Note 10 - Segment Information, Significant Customers, Industry Concentration and Geographic Areas (Details Textual) - Customer Concentration Risk [Member] - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Sales [Member] | Five Largest Customers [Member]
Concentration Risk, Percentage	33.00%	35.00%	40.00%
Sales [Member] | General Motors Company [Member]
Concentration Risk, Percentage	11.00%	15.00%	19.00%
Revenue Provided to the Automobile Manufacturing Industry [Member] | Other Manufacturers [Member]
Concentration Risk, Percentage	27.00%	30.00%	40.00%
Accounts Receivable [Member]
Accounts Receivable, before Allowance for Credit Loss, Current	$ 31,049,000	$ 25,593,000