The Company has a lease agreement for approximately 2,700 square feet of space for its headquarters located in Cambridge, Massachusetts that commenced in September 2017 for a term of five years.

In April 2018, the Company entered into a lease agreement for approximately 8,800 square feet of office and research laboratory space located in Porton Down, United Kingdom for a term of ten years. In February 2020, the Company entered into a lease agreement, pursuant to which the Company leases approximately 4,600 square feet of additional office and research laboratory space located at the Porton Down facility for a term of eight years. The Company has the right to terminate the lease agreements on or after April 30, 2023. It is not likely that the Company will terminate either lease at that time, therefore the entire lease terms are included in the calculation of the lease liabilities. Options to renew a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew.

The Company is also party to several operating leases for office and laboratory space as well as certain lab equipment. Total rent expense was $743,000, $677,000 and $638,000 for the years ended April 30, 2020, 2019 and 2018, respectively and is reflected in general and administrative expenses and research and development expenses as determined by the underlying activities.

Incremental borrowing rate – The Company’s lease agreements do not provide an implicit rate. The Company estimated the incremental borrowing rate based on the rate of interest the Company would have to pay to borrow a similar amount on a collateralized basis over a similar term and economic environment.

Lease and non-lease components – The Company has elected the practical expedient which allows non-lease components to be combined with lease components for all existing asset classes and will therefore include any fixed additional rent amounts in its lease payments. Any variable lease payments are excluded from the lease liability and are recognized in the period incurred.

The following table summarizes lease costs included in research and development and general and administrative expense for the year ended April 30, 2020 (in thousands):

	Year Ended
	April 30, 2020
Operating lease costs	$	743
Finance lease costs		54
Short-term lease costs		13
Variable lease costs		47
Total lease costs	$	857

The following table summarizes the maturity of undiscounted payments due under lease liabilities and the present value of those liabilities as of April 30, 2020 (in thousands):

Years ending April 30,	Operating Leases
2021	$	679
2022		383
2023		239
2024		142
2025		142
Thereafter		439
Total lease payments		2,024
Less: imputed interest	379
Total lease liabilities		1,645
Current lease liabilities	588
Long-term lease liabilities	$	1,057

Future minimum payments under these leases as of April 30, 2019 are as follows (in thousands):

Years ending April 30,	Finance Leases		Operating Leases
2020	$	54	$	687
2021		—		474
2022		—		328
2023		—		194
2024 and thereafter		—		495
Total minimum lease payments	$	54	$	2,178
Less amounts representing interest		—
Present Value of minimum payments		54
Current portion		54
Long-term portion	$	—

The following table summarizes the lease term and discount rate as of April 30, 2020:

	April 30, 2020
Weighted-average remaining lease term (years)
Operating leases	4.8
Weighted-average discount rate
Operating leases		9.0	%

The following table summarizes the cash paid for amounts included in the measurement of lease liabilities for the year ended April 30, 2020 (in thousands):