Leases

12 Months Ended

Dec. 31, 2021

Our building leases are comprised of office and laboratory space under non-cancelable operating leases. These lease agreements have remaining lease terms of six years and contain various clauses for renewal at our option. The renewal options were not included in the calculation of the operating lease assets and the operating lease liabilities as the renewal option is not reasonably certain of being exercised. The lease agreements do not contain residual value guarantees.

On April 11, 2019, we entered into an agreement to lease approximately 13,000 square feet of office space located at 38 Sidney Street, Cambridge, Massachusetts, or the 38 Sidney Lease, with Thirty-Eight Sidney Street, LLC. The initial term of the 38 Sidney Lease commenced on May 1, 2019 and expires on February 29, 2028. At the end of the lease term, we have the option to extend the 38 Sidney Lease for two consecutive terms of five years at fair market rent at the time of the extension. The 38 Sidney Lease provides us with the right to lease additional space within the 38 Sidney Street building and also includes rent escalation clauses and a tenant improvement allowance of $1.0 million.

In connection with the 38 Sidney Lease, we also amended our existing building leases at 88 Sidney Street, Cambridge, Massachusetts and at 64 Sidney Street, Cambridge, Massachusetts to extend the initial terms of those leases by approximately three years through February 29, 2028. The amendments also provide us with the right to lease additional space at the 64 Sidney Street building. Our existing extension options for the 88 Sidney Street building and 64 Sidney Street building continue as set forth in the existing leases for those buildings.

The components of lease expense and other information related to leases were as follows:


(In millions)	2021		2020		2019
Operating Lease Costs	$	15.2	$	15.2	$	15.1
Cash paid for amounts included in the measurement of operating lease liabilities	14.4		14.4		12.8

We have not entered into any material short-term leases or financing leases as of December 31, 2021.

In arriving at the operating lease liabilities as of December 31, 2021, we applied the weighted-average incremental borrowing rate of 5.7% from inception over a weighted-average remaining lease term of 6.2 years. In arriving at the operating lease liabilities as of December 31, 2020, we applied the weighted-average incremental borrowing rate of 5.7% over a weighted-average remaining lease term of 7.2 years.

As of December 31, 2021, undiscounted minimum rental commitments under non-cancelable leases, for each of the next five years and total thereafter, were as follows:


(In thousands)
2022	$	15,560
2023	18,126
2024	18,660
2025	19,507
2026	20,151
Thereafter	24,234
Undiscounted minimum rental commitments	116,238
Interest	(19,751)
Total operating lease liabilities	$	96,487

We provided our landlord a standby letter of credit of $2.9 million as security for our leases. We are not required to maintain any cash collateral for the standby letter of credit.

In August 2021, we entered into a long-term sublease agreement for 13,000 square feet of the office space at 38 Sidney Street Cambridge, Massachusetts. The term of the lease runs until December 2024. We recorded operating sublease income of $0.5 million for the year ended December 31, 2021 in other income, net in the consolidated statements of operations.

As of December 31, 2021, the future minimum lease payments to be received under the long-term sublease agreement were as follows:


(In thousands)
2022	1,118
2023	1,152
2024	1,186
Total	$	3,456