Note 4. Balance Sheet Components

Property and Equipment, Net

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

	January 31,
	2015			2016
Test equipment	$	37,059		$	65,663
Computer equipment and software		19,022			31,388
Furniture and fixtures		2,460			2,852
Leasehold improvements		3,776			4,935
Total property and equipment		62,317			104,838
Less: accumulated depreciation and amortization		(22,458	)		(52,209	)
Property and equipment, net	$	39,859		$	52,629

Depreciation and amortization expense related to property and equipment was $4.4 million, $14.6 million and $31.0 million for the fiscal years ended January 31, 2014, 2015 and 2016, respectively.

Intangible Assets, Net

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

	January 31,
	2015			2016
Technology patents	$	9,125		$	9,125
Accumulated amortization		(841	)		(2,145	)
Intangible assets, net	$	8,284		$	6,980

Intangible assets amortization expense was $841,000 and $1.3 million for the fiscal years ended January 31, 2015 and 2016, respectively. No intangible assets amortization expense was recorded for the fiscal year ended January 31, 2014. Due to the defensive nature of these patents, the amortization is included in general and administrative expenses in the consolidated statements of operations.

As of January 31, 2016, expected amortization expense for intangible assets for each of the next five years and thereafter is as follows (in thousands):

Fiscal Year Ending January 31,	Estimated Future Amortization Expense
2017	$	1,304
2018		1,304
2019		1,304
2020		1,304
2021		1,304
Thereafter		460
Total	$	6,980

Accrued Expenses and Other Liabilities

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

	January 31,
	2015		2016
Sales and use tax payable	$	591	$	299
Accrued professional fees		1,502		3,044
Accrued travel and entertainment expenses		1,138		2,182
Income tax payable		779		1,791
Other accrued liabilities		2,096		6,760
Total accrued expenses and other liabilities	$	6,106	$	14,076