Property, plant, and equipment consist of the following (in thousands):


	As of December 31,
	2023			2022
Machinery and equipment	$	30,082		$	19,433
Office furniture and equipment		842			628
Vehicles		291			229
Leasehold improvements		24,673			12,093
		55,888			32,383
Less—Accumulated depreciation		(7,528	)		(4,520	)
		48,360			27,863
Construction in progress		2,004			23,714
Total property, plant, and equipment, net	$	50,364		$	51,577

Depreciation expense related to property, plant, and equipment recorded for the years ended December 31, 2023 and 2022 was $4.5 million and $2.0 million, respectively.

Teknova capitalizes interest on funds borrowed to finance certain of its capital expenditures. Capitalized interest is recorded as part of an asset’s cost and depreciated over the asset’s useful life. Capitalized interest costs were $0.9 million and $1.6 million for the years ended December 31, 2023 and 2022, respectively.

In June 2023, the Company identified circumstances that indicated certain of its machinery and equipment may not be fully recoverable. Specifically, these circumstances included changes in the market price of the asset group, continued losses, and an expectation that, more likely than not, the long-lived assets in question would be sold or otherwise disposed of significantly before the end of their previously estimated useful life. The Company reviewed the recoverability of the carrying value of these assets and determined that their carrying value exceeded their fair value. The fair value of these assets was measured employing cost and market approaches, using Level 3 inputs under ASC 820, Fair Value Measurement. Unobservable inputs included salvage value estimates, replacement or reproduction cost estimates, as well as consideration of physical deterioration, and functional and economic obsolescence, where measurable. As a result of this fair value analysis, an impairment charge of $2.2 million was recorded related to these long-lived assets in the quarter ended June 30, 2023. Subsequently, the Company sold these assets during the quarter ended September 30, 2023 at an amount that approximated carrying value after the impairment charges recorded.

In December 2022, the Company decided to cease further use and development of certain manufacturing machinery and equipment. The Company reviewed the recoverability of the carrying value of these assets and determined that their carrying value exceeded their fair value. The fair value of these assets was measured employing cost and market approaches, using Level 3 inputs under ASC 820, Fair Value Measurement.

Unobservable inputs included salvage value estimates, replacement or reproduction cost estimates as well as consideration of physical deterioration, functional and economic obsolescence, where measurable. As a result of this fair value analysis, an impairment charge of $4.2 million was recorded during the year ended December 31, 2022 related to these long-lived assets. Carrying value after the impairment charges approximates fair value.