Consolidated Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jan. 31, 2025	Apr. 30, 2024
Short-Term Investments	$ 26,005	$ 4,136
Accounts Receivable, Allowance for Credit Loss, Current	$ 16	$ 31
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.1	$ 0.1
Common Stock, Shares Authorized (in shares)	30,000,000	30,000,000
Common Stock, Shares, Issued (in shares)	10,000,000	10,000,000
Treasury Stock, Common, Shares (in shares)	584,036	577,517