Supplemental Schedule of Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Supplemental cash flow information:
Cash paid for interest	$ 0	$ 0
Cash paid for income taxes	0	0
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable	$ 0	$ 192