Note 2 - Concentration of Credit Risk and Major Customers (Details Textual) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021	Jun. 30, 2022 USD ($)	Jun. 30, 2021	Dec. 31, 2021
Excess Cash Balances, Number of High Credit Quality Financial Institutions			2
Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member] | One Customer [Member]
Concentration Risk, Percentage	28.00%	25.00%	26.00%	27.00%
Concentration Risk Number of Customers	1	1	1	1
Customer Concentration Risk [Member] | Revenue from Contract with Customer Benchmark [Member] | Largest Customer [Member]
Concentration Risk, Percentage	4.00%	2.00%	4.00%	3.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Two Customers [Member]
Concentration Risk, Percentage			37.00%		19.00%
Concentration Risk Number of Customers			2		1
UNITED STATES
Excess Cash Balances, Number of High Credit Quality Financial Institutions			1,000
Cash	$ 1,175		$ 1,175
CHINA
Excess Cash Balances, Number of High Credit Quality Financial Institutions			1
Cash	691		$ 691
MEXICO
Cash	$ 54		$ 54