2. Balance Sheet Components

Inventory

Inventory consists of the following (in thousands):

	March 31,		December 31,
	2018		2017
Work in process	$	979	$	1,214
Finished goods		812		1,633
Total inventory	$	1,791	$	2,847

Property and Equipment - Net

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

	March 31,			December 31,
	2018			2017
Computer equipment	$	741		$	687
Leasehold improvements		59			59
Furniture		30			30
Total property and equipment		830			776
Less: accumulated depreciation		(501	)		(451	)
Total property and equipment - net	$	329		$	325

The Company recorded $0.1 million and $0.1 million of depreciation expense for the three months ended March 31, 2018 and 2017, respectively.

Accrued Liabilities

Accured liabilities consist of the following (in thousands):

	March 31,		December 31,
	2018		2017
Engineering services	$	486	$	131
Payroll-related expenses		348		291
Professional fees		67		23
Accrued warranty		62		73
Taxes payable		35		37
Other		21		18
Total accrued liabilities	$	1,019	$	573

Customer Deposits

Customer deposits represent payments received in advance of shipments and fluctuate depending on timing of customer pre-payments and product shipment. Customer deposits were $0.1 million and $6,000 as of March 31, 2018 and December 31, 2017, respectively. The Company generally expects to recognize revenue from customer deposits during the three month interim period immediately following the balance sheet date. During the three months ended March 31, 2018, the Company recognized revenue of $6,000 from the December 31, 2017 customer deposits balance.