Property, Plant and Equipment

9 Months Ended

12 Months Ended

Sep. 30, 2020

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

4. Property, Plant and Equipment

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

	Estimated Useful Lives (Years)		December 31, 2019			September 30, 2020 (unaudited)
Land		N/A	$	1,340		$	1,340
Buildings and land improvements		15-39		2,464			2,487
Manufacturing equipment		7		12,631			13,002
Furniture, fixtures and equipment		5-7		277			287
Vehicles		5		140			140
Hardware and software		3-5		398			589
				17,250			17,845
Less: accumulated depreciation				(6,590	)		(8,225	)
Total			$	10,660		$	9,620

Depreciation expense was $1.6 million and $1.7 million, respectively, for the nine months ended September 30, 2019 and 2020, of which $1.4 million and $1.5 million, respectively, has been allocated to cost of revenue and $0.2 million and $0.2 million, respectively, is included in depreciation and amortization in the accompanying consolidated statements of operations for the nine months ended September 30, 2019 and 2020.

4. Property, Plant and Equipment

Property, plant and equipment consisted of the following at December 31, (in thousands):

	Estimated Useful Lives (Years)		2018			2019
Land		N/A	$	1,340		$	1,340
Buildings and land improvements		15-39		2,448			2,464
Manufacturing equipment		7		10,954			12,631
Furniture, fixtures and equipment		5-7		332			277
Vehicles		5		123			140
Hardware and software		3-5		358			398
				15,555			17,250
Less: accumulated depreciation				(4,526	)		(6,590	)
Total			$	11,029		$	10,660

Depreciation expense was $1.9 million and $2.1 million, respectively, for the years ended December 31, 2018 and 2019, of which $1.7 million and $1.8 million, respectively, has been allocated to cost of revenue and $0.2 million and $0.3 million, respectively, is included in depreciation and amortization in the accompanying consolidated statements of operations for the years ended December 31, 2018 and 2019.