6. Leases

The Company has entered into operating leases primarily for commercial buildings. These leases have terms that range from 2 years to 11 years, some of which include options to extend the leases for up to 5 years. Rent expense, including short-term lease cost, was $1,008 and $960 for the three months ended September 30, 2023 and 2022, respectively, and $2,944 and $2,889 for the nine months ended September 30, 2023 and 2022, respectively.

In July 2023, the Company entered into an Assignment and Assumption of Lease Agreement (the Assignment) in which a third party (the Assignee) assumed the rights, title, and interest in the lease, including assumption of lease payments. As inducement for the Assignee to enter into the agreement, the Company paid an incentive of $395, provided for four months of free rent for the period October 1, 2023 through January 31, 2024, and conveyed ownership of certain items of the facility's furniture and equipment. Commencing February 1, 2024 and ending May 31, 2031, the Assignee assumes responsibility for the monthly lease payments. Notwithstanding the Assignee's assumption of lease payments, Inogen remains the primary obligor under the lease to the landlord. The Assignee gained control to the facilities on September 29, 2023.