The Company has operating leases for its corporate office, laboratory and vivarium space in Redwood City, California. On August 7, 2020, the Company executed a non-cancellable lease agreement for 71,646 square feet of space (the “Chesapeake Master Lease”), which consists of 45,690 square feet of additional office, laboratory and vivarium space and includes an extension of 25,956 square feet under an existing lease. The Chesapeake Master Lease has an initial term of ten years from the Commencement Date, with an option to extend the lease for an additional eight-year term. The Chesapeake Master Lease contains rent escalation, and the Company is also responsible for certain operating expenses and taxes throughout the lease term. In addition, the Company is entitled to up to $4.8 million of tenant improvement allowance, which was paid directly by the landlord to various vendors. Upon execution of the non-cancellable lease agreement, the Company took control of 10,000 square feet of space, which is subleased as further described below. The remaining 35,690 square feet of additional office, laboratory and vivarium space commenced in June 2021 and the extension of the 25,956 square feet under an existing lease is expected to commence in 2025.

In connection with the execution of the Chesapeake Master Lease, the Company entered into two operating lease agreements to sublease portions of the premises to two unrelated third parties. The first sublease agreement, to sublease 10,000 square feet, commenced in August 2020 and expired on August 31, 2022. The second sublease agreement, to sublease 10,500 square feet, commenced in June 2021 and expires on July 31, 2023. In August 2022, the second sublease agreement was amended to expand the subleased premises to 11,655 square feet in the first year and further increase to 13,743 square feet in the second year. In addition, the expiration date of the second sublease was also amended to the expiration date of the Chesapeake Master Lease. The subtenant has an early termination option with the early termination date no earlier than September 30, 2024, and no option to extend the sublease term. Rent for the second sublease is subject to scheduled annual increases and the subtenant is responsible for certain operating expenses and taxes throughout the term under the sublease agreement. Sublease income under the two sublease agreements was approximately $0.8 million and $0.9 million for the years ended December 31, 2022 and 2021, respectively.

At December 31, 2022, we have no leases accounted for as finance right-of-use lease and finance right-of-use leases used in 2021 to finance capital equipment such as printers or ozone generators were immaterial.

The weighted-average remaining lease term and discount rate related to the Company’s lease liabilities as of December 31, 2022 were 7.4 years and 11.0%, respectively, for the operating leases. The weighted-average remaining lease term and discount rate related to the Company’s lease liabilities as of December 31, 2021 were 8.0 years and 10.7%, respectively, for the operating leases. The Company lease discount rates are based on estimates of its incremental borrowing rate, as the discount rates implicit in the Company’s leases cannot be readily determined. As the Company does not have any outstanding debt, the Company estimates the incremental borrowing rate based on its estimated credit rating and available market information.

Cash required as security for our operation leases is secured by a letter of credit on behalf of the lessor in the amount of approximately $1.6 million and is recorded as restricted cash on the balance sheet as of December 31, 2022 and 2021.

The components of lease expense were as follows (in thousands):


	Years Ended December 31,
	2022		2021
Total operating lease cost	$	4,346	$	3,842

Supplemental cash flow information related to cash paid for amounts included in the measurement of lease liabilities was as follows (in thousands):


	Years Ended December 31,
	2022		2021
Operating cash flows from operating leases	$	4,660	$	3,112

The following is a schedule by year for future maturities of the Company’s operating lease liabilities and sublease income to be received as of December 31, 2022 (in thousands):



	Operating Leases			Sublease Income
2023	$	4,726		$	699
2024		4,886			540
2025		4,340			—
2026		3,484			—
2027		3,602			—
Thereafter		13,238			—
Total lease payments		34,276			1,239
Less interest		(11,665	)		—
Total	$	22,611			1,239

The Company has entered into a supply agreement with a contract manufacturer pursuant to which the Company may be required to pay milestone payments upon the achievement of specified regulatory milestones. The agreement is cancellable by the Company upon delivering the appropriate prior written notice. At December 31, 2022, potential future milestone payments under this agreement were up to $2.0 million.

In the normal course of business, the Company enters into agreements that contain a variety of representations and provide for general indemnification. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. As of December 31, 2022, the Company does not have any material indemnification claims that were probable or reasonably possible and consequently has not recorded related liabilities.