4. INTANGIBLE ASSETS (Details) (USD $)	Oct. 31, 2013	Apr. 30, 2013
Value Assigned	$ 1,370,033	$ 1,328,445
Impairments		(27,279)
Accumulated Amortization	(406,223)	(376,468)
Carrying Value (Net of Impairments and Accumulated Amortization)	963,810	924,698
Patents
Value Assigned	674,501	645,918
Weighted Average Amortization Period (in Years)	11 years 1 month 6 days	11 years 2 months 12 days
Impairments		(27,279)
Accumulated Amortization	(273,229)	(258,499)
Carrying Value (Net of Impairments and Accumulated Amortization)	401,272	360,140
License Rights
Value Assigned	589,356	572,370
Weighted Average Amortization Period (in Years)	15 years 1 month 6 days	15 years 7 months 6 days
Impairments
Accumulated Amortization	(132,994)	(117,969)
Carrying Value (Net of Impairments and Accumulated Amortization)	456,362	454,401
Trademarks
Value Assigned	106,176	110,157
Impairments
Accumulated Amortization
Carrying Value (Net of Impairments and Accumulated Amortization)	$ 106,176	$ 110,157