Lease Commitments (Detail Textuals) (USD $)	0 Months Ended	12 Months Ended			167 Months Ended	12 Months Ended	0 Months Ended
	Jun. 04, 1993	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2007	Apr. 30, 2011 General and Administrative Expense	Feb. 07, 2013 Company and Citibank, N.A. (the "Sublandlord") sqft
Operating Leased Assets [Line Items]
Term of lease	15 years
Extended term of lease					5 years
Area of land for lease							44,493
Base rent under the sublease agreement per annum							$ 1,468,269
Security deposit in cash							489,423
Rental expenses		2,509,000	2,509,000	3,862,000
Operating lease exit cost related to relocation		$ 37,000	$ 475,000			$ 914,000