Note 5 - Accrued Expenses - Level 3 Transactions (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Apr. 30, 2021	Jan. 31, 2021	Oct. 31, 2020
Beginning balance	$ 296	$ 370	$ 1,249
Change in value	(296)	(74)	(879)
Ending balance	$ 0	$ 296	$ 370

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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