Organization and Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2014	Apr. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 5,482	$ 6,312
Securities available-for-sale	9,226	6,682
Investments, fair value disclosure	14,708	12,994
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	5,482	6,312
Securities available-for-sale	9,226	6,682
Investments, fair value disclosure	14,708	12,994
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents
Securities available-for-sale
Investments, fair value disclosure
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents
Securities available-for-sale
Investments, fair value disclosure