Note 9 - Intangible Assets, Net (Tables)

9 Months Ended

Sep. 30, 2020

Notes Tables

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

	September 30, 2020
	Gross		Accumulated			Intangible
	Amount		amortization			assets, net
Patents	$	8,029	$	(4,005	)	$	4,024
Trademarks		22		(15	)		7
Total intangible assets	$	8,051	$	(4,020	)	$	4,031

	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

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

2021	$	570
2022		570
2023		570
2024		570
2025		570
thereafter		1,181
	$	4,031