The Company’s leases consist primarily of operating leases for administrative office space, research and development facilities, a manufacturing facility, and sales offices in various countries around the world. The Company determines if an arrangement is a lease at inception. Some lease agreements contain lease and non-lease components, which are accounted for as a single lease component. Total rent expense was $0.3 million and $0.6 million for the three and six months ended June 30, 2021, respectively, and $0.4 million and $0.8 million for the three and six months ended June 30, 2020, respectively.

Initial lease terms are determined at commencement and may include options to extend or terminate the lease when it is reasonably certain the Company will exercise the option. Remaining lease terms range from one to five years, some of which include options to extend for up to five years. Leases with an initial term of twelve months or less are not recorded on the condensed consolidated balance sheets. As the Company’s leases do not provide an implicit rate, the present value of future lease payments is determined using the Company’s incremental borrowing rate based on information available at the lease commencement date.

The table below reconciles the undiscounted cash flows for the first five years and the total of the remaining years to the operating lease liabilities recorded on the condensed consolidated balance sheet as of June 30, 2021 (in thousands):

	June 30,
	2021
2021 (remaining six months)	$	729
2022		1,422
2023		488
2024		244
2025		234
Thereafter		42
Total minimum lease payments		3,159
Less: amount of lease payments representing interest		(338	)
Present value of future minimum lease payments		2,821
Less: current liabilities under operating leases		(1,265	)
Long-term operating lease liabilities	$	1,556

As of June 30, 2021, the weighted average remaining lease term for the Company’s operating leases was 2.6 years, and the weighted average discount rate used to determine the present value of the Company’s operating leases was 6.3%. Sublease rental income due in the future under non-cancelable subleases was $1.6 million. As discussed in Note 14, Restructuring and Severance, sublease income is associated with office space acquired in an acquisition where the tenant went into default due to non-payment of rent beginning April 1, 2020. No cash has been received from the tenant since April 1, 2020.

Cash paid for amounts included in the measurement of operating lease liabilities was $0.4 million and $0.8 million for the three and six months ended June 30, 2021, respectively.