Note M - Segment Information (Details Textual)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Number of Reportable Segments			3
Product Concentration Risk [Member] | Sales Revenue, Segment [Member] | Home [Member] | Telephony [Member]
Concentration Risk, Percentage	48.00%	53.00%	49.00%	56.00%
Product Concentration Risk [Member] | Sales Revenue, Segment [Member] | Home [Member] | Smart Home [Member]
Concentration Risk, Percentage	12.00%	17.00%	13.00%	16.00%
Product Concentration Risk [Member] | Sales Revenue, Segment [Member] | Office [Member] | VoIP [Member]
Concentration Risk, Percentage	32.00%	28.00%	31.00%	26.00%
Product Concentration Risk [Member] | Sales Revenue, Net [Member] | SmartVoice [Member] | HDClear [Member]
Concentration Risk, Percentage	7.00%	3.00%	6.00%	2.00%