Note 5 - Stockholders' Equity (Details) - Stock Options Valuation Assumptions	3 Months Ended
	Jul. 31, 2013	Jul. 31, 2012
Minimum [Member]
Note 5 - Stockholders' Equity (Details) - Stock Options Valuation Assumptions [Line Items]
Risk-free interest rate	2.97%	2.97%
Expected life, in years	6 years	6 years
Expected volatility	82.59%	65.52%
Dividend yield	0.00%	0.00%
Forfeiture rate	11.40%	9.70%
Maximum [Member]
Note 5 - Stockholders' Equity (Details) - Stock Options Valuation Assumptions [Line Items]
Expected volatility	82.61%	78.85%