Balance Sheet Components

Inventory

Inventory consists of the following (in thousands):



	As of January 31, 2018		As of October 31, 2018
Raw materials	$	1,181	$	4,880
Finished goods	33,316		45,857
Inventory	$	34,497	$	50,737

Property and Equipment, Net

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



	As of January 31, 2018			As of October 31, 2018
Test equipment	$	142,311		$	166,936
Computer equipment and software	72,329			103,366
Furniture and fixtures	5,363			5,619
Leasehold improvements	15,032			31,707
Total property and equipment	235,035			307,628
Less: accumulated depreciation and amortization	(145,893		)	(192,362		)
Property and equipment, net	$	89,142		$	115,266

Depreciation and amortization expense was $15.2 million and $16.9 million for the three months ended October 31, 2017 and 2018, and $44.4 million and $49.8 million for the nine months ended October 31, 2017 and 2018.

Intangible Assets, Net

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



	As of January 31, 2018							As of October 31, 2018
	Gross Carrying Value		Accumulated Amortization			Net Carrying Amount		Gross Carrying Value		Accumulated Amortization			Net Carrying Amount
Technology patents	$	10,125	$	(5,068	)	$	5,057	$	10,125	$	(6,196	)	$	3,929
Developed technology	—		—			—		17,700		(503		)	17,197
Intangible assets, net	$	10,125	$	(5,068	)	$	5,057	$	27,825	$	(6,699	)	$	21,126

Total intangible assets amortization expense was $0.4 million and $0.9 million for the three months ended October 31, 2017 and 2018, and $1.1 million and $1.6 million for the nine months ended October 31, 2017 and 2018. The weighted-average remaining amortization period is 2.6 years for technology patents and 6.8 years for developed technology. Amortization expense related to the technology patents is included in general and administrative expenses. Amortization of developed technology is included in cost of product revenue.

As of October 31, 2018, future expected amortization expense for intangible assets is as follows (in thousands):



Fiscal Years Ending January 31,	Estimated Future Amortization Expense
Remainder of 2019	$	1,008
2020	4,032
2021	4,032
2022	3,074
2023	2,529
Thereafter	6,451
Total	$	21,126

Goodwill

The change in the carrying amount of goodwill is as follows (in thousands):



	Amount
Balance as of January 31, 2018	$	—
Goodwill acquired	10,997
Balance as of October 31, 2018	$	10,997

Accrued Expenses and Other Liabilities

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



	As of January 31, 2018		As of October 31, 2018
Taxes payable	$	4,052	$	6,907
Accrued marketing	5,928		8,561
Accrued travel and entertainment expenses	4,386		4,108
Acquisition consideration held back	—		3,725
Other accrued liabilities	12,463		20,332
Total accrued expenses and other liabilities	$	26,829	$	43,633