Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Apr. 30, 2014	Apr. 30, 2013
Statement Of Financial Position [Abstract]
Short term investments (in dollars)	$ 5,482	$ 6,312
Allowance for doubtful accounts (in dollars)	$ 39	$ 17
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	10,000,000	10,000,000
Treasury stock, shares	182,071	123,572