Leases	9 Months Ended
Sep. 30, 2023
Leases [Abstract]
Leases	10. Leases In January 2023, the Company performed a remeasurement of their lease for office and laboratory space located at 640 Memorial Drive, Cambridge, Massachusetts, as the Company’s rentable square footage had been modified. This remeasurement included an update to the incremental borrowing rate from 7.99% to 8.4%, and resulted in a decrease in the right of use asset and lease liability of $0.2 million. Also in January 2023, the Company executed a sublease for a portion of their leased office and laboratory space at 730 Main Street, Cambridge, Massachusetts. In February 2022, the Company entered into an agreement to lease approximately 140,000 square feet of manufacturing space located at 840 Winter Street, Waltham, Massachusetts (the “840 Winter Lease”), which will provide the Company with the ability to manufacture its own products in a good manufacturing practice (“GMP”) compliant facility as well as to supplement the Company’s current leased premises in Cambridge, Massachusetts. The 840 Winter Lease, including the obligation to pay rent, is expected to commence in 2024 for an initial term of twelve years. The base rent under the 840 Winter Lease is $73.50 per square foot per year during the first year of the term, which is subject to scheduled 3% annual increases, plus certain operating expenses and taxes. The Company has the option to extend the 840 Winter Lease for two five-year terms. In June 2023, the Company executed an amendment to the 840 Winter Lease, which outlines the Company’s and the landlord’s responsibilities regarding the construction of the leased space. The Company will be responsible for the oversight of the construction of the tenant improvements, which will be primarily funded by a tenant improvement allowance of $250 per rentable square foot. The Company has elected an additional tenant improvement allowance of $50 per rentable square foot to be repaid over the term of the lease with interest, with an option to increase the allowance by an additional $100 per rentable square foot which would also be repaid over the term of the lease with interest. The Company will also be responsible for certain future construction costs to the extent that they exceed the tenant improvement allowance. The Company anticipates a phased move-in process during the second half of 2024. As of September 30, 2023, the Company had not taken control of the premises and therefore there are no right of use assets or liabilities recorded related to the 840 Winter Lease under ASC 842, Leases (Topic 842) (“ASC 842”).

Leases

9 Months Ended

Sep. 30, 2023

10. Leases

In January 2023, the Company performed a remeasurement of their lease for office and laboratory space located at 640 Memorial Drive, Cambridge, Massachusetts, as the Company’s rentable square footage had been modified. This remeasurement included an update to the incremental borrowing rate from 7.99% to 8.4%, and resulted in a decrease in the right of use asset and lease liability of $0.2 million.

Also in January 2023, the Company executed a sublease for a portion of their leased office and laboratory space at 730 Main Street, Cambridge, Massachusetts.

In February 2022, the Company entered into an agreement to lease approximately 140,000 square feet of manufacturing space located at 840 Winter Street, Waltham, Massachusetts (the “840 Winter Lease”), which will provide the Company with the ability to manufacture its own products in a good manufacturing practice (“GMP”) compliant facility as well as to supplement the Company’s current leased premises in Cambridge, Massachusetts. The 840 Winter Lease, including the obligation to pay rent, is expected to commence in 2024 for an initial term of twelve years. The base rent under the 840 Winter Lease is $73.50 per square foot per year during the first year of the term, which is subject to scheduled 3% annual increases, plus certain operating expenses and taxes. The Company has the option to extend the 840 Winter Lease for two five-year terms.

In June 2023, the Company executed an amendment to the 840 Winter Lease, which outlines the Company’s and the landlord’s responsibilities regarding the construction of the leased space. The Company will be responsible for the oversight of the construction of the tenant improvements, which will be primarily funded by a tenant improvement allowance of $250 per rentable square foot. The Company has elected an additional tenant improvement allowance of $50 per rentable square foot to be repaid over the term of the lease with interest, with an option to increase the allowance by an additional $100 per rentable square foot

which would also be repaid over the term of the lease with interest. The Company will also be responsible for certain future construction costs to the extent that they exceed the tenant improvement allowance. The Company anticipates a phased move-in process during the second half of 2024. As of September 30, 2023, the Company had not taken control of the premises and therefore there are no right of use assets or liabilities recorded related to the 840 Winter Lease under ASC 842, Leases (Topic 842) (“ASC 842”).