Note 18 - Subsequent Event (Details Textual) - USD ($)		12 Months Ended
May 16, 2019	Dec. 31, 2017
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Subsequent Event [Member] \| Vice President and Chief Financial Officer [Member]
Employment Agreement, Compensation, Shares of Common Stock	1,250,000
Employment Agreement, Base Annual Salary	$ 31,200
Subsequent Event [Member] \| Vice President and Chief Financial Officer [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Employment Agreement, Compensation, Shares of Restricted Stock	350,000
Subsequent Event [Member] \| Vice President and Chief Financial Officer [Member] \| Share-based Payment Arrangement, Tranche Two [Member]
Employment Agreement, Compensation, Shares of Restricted Stock	900,000
Subsequent Event [Member] \| Vice President and Chief Financial Officer [Member] \| Share-based Payment Arrangement, Tranche Two [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Subsequent Event [Member] \| Vice President and Chief Financial Officer [Member] \| Vesting One Month After Grant [Member]
Employment Agreement, Compensation, Shares of Restricted Stock	25,000
Subsequent Event [Member] \| Vice President and Chief Financial Officer [Member] \| Vesting One Month After Grant [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	30 days
Subsequent Event [Member] \| Vice President and Chief Financial Officer [Member] \| Vesting at The End of Each One Month Anniversary of rant Date [Member]
Employment Agreement, Compensation, Shares of Restricted Stock	25,000

The base annual salary pursuant to the employment agreement.

No definition available.

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

- Definition

The number of common shares issued to the employee as compensation for service pursuant to the employment agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	cenb_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares would issue to the employee as compensation for service pursuant to the employment agreement.

+ References

No definition available.

+ Details

Name:	cenb_EmploymentAgreementCompensationSharesOfRestrictedStock
Namespace Prefix:	cenb_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ 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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- Details

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- Details

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- Details

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