Note N - Segment Information (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Number of Reportable Segments			3
Product Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Home [Member] | Telephony [Member]
Concentration Risk, Percentage	40.00%	42.00%	39.00%	47.00%
Product Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Home [Member] | Smart Home [Member]
Concentration Risk, Percentage	12.00%	12.00%	13.00%	13.00%
Product Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Office [Member] | VoIP [Member]
Concentration Risk, Percentage	32.00%	37.00%	32.00%	33.00%
Product Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | SmartVoice [Member] | HDClear [Member]
Concentration Risk, Percentage	16.00%	9.00%	16.00%	7.00%