Customer Deposits (Details) (USD $)			9 Months Ended
Jan. 31, 2013	Apr. 30, 2012	Jan. 31, 2013 Customer Advances [Member]	Jan. 31, 2013 Customer Deposits [Member]
Customer Advances and Deposits [Line Items]
Customer Advances Not Received			$ 1,400,000
Customer Advances Received			1,086,000
Customer Advances, Current			22,000
Customer deposits	$ 887,000	$ 206,000		$ 19,000

The current portion of money or property received from customers which is either to be returned upon satisfactory contract completion or applied to customer receivables in accordance with the terms of the contract or the understandings.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_CustomerDepositsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant