Business Segments - Segment Activity (Details)	3 Months Ended
	Jun. 30, 2019 USD ($) segment product	Jul. 01, 2018 USD ($)
Business Segments
Number of reportable segment | segment	2
Number of product categories | product	4
Market unit activity
Revenues	$ 130,729,300	$ 150,919,400
Gross Profit	25,263,500	30,698,100
(Loss) income before provision for income taxes	(3,529,700)	1,562,400
Segments
Market unit activity
Directly allocable expenses	12,585,000	11,890,000
(Loss) income before provision for income taxes	12,679,000	18,808,000
Corporate
Market unit activity
Directly allocable expenses	16,209,000	17,246,000
Public carrier
Market unit activity
Revenues	33,486,000	40,360,000
Gross Profit	4,253,000	5,626,000
Value-added resellers and Integrators
Market unit activity
Revenues	65,194,000	65,547,000
Gross Profit	15,969,000	15,917,000
Retail
Market unit activity
Revenues	32,049,000	45,012,000
Gross Profit	5,042,000	9,155,000
Commercial Segment
Market unit activity
Revenues	98,680,000	105,907,000
Gross Profit	20,222,000	21,543,000
Commercial Segment | Segments
Market unit activity
Directly allocable expenses	9,570,000	8,081,000
(Loss) income before provision for income taxes	10,652,000	13,462,000
Commercial Segment | Public carrier
Market unit activity
Revenues	33,486,000	40,360,000
Gross Profit	4,253,000	5,626,000
Commercial Segment | Value-added resellers and Integrators
Market unit activity
Revenues	65,194,000	65,547,000
Gross Profit	15,969,000	15,917,000
Retail Segment
Market unit activity
Revenues	32,049,000	45,012,000
Gross Profit	5,042,000	9,155,000
Retail Segment | Segments
Market unit activity
Directly allocable expenses	3,015,000	3,809,000
(Loss) income before provision for income taxes	2,027,000	5,346,000
Retail Segment | Retail
Market unit activity
Revenues	32,049,000	45,012,000
Gross Profit	$ 5,042,000	$ 9,155,000