Goodwill and Intangible Assets

6 Months Ended

Jun. 30, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

The gross carrying amount of goodwill was as follows (in thousands):



Balance at December 31, 2019	$	920,018
Foreign exchange	(1,997		)
Balance at June 30, 2020	$	918,021

The gross carrying amounts and net book values of our intangible assets were as follows (in thousands):



	June 30, 2020								December 31, 2019
	Remaining Weighted- Average Useful Life (In years)	Gross Carrying Amount		Accumulated Amortization			Net Book Value		Gross Carrying Amount		Accumulated Amortization			Net Book Value
Acquired developed technologies	12.9	$	3,275,569	$	(989,443	)	$	2,286,126	$	3,166,485	$	(864,834	)	$	2,301,651
Manufacturing contracts	—	11,987		(11,987		)	—		12,025		(12,025		)	—
Trademarks	—	2,889		(2,889		)	—		2,890		(2,890		)	—
Priority review voucher	—	—		—			—		111,101		(111,101		)	—
Total finite-lived intangible assets		3,290,445		(1,004,319		)	2,286,126		3,292,501		(990,850		)	2,301,651
Acquired IPR&D assets		—		—			—		139,326		—			139,326
Total intangible assets		$	3,290,445	$	(1,004,319	)	$	2,286,126	$	3,431,827	$	(990,850	)	$	2,440,977

The decrease in the gross carrying amount of intangible assets as of June 30, 2020 compared to December 31, 2019 reflects the impairment of our acquired IPR&D asset of $136.1 million following the decision to stop enrollment in our Phase 3 clinical study of defibrotide for the prevention of VOD due to a determination that the study is highly unlikely to reach one of its primary endpoints, the redemption of the priority review voucher in January 2020 and the negative impact of foreign currency translation adjustments due to the weakening of the euro against the U.S. dollar, partially offset by the capitalization of milestone payments of $100.0 million and $13.0 million triggered by FDA approval of Zepzelca in June 2020 and European Marketing Authorization of Sunosi in January 2020, respectively.

The assumptions and estimates used to determine future cash flows and remaining useful lives of our intangible and other long-lived assets are complex and subjective. They can be affected by various factors, including external factors, such as industry and economic trends, and internal factors such as changes in our business strategy and our forecasts for specific product lines.

Based on finite-lived intangible assets recorded as of June 30, 2020, and assuming the underlying assets will not be impaired and that we will not change the expected lives of the assets, future amortization expenses were estimated as follows (in thousands):



Year Ending December 31,	Estimated Amortization Expense
2020 (remainder)	$	130,647
2021	215,415
2022	170,572
2023	170,572
2024	170,572
Thereafter	1,428,348
Total	$	2,286,126