CAPITALIZED FEES PAID

12 Months Ended

Dec. 31, 2023

Capitalized Contract Cost [Abstract]

CAPITALIZED FEES PAID

7. CAPITALIZED FEES PAID

Capitalized fees paid, which consist of registrational and launch-related milestone fees paid to GSK, were as follows:

		December 31,
(In thousands)	Amortization period	2023			2022
United States	2013-2030	$	120,000		$	120,000
Europe	2013-2029		60,000			60,000
Japan	2013-2029		40,000			40,000
Gross carrying value			220,000			220,000
Accumulated amortization			(136,216	)		(122,393	)
Net carrying value		$	83,784		$	97,607

These milestone fees are amortized over their estimated useful lives commencing upon the commercial launch of the product in their respective regions with the amortization recorded as a reduction in revenue from collaborative arrangements. As of December 31, 2023, the weighted average remaining amortization period was 6.2 years.

Additional information regarding these milestone fees is included in Note 3, “Revenue Recognition”. Amortization for each of the years ended December 31, 2023, 2022 and 2021 was $13.8 million. The remaining estimated amortization is $13.8 million for each of the years from 2024 to 2027, $13.7 million for the year 2028, and $14.8 million thereafter.