Property and Equipment, Net

6 Months Ended

Jun. 30, 2021

Property Plant And Equipment [Abstract]

5. PROPERTY AND EQUIPMENT, NET

Property and equipment are stated at cost or estimated fair value for assets acquired through business combinations. Depreciation and amortization are provided using the straight-line method over the estimated useful lives of the assets. Leasehold

improvements are amortized using the straight-line method over the shorter of the remaining lease term, including options that are deemed to be reasonably assured, or the estimated useful life of the improvement.

Property and equipment, net, consisted of the following:

	Estimated	June 30,			December 31,
	Useful Life	2021			2020
Lab and test equipment	7 years	$	17,401		$	18,631
Vehicles	5 years		5,059			13,320
Equipment	3-7 years		33,315			32,177
Furniture and fixtures	7 years		2,998			2,938
Leasehold improvements	7 years		6,824			6,767
Aircraft	10 years		834			834
Building	39 years		2,975			2,975
			69,406			77,642
Land			725			725
Construction in progress			1,292			219
Less accumulated depreciation			(41,871	)		(44,187	)
Total property and equipment— net		$	29,552		$	34,399

Total depreciation expense included in the unaudited condensed consolidated statements of operations was $2.5 million and $4.7 million for the three and six months ended June 30, 2021, respectively, and $2.0 million and $4.0 million for the three and six months ended June 30, 2020, respectively.

Total property and equipment, net as of December 31, 2020 included $7.2 million related to financed assets, which, following the adoption of ASC 842, are presented as part of finance lease liabilities and excluded from property and equipment, net on the face of the condensed consolidated balance sheet as of June 30, 2021.