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Subsequent Events - Additional Information (Details) $ / shares in Units, $ in Thousands	Jan. 10, 2025 USD ($)	Jan. 09, 2025 $ / shares	Dec. 31, 2024 $ / shares	Dec. 31, 2023 $ / shares	May 15, 2023 $ / shares
Subsequent Event [Line Items]
Common stock, par value \| $ / shares			$ 0.0001	$ 0.0001	$ 0.0001
Subsequent Event
Subsequent Event [Line Items]
Reverse stock split		On January 9, 2025, the board of directors (the “Board”) of AlloVir, Inc. determined to effect a 1-for-23 reverse stock split of AlloVir’s common stock, par value $0.0001 per share.
Reverse stock split conversion ratio		0.043478261
Common stock, par value \| $ / shares		$ 0.0001
Subsequent Event \| Convertible Promissory Note
Subsequent Event [Line Items]
Debt instrument, issued, principal amount	$ 3,750
Subsequent Event \| Maximum \| Convertible Promissory Note
Subsequent Event [Line Items]
Debt instrument, issued, principal amount	7,500
Subsequent Event \| AlloVir \| Maximum \| Convertible Promissory Note
Subsequent Event [Line Items]
Debt instrument, issued, principal amount	7,500
Subsequent Event \| Kalaris Therapeutics, Inc. \| Convertible Promissory Note
Subsequent Event [Line Items]
Debt instrument, issued, principal amount	$ 3,750