14. Product Warranties (Details) - Schedule of Product Warranty Liability (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Schedule of Product Warranty Liability [Abstract]
Balance at beginning of year	$ 778	$ 145
Acquired reserve of FEI-Elcom	0	370
Warranty costs incurred	(324)	(192)
Product warranty accrual	144	455
Balance at end of year	$ 598	$ 778