Severance and Reorganization (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	9 Months Ended
	Jan. 31, 2013	Jan. 31, 2013	Jan. 31, 2013
Reorganization Items [Line Items]
One-time severance and reorganization charge	$ 1,636	$ 1,793	$ 3,463
Liability associated with severance and reorganization	$ 1,111	$ 1,111	$ 1,111