Note N - Segment Information (Details Textual)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Number of Reportable Segments			3
Product Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Home [Member] | Telephony [Member]
Concentration Risk, Percentage	39.00%	48.00%	38.00%	49.00%
Product Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Home [Member] | Smart Home [Member]
Concentration Risk, Percentage	13.00%	12.00%	14.00%	13.00%
Product Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Office [Member] | VoIP [Member]
Concentration Risk, Percentage	30.00%	32.00%	32.00%	31.00%
Product Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | SmartVoice [Member] | HDClear [Member]
Concentration Risk, Percentage	18.00%	7.00%	17.00%	6.00%