7. EQUITY COMPENSATION PLANS (Details 2) (USD $)	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Share based compensation	$ 3,435,000	$ 2,769,000	$ 2,837,000
Cost of contract manufacturing
Share based compensation	89,000	12,000	8,000
Research and development
Share based compensation	1,646,000	1,018,000	1,134,000
Selling, general and administrative
Share based compensation	$ 1,700,000	$ 1,739,000	$ 1,695,000