Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2022

Goodwill And Intangible Assets Disclosure [Abstract]

Reconciliation of Intangible Assets

The reconciliation of intangible assets for the three months ended March 31, 2022 and 2021 (in thousands) was as follows:

	March 31,			March 31,
	2022			2021
Patented technologies
Gross carrying amount at beginning of period	$	68,322		$	68,322
Gross carrying amount at end of period		68,322			68,322
Accumulated amortization at beginning of period		(45,573	)		(43,113	)
Amortization expense		(615	)		(615	)
Accumulated amortization at end of period		(46,188	)		(43,728	)
Net book value at end of period	$	22,134		$	24,594