Intangible Assets and Goodwill

Intangible assets consist of the following (in millions):



	December 31, 2018
	Gross Amount		Accumulated Amortization			Net Amount
Core and developed technology	$	7,064.4	$	(984.5	)	$	6,079.9
Customer-related	1,043.8		(512.3		)	531.5
Backlog	27.9		(19.5		)	8.4
In-process research and development	7.7		—			7.7
Distribution rights	0.3		(0.2		)	0.1
Other	7.4		(2.1		)	5.3
Total	$	8,151.5	$	(1,518.6	)	$	6,632.9



	March 31, 2018
	Gross Amount		Accumulated Amortization			Net Amount
Core and developed technology	$	1,952.3	$	(644.4	)	$	1,307.9
Customer-related	716.9		(375.9		)	341.0
In-process research and development	12.1		—			12.1
Distribution rights	0.3		(0.1		)	0.2
Other	1.5		(0.7		)	0.8
Total	$	2,683.1	$	(1,021.1	)	$	1,662.0

The Company amortizes intangible assets over their expected useful lives, which range between 1 and 15 years. During the nine months ended December 31, 2018, due to the acquisition of Microsemi, the Company acquired $4.31 billion of core and developed technology which has a weighted average amortization period of 15 years, $326.9 million of customer-related intangible assets which have a weighted average amortization period of 12 years, $27.9 million of intangible assets related to backlog with an amortization period of 1 year, $5.8 million of other intangible assets which have a weighted average amortization period of 4 years, and $794.2 million of in-process technology. In the nine months ended December 31, 2018, $798.6 million of in-process research and development intangible assets, primarily consisting of intangible assets acquired in the acquisition of Microsemi, reached technological feasibility and was reclassified as core and developed technology and began being amortized over the respective estimated useful lives. The following is an expected amortization schedule for the intangible assets for the remainder of fiscal 2019 through fiscal 2023, absent any future acquisitions or impairment charges (in millions):



Fiscal Year Ending March 31,	Projected Amortization Expense
2019	$196.8
2020	$992.0
2021	$926.7
2022	$851.8
2023	$660.5

Amortization expense attributed to intangible assets was $196.9 million and $505.5 million for the three and nine months ended December 31, 2018, respectively. Amortization expense attributed to intangible assets was $122.6 million and $368.1 million for the three and nine months ended December 31, 2017, respectively. In the three and nine months ended December 31, 2018, approximately $1.8 million and $4.9 million of amortization expense, respectively, was charged to cost of sales, and approximately $195.1 million and $500.6 million, respectively, was charged to operating expenses. In the three and nine months ended December 31, 2017, approximately $1.5 million and $4.9 million of amortization expense, respectively, was charged to cost of sales, and approximately $121.1 million and $363.2 million, respectively, was charged to operating expenses. The Company recognized $3.1 million of intangible asset impairment charges in the nine months ended December 31, 2018. The impairment charges in the nine months ended December 31, 2018 were recognized as a result of writing off intangible assets purchased from Microsemi prior to the close of the acquisition and as a result of changes in the combined product roadmaps after the acquisition that affected the use and life of these assets. The Company recognized an immaterial amount of intangible asset impairment charges in the nine months ended December 31, 2017.

Goodwill activity for the three and nine months ended December 31, 2018 was as follows (in millions):



	Semiconductor Products Reporting Unit		Technology Licensing Reporting Unit
Balance at March 31, 2018	$	2,279.8	$	19.2
Additions due to the acquisition of Microsemi	4,483.0		—
Balance at December 31, 2018	$	6,762.8	$	19.2

At March 31, 2018, the Company applied a qualitative goodwill impairment test to its two reporting units, concluding it was not more likely than not that goodwill was impaired. Through December 31, 2018, the Company has never recorded an impairment charge against its goodwill balance.