Note 4 - Supplementary Cash Flow Information - Supplementary Cash Flow Elements (Details) - USD ($) $ in Thousands	3 Months Ended
Jul. 31, 2018	Jul. 31, 2017	Apr. 30, 2018	Apr. 30, 2017
Cash and cash equivalents	$ 4,992	$ 6,309	$ 5,941
Restricted cash	469	469
Total cash, cash equivalents, and restricted cash shown in the Consolidated Condensed Statement of Cash Flows	5,461	6,778	$ 6,410	$ 7,026
State and local income tax payments	102	27
Federal income tax payments to the Parent

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including, but not limited to, disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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