Lease obligation	3 Months Ended
Mar. 31, 2024
Lease obligation
Lease obligation	6. Lease obligation Operating Leases As of March 31, 2024, the Company has a lease for laboratory and office space at 75 Hayden Avenue in Lexington, Massachusetts through January 31, 2031 and a lease for additional office and laboratory space at 64 Sidney Street in Cambridge, Massachusetts through November 30, 2026. On August 11, 2023, the Company entered into a first amendment (the “First Amendment”) to its existing lease for laboratory and office space at 75 Hayden Avenue in Lexington, Massachusetts, pursuant to which the Company agreed to lease approximately 61,307 square feet of additional office and laboratory space through January 31, 2031. The Company received $1.8 million of leasehold improvement incentives associated with the First Amendment. The Company gained control of the space on February 1, 2024 and recorded a $26.7 million right-of-use asset and a $26.7 million operating lease liability, accordingly, which reflect the leasehold improvement incentive. The Company’s lease agreements require the Company to maintain a cash deposit or irrevocable letter of credit in the aggregate amount of $2.9 million payable to its landlords as security for the performance of its obligations under the leases. These amounts are recorded as restricted cash and are included in deposits and other non-current assets in the accompanying condensed consolidated balance sheets. During the three months ended March 31, 2024 and 2023, the Company incurred lease expenses of $1.7 million and $0.9 million, respectively, for operating leases. As of March 31, 2024, the weighted average remaining lease term was 5.5 years and the weighted average incremental borrowing rate used to determine the operating lease liability was 6.9%.

Lease obligation

3 Months Ended

Mar. 31, 2024

6. Lease obligation

Operating Leases

As of March 31, 2024, the Company has a lease for laboratory and office space at 75 Hayden Avenue in Lexington, Massachusetts through January 31, 2031 and a lease for additional office and laboratory space at 64 Sidney Street in Cambridge, Massachusetts through November 30, 2026.

On August 11, 2023, the Company entered into a first amendment (the “First Amendment”) to its existing lease for laboratory and office space at 75 Hayden Avenue in Lexington, Massachusetts, pursuant to which the Company agreed to lease approximately 61,307 square feet of additional office and laboratory space through January 31, 2031. The Company received $1.8 million of leasehold improvement incentives associated with the First Amendment. The Company gained control of the space on February 1, 2024 and recorded a $26.7 million right-of-use asset and a $26.7 million operating lease liability, accordingly, which reflect the leasehold improvement incentive.

The Company’s lease agreements require the Company to maintain a cash deposit or irrevocable letter of credit in the aggregate amount of $2.9 million payable to its landlords as security for the performance of its obligations under the leases. These amounts are recorded as restricted cash and are included in deposits and other non-current assets in the accompanying condensed consolidated balance sheets.

During the three months ended March 31, 2024 and 2023, the Company incurred lease expenses of $1.7 million and $0.9 million, respectively, for operating leases. As of March 31, 2024, the weighted average remaining lease term was 5.5 years and the weighted average incremental borrowing rate used to determine the operating lease liability was 6.9%.