Commitment and Contingencies - Additional Information (Details) $ in Thousands	1 Months Ended	6 Months Ended
	Sep. 30, 2024 USD ($) ft²	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Commitments And Contingencies [Line Items]
Restricted cash		$ 1,400	$ 1,400
Operating lease, description		In September 2024, the Company entered into a lease agreement for the lease of approximately 15,000 square feet of office space in Cambridge, Massachusetts, which will be used as the Company's new headquarters facility. The accounting lease commencement occurred on June 1, 2025, at which time the Company recognized a right-of-use, or ROU, asset and corresponding lease liability of $5.1 million. The contractual term of the lease commenced on June 1, 2025, with an initial term of approximately 67 months. The Company’s obligation for the payment of rent for the new lease begins seven months after the lease commencement. In addition to base rent, the Company has agreed to reimburse the landlord for certain operating expenses under the terms of the lease. The Company has the option to extend the new lease one time for an additional five-year period, subject to the terms therein; however, the exercise of the option to extend the lease term was not determined to be reasonably certain, and the Company will therefore recognize lease expense through the expiration of the initial lease term in December 2030.
Area of lease property \| ft²	15,000
Operating lease right-of-use assets	$ 5,100	$ 5,812	$ 1,771
Operating lease liability	$ 5,100
Lease commencement date	Jun. 01, 2025
Rent payment obligation beginning period after lease commencement	7 months
Operating lease, term of contract	67 months
Lessee, Operating Lease, Existence of Option to Extend [true false]	true
Operating lease renewal term	5 years
Description of lease extension		The Company has the option to extend the new lease one time for an additional five-year period, subject to the terms therein; however, the exercise of the option to extend the lease term was not determined to be reasonably certain
Collateral for Letter of Credit Issued
Commitments And Contingencies [Line Items]
Restricted cash		$ 900
Collateral for Corporate Credit Card Program
Commitments And Contingencies [Line Items]
Restricted cash		$ 500

Amylyx Pharmaceuticals, Inc. 10-Q