v3.26.1
Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)
 12 Months Ended
Jan. 02, 2027
Jan. 01, 2027
Dec. 31, 2026
Dec. 30, 2026
Oct. 30, 2024
Oct. 22, 2024
Aug. 01, 2023
May 02, 2023
Dec. 31, 2025
Dec. 31, 2024
Mar. 31, 2026
Dec. 31, 2023
Feb. 09, 2023
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Sales and marketing                 $ 10,804,000 $ 25,933,000      
Advertising and marketing costs                 1,500,000 4,900,000      
Uncertain tax positions for which reserves would be required                 $ 0 $ 0      
Revenue Interest Financing Agreement                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Principal amount of Revenue Interest Financing             $ 40,000,000            
RTW Side Letter                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Number of surrender shares of common stock           30,000              
Surrender common stock value           $ 7,500,000              
RTW Side Letter | Revenue Interest Financing Agreement                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Number of surrender shares of common stock           30,000              
Surrender common stock value           $ 7,500,000              
Conversion of RTW PIPE investment to revenue interest finance         $ 7,500,000                
Principal amount of Revenue Interest Financing         47,500,000                
Royalty rates increased by factor of principal amount         $ 47,500,000                
Percentage of royalty rate         14.30%                
New Allurion | Revenue Interest Financing Agreement                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Proceeds from revenue interest financing             $ 40,000,000            
ASU 2023-09                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Change in accounting principle accounting standards update adopted                 true        
Total Revenue | Customer Concentration Risk | Customers                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Concentration risk, percentage                 10.00% 10.00%      
Accounts Receivable | Customer Concentration Risk | Customers                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Concentration risk, percentage                 10.00% 10.00%      
Forecast | RIFA Amendment                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Percentage of net sales     12.00% 6.00%                  
Percentage of Increase in Net Sales 12.00% 10.00%                      
Percentage of Internal Rate of Return                     20.00%    
Maximum                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Earn-out shares receivable             360,000            
Maximum | Revenue Interest Financing Agreement                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Percentage of annual net sales                         6.00%
Remittance of revenue interest payments percentage                         10.00%
Additional revenue interest               $ 7,500,000          
Conversion of RTW PIPE investment to revenue interest finance                       $ 7,500,000  
Maximum | New Allurion | Revenue Interest Financing Agreement                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Percentage of annual net sales                         6.00%
Remittance of revenue interest payments percentage                         10.00%
Maximum | Forecast | RIFA Amendment                          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                          
Sales Revenue Net       $ 100,000,000                  
Increase in Sales Revenue Net   $ 100,000,000