Nature of Business and Summary of Significant Accounting Policies - Schedule of Property and Equipment (Details) - USD ($)	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018
Total	$ 5,084,000	$ 4,955,000
Accumulated depreciation	(4,100,000)	(3,879,000)
Net	984,000	1,076,000
Dies, Jigs, and Molds [Member]
Total	$ 1,808,000	1,808,000
Dies, Jigs, and Molds [Member] | Minimum [Member]
Useful Life in Years	3 years
Dies, Jigs, and Molds [Member] | Maximum [Member]
Useful Life in Years	7 years
Machinery and Equipment [Member]
Total	$ 1,533,000	1,414,000
Machinery and Equipment [Member] | Minimum [Member]
Useful Life in Years	5 years
Machinery and Equipment [Member] | Maximum [Member]
Useful Life in Years	10 years
Furniture and Fixtures [Member]
Total	$ 142,000	145,000
Furniture and Fixtures [Member] | Minimum [Member]
Useful Life in Years	5 years
Furniture and Fixtures [Member] | Maximum [Member]
Useful Life in Years	10 years
Leasehold Improvements [Member]
Total	$ 256,000	250,000
Leasehold Improvements [Member] | Minimum [Member]
Useful Life in Years	5 years
Leasehold Improvements [Member] | Maximum [Member]
Useful Life in Years	32 years
Buildings [Member]
Total	$ 853,000	853,000
Buildings [Member] | Minimum [Member]
Useful Life in Years	20 years
Buildings [Member] | Maximum [Member]
Useful Life in Years	39 years
Automotive [Member]
Total	$ 89,000	90,000
Automotive [Member] | Minimum [Member]
Useful Life in Years	3 years
Automotive [Member] | Maximum [Member]
Useful Life in Years	5 years
Software [Member]
Total	$ 390,000	382,000
Software [Member] | Minimum [Member]
Useful Life in Years	2 years
Software [Member] | Maximum [Member]
Useful Life in Years	5 years
Land [Member]
Total	$ 13,000	$ 13,000
Useful Life in Years	0 years