Note 9 - Warranty (Details)	3 Months Ended
Jul. 31, 2013
Product Warranties Disclosures [Abstract]
Standard Product Warranty Description	The Company provides a limited warranty for a period of one year from the date of a customer's receipt of its products, or one year from the installation date for some of its products, and will also provide an extended warranty for additional purchase price to the customer.The Company's standard warranties require the Company to repair or replace defective products at no cost to the customer or refund the customer's purchase price.

Describes the nature of the product warranty, including the approximate term of the product warranty, how the product warranty arose, and the events or circumstances that would require the warrantor to perform under the product warranty.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration