Provision for Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Apr. 30, 2012
Accrued liabilities	$ 89	$ 62
Depreciation and amortization	51	80
State taxes	7	5
Stock-based compensation expense	3,582	2,685
Capitalized research and development costs	688	798
Foreign net operating loss carry-forward	365	265
Net operating loss carry-forward	4,144	2,478
Total deferred tax assets	8,926	6,373
Less: Valuation allowance	(8,926)	(6,373)
Net deferred tax asset	$ 0	$ 0