Debt (Tables)

3 Months Ended

Mar. 31, 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 three months ended March 31, 2020 and 2019 (in thousands):

	Three Months Ended March 31,
	2020		2019
Carrying value of liability related to sale of future royalties, beginning of the period	$	261,224	$	221,295
Interest expense recognized	13,482		9,962
Carrying value of liability related to sale of future royalties, end of period	$	274,706	$	231,257