Debt (Tables)

6 Months Ended

Jun. 30, 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 six months ended June 30, 2019 (in thousands):

Carrying value of liability related to sale of future royalties at December 31, 2018	$	221,295
Interest expense recognized	20,373
Carrying value of liability related to sale of future royalties at June 30, 2019	$	241,668