Annual report [Section 13 and 15(d), not S-K Item 405]

Document and Entity Information

v3.25.1
Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Mar. 27, 2025
Jun. 30, 2024
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2024    
Document Fiscal Year Focus 2024    
Document Fiscal Period Focus FY    
Trading Symbol CABA    
Entity Registrant Name CABALETTA BIO, INC.    
Entity Current Reporting Status Yes    
Entity Central Index Key 0001759138    
Entity Voluntary Filers No    
Current Fiscal Year End Date --12-31    
Entity Filer Category Non-accelerated Filer    
Entity Well-known Seasoned Issuer No    
Entity Shell Company false    
Entity Small Business true    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] false    
Entity Common Stock, Shares Outstanding   50,743,101  
Entity Public Float     $ 350
Entity File Number 001-39103    
Entity Tax Identification Number 82-1685768    
Entity Address, Address Line One 2929 Arch Street    
Entity Address, Address Line Two Suite 600    
Entity Address, City or Town Philadelphia    
Entity Address, State or Province PA    
Entity Address, Postal Zip Code 19104    
City Area Code 267    
Local Phone Number 759-3100    
Entity Interactive Data Current Yes    
Title of 12(b) Security Common Stock, par value $0.00001 per share    
Security Exchange Name NASDAQ    
Entity Incorporation, State or Country Code DE    
Document Annual Report true    
Document Transition Report false    
Auditor Firm ID 42    
Auditor Name Ernst & Young LLP    
Auditor Location Philadelphia, Pennsylvania    
Auditor Opinion

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Cabaletta Bio, Inc. (the Company) as of December 31, 2024 and 2023, the related consolidated statements of operations and comprehensive loss, stockholders’ equity and cash flows for each of the two years in the period ended December 31, 2024, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2024, in conformity with U.S. generally accepted accounting principles.