Note 9 - Intangible Assets, Net (Tables)

9 Months Ended

Sep. 30, 2021

Notes Tables

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	September 30, 2021
	Gross		Accumulated			Intangible
	Amount		amortization			assets, net
Patents	$	8,494	$	(4,626	)	$	3,868
Trademarks		25		(16	)		9
Total intangible assets	$	8,519	$	(4,642	)	$	3,877

	December 31, 2020
	Gross		Accumulated			Intangible
	Amount		amortization			assets, net
Patents	$	8,158	$	(4,165	)	$	3,993
Trademarks		21		(15	)		6
Total intangible assets	$	8,179	$	(4,180	)	$	3,999

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

2022	$	584
2023		584
2024		584
2025		584
2026		584
thereafter		957
	$	3,877