6. LEASE ARRANGEMENTS

The total amount of equipment capitalized under capital lease obligations as of September 30, 2019 and 2018 was $6,252 and $6,252, respectively. Accumulated amortization on capital leases at September 30, 2019 and 2018 was $6,218 and $6,136, respectively. Amortization of assets acquired through capital leases is included in depreciation expense.

Future minimum lease payments on capital leases at September 30, 2019 for the next five years are as follows:


	Principal		Interest		Total

2020	$	18	$	2	$	20
2021		18		1		19
	$	36	$	3	$	39

We lease office and laboratory space from the St. Louis University School of Medicine under operating leases that terminate at various dates through 2028. We also lease our facility in Maryland Heights, MO under an operating lease with an initial term lasting through 2025. Further, we lease other office equipment under non-cancelable operating leases that terminate at various dates through 2021. Certain of these leases contain renewal options. Total rental expense under these leases was $1,114 and $193 in fiscal 2019 and 2018, respectively. The UK building lease discussed in Note 13 expires in 2023 but includes an opt out provision after 7 years, which occurred in our fourth fiscal quarter of 2015 and was exercised.

Future minimum lease payments, exclusive of rent related to the UK restructuring discussed in Note 13, for the following fiscal years under operating leases at September 30, 2019 are as follows:


2020	$	1,116
2021		1,230
2022		1,286
2023		1,363
2024		1,651
	$	6,646

We lease a portion of our headquarters’ building in West Lafayette, Indiana to Cook Biotech, Inc. (Tenant) as part of the Lease Agreement signed in January 2015. The Lease Agreement has an initial term ending December 31, 2024 with escalating rents each year. The Tenant took full possession of the space on May 1, 2015. We recognize the escalating rents on a straight-line basis as a reduction to general and administrative expenses on the consolidated statements of operations and comprehensive income (loss) and lease rent receivable on the consolidated balance sheets. The cash rent received is recorded to the client account and as a reduction to the other accounts receivable on the consolidated balance sheets. The variance between the straight line rents recognized and the actual cash rents received will net to zero in other accounts receivable by the end of the agreement on December 31, 2024. As of September 30, 2019, the rents recognized amounted to $2,808 and cash rent received amounted to $2,678. Future rental income recognized and cash rents received for the next five years are as follows:


	Straight line		Cash rent
	rents to be		to be
	recognized		received

2020	$	636	$	633
2021		636		646
2022		636		659
2023		636		672
2024		636		685
	$	3,180	$	3,295