Note I - Intangible Assets

12 Months Ended

Dec. 31, 2019

Notes to Financial Statements

Intangible Assets Disclosure [Text Block]

NOTE I—INTANGIBLE ASSETS

Intangible assets consisted of the following for the periods indicated (in thousands):

	December 31, 2019
	Gross		Accumulated			Intangible
	Amount		amortization			assets, net
Patents	$	7,638	$	(3,560	)	$	4,078
Trademarks		17		(14	)	$	3
Total intangible assets	$	7,655	$	(3,574	)	$	4,081

	December 31, 2018
	Gross		Accumulated			Intangible
	Amount		amortization			assets, net
Patents	$	6,983	$	(3,008	)	$	3,975
Trademarks		15		(13	)		2
Total intangible assets	$	6,998	$	(3,021	)	$	3,977

For the years ended December 31, 2019, 2018 and 2017, amortization expense for intangible assets, included in general and administrative expenses on the income statement, was $0.5 million each year. The remaining weighted average amortization period for intangible assets is approximately 7 years.

At December 31, 2019, future amortization expense for intangible assets is estimated to be (in thousands):

2020	$	537
2021		537
2022		537
2023		537
2024		537
thereafter		1,396
	$	4,081