7. Leases

The Company determines whether an arrangement is or contains a lease based on the unique facts and circumstances present at the inception of an arrangement. The Company leases office and laboratory space under operating leases that have a weighted average remaining term of 1.8 years as of September 30, 2023. The Company also leases office space under short-term leases that provide for either party to terminate the lease without cause and with 30 days’ notice. The Company’s operating leases include rent escalations and are subject to additional variable charges, including common area maintenance, property taxes and property insurance. Given the variable nature of such costs, they are recognized as expense as incurred. Additionally, some of the Company’s leases are subject to certain fixed fees which the Company has determined to be non-lease components. The Company has elected the practical expedient to account for lease and non-lease components as a single-lease component and has included fixed payments related to non-lease components in calculating the operating lease liability.

The weighted average discount rate for the Company’s operating leases as of September 30, 2023 is 8.8%, representing the Company's incremental borrowing rate at the beginning of each lease. For the nine months ended September 30, 2023, total lease cost was $2,245, consisting of $1,697 operating lease cost, $50 of variable lease costs and $498 of short-term lease cost. Cash paid for amounts included in the measurement of operating lease liabilities was $1,709 for the nine months ended September 30, 2023. Rent expense for the nine months ended September 30, 2022 was $1,127.