The Company has one reporting unit. The Company assesses goodwill for impairment at the reporting unit level at least annually, or on an interim basis if an event occurs or circumstances change that would, more likely than not, reduce the fair value of the reporting unit below its carrying value. The Company completed its annual impairment test on January 31, 2022 using the qualitative assessment as the Company concluded that it was more likely than not that the fair value of the reporting unit exceeded its carrying value.

At December 31, 2022 and March 31, 2022, the carrying amount of goodwill was $1.7 billion. The change in the carrying amount of goodwill for the nine months ended December 31, 2022 was due to the impact of foreign currency translation adjustments related to asset balances that are recorded in currencies other than the U.S. Dollar.

The following table summarizes the changes in the carrying amount of goodwill for the nine months ended December 31, 2022 as follows (in thousands):

The net carrying amounts of intangible assets were $382.3 million and $433.4 million at December 31, 2022 and March 31, 2022, respectively. Intangible assets acquired in a business combination are recorded under the acquisition method of accounting at their estimated fair values at the date of acquisition. The Company amortizes acquired intangible assets over their estimated useful lives.


	Estimated Useful Life in Years	Cost		Accumulated Amortization		Net
Developed technology	3 - 13 years	$	249,470	$	(230,700)	$	18,770
Customer relationships	8 - 18 years	766,635		(420,678)		345,957
Distributor relationships and technology licenses	1 - 6 years	11,521		(9,803)		1,718
Definite-lived trademark and trade name	2 - 9 years	57,627		(42,026)		15,601
Core technology	10 years	7,192		(7,192)		—

Non-compete agreements	3 years	292		(292)		—


Capitalized software	3 years	3,317		(3,317)		—

Other	1 - 20 years	1,208		(997)		211
		$	1,097,262	$	(715,005)	$	382,257


	Estimated Useful Life in Years	Cost		Accumulated Amortization		Net
Developed technology	3 - 13 years	$	250,247	$	(224,426)	$	25,821
Customer relationships	8 - 18 years	769,404		(384,347)		385,057
Distributor relationships and technology licenses	1 - 6 years	11,408		(8,896)		2,512
Definite-lived trademark and trade name	2 - 9 years	57,748		(37,944)		19,804
Core technology	10 years	7,192		(7,192)		—

Non-compete agreements	3 years	292		(292)		—


Capitalized software	3 years	3,317		(3,317)		—
Other	1 - 20 years	1,208		(983)		225
		$	1,100,816	$	(667,397)	$	433,419

Amortization included as cost of product revenue consists of amortization of developed technology, distributor relationships and technology licenses, core technology and software. Amortization included as operating expense consists of all other intangible assets. The following table provides a summary of amortization expense for the three and nine months ended December 31, 2022 and 2021, respectively (in thousands):


	Three Months Ended				Nine Months Ended
	December 31,				December 31,
	2022		2021		2022		2021
Amortization of intangible assets included as:

Cost of product revenue	$	2,627	$	3,643	$	7,908	$	10,959
Operating expense	13,823		14,924		41,515		44,910
	$	16,450	$	18,567	$	49,423	$	55,869