Leases
The Company’s operating lease activity is comprised of non-cancelable facility leases for office and laboratory space in Boston, Massachusetts.
IDB Lease
On March 16, 2022, the Company and IDB 17-19 Drydock Limited Partnership, as landlord (“Landlord), entered into a lease agreement (“IDB Lease”) with respect to approximately 81,229 square feet of office and laboratory space (“Premises”) in Boston, Massachusetts. The initial fixed rental rate is $0.5 million per month, which is for a 12 month period during which the base rent is payable for 65,000 square feet, and will increase 3% per annum thereafter for the entire 81,229 square feet leased.
The IDB Lease has a term of approximately 10 years, unless earlier terminated in accordance with the terms of the IDB Lease. The Company has (i) the option to extend the IDB Lease for an additional period of 5 years, and (ii) a right of first offer on adjacent space to the Premises, subject to the terms and conditions of the IDB Lease. As these options are not reasonably certain of occurring, they have not been included in the initial calculation of the Company's ROU asset upon lease commencement.
In connection with the execution of the IDB Lease, the Company executed a cash-collateralized letter of credit, which may be reduced in the future subject to reduction requirements specified in the IDB Lease therein. The $4.0 million of cash collateralizing the letter of credit is classified as restricted cash on the Company's consolidated balance sheets.
6 Tide Street Lease
The Company entered into an operating lease for office and laboratory space at 6 Tide Street in Boston, Massachusetts in February 2020, and entered into subsequent amendments through 2021 to lease additional space (“6 Tide Street Lease”). Such amendments ran co-terminus with the original lease.
The 6 Tide Street Lease expired during 2025 and the Company has no remaining right of use asset or lease liability associated with the lease as of December 31, 2025. The Company's $0.4 million security deposit related to the 6 Tide Street lease was received during the year ended December 31, 2025.
Summary of all lease costs recognized under ASC 842
The components of all operating lease cost were as follows (in thousands):
| | | | | |
| Year ended December 31, 2025 |
| Operating lease cost | $ | 15,050 | |
| Variable lease cost | — | |
| Total lease cost | $ | 15,050 | |
Supplemental information related to all operating leases was as follows:
| | | | | |
| Other information | Year ended December 31, 2025 |
| Operating cash flows used for operating leases (in thousands) | $ | 12,657 | |
| Weighted average remaining lease term | 7.1 years |
| Weighted average discount rate | 8.15% |
Future payments due under all operating leases as of December 31, 2025 were as follows (in thousands):
| | | | | |
Maturity of lease liabilities | Amount |
| 2026 | 8,109 | |
| 2027 | 9,083 | |
| 2028 | 9,349 | |
| 2029 | 9,622 | |
| 2030 | 9,904 | |
| Thereafter | 21,564 | |
| Total lease payments | $ | 67,631 | |
| Less: imputed interest | (16,699) | |
| Present value of operating lease liabilities | $ | 50,932 | |
IDB Sublease
In December 2022, the Company entered into a sublease agreement to sublease a portion of the office and laboratory space leased under the IDB Lease to a third-party (“Subtenant”). The term of the sublease extends through August 2026. The rental rate is approximately $0.2 million per month for the remainder of the term. The Subtenant is obligated to pay its ratable portion of operating expenses during the sublease term. The Company received a letter of credit of $0.5 million in place of a security deposit. As of December 31, 2025, no amounts have been drawn on the letter of credit.
The sublease accounting commencement date occurred in April 2023. During the year ended December 31, 2025, the Company recognized $2.1 million of sublease income. Such amount is recorded as a reduction to rent expense.