Leases	3 Months Ended
Mar. 31, 2023
Leases [Abstract]
Leases	7. Leases In May 2021, the Company signed a 12-month membership agreement to lease space with WeWork at 501 Boylston Street, Boston, Massachusetts, commencing on August 1, 2021. The agreement was extended for six months on August 1, 2022. The 12-month agreement and 6-month extension are accounted for as short-term leases. The Company recorded a de minimis amount and approximately $0.1 million, in lease expense associated with the membership agreement during the three months ended March 31, 2023 and 2022, respectively. On September 15, 2020, the Company entered into a Sublease Termination Agreement (the "Sublease Termination Agreement") to terminate its sublease of 15,700 rentable square feet of its leased premises under the Head Lease. Under the terms of the Sublease Termination Agreement, the subtenant was relieved of its obligation to provide future cash rental payments to the Company. The agreements requiring the former subtenant to provide licensed rooms and services to the Company free of charge through the original sublease term survived the sublease termination. The Company gained access to the licensed rooms and services beginning in the third quarter of 2021. The letter of credit security deposit related to the sublease was released. The Company determined that the Sublease Termination Agreement constituted a non-monetary exchange under ASC 845 Nonmonetary Transactions ("ASC 845") where, in return for the free rooms and the services, the Company agreed to terminate its rights and obligations under the sublease agreement. In accordance with ASC 845, the Company determined that the accounting for the transaction should be based on the fair value of assets or services involved. The Company estimated the fair value of the rooms and services to be approximately $1.5 million and $2.9 million, respectively. The Company determined that the licensed rooms represent a lease under ASC Topic 842, Leases. The Company obtained control of the rooms in the third quarter of 2021 and the prepaid rooms balance of approximately $1.4 million was reclassified from other assets to a ROU asset. The related lease expense is recognized on a straight-line basis over the lease term of 8.88 years. The Company recorded $0.1 million and $0.1 million of lease expense during the three months ended March 31, 2023 and 2022, respectively. The Company determined that the licensed services represent a non-lease component, which is recognized separately from the lease component for this asset class. The expense related to the licensed services is recognized on a straight-line basis over the period the services are received. The Company recorded $0.1 million and $0.1 million for the three months ended March 31, 2023 and 2022, respectively. Both the lease expense and services expense are recognized as a component of research and development costs in the condensed consolidated statements of operations and comprehensive loss.

Leases

3 Months Ended

Mar. 31, 2023

7. Leases

In May 2021, the Company signed a 12-month membership agreement to lease space with WeWork at 501 Boylston Street, Boston, Massachusetts, commencing on August 1, 2021. The agreement was extended for six months on August 1, 2022. The 12-month agreement and 6-month extension are accounted for as short-term leases. The Company recorded a de minimis amount and approximately $0.1 million, in lease expense associated with the membership agreement during the three months ended March 31, 2023 and 2022, respectively.

On September 15, 2020, the Company entered into a Sublease Termination Agreement (the "Sublease Termination Agreement") to terminate its sublease of 15,700 rentable square feet of its leased premises under the Head Lease. Under the terms of the Sublease Termination Agreement, the subtenant was relieved of its obligation to provide future cash rental payments to the Company. The agreements requiring the former subtenant to provide licensed rooms and services to the Company free of charge through the original sublease term survived the sublease termination. The Company gained access to the licensed rooms and services beginning in the third quarter of 2021. The letter of credit security deposit related to the sublease was released.

The Company determined that the Sublease Termination Agreement constituted a non-monetary exchange under ASC 845 Nonmonetary Transactions ("ASC 845") where, in return for the free rooms and the services, the

Company agreed to terminate its rights and obligations under the sublease agreement. In accordance with ASC 845, the Company determined that the accounting for the transaction should be based on the fair value of assets or services involved. The Company estimated the fair value of the rooms and services to be approximately $1.5 million and $2.9 million, respectively.

The Company determined that the licensed rooms represent a lease under ASC Topic 842, Leases. The Company obtained control of the rooms in the third quarter of 2021 and the prepaid rooms balance of approximately $1.4 million was reclassified from other assets to a ROU asset. The related lease expense is recognized on a straight-line basis over the lease term of 8.88 years. The Company recorded $0.1 million and $0.1 million of lease expense during the three months ended March 31, 2023 and 2022, respectively. The Company determined that the licensed services represent a non-lease component, which is recognized separately from the lease component for this asset class. The expense related to the licensed services is recognized on a straight-line basis over the period the services are received. The Company recorded $0.1 million and $0.1 million for the three months ended March 31, 2023 and 2022, respectively. Both the lease expense and services expense are recognized as a component of research and development costs in the condensed consolidated statements of operations and comprehensive loss.