XML 22 R53.htm IDEA: XBRL DOCUMENT

Amortized Cost and Fair Values of Marketable Securities Classified as Available-For-Sale Investments (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Apr. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Marketable securities that have been in a continuous unrealized loss position for 12 months or more	$ 0	$ 0

This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer.

+ References+ Details