Note M - Segment Information (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Number of Reportable Segments			3
Product Concentration Risk [Member] | Sales Revenue, Segment [Member] | Home [Member] | Telephony [Member]
Concentration Risk, Percentage	42.00%	53.00%	47.00%	55.00%
Product Concentration Risk [Member] | Sales Revenue, Segment [Member] | Home [Member] | Smart Home [Member]
Concentration Risk, Percentage	12.00%	13.00%	13.00%	15.00%
Product Concentration Risk [Member] | Sales Revenue, Segment [Member] | Office [Member] | VoIP [Member]
Concentration Risk, Percentage	37.00%	30.00%	33.00%	27.00%
Product Concentration Risk [Member] | Sales Revenue, Net [Member] | SmartVoice [Member] | HDClear [Member]
Concentration Risk, Percentage	9.00%	4.00%	7.00%	3.00%