Intangible Assets (Tables)

6 Months Ended

Jun. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets

Intangible asset balances as of June 30, 2018 and December 31, 2017 are as follows:

	June 30, 2018
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value
	(in thousands)
Developed technology - lomitapide	$	42,300	$	(6,230	)	$	36,070
Developed technology - metreleptin	210,158		(33,504		)	176,654
Total intangible assets	$	252,458	$	(39,734	)	$	212,724

	December 31, 2017
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value
	(in thousands)
Developed technology - lomitapide	$	42,300	$	(4,262	)	$	38,038
Developed technology - metreleptin	210,158		(22,924		)	187,234
Total intangible assets	$	252,458	$	(27,186	)	$	225,272

Estimated Future Amortization Expense of Acquired Intangibles

As of June 30, 2018, the estimated amortization expense related to intangibles for future periods is as follows: 

	Amount
Years Ending December 31,	(in thousands)
2018 (remaining 6 months)	$	12,547
2019	25,095
2020	25,095
2021	25,095
2022	25,095
Thereafter	99,797
Total intangible assets subject to amortization	$	212,724