Acquired Intangible Assets, net

Acquired intangible assets as of April 1, 2017 and April 2, 2016 consisted of the following:



(In thousands, except years)	Weighted Average Useful Life (In years)	2017			2016
Developed technology	7.5	$	18,646		$	19,457
Customer relationships	5.3	3,914			3,154
Customer backlog	1.0	1,270			1,341
Trade name and trademarks	3.8	793			463
Fair value of below-market lease (non-current portion)	3.8	310			310
Change of control agreements and non-compete agreements	2.1	160			100
Patents	13.3	3,465			3,467
		28,558			28,292
Less accumulated amortization		(21,994		)	(21,146		)
		$	6,564		$	7,146

On August 1, 2016, the Company acquired Visicon and, as part of that acquisition, recognized $3.3 million of identifiable intangible assets. The acquired intangible assets consisted primarily of approximately $2.1 million of developed technology. (See Note 6 "Business Acquisitions" for further discussion).

The Company performed a review of our acquired intangible assets in the fourth quarter of 2017, including a review for impairment based on certain triggering events of amortizing intangible assets. As a result, the Company recognized a $2.3 million impairment of intangibles associated with developed technology related to the Topwin reporting unit. This impairment was driven primarily by historical and projected financial performance lower than expectations of the Company and that of comparable companies. The value of intangibles was also negatively impacted by a re-evaluation of our product portfolio in connection with announced restructuring plans. This review resulted in the Company prioritizing away from some of the lower-cost systems that were planned for manufacturing at Topwin, impacting the value of the reporting unit. The Company determined that the carrying value was greater than the estimated fair value and that it was improbable that the carrying value of the related intangibles would be recovered. The impairment loss was recorded as a component of costs of sales in the Consolidated Statements of Operations.

Amortization expense for acquired intangible assets has been recorded in the Consolidated Statements of Operations as follows:



(In thousands)	2017		2016		2015
Cost of sales	$	1,133	$	1,140	$	1,095
Selling, general and administration	209		36		210
Research, development and engineering	188		200		197
	$	1,530	$	1,376	$	1,502

The estimated amortization expense for acquired intangible assets in future years is as follows (in thousands):



Year	Amortization
2018	$	1,433
2019	1,439
2020	1,406
2021	1,228
2022	690
Future years	368
	$	6,564