The Company enters into lease arrangements for its facilities as well as certain equipment. A summary of the arrangements is as follows:

The Company leases office and laboratory space at Technology Square in Cambridge, Massachusetts under a Lease Agreement, dated as of June 15, 2012, as amended (the "Technology Square Lease") with ARE-TECH Square, LLC, a Delaware limited liability company.

In May 2017, the Company exercised its option to extend the term of the Technology Square Lease to November 30, 2022. Under the Technology Square Lease as amended, the Company agreed to pay a monthly base rent of approximately $0.2 million for the period commencing December 1, 2017 through May 31, 2018, with an increase on June 1, 2018 of approximately $33,000 and annual increases of approximately $9,000 on December 1 of each subsequent year until the last increase, which occurred on December 1, 2021.

On August 11, 2021, the Company, entered into a fifth amendment to the Technology Square Lease (the “Fifth Amendment”) with ARE-TECH Square, LLC. Under the Fifth Amendment, the Company extended the term of the Technology Square Lease through

November 30, 2024. Under the Fifth Amendment, the Company will continue to pay the landlord the current monthly base rent amount contemplated by the Technology Square Lease through November 30, 2022, with an increase commencing on December 1, 2022 and adjusting the monthly base rent amount to approximately $377,000 and an increase commencing on December 1, 2023 and adjusting the monthly base rent amount to approximately $388,000 through November 30, 2024. In addition, under the Fifth Amendment, the landlord agreed to provide the Company with a tenant improvement allowance of up to approximately $430,000 if requested by the Company by August 11, 2022, subject to specified terms and conditions. In accordance with ASU 2016-02, Leases, or ASC 842, the Company accounted for the Fifth Amendment as a lease modification and remeasured the operating lease liability, resulting in an additional $7.0 million operating lease liability and right of use asset. Under the current terms of the Technology Square Lease and Fifth Amendment, the Company does not have any further right to extend the term beyond November 30, 2024.

The Company has a $0.5 million letter of credit as a security deposit for the Technology Square Lease and has recorded cash held to secure this letter of credit as restricted cash and other assets on the Company's condensed consolidated balance sheets.

On August 16, 2019, the Company entered into a lease (the "Hampshire Street Lease") with BMR-Hampshire LLC ("BMR"). The Hampshire Street Lease is for 33,525 rentable square feet of office space in Cambridge, Massachusetts. The Hampshire Street Lease commenced as of December 1, 2019. The Hampshire Street Lease has an initial term of seven years and four months from the commencement date and provides the Company with an option to extend the lease term for one additional five-year period. After a four-month period during which base rent was not payable, the Hampshire Street Lease provides for monthly rent payments starting at approximately $0.2 million and increasing 2.5% per year. In the event that the Company exercises its option to extend the lease term, the Hampshire Street Lease provides for monthly rent payments during the additional five-year period at the greater of the base rent rate at the end of the initial term or the then-current market rent.

The Company has a $1.0 million letter of credit in favor of BMR as a security deposit for the Hampshire Street Lease and has recorded cash held to secure this letter of credit as restricted cash and other assets on the Company's condensed consolidated balance sheets. In applying ASC 842, the Company determined the classification of the Hampshire Street Lease to be operating and recorded a lease liability and a right-of-use asset as of December 31, 2019.

The Company is required to pay certain variable costs to its landlords in addition to fixed rent. These costs include common area maintenance, real estate taxes, and parking and are included in lease expense.

The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the three and six months ended June 30, 2022 and 2021:


	Three Months Ended June 30,						Six Months Ended June 30,
	2022			2021			2022			2021
	(in thousands)
Lease cost
Operating lease cost	$	1,689		$	1,515		$	3,378		$	3,031
Variable lease cost		491			566			933			1,046
Total lease cost	$	2,180		$	2,081		$	4,311		$	4,077

Other information
Operating cash flows used for operating leases	$	1,589		$	1,621		$	3,216		$	3,225
Weighted average remaining lease term	3.7 years			4.6 years			3.7 years			4.6 years
Weighted average discount rate		9.75	%		9.86	%		9.75	%		9.86	%

Future minimum lease payments under the Company’s non-cancelable operating leases as of June 30, 2022, are as follows:



	(In thousands)
2022	$	3,361
2023		7,517
2024		7,322
2025		3,057
Thereafter		3,909
Total lease payments	$	25,166
Less: imputed interest		(4,338	)
Total operating lease liabilities at June 30, 2022	$	20,828