Long-Term Debt (Narrative) (Details) (USD $)	9 Months Ended	3 Months Ended
	Jan. 31, 2012	Jul. 31, 2011 Hercules Term Loan and Credit Facility [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ (2,166,000)	$ 2,200,000
Unamortized loan costs		1,000,000
Warrant discounts		800,000
Prepayment fees		$ 400,000