Note 10 - Accounting for the Costs of Computer Software Developed for Internal Use (Details Textual) - USD ($)	6 Months Ended
Oct. 31, 2019	Oct. 31, 2018
Capitalized Computer Software, Amortization	$ 35,000	$ 79,000
Internal Costs to Develop Software	$ 0	$ 0
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life	3 years
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life	5 years

Amount of expense for amortization of capitalized computer software costs.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 985
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128462-111756

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 985
-SubTopic 20
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128487-111756

Name:	us-gaap_CapitalizedComputerSoftwareAmortization1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration