Note 2. Balance Sheet Components.

Accounts Receivable, Net.

Accounts receivable, net consisted of the following (in thousands):


	December 31,
	2017		2016
Accounts receivable	$	12,500	$	8,800
Allowance for SSDs, price protection, rights of return and other activities		(3,832)		(2,689)
Total accounts receivable, net	$	8,668	$	6,111

Inventories.

Inventories consisted of the following (in thousands):


	December 31,
	2017		2016
Raw materials	$	2,213	$	212
Work-in-process		2,408		3,793
Finished goods		1,193		1,177
Total inventories	$	5,814	$	5,182

For the years ended December 31, 2017, 2016 and 2015, we realized a benefit of $1.3 million, $1.1 million and $0.9 million, respectively, from sales of previously written-down products. Inventory write-downs were primarily associated with products built in excess of customer demand which resulted in excess inventory levels, legacy products for which no demand exists and lower of cost or net realizable value write-downs associated with CBRAM products for which costs exceeded net realizable value.

Property and Equipment, Net.

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


	December 31,
	2017		2016
Machinery and equipment	$	9,457	$	7,351
Furniture and fixtures		83		77
Leasehold improvements		4,252		4,252
Computer software		675		668
Construction in progress		1,301		1,098
Property and equipment, at cost		15,768		13,446
Accumulated depreciation and amortization		(8,935)		(7,484)
Property and equipment, net	$	6,833	$	5,962

Depreciation and amortization expense of property and equipment for the years ended December 31, 2017, 2016, and 2015 was $1.4 million, $1.0 million, and $1.5 million, respectively.

Accrued Expenses and Other Current Liabilities.

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


	December 31,
	2017		2016
Accrued sales commission payable	$	310	$	366
Accrued manufacturing expenses		265		149
Deferred rent, current portion		422		388
Liabilities to certain customers		468		663
Other accrued liabilities		894		610
Total accrued expenses and other current liabilities	$	2,359	$	2,176