GOODWILL AND IDENTIFIED INTANGIBLE ASSETS

Goodwill

Goodwill represents the difference between the purchase price and the estimated fair value of the identifiable assets acquired and liabilities assumed. Goodwill is allocated among and evaluated for impairment at the reporting unit level, which is defined as an operating segment or one level below an operating segment. The Company has two reporting units, Video and Cable Access.

The Company tests for goodwill impairment at the reporting unit level on an annual basis in the fiscal fourth quarter, or more frequently, if events or changes in circumstances indicate that the asset is more likely than not impaired. The Company performed its annual goodwill impairment review at the reporting unit level as of October 31, 2017, with no goodwill impairment indicated. There were no events or circumstances which triggered additional impairment reviews for the periods presented.

The changes in the carrying amount of goodwill by reportable segments for the nine months ended September 28, 2018 were as follows (in thousands):



	Video			Cable Access			Total
Balance as of December 31, 2017	$	182,012		$	60,815		$	242,827
Foreign currency translation adjustment	(1,297		)	(18		)	(1,315		)
Balance as of September 28, 2018	$	180,715		$	60,797		$	241,512

Intangible Assets, Net

The following is a summary of intangible assets, net (in thousands):



		September 28, 2018							December 31, 2017
	Weighted Average Remaining Life (Years)	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Developed core technology	1.4	$	31,707	$	(24,281	)	$	7,426	$	31,707	$	(20,396	)	$	11,311
Customer relationships/contracts	2.4	44,718		(37,431		)	7,287		44,819		(35,205		)	9,614
Trademarks and trade names	1.4	635		(410		)	225		654		(300		)	354
Maintenance agreements and related relationships	n/a	5,500		(5,500		)	—		5,500		(5,500		)	—
Order Backlog	n/a	3,138		(3,138		)	—		3,177		(3,177		)	—
Total identifiable intangibles		$	85,698	$	(70,760	)	$	14,938	$	85,857	$	(64,578	)	$	21,279

Amortization expense for the identifiable purchased intangible assets for the three and nine months ended September 28, 2018 and September 29, 2017 was allocated as follows (in thousands):



	Three months ended				Nine months ended
	September 28, 2018		September 29, 2017		September 28, 2018		September 29, 2017
Included in cost of revenue	$	1,295	$	1,295	$	3,885	$	3,885
Included in operating expenses	792		793		2,396		2,347
Total amortization expense	$	2,087	$	2,088	$	6,281	$	6,232

The estimated future amortization expense of purchased intangible assets with definite lives is as follows (in thousands):



	Cost of Revenue		Operating Expenses		Total
Year ended December 31,
2018 (remaining three months)	$	1,295	$	794	$	2,089
2019	5,180		3,174		8,354
2020	951		3,042		3,993
2021	—		502		502
Total future amortization expense	$	7,426	$	7,512	$	14,938