Note 16 - Fair Value Disclosures - Fair Value of Financial Instruments (Details) - USD ($)	Sep. 30, 2020	Sep. 30, 2019
Reported Value Measurement [Member]
Cash and cash equivalents	$ 252	$ 3,757
Other receivables	279,866	424,110
Note receivable - related party	44,859	44,859
Ukraine, LLC - related party	1,170,328	1,065,328
Loans payable	10,113,634	10,121,411
Loans payable – related parties	1,361,618	1,362,600
Patent acquisition liability	720,000	720,000
Convertible notes payable	6,721,010	6,224,325
Convertible notes payable – related parties	2,558,681	2,558,681
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	252	3,757
Other receivables	279,866	424,110
Note receivable - related party	44,859	44,859
Ukraine, LLC - related party	1,170,328	1,065,328
Loans payable	10,113,634	10,121,411
Loans payable – related parties
Patent acquisition liability	720,000	720,000
Convertible notes payable	7,660,811	6,918,486
Convertible notes payable – related parties
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents
Other receivables
Note receivable - related party
Ukraine, LLC - related party
Loans payable
Loans payable – related parties
Patent acquisition liability
Convertible notes payable
Convertible notes payable – related parties
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	252	3,757
Other receivables
Note receivable - related party
Ukraine, LLC - related party
Loans payable
Loans payable – related parties
Patent acquisition liability
Convertible notes payable
Convertible notes payable – related parties
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents
Other receivables	279,866	424,110
Note receivable - related party	44,859	44,859
Ukraine, LLC - related party	1,170,328	1,065,328
Loans payable	10,113,634	10,121,411
Loans payable – related parties
Patent acquisition liability	720,000	720,000
Convertible notes payable	7,660,811	6,918,486
Convertible notes payable – related parties

Fair value portion of advances to subsidiary.

No definition available.

Name:	cenb_AdvancesToSubsidiaryFairValuedisclosure
Namespace Prefix:	cenb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of convertible debt payable to related party.

+ References

No definition available.

+ Details

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Namespace Prefix:	cenb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of loans payable to related party.

+ References

No definition available.

+ Details

Name:	cenb_LoansPayableRelatedPartyFairValueDisclosure
Namespace Prefix:	cenb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of notes receivable from related party.

+ References

No definition available.

+ Details

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Namespace Prefix:	cenb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The fair value amount of patent acquisition liability.

+ References

No definition available.

+ Details

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Namespace Prefix:	cenb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes 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.

+ References

No definition available.

+ Details

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

- Definition

Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.

+ References

No definition available.

+ Details

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

- Definition

Fair value portion of contractual obligation to pay money on demand or on fixed or determinable dates.

+ References

No definition available.

+ Details

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

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

+ Details

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

- Details

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- Details

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- Details

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- Details

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- Details

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