Related Party Transactions	3 Months Ended
Mar. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	16. Related Party Transactions The majority ownership of the Company is held by Flagship, in which it holds shares representing approximately 53% of the Company’s outstanding voting stock as of March 31, 2023. Flagship historically provided management services to the Company, and the Company reimburses Flagship for certain expenses, including insurance and benefits, and related fees, and software licenses incurred on the Company’s behalf. For the three months ended March 31, 2023 and 2022, the Company incurred $0.2 million and $0.4 million, respectively, primarily for reimbursable expenses. These expenses are recorded as related party expense in the accompanying condensed consolidated statements of operations and comprehensive loss. As of March 31, 2023 and December 31, 2022, there was an immaterial amount of outstanding payments due to Flagship. In September 2020, the Company sublet the entire space of its 325 Vassar Street facility, approximately 19,404 square feet, to LARONDE, Inc. (“LARONDE”, formerly known as VL50, Inc.), which is an affiliate of Flagship. The sublease term will expire at the end of the Company’s lease agreement with the landlord in September 2024. The rental rate for the sublease arrangement is equal to the Company’s rental obligation per the agreement with BMR-325 Vassar Street LLC, reduced by the sublease income received from Cygnal Therapeutics, Inc. (“Cygnal”), approximating $1.3 million per year. The sublessee is obligated to pay all real estate taxes and costs related to the subleased premises, including cost of operations, maintenance, repair, replacement and property management. Under the sublease agreement, the Company received rental income, which was recorded as a reduction of rental expense, of $0.6 million and $0.8 million during the three months ended March 31, 2023 and 2022, respectively. Such rental income was reflected as a reduction of related party expense in the accompanying condensed consolidated statements of operations and comprehensive loss. There was no outstanding receivable due from LARONDE as of March 31, 2023 and December 31, 2022. In September 2019, the Company sublet approximately 1,445 square feet of its 325 Vassar Street facility to Cygnal, which is an affiliate of Flagship, for two years. The lease term was to continue on a month-to-month basis until advanced notice is provided to the Company. Cygnal gave notice, terminated the agreement and vacated the property in May 2022. The rental rate for the sublease arrangement was equal to the Company’s rental obligation per the agreement with BMR-325 Vassar Street LLC, approximating $0.1 million per year. The sublessee was obligated to pay all real estate taxes and costs related to the subleased premises, including cost of operations, maintenance, repair, replacement and property management. Under the sublease agreement, the Company received rental income of less than $0.1 million for the three months ended 2022, which was recorded as a reduction of rental expenses. Such rental income was reflected as a reduction of related party expense in the accompanying condensed consolidated statements of operations and comprehensive loss. There was no outstanding receivable due from Cygnal as of March 31, 2023 and December 31, 2022. Refer to other related party transactions as described in Note 9, Commitments and contingencies, Note 10, License agreements and Note 11, Collaboration agreement.

Related Party Transactions

3 Months Ended

Mar. 31, 2023

16. Related Party Transactions

The majority ownership of the Company is held by Flagship, in which it holds shares representing approximately 53% of the Company’s outstanding voting stock as of March 31, 2023. Flagship historically provided management services to the Company, and the Company reimburses Flagship for certain expenses, including insurance and benefits, and related fees, and software licenses incurred on the Company’s behalf. For the three months ended March 31, 2023 and 2022, the Company incurred $0.2 million and $0.4 million, respectively, primarily for reimbursable expenses. These expenses are recorded as related party expense in the accompanying condensed consolidated statements of operations and comprehensive loss. As of March 31, 2023 and December 31, 2022, there was an immaterial amount of outstanding payments due to Flagship.

In September 2020, the Company sublet the entire space of its 325 Vassar Street facility, approximately 19,404 square feet, to LARONDE, Inc. (“LARONDE”, formerly known as VL50, Inc.), which is an affiliate of Flagship. The sublease term will expire at the end of the Company’s lease agreement with the landlord in September 2024. The rental rate for the sublease arrangement is equal to the Company’s rental obligation per the agreement with BMR-325 Vassar Street LLC, reduced by the sublease income received from Cygnal Therapeutics, Inc. (“Cygnal”), approximating $1.3 million per year. The sublessee is obligated to pay all real estate taxes and costs related to the subleased premises, including cost of operations, maintenance, repair, replacement and property management. Under the sublease agreement, the Company received rental income, which was recorded as a reduction of rental expense, of $0.6 million and $0.8 million during the three months ended March 31, 2023 and 2022, respectively. Such rental income was reflected as a reduction of related party expense in the accompanying condensed consolidated statements of operations and comprehensive loss. There was no outstanding receivable due from LARONDE as of March 31, 2023 and December 31, 2022.

In September 2019, the Company sublet approximately 1,445 square feet of its 325 Vassar Street facility to Cygnal, which is an affiliate of Flagship, for two years. The lease term was to continue on a month-to-month basis until advanced notice is provided to the Company. Cygnal gave notice, terminated the agreement and vacated the property in May 2022. The rental rate for the sublease arrangement was equal to the Company’s rental obligation per the agreement with BMR-325 Vassar Street LLC, approximating $0.1 million per year. The sublessee was obligated to pay all real estate taxes and costs related to the subleased premises, including cost of operations, maintenance, repair, replacement and property management. Under the sublease agreement, the Company received rental income of less than $0.1 million for the three months ended 2022, which was recorded as a reduction of rental expenses. Such rental income was reflected as a reduction of related party expense in the accompanying condensed consolidated statements of operations and comprehensive loss. There was no outstanding receivable due from Cygnal as of March 31, 2023 and December 31, 2022.

Refer to other related party transactions as described in Note 9, Commitments and contingencies, Note 10, License agreements and Note 11, Collaboration agreement.