Interest Expense (Tables)

6 Months Ended

Jun. 30, 2020

Other Income and Expenses [Abstract]

Schedule of interest expense

Interest expense consists of the following (dollars in thousands):

	Three Months ended June 30,				Six Months ended June 30,
	2020		2019		2020		2019
	(unaudited)				(unaudited)
Interest expense	$	(4,792)	$	(4,253)	$	(9,485)	$	(8,972)
Interest expense on nonrecourse liability related to sale of future royalties	(1,023)		(1,136)		(2,085)		(2,296)
Total	$	(5,815)	$	(5,389)	$	(11,570)	$	(11,268)