Intangible Assets

Intangible assets with finite lives as of July 31, 2019 and 2018 are as follows:



	July 31, 2019
	Weighted Average Amortization Period	Gross Carrying Amount		Accumulated Amortization	Net Carrying Amount
Customer relationships	20.5	$	276,834,000	66,484,000	$	210,350,000
Technologies	12.7	92,649,000		59,522,000	33,127,000
Trademarks and other	16.7	31,026,000		12,613,000	18,413,000
Total		$	400,509,000	138,619,000	$	261,890,000



	July 31, 2018
	Weighted Average Amortization Period	Gross Carrying Amount		Accumulated Amortization	Net Carrying Amount
Customer relationships	21.0	$	249,831,000	55,350,000	$	194,481,000
Technologies	12.8	82,370,000		54,386,000	27,984,000
Trademarks and other	16.4	28,894,000		10,563,000	18,331,000
Total		$	361,095,000	120,299,000	$	240,796,000

The weighted average amortization period in the above table excludes fully amortized intangible assets.

Amortization expense for the fiscal years ended July 31, 2019, 2018 and 2017 was $18,320,000, $21,075,000 and $22,823,000, respectively.

As further discussed in Note (2) -"Acquisitions," intangible assets as of July 31, 2019 include recently acquired intangibles resulting from the acquisitions of Solacom and the GD NG-911 business.

The estimated amortization expense consists of the following for the fiscal years ending July 31:



2020	$	20,700,000
2021	19,563,000
2022	18,322,000
2023	18,322,000
2024	17,631,000

We review net intangible assets with finite lives for impairment when an event occurs indicating the potential for impairment. No such event has occurred during the fiscal year ended July 31, 2019. We believe that the carrying values of our net intangible assets were recoverable as of July 31, 2019. Any impairment charges that we may record in the future could be material to our results of operations and financial condition.