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

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

Fair Value Measurements - Schedule of Debt Securities Classified as Available-for-Sale Investments (Details)

Fair Value Measurements - Schedule of Debt Securities Classified as Available-for-Sale Investments (Details) $ in Thousands	Dec. 31, 2025 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 133,574
Gross Unrealized Gains	25
Fair value	133,599
Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	81,470
Gross Unrealized Gains	0
Fair value	81,470
Included in Cash and Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	82,982
Gross Unrealized Gains	0
Fair value	82,982
Cash
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,512
Gross Unrealized Gains	0
Fair value	1,512
U.S. Treasury securities - due in one year or less
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	50,592
Gross Unrealized Gains	25
Fair value	$ 50,617

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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