Debt (Tables)

6 Months Ended

Jun. 30, 2020

Debt Disclosure [Abstract]

Schedule of Deferred Revenue, by Arrangement

The following table shows the activity within the liability related to sale of future royalties during the six months ended June 30, 2020 and 2019 (in thousands):

	Six Months Ended June 30,
	2020		2019
Carrying value of liability related to sale of future royalties, beginning of the period	$	261,224	$	221,295
Interest expense recognized	27,469		20,373
Carrying value of liability related to sale of future royalties, end of period	$	288,693	$	241,668