The Company has elected not to record operating right-of-use assets or operating lease liabilities on its consolidated balance sheet for leases having a minimum term of 12 months or less. Such leases are expensed on a straight-line basis over the lease term. Variable lease payments are excluded from the measurement of operating right-of-use assets and operating liabilities and recognized in the period in which the obligation for those payments is incurred. As of September 30, 2021, the Company has two operating right-of use assets related to leased facilities in Austin, Texas and Melbourne, Florida.

Maturities of the operating lease liabilities as of September 30, 2021 were as follows (in thousands):

For fiscal years ending September 30,
2022	$	262
2023		270
2024		278
2025		186
2026		130
Thereafter		225
Future minimum lease payments	$	1,351
Less interest		(117	)
Present value of minimum lease payments	$	1,234
Less current portion		(225	)
Long-term portion	$	1,009

Lease costs recognized in the consolidated statements of operations for the fiscal years ended September 30, 2021 and 2020 is as follows (in thousands):

	YEAR ENDED SEPTEMBER 30,
	2021		2020
Right-of-use operating lease costs	$	246	$	151
Short-term lease costs		239		309
Total	$	485	$	460

Right-of-use operating lease costs and short-term lease costs are included as a component of total operating expenses.

	YEAR ENDED SEPTEMBER 30,
	2021			2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	211		$	165
Operating lease assets obtained in exchange for new lease liabilities		1,336			219

Weighted average remaining lease term	5.6 years			0.5 years
Weighted average discount rate		3.25	%		5.00	%

The discount rate used on the operating right-of-use assets represented the Company’s incremental borrowing rate at lease inception.

The Company leases equipment to customers primarily for minimum terms of six months or less. The majority of the Company’s rental revenue is generated from its marine-based wireless seismic data acquisition system.

All of the Company’s leasing arrangements as lessor are classified as operating leases except for one sales-type lease. See Note 7 for more information on the Company’s sales-type lease.

The Company regularly evaluates the collectability of its lease receivables on a lease by lease basis. The evaluation primarily consists of reviewing past due account balances and other factors such as the credit quality of the customer, historical trends of the customer and current economic conditions. The Company suspends revenue recognition when the collectability of amounts due are no longer probable and concurrently records a direct write-off of the lease receivable to rental revenue to limit rental revenue recognized to the cash collections received. As of September 30, 2021, the Company’s trade accounts receivables included lease receivables of $7.5 million.

Rental revenue for fiscal years 2021 and 2020 was $19.0 million and $53.7 million, respectively.

At September 30, 2021, future minimum lease obligations due from the Company’s leasing customers on operating leases (all in fiscal year 2022) were $0.8 million.

	AS OF SEPTEMBER 30,
	2021			2020
Rental equipment, primarily wireless recording equipment	$	95,827		$	114,783
Accumulated depreciation and impairment		(56,922	)		(60,466	)
	$	38,905		$	54,317

Rental equipment depreciation expense was $15.1 million and $17.9 million in fiscal years 2021 and 2020, respectively.