The Company is party as a lessee to various non-cancelable operating leases with varying terms through March 2028 primarily for laboratory and office space and equipment. The Company has options to renew some of these leases after their expirations. On a lease-by-lease basis, the Company considers such options, which may be elected at the Company’s sole discretion, in determining the lease term. The Company also has various finance leases for lab equipment with varying terms through December 2026, of which, some were acquired in business combinations. The Company does not have any leases with variable lease payments. The Company’s operating lease agreements do not contain any residual value guarantees, material restrictive covenants, bargain purchase options or asset retirement obligations.

The Company’s headquarters are located in Temple City, California, which is comprised of various corporate offices and a laboratory certified under the Clinical Laboratory Improvement Amendments of 1988, or CLIA, accredited by the College of American Pathologists, or CAP, and licensed by the State of California Department of Public Health. Other CLIA-certified laboratories are located in El Monte, California; Houston and Irving, Texas; Needham, Massachusetts; Phoenix, Arizona; Alpharetta, Georgia; and New York, New York.

The operating and finance lease right-of-use asset, short-term lease liabilities, and long-term lease liabilities as of December 31, 2022, and 2021 were as follows:


	December 31,
	2022		2021
	(in thousands)
Operating lease ROU asset, net	$	14,784	$	7,141
Operating lease liabilities, short term	$	6,132	$	1,842
Operating lease liabilities, long term	$	8,795	$	5,344
Finance lease ROU asset, net	$	2,784	$	1,735
Finance lease liabilities, short term	$	943	$	332
Finance lease liabilities, long term	$	1,818	$	1,398

The following was operating and finance lease expense:


	Year Ended December 31,
	2022		2021		2020
	(in thousands)
Operating lease cost	$	5,429	$	1,262	$	566
Finance lease cost:
Amortization of ROU assets		683		7		—
Interest on lease liabilities		95		1		—
Short-term lease cost		1,528		296		142
Total lease cost	$	7,735	$	1,566	$	708


	December 31, 2022
Weighted average remaining lease term - operating leases	3.24 years
Weighted average discount rate - operating leases		3.81	%
Weighted average remaining lease term -finance leases	3.10 years
Weighted average discount rate - finance leases		3.98	%

The following is a maturity analysis of operating and finance lease liabilities using undiscounted cash flows on an annual basis with renewal periods included:


	Operating Leases			Financing Leases
	(in thousands)
Year Ending December 31,
2023	$	6,590		$	986
2024		4,072			1,033
2025		2,118			547
2026		1,522			366
2027		1,360			—
Thereafter		217			—
Total lease payments		15,879			2,932
Less imputed interest		(952	)		(171	)
Total	$	14,927		$	2,761

The Company leases out space in buildings it owns to third-party tenants under noncancelable operating leases. As of December 31, 2022, the remaining lease terms left range from 1 year to 2 years, including renewal options and may include rent escalation clauses. Lease income primarily represents fixed lease payments from tenants recognized on a straight-line basis over the application lease term. Variable lease income represents tenant payments for real estate taxes, insurance and maintenance.

The lease income was included in interest and other income, net, in the accompanying Consolidated Statements of Income. Total lease income was as follows:


	Year Ended December 31,
	2022		2021		2020
	(in thousands)
Lease income	$	269	$	413	$	144
Variable lease income		12		7		1
Total lease income	$	281	$	420	$	145

Future fixed lease payments from tenants for all noncancelable operating leases as of December 31, 2022 are as follows:


	Lease Payments
	from Tenants
	(in thousands)
Year Ending December 31,
2023	$	181
2024		94
Total	$	275