Cabaletta Bio, Inc. Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income tax benefit	$ 0	$ 0	$ 0	$ 0
Unrecognized tax benefits	$ 0		$ 0		$ 0

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.