Intangible Assets

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

Intangible Assets

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

	December 31, 2019			December 31, 2018			Estimated useful life (years)
Acquired and in-licensed rights	$	8,712		$	8,712		11
Less: accumulated amortization	(2,129		)	(1,330		)
Total intangible asset, net	$	6,583		$	7,382

The acquired and in-licensed rights relate to the milestone of €8.0 million (approximately $8.7 million) paid to Ipsen, which was triggered by the FDA approval of TYMLOS on April 28, 2017.

The Company recorded approximately $0.8 million, $0.8 million, and $0.5 million in amortization expense related to intangible assets, using the straight-line methodology which is considered the best estimate of economic benefit, during each of the twelve months ended December 31, 2019, 2018, and 2017, respectively. Estimated future amortization expense for intangible assets as of December 31, 2019 is approximately $0.8 million per year over the remaining life of 8.25 years.