Goodwill and Intangible Assets

The changes in the carrying amount of goodwill for the year ended December 31, 2018 were as follows (in thousands):



	TASER			Software and Sensors			Total
Balance, January 1, 2018	$	1,453		$	13,474		$	14,927
Goodwill acquired	—			10,285			10,285
Foreign currency translation adjustments	(115		)	(116		)	(231		)
Balance, December 31, 2018	$	1,338		$	23,643		$	24,981

Intangible assets (other than goodwill) consisted of the following (in thousands):



		December 31, 2018							December 31, 2017
	Useful Life	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Amortizable (definite-lived) intangible assets:
Domain names	5-10 years	$	3,161	$	(732	)	$	2,429	$	3,161	$	(428	)	$	2,733
Issued patents	4-15 years	2,940		(1,106		)	1,834		2,697		(913		)	1,784
Issued trademarks	3-11 years	1,053		(599		)	454		860		(397		)	463
Customer relationships	4-8 years	3,701		(880		)	2,821		1,377		(451		)	926
Non-compete agreements	3-4 years	540		(439		)	101		556		(346		)	210
Developed technology	3-7 years	13,404		(7,081		)	6,323		13,469		(3,956		)	9,513
Re-acquired distribution rights	2 years	1,928		(1,813		)	115		2,133		(711		)	1,422
Total amortizable		26,727		(12,650		)	14,077		24,253		(7,202		)	17,051
Non-amortizable (indefinite-lived) intangible assets:
TASER trademark		900					900		900					900
Patents and trademarks pending		958					958		872					872
Total non-amortizable		1,858					1,858		1,772					1,772
Total intangible assets		$	28,585	$	(12,650	)	$	15,935	$	26,025	$	(7,202	)	$	18,823

Amortization expense of intangible assets was $5.7 million, $4.7 million and $0.9 million for the years ended December 31, 2018, 2017 and 2016, respectively. Estimated amortization for intangible assets with definitive lives for the next five years ended December 31, and thereafter, is as follows (in thousands):



2019	$	3,463
2020	3,294
2021	2,852
2022	1,211
2023	934
Thereafter	2,323
Total	$	14,077