Note 12 - Geographic Information and Major Customer and Product Data - Revenues Based On Customer Location (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues	$ 100,326,000	$ 87,152,000	$ 77,877,000
UNITED STATES
Revenues	20,813,000	16,627,000	8,354,000
Europe and Middle East [Member]
Revenues	11,966,000	21,493,000	17,370,000
Asia Pacific [Member]
Revenues	67,547,000	49,032,000	52,153,000
CHINA
Revenues	$ 51,726,000	33,233,000	33,672,000
KOREA, REPUBLIC OF
Revenues			$ 7,989
GERMANY
Revenues		$ 16,100,000