OTHER INCOME (LOSS)

12 Months Ended

Dec. 31, 2021

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,
	2021			2020			2019
	(in thousands)
Interest expense	$	(63,525	)	$	(59,947	)	$	(30,669	)
Interest income		354			2,970			7,238
Amortization of investment discount		157			4,489			15,350
Gain from sale of Priority Review Voucher		102,000			108,069			—
Gain (loss) on contingent consideration, net*		7,200			(45,000	)		—
Impairment of equity investment		(4,488	)		—			—
Other (expense) income		(936	)		517			(236	)
Total other income (loss)	$	40,762		$	11,098		$	(8,317	)