Condensed consolidated financial statement details

The following sections and tables provide details of selected balance sheet items.

Inventory



(in thousands)	June 30, 2016		December 31, 2015
Components	$	8,190	$	9,476
Finished goods	81,699		178,756
Total inventory	$	89,889	$	188,232

Property and equipment, net



(in thousands)	June 30, 2016			December 31, 2015
Leasehold improvements	$	42,369		$	40,841
Production, engineering and other equipment	26,957			25,174
Tooling	20,156			19,537
Computers and software	15,971			14,581
Furniture and office equipment	12,006			11,389
Construction in progress	6,528			4,632
Tradeshow equipment and other	6,448			4,136
Gross property and equipment	130,435			120,290
Less: Accumulated depreciation and amortization	(63,910		)	(50,240		)
Property and equipment, net	$	66,525		$	70,050

In June 2016, the Company committed to a plan to vacate and sublet certain leased office facilities that are auxiliary to our main headquarters. Changes in estimated useful life of associated leasehold improvements and office equipment are expected to result in accelerated depreciation expense of approximately $7 million over the next 13 months, including approximately $4 million in the third quarter of 2016 and approximately $3 million ratably over the remaining period.

Intangible assets and goodwill



	June 30, 2016
(in thousands)	Gross carrying value		Accumulated amortization			Net carrying value
Purchased technology	$	48,184	$	(12,486	)	$	35,698
In-process research and development (IPR&D)	10,375		—			10,375
Total intangible assets	$	58,559	$	(12,486	)	$	46,073



	December 31, 2015
(in thousands)	Gross carrying value		Accumulated amortization			Net carrying value
Purchased technology	$	32,952	$	(8,540	)	$	24,412
IPR&D	6,615		—			6,615
Total intangible assets	$	39,567	$	(8,540	)	$	31,027

Purchased technology acquired in 2016 has an estimated useful life of four years. As of June 30, 2016, technological feasibility has not been established for IPR&D assets, which have no alternative future use and, as such, continue to be accounted for as indefinite-lived intangible assets.

Amortization expense was $3.9 million and $1.2 million in the six months ended June 30, 2016 and 2015, respectively. At June 30, 2016, the expected amortization expense of amortizable intangible assets for future periods is as follows:



(in thousands)	Total
Year ending December 31,
2016 (remaining 6 months)	$	5,075
2017	9,388
2018	8,452
2019	7,669
2020	4,244
Thereafter	870
	$	35,698

The carrying amount of goodwill was $146.5 million and $57.1 million as of June 30, 2016 and December 31, 2015, respectively. The increase in 2016 was entirely attributable to the acquisitions described above in Note 2.

Accrued liabilities



(in thousands)	June 30, 2016		December 31, 2015
Accrued payables	$	70,083	$	64,831
Excess purchase order commitments	12,172		38,477
Accrued sales incentive	20,020		29,298
Employee related liabilities	25,590		26,491
Warranty liability	8,594		10,400
Customer deposits	4,127		8,877
Income taxes payable	3,070		7,536
Other	7,446		6,536
Accrued liabilities	$	151,102	$	192,446