Major classes of fixed assets consisted of the following:


	Useful Lives	June 30, 2024			December 31, 2023
		(in thousands)
Medical lab equipment	5 months to 12 Years	$	54,152		$	56,025
Building improvements	6 months to 39 Years		16,383			7,748
Building	39 Years		15,923			9,781
Computer software	1 to 5 Years		8,039			7,982
Computer hardware	1 to 5 Years		6,882			6,805
Aircraft	7 Years		6,400			6,400
Leasehold improvements	Shorter of lease term or estimated useful life		5,556			11,222
Furniture and fixtures	1 to 5 Years		3,491			3,860
Land improvements	5 to 15 Years		904			904
Automobile	3 to 7 Years		450			445
General equipment	3 to 5 Years		108			115
Land			12,675			8,800
Assets not yet placed in service			7,842			15,010
Total			138,805			135,097
Less: Accumulated depreciation			(45,437	)		(51,633	)
Fixed assets, net		$	93,368		$	83,464

Depreciation expenses on fixed assets totaled $4.0 million and $8.6 million for the three and six months ended June 30, 2024, respectively, and $4.1 million and $8.8 million for the three and six months ended June 30, 2023, respectively.