Balance Sheet Components

Inventory

Inventory consists of the following (in thousands):



	As of January 31, 2017		As of October 31, 2017
Raw materials	$	3,003	$	5,926
Finished goods	20,495		31,282
Inventory	$	23,498	$	37,208

Property and Equipment, Net

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



	As of January 31, 2017			As of October 31, 2017
Test equipment	$	105,955		$	135,497
Computer equipment and software	54,521			66,270
Furniture and fixtures	4,494			5,337
Leasehold improvements	10,332			13,815
Total property and equipment	175,302			220,919
Less: accumulated depreciation and amortization	(93,607		)	(136,655		)
Property and equipment, net	$	81,695		$	84,264

Depreciation and amortization expense was $13.2 million and $15.2 million for the three months ended October 31, 2016 and 2017, and $34.9 million and $44.4 million for the nine months ended October 31, 2016 and 2017.

Intangible Assets, Net

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



	As of January 31, 2017			As of October 31, 2017
Technology patents	$	10,125		$	10,125
Accumulated amortization	(3,565		)	(4,693		)
Intangible assets, net	$	6,560		$	5,432

Intangible assets amortization expense was $376,000 for three months ended October 31, 2016 and 2017, and $1.0 million and $1.1 million for the nine months ended October 31, 2016 and 2017. The weighted-average remaining useful life of technology patents is 3.6 years. Due to the defensive nature of these patents, the amortization expense is included in general and administrative expenses in the condensed consolidated statements of operations.

As of October 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	$	376
2019	1,504
2020	1,504
2021	1,504
2022	544
Total	$	5,432

Accrued Expenses and Other Liabilities

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



	As of January 31, 2017		As of October 31, 2017
Sales and use tax payable	$	540	$	1,256
Accrued professional fees	1,765		1,430
Accrued marketing	6,718		8,899
Accrued travel and entertainment expenses	2,235		4,112
Income tax payable	1,135		1,620
Other accrued liabilities	9,304		7,628
Total accrued expenses and other liabilities	$	21,697	$	24,945