Business Segments - Schedule of Financial Information Relating to Industry Segments (Details) - USD ($)	3 Months Ended	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2017	Apr. 30, 2016
Total net revenue	$ 2,710,000	$ 10,904,000	$ 11,240,000
Total income from operations	657,000	2,783,000	3,362,000
Total depreciation and amortization	49,000	187,000	182,000
Total capital expenditures	24,000	170,000	276,000
Total assets	38,464,000	38,464,000	36,668,000
Security Alarm Products [Member]
Total net revenue	2,232,000	6,968,000	8,989,000
Total income from operations	420,000	1,778,000	2,689,000
Total depreciation and amortization	9,000	38,000	16,000
Total capital expenditures	14,000	14,000	24,000
Total assets	3,180,000	3,180,000	4,203,000
Other Products [Member]
Total net revenue	478,000	3,936,000	2,251,000
Total income from operations	237,000	1,005,000	673,000
Total depreciation and amortization	28,000	108,000	123,000
Total capital expenditures	10,000	140,000	33,000
Total assets	1,517,000	1,517,000	1,142,000
Corporate General [Member]
Total depreciation and amortization	12,000	41,000	43,000
Total capital expenditures		16,000	219,000
Total assets	$ 33,767,000	$ 33,767,000	$ 31,323,000