Accounts receivable (Details) (USD $)	Oct. 31, 2012	Apr. 30, 2012
Notes to Financial Statements
Trade receivables	$ 2,774,300	$ 2,620,461
VAT receivable	76,376	184,314
Allowance for doubtful accounts and sales returns	200,000	200,000
Accounts receivable	$ 2,650,676	$ 2,604,775