Note 8 - Segment Reporting (Detail) - Segment Reporting (USD $)	3 Months Ended		6 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012	Apr. 30, 2012
Total sales	$ 7,458,000	$ 5,218,000	$ 7,458,000	$ 5,218,000	$ 17,853,000	$ 17,024,000
Segment gross margin	2,803,000	1,990,000			6,603,000	6,091,000
Goodwill	1,942,000	1,942,000	1,942,000	1,942,000	1,942,000	1,942,000	1,942,000
Electronic Manufacturing Services [Member]
Total sales	4,424,000	2,665,000			9,968,000	9,748,000
Segment gross margin	1,226,000	723,000			2,574,000	2,346,000
Proprietary Products [Member]
Total sales	3,034,000	2,553,000			7,885,000	7,276,000
Segment gross margin	1,577,000	1,267,000			4,029,000	3,745,000
Goodwill	$ 1,942,000	$ 1,942,000	$ 1,942,000	$ 1,942,000	$ 1,942,000	$ 1,942,000