Note 8 - Federal, State and Local Income Taxes - Effective Income Tax Rate Reconciliation (Details) (Parentheticals)	4 Months Ended	9 Months Ended	12 Months Ended
Apr. 30, 2018	Jan. 31, 2018	Jan. 31, 2017	Apr. 30, 2019	Apr. 30, 2018
U.S. statutory federal tax rate		30.33%	35.00%
Scenario, Forecast [Member]
U.S. statutory federal tax rate	21.00%			21.00%	30.33%

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

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