Restructuring Expenses and Provision for Settlement (Detail Textuals) (USD $)	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring transaction			$ 3,764,000
Value line funds
Restructuring Cost and Reserve [Line Items]
Restructuring transaction			3,764,000
Fair fund administration and other cost settlement amount			1,767,000
Payment to administrator of fair fund	32,000	1,189,000	2,783,000
Outstanding provision for settlement reflected as liability	$ 243,000