Note 9 - Intangible Assets, Net - Finite Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Intangible assets, gross amount	$ 8,384	$ 8,179
Intangible assets, accumulated amortization	(4,496)	(4,180)
Intangible assets, net	3,888	3,999
Patents [Member]
Intangible assets, gross amount	8,362	8,158
Intangible assets, accumulated amortization	(4,480)	(4,165)
Intangible assets, net	3,882	3,993
Trademarks [Member]
Intangible assets, gross amount	22	21
Intangible assets, accumulated amortization	(16)	(15)
Intangible assets, net	$ 6	$ 6