Note 13 - Restricted Cash and Deposits (Details Textual) - USD ($)	Jan. 31, 2022	Oct. 31, 2021	Apr. 30, 2021
Restricted Investments, Noncurrent	$ 305,000	$ 469,000	$ 469,000
Cash Securing a Letter of Credit Issued as Security Deposit [Member]
Security Deposit	$ 305,000

This element represents the noncurrent portion of investments which are not defined as or included in marketable (debt, equity, or other) securities that are pledged or subject to withdrawal restrictions.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 210
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=120413173&loc=SL6242262-115580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 210
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120413209&loc=SL6242269-115581

Name:	us-gaap_RestrictedInvestmentsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant