Intangible Assets

6 Months Ended

Jun. 30, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

Intangible Assets

The following table presents intangible assets as of June 30, 2019 and December 31, 2018 (in thousands):

	June 30, 2019			December 31, 2018			Estimated useful life
Acquired and in-licensed rights	$	8,712		$	8,712		11 years
Less: accumulated amortization	(1,730		)	(1,330		)
Total intangible asset, net	$	6,982		$	7,382

Acquired and in-licensed rights as of June 30, 2019 consist of the €8.0 million (approximately $8.7 million on the date paid) milestone paid to Ipsen, which was triggered by FDA approval of TYMLOS on April 28, 2017.

The Company recorded approximately $0.2 million and $0.4 million in amortization expense related to intangible assets, using the straight-line methodology, which is considered the best estimate of economic benefit, during the three and six months ended June 30, 2019 and 2018, respectively. Estimated future amortization expense for intangible assets as of June 30, 2019 is approximately $0.4 million for the remainder of 2019, and approximately $0.8 million per year over the remaining life of 8.75 years.