Note 7 - Deferred Credits Payable (Details Textual)	Oct. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2001 USD ($) T Rate
Customer Advances or Deposits, Noncurrent \| $	$ 600,000	$ 600,000	$ 600,000
Deferred Credits Payable Option Details \| T			500,000
Deferred Credits Payable Market Discount Rate			30.00%
Deferred Credits Payable Market Liquidated Damages Rate			30.00%

Aggregate noncurrent portion of prepayments received from customers for goods or services to be provided in the future, as well as the current portion of money or property received from customers that is to be returned upon satisfactory contract completion or as partial prepayment for goods or services to be provided in the future.

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 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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