Intangible Assets

12 Months Ended

Dec. 31, 2022

Intangible Assets

Intangible Assets

5. Intangible Assets

The Company’s intangible assets consist of the following (in thousands):

		Gross
	Estimated	Carrying		Accumulated				Net Book
	Useful Lives	Value		Amortization		Impairment		Value
December 31, 2022:
IPR&D assets	Indefinite	$	12,419	$	—	$	—	$	12,419
Total		$	12,419	$	—	$	—	$	12,419
December 31, 2021:
Internally developed patents	6–20 years	$	1,079	$	(500)	$	(579)	$	—
Acquired licenses	16–20 years		285		(285)		—		—
Total intangible assets subject to amortization			1,364		(785)		(579)		—
IPR&D assets	Indefinite		12,419		—		—		12,419
Total		$	13,783	$	(785)	$	(579)	$	12,419

As of December 31, 2021, the Company recorded an impairment loss of $0.6 million for the remaining net book value of the internally developed patents that are associated with the Company's discontinued development programs. The impairment loss has been recorded to research and development expenses in the accompanying audited consolidated statements of operations and comprehensive loss. There was no IPR&D impairment loss during the years ended December 31, 2022 and 2021