Note 9 - Intangible Assets, Net - Finite Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Intangible assets, gross amount	$ 8,519	$ 8,179
Intangible assets, accumulated amortization	(4,642)	(4,180)
Intangible assets, net	3,877	3,999
Patents [Member]
Intangible assets, gross amount	8,494	8,158
Intangible assets, accumulated amortization	(4,626)	(4,165)
Intangible assets, net	3,868	3,993
Trademarks [Member]
Intangible assets, gross amount	25	21
Intangible assets, accumulated amortization	(16)	(15)
Intangible assets, net	$ 9	$ 6