OTHER INCOME (LOSS)

12 Months Ended

Dec. 31, 2020

Other Income And Expenses [Abstract]

OTHER INCOME (LOSS)

17. OTHER INCOME (LOSS)

The following table summarizes other income (loss) for the periods indicated:

	For the Year Ended December 31,
	2020			2019			2018
	(in thousands)
Interest expense	$	(59,947	)	$	(30,669	)	$	(33,709	)
Interest income		2,970			7,238			6,810
Amortization of investment discount		4,489			15,350			8,573
Gain from sale of Priority Review Voucher		108,069			—			—
Loss on contingent consideration*		(45,000	)		—			—
Other expense		517			(236	)		(656	)
Total other income (loss)	$	11,098		$	(8,317	)	$	(18,982	)