Cabaletta Bio, Inc. Quarterly report [Sections 13 or 15(d)]

Quarterly report [Sections 13 or 15(d)]

Cover
- Document and Entity Information
Financial Statements
Notes to Financial Statements
Accounting Policies
- Summary of Significant Accounting Policies (Policies)
Notes Tables
Notes Details

Common Stock - Summary of Stock Option Activity (Details)

v3.26.1

Common Stock - Summary of Stock Option Activity (Details) - Employee Stock Option - Two Thousand Nineteen Stock Option And Incentive Plan [Member] - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2026	Dec. 31, 2025
Number of Shares
Number of Shares, Beginning Balance	13,835,372
Number of Shares, Granted	4,166,000
Number of Shares, Exercised	(34,257)
Number of shares, Forfeited/Cancelled	(143,975)
Number of Shares, Ending Balance	17,823,140	13,835,372
Number of Shares, Options Exercisable	9,518,318
Weighted Average Exercise Price
Weighted Average Exercise Price, Beginning Balance	$ 1.85
Weighted Average Exercise Price, Granted	3.28
Weighted Average Exercise Price, Exercised	1.94
Weighted Average Exercise Price, Forfeited/Cancelled	2.81
Weighted Average Exercise Price, Ending Balance	2.17	$ 1.85
Weighted Average Exercise Price, Options Exercisable	$ 1.83
Weighted Average Remaining Contractual Term (years)
Term (years)	7 years 3 months 18 days	7 years 1 month 6 days
Weighted Average Remaining Contractual Term (years), Options Exercisable	5 years 9 months 18 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Beginning Balance	$ 4,968
Aggregate Intrinsic Value, Options Exercisable	49
Aggregate Intrinsic Value, Ending Balance	17,451	$ 4,968
Aggregate Intrinsic Value, Options Exercisable	$ 12,152

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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