CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($)	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Common Stock
Stock Issuance costs	$ 677,000	$ 513,000	$ 1,504,000
Series E Preferred Stock [Member]
Stock Issuance costs	$ 1,000	$ 1,002,000	$ 1,458,000