Common stock, outstanding (in shares)   84,869,054         83,476,590           84,869,054 82,960,790 84,869,054 82,960,790 83,380,010 82,769,890 82,642,684    
Exercise of stock options (in shares)                             1,229,353            
Cash proceeds | $                             $ 33            
Cashless exercise of common stock warrants (in shares)                         503,821   503,821            
Series A                                          
Class of Stock [Line Items]                                          
Purchase of convertible preferred stock by consolidated VIE Prosper Grantor Trust (in shares)   55,395                                      
Conversion ratio   1                     1   1            
Times the original issue | time                             3            
Liquidation preference (in dollars per share) | $ / shares   $ 0.29                     $ 0.29   $ 0.29            
Convertible preferred stock, authorized (in shares)   68,558,220                     68,558,220   68,558,220            
Series B                                          
Class of Stock [Line Items]                                          
IPO value (at least) | $                             $ 2,000,000            
Aggregate proceeds (at least) | $                             $ 100,000            
Voting power (at least) (as a percent)                             60.00%            
Liquidation preference (in dollars per share) | $ / shares   $ 0.60                     $ 0.60   $ 0.60            
Convertible preferred stock, authorized (in shares)   35,775,880                     35,775,880   35,775,880            
Series A-1                                          
Class of Stock [Line Items]                                          
Purchase of convertible preferred stock by consolidated VIE Prosper Grantor Trust (in shares)   58,165                                      
Voting power (at least) (as a percent)                             14.00%            
Conversion ratio   1,000,000                     1,000,000   1,000,000            
Liquidation preference (in dollars per share) | $ / shares   $ 2.00                     $ 2.00   $ 2.00            
Convertible preferred stock, authorized (in shares)   24,760,915                     24,760,915   24,760,915            
Series D                                          
Class of Stock [Line Items]                                          
Voting power (at least) (as a percent)                             60.00%            
Liquidation preference (in dollars per share) | $ / shares   $ 6.91                     $ 6.91   $ 6.91            
Series E-1 And Series E-2 Convertible Preferred Stock                                          
Class of Stock [Line Items]                                          
Voting power (at least) (as a percent)                             60.00%            
Series F convertible preferred stock warrants                                          
Class of Stock [Line Items]                                          
Voting power (at least) (as a percent)                             60.00%            
Preferred stock, liquidation preference, conversion basis                             0.6667            
Preferred stock, liquidation preference, conversion basis, after payment                             0.3333            
Liquidation preference (in dollars per share) | $ / shares   $ 0.84                     $ 0.84   $ 0.84            
Exercise of warrant (in shares)     41,833,904 41,833,904       41,833,904     177,720,706                    
Exercise price (in dollars per share) | $ / shares                     $ 0.01                    
Aggregate fair value of warrants | $     $ 47,700 $ 42,700       $ 42,300                          
Warrant expiration period (in years)                     10 years                    
Proceeds from issuance of convertible preferred stock | $     $ 400 $ 400       $ 400                          
Class of warrant or right, outstanding (in shares)   604,868                     604,868   604,868            
Change in fair value | $                         $ (5,900) $ (49,800) $ 44,500 $ (1,800)          
Convertible preferred stock, authorized (in shares)   177,720,707                     177,720,707   177,720,707            
Series F convertible preferred stock warrants | Subsequent Event                                          
Class of Stock [Line Items]                                          
Exercise of warrant (in shares) 51,614,124                                        
Aggregate fair value of warrants | $ $ 73,300                                        
Proceeds from issuance of convertible preferred stock | $ $ 500                                        
Series G                                          
Class of Stock [Line Items]                                          
Voting power (at least) (as a percent)                             60.00%            
Conversion ratio   1.36                     1.36   1.36            
Liquidation preference (in dollars per share) | $ / shares   $ 1.34                     $ 1.34   $ 1.34            
Convertible preferred stock, authorized (in shares)   37,249,497                     37,249,497   37,249,497            
Series C                                          
Class of Stock [Line Items]                                          
Liquidation preference (in dollars per share) | $ / shares   $ 2.87                     $ 2.87   $ 2.87            
Convertible preferred stock, authorized (in shares)   24,404,770                     24,404,770   24,404,770            
Series E-1                                          
Class of Stock [Line Items]                                          
Liquidation preference (in dollars per share) | $ / shares   $ 0.84                     $ 0.84   $ 0.84            
Exercise of warrant (in shares)                     15,277,006                    
Warrant or right, exercised, fair value | $             $ 38,700                            
Convertible preferred stock, authorized (in shares)   35,544,141                     35,544,141   35,544,141            
Series E-2                                          
Class of Stock [Line Items]                                          
Preferred stock, liquidation preference, conversion basis                             0.6667            
Preferred stock, liquidation preference, conversion basis, after payment                             0.3333            
Liquidation preference (in dollars per share) | $ / shares   $ 0.84                     $ 0.84   $ 0.84            
Convertible preferred stock, authorized (in shares)   16,858,078                     16,858,078   16,858,078            
Series E-1 Warrants                                          
Class of Stock [Line Items]                                          
Exercise of warrant (in shares)             35,544,141                           20,267,135
Exercise price (in dollars per share) | $ / shares             $ 0.01                            
Proceeds from Exercises of Series E-1 and Series F Convertible Preferred Stock Warrants (Note 13) | $             $ 400                            
Aggregate fair value of warrants | $                         $ 13,500 $ 9,600 $ 13,500 $ 400          
Common Stock                                          
Class of Stock [Line Items]                                          
Purchase of stock by consolidated VIE (in shares)                   2,196,665                      
Convertible Preferred Stock Held by Consolidated VIE | Series A                                          
Class of Stock [Line Items]                                          
Purchase of convertible preferred stock by consolidated VIE Prosper Grantor Trust (in shares)                 34,670,420                        
Return of convertible preferred stock (in shares)         289,560                                
Convertible Preferred Stock Held by Consolidated VIE | Series B                                          
Class of Stock [Line Items]                                          
Purchase of convertible preferred stock by consolidated VIE Prosper Grantor Trust (in shares)                 16,577,495