Financial Statement Details

Inventories

Inventories consist of the following (in thousands):



	December 31,
	2018		2017
Finished goods	$	14,797	$	14,331
Raw materials and components	11,634		6,072
	$	26,431	$	20,403

Property, Plant and Equipment

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



	December 31,
	2018			2017
Land	$	247		$	288
Buildings	2,247			2,614
Test equipment	14,444			23,396
Computer equipment and purchased software	4,889			5,548
Product tooling	504			449
Furniture and fixtures	677			564
Vehicles	1,990			2,003
Leasehold improvements	136			267
	25,134			35,129
Less—accumulated depreciation and amortization	(18,436		)	(28,138		)
	$	6,698		$	6,991

At December 31, 2018, the Company had vehicles and equipment under capital leases with an aggregate carrying value of $1.9 million, net of accumulated amortization of $2.0 million. At December 31, 2017, the Company had vehicles and equipment under capital leases with an aggregate carrying value of $1.6 million, net of accumulated amortization of $1.5 million.

Rental Assets

Rental assets consist of the following (in thousands):



	December 31,
	2018			2017
Rental assets	$	16,648		$	16,602
Less—accumulated depreciation	(10,879		)	(9,039		)
	$	5,769		$	7,563

Depreciation and amortization expense related to property, plant and equipment, including equipment under capital leases, and rental assets was $7.0 million and $8.0 million for the years ended December 31, 2018 and 2017, respectively.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):



	December 31,
	2018		2017
Royalties	$	1,727	$	1,558
Payroll and related expenses	2,415		2,870
Professional fees	514		1,789
Accrued interest	239		239
Deferred revenue	2,048		1,823
Acquisition-related liabilities	1,000		13,186
Other	5,081		6,093
	$	13,024	$	27,558