Other Income (Expenses) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Component of Other Income, Nonoperating [Line Items]
Other income (expenses), net	$ (234)	$ (68)	$ 8
Interest Income [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expenses), net	7	11	7
Foreign Currency Loss [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expenses), net	(241)	(80)	(151)
Other [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expenses), net		$ 1	$ 152