Intangible Assets and Goodwill

Intangible Assets

Intangible assets, net of accumulated amortization, impairment charges and adjustments, are summarized as follows:



		As of March 31, 2019							As of December 31, 2018
(In millions)	Estimated Life	Cost		Accumulated Amortization			Net		Cost		Accumulated Amortization			Net
Out-licensed patents	13-23 years	$	543.3	$	(542.4	)	$	0.9	$	543.3	$	(542.3	)	$	1.0
Developed technology	15-23 years	3,005.3		(2,744.1		)	261.2		3,005.3		(2,734.8		)	270.5
In-process research and development	Indefinite until commercialization	480.5		—			480.5		476.0		—			476.0
Trademarks and tradenames	Indefinite	64.0		—			64.0		64.0		—			64.0
Acquired and in-licensed rights and patents	4-18 years	3,638.7		(1,389.1		)	2,249.6		3,638.7		(1,330.2		)	2,308.5
Total intangible assets		$	7,731.8	$	(4,675.6	)	$	3,056.2	$	7,727.3	$	(4,607.3	)	$	3,120.0

For the three months ended March 31, 2019, amortization and impairment of acquired intangible assets totaled $68.2 million, compared to $103.9 million in the prior year comparative period. The decrease in amortization and impairment of acquired intangible asset was primarily due to a net overall decrease in our expected rate of amortization for acquired intangible assets. This was primarily due to lower amortization subsequent to the impairment in the fourth quarter of 2018 of the U.S. license to Forward Pharma A/S' (Forward Pharma) intellectual property, including Forward Pharma's intellectual property related to TECFIDERA, and higher expected lifetime revenues of TYSABRI. For the three months ended March 31, 2019 and 2018, we had no impairment charges.

Developed Technology

Developed technology primarily relates to our AVONEX product, which was recorded in connection with the merger of Biogen, Inc. and IDEC Pharmaceuticals Corporation in 2003. The net book value of this asset as of March 31, 2019, was $256.2 million.

Acquired and In-licensed Rights and Patents

Acquired and in-licensed rights and patents primarily relate to our acquisition of all remaining rights to TYSABRI from Elan Pharma International Ltd., an affiliate of Elan Corporation plc. Acquired and in-licensed rights and patents also includes our rest of world license to Forward Pharma's intellectual property, including Forward Pharma's intellectual property related to TECFIDERA, and other amounts related to our other marketed products and other programs acquired through business combinations. The net book value of the TYSABRI asset as of March 31, 2019, was $1,980.8 million and the net book value of the TECFIDERA asset as of March 31, 2019, was $63.1 million. For additional information on our TECFIDERA license rights, please read Note 7, Intangible Assets and Goodwill, to our consolidated financial statements included in our 2018 Form 10-K.

Estimated Future Amortization of Intangible Assets

Our amortization expense is based on the economic consumption and impairment of intangible assets. Our most significant intangible assets are related to our TYSABRI, AVONEX, SPINRAZA and TECFIDERA products and other programs acquired through business combinations. Annually, during our long-range planning cycle, we perform an analysis of anticipated lifetime revenues of our TYSABRI, AVONEX, SPINRAZA and TECFIDERA products. This analysis is also updated whenever events or changes in circumstances would significantly affect the anticipated lifetime revenues of any of these products. Impairments are recorded in the period in which they are incurred.

Our most recent long-range planning cycle was completed in the third quarter of 2018. Based upon this most recent analysis, the estimated future amortization of acquired intangible assets for the next five years is expected to be as follows:



(In millions)	As of March 31, 2019
2019 (remaining nine months)	$	200.0
2020	290.0
2021	250.0
2022	250.0
2023	230.0
2024	190.0

Goodwill

The following table provides a roll forward of the changes in our goodwill balance:



(In millions)	As of March 31, 2019
Goodwill, beginning of period	$	5,706.4
Reclassification of goodwill to assets held for sale	(69.5		)
Other	2.8
Goodwill, end of period	$	5,639.7

The reclassification of goodwill to assets held for sale relates to an allocation based upon the relative fair value of the proposed divestiture of our Hillerød, Denmark manufacturing operations.

During the three months ended March 31, 2019, goodwill was reviewed for impairment due to the proposed divestiture of our Hillerød, Denmark manufacturing operations, and based upon this review, no impairments were recognized. As of March 31, 2019, we had no accumulated impairment losses related to goodwill.

For additional information on the proposed divestiture of our Hillerød, Denmark manufacturing operations, please read Note 3, Divestitures, to these condensed consolidated financial statements.

Other includes changes related to foreign currency exchange rate fluctuations.