Note 1 - General - Sales as Percentage of the Company's Total Revenue by Major Customers (Details) - Customer Concentration Risk [Member] - Revenue Benchmark [Member]		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
VTech Holdings Ltd [Member]
Major Customers/ Distributors		21.00%	24.00%	27.00%
Nexty Electronics Corporation [Member]
Major Customers/ Distributors	[1],[2]		11.00%	12.00%
Ascend Technology Inc [Member]
Major Customers/ Distributors	[1],[3]	27.00%	26.00%	23.00%

[1] Distributor

[2] Nexty Electronics sells the Company's products to a limited number of customers. One customer, Panasonic Communications Co., Ltd. ("Panasonic") has continually accounted for a majority of the sales of Nexty Electronics. Sales to Panasonic through Nexty Electronics generated approximately 7%, 9% and 10% of the Company's total revenues for 2019, 2018 and 2017, respectively.

[3] Ascend Technology sells our products to a limited number of customers. one of those customers - Cisco Systems, Inc. ("Cisco") - accounted for 10%, 8% and 6% of our total revenues for the years ended December 31, 2019, 2018 and 2017, respectively.