In February 2018, the Company entered into a noncancelable facility lease agreement (the “Lease”) for 9,836 square feet of research and development and office space in Cambridge, Massachusetts. In March 2020, the Company signed a termination agreement for this lease which was determined to be a lease modification that resulted in a reduction of the right-of-use asset and liability of $2.2 million. The lease termination was effective July 31, 2020 and the Company no longer has any obligations under the Lease.

In April 2019, the Company entered into a facility sublease agreement (the “Sublease”) for 1,471 square feet of office space in Cambridge, Massachusetts. The term of the lease began on June 24, 2019 and terminated on June 30, 2020, and following termination, the Company had no further obligations under the Sublease. The Sublease required the Company to share in prorated operating expenses and property taxes based upon actual amounts incurred; those amounts were considered variable lease costs and, therefore, are not included in the measurement of the lease and are instead recognized to expense as incurred.

In October 2019, the Company entered into a noncancelable facility lease agreement (the “the 2019 Lease”) for 34,522 square feet of research and development and office space in Watertown, Massachusetts. The term of the 2019 Lease is 120 months and expires on March 31, 2030. The 2019 Lease has an option to be extended for an additional five years. The lease is not reasonably certain to be extended and as such the additional term is not included in the measurement of the lease. The 2019 Lease includes a rent escalation clause, and rent expense is being recorded on a straight-line basis. The Company received a tenant incentive allowance of $5.5 million in 2020 as the tenant improvements were completed all of which has been collected from its landlord as of December 31, 2020. In accordance with the lease agreement, the Company is required to maintain a security deposit and provided a letter of credit to the landlord for $1.6 million, which is recorded in restricted cash as of December 31, 2021 and 2020.

In December 2021, the Company entered into a noncancelable lease (the "2021 Lease") for 100,624 square feet of office and laboratory space in Watertown, Massachusetts, which the Company expects to begin occupying in November 2023. The 2021 Lease is subject to base rent of $0.8 million per month beginning two months after the commencement date, plus the Company’s ratable share of taxes, maintenance and other operating expenses. Base rent is subject to a 3% annual increase over the lease term of approximately 134 months following the commencement date. The Company also has two consecutive options to extend the term of the lease for five years each at then-market rates. The 2021 Lease also includes a tenant improvement allowance of approximately $20.1 million. In connection with the signing of the 2021 Lease, the Company issued a letter of credit for $4.5 million which is classified as restricted cash as of December 31, 2021. The Company also paid first month’s rent of $0.8 million upon execution of the 2021 Lease in December 2021 which is classified as other non-current assets as of December 31, 2021. As of December 31, 2021, the Company has not taken control of the space associated with the 2021 Lease and therefore, the Company has not recorded a right of use asset or lease liability related to the space as of December 31, 2021.

The Company’s financing lease obligations consist of certain property and equipment financed through capital leases.

The components of the lease costs for the years ended December 31, 2021 and 2020 (in thousands):


	Year ended December 31,
	2021		2020
Operating lease costs	$	2,095	$	2,719
Financing lease costs:
Amortization of right-to-use assets, financing leases		906		716
Interest expense for financing lease liabilities		158		121
Variable lease costs		1,015		621
Total lease costs	$	4,174	$	4,177

Supplemental cash flow information relating to the Company’s leases for the years ended December 31, 2021 and 2020 was as follows (in thousands):


	Year ended December 31,
	2021		2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows used in (provided by) operating leases	$	2,691	$	(3,024	)
Operating cash flows used in finance leases	$	933	$	587
Financing cash flows used in finance leases	$	158	$	121

Weighted average remaining lease terms and discount rates as of December 31, 2021 and 2020 were as follows:


	Year ended December 31,
	2021			2020
Remaining lease term:
Operating lease		8.3			9.3
Financing lease	2.4 Years			2.8 Years
Discount Rate:
Operating lease		10.5	%		10.5	%
Financing lease		8.8	%		8.0	%

The undiscounted future lease payments for operating and finance leases as of December 31, 2021, were as follows (in thousands):


Fiscal Year	Operating Leases			Financing Leases
2022	$	2,581		$	1,183
2023		2,659			968
2024		2,732			345
2025		2,814			—
2026		2,898			—
Thereafter		10,027			—
Total minimum lease payments		23,711			2,496
Less amounts representing interest or imputed interest		(8,026	)		(218	)
Present value of lease liabilities	$	15,685		$	2,278