Balance Sheet Components

Inventory

Inventory consists of the following (in thousands):



	As of January 31, 2017		As of July 31, 2017
Raw materials	$	3,003	$	2,966
Finished goods	20,495		30,694
Inventory	$	23,498	$	33,660

Property and Equipment, Net

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



	As of January 31, 2017			As of July 31, 2017
Test equipment	$	105,955		$	125,348
Computer equipment and software	54,521			60,838
Furniture and fixtures	4,494			5,045
Leasehold improvements	10,332			13,092
Total property and equipment	175,302			204,323
Less: accumulated depreciation and amortization	(93,607		)	(122,473		)
Property and equipment, net	$	81,695		$	81,850

Depreciation and amortization expense was $11.6 million and $14.8 million for the three months ended July 31, 2016 and 2017, and $21.7 million and $29.2 million for the six months ended July 31, 2016 and 2017, respectively.

Intangible Assets, Net

Intangible assets, net, consist of the following (in thousands):



	As of January 31, 2017			As of July 31, 2017
Technology patents	$	10,125		$	10,125
Accumulated amortization	(3,565		)	(4,317		)
Intangible assets, net	$	6,560		$	5,808

Intangible assets amortization expense was $342,000 and $376,000 for the three months ended July 31, 2016 and 2017, and $668,000 and $752,000 for the six months ended July 31, 2016 and 2017. The weighted-average remaining useful life of technology patents is 3.9 years. Due to the defensive nature of these patents, the amortization is included in general and administrative expenses in the condensed consolidated statements of operations.

As of July 31, 2017, expected amortization expense for intangible assets for each of the next five years is as follows (in thousands):



Years Ending January 31,	Estimated Future Amortization Expense
Remainder of 2018	$	752
2019	1,504
2020	1,504
2021	1,504
2022	544
Total	$	5,808

Accrued Expenses and Other Liabilities

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



	As of January 31, 2017		As of July 31, 2017
Sales and use tax payable	$	540	$	298
Accrued professional fees	1,765		1,325
Accrued marketing	6,718		6,164
Accrued travel and entertainment expenses	2,235		4,014
Income tax payable	1,135		1,317
Other accrued liabilities	9,304		5,191
Total accrued expenses and other liabilities	$	21,697	$	18,309