Impairment and Restructuring Charges (Narrative) (Details)			1 Months Ended	3 Months Ended		9 Months Ended		21 Months Ended
	Dec. 31, 2018 USD ($) employee	Jun. 01, 2018 employee	Aug. 31, 2018 employee	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets				$ 33,000	$ 200,000	$ 33,000	$ 730,000
Property and equipment, net				8,088,000		8,088,000				$ 9,830,000
Positions eliminated | employee		20	7
Percentage of positions eliminated		20.00%
Cost-Reduction Actions [Member]
Restructuring Cost and Reserve [Line Items]
Positions eliminated | employee	20
Percentage of positions eliminated	30.00%
Severance costs				34,000		206,000
Facility exit costs						28,000
Forecast [Member] | Cost-Reduction Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges incurred								$ 57,000
TeamConnect LLC [Member]
Restructuring Cost and Reserve [Line Items]
Property and equipment, net									$ 72,000
TeamConnect LLC [Member] | Radios And Related Accessories [Member]
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets					200,000		700,000
Property and equipment, net	$ 0				$ 0		$ 0
Property, Plant and Equipment [Member]
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets						22,000
Right Of Use Asset [Member]
Restructuring Cost and Reserve [Line Items]
Impairment of long-lived assets				11,000		11,000
Property and equipment, net				$ 0		$ 0