2. Balance Sheet Components

Inventory

Inventory consists of the following (in thousands):

	September 30,		December 31,
	2018		2017
Work in process	$	1,376	$	1,214
Finished goods		1,133		1,633
Total inventory	$	2,509	$	2,847

Property and Equipment - Net

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

	September 30,			December 31,
	2018			2017
Computer equipment and software	$	980		$	687
Leasehold improvements		61			59
Furniture		30			30
Total property and equipment		1,071			776
Less: accumulated depreciation		(619	)		(451	)
Total property and equipment - net	$	452		$	325

The Company recorded $0.1 million and $0.1 million of depreciation expense for the three months ended September 30, 2018 and 2017, respectively, and $0.2 million and $0.2 million for the nine months ended September 30, 2018 and 2017, respectively.

Accrued Liabilities

Accured liabilities consist of the following (in thousands):

	September 30,		December 31,
	2018		2017
Engineering services	$	407	$	131
Payroll-related expenses		359		291
Professional fees		86		23
Accrued warranty		66		73
Taxes payable		22		37
Other		34		18
Total accrued liabilities	$	974	$	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 $0.2 million, $29,000, and $6,000 as of September 30, 2018, June 30, 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 September 30, 2018, the Company recognized $29,000 of revenue from the June 30, 2018 customer deposits balance. During the nine months ended September 30, 2018, the Company recognized $6,000 of revenue from the December 31, 2017 customer deposits balance.