Debt (Tables)

3 Months Ended

Mar. 31, 2019

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, 2019 (in thousands):

Carrying value of liability related to sale of future royalties at December 31, 2018	$	221,295
Interest expense recognized	9,962
Carrying value of liability related to sale of future royalties at March 31, 2019	$	231,257