Note 5 - Property and Equipment (Details) (USD $)	9 Months Ended
Jan. 31, 2014	Jan. 31, 2013
Details
Depreciation expense	$ 1,346,728	$ 1,240,136

Amount of total depreciation expense for property, plant and equipment. Includes production and non-production related depreciation.

No definition available.

Name:	us-gaap_DepreciationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration