Debt Instrument, Convertible, Threshold Cash Settlement

No definition available.

Name:	cien_DebtInstrumentConvertibleThresholdCashSettlement
Namespace Prefix:	cien_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Repayments of Convertible Debt, Embedded Derivative

+ References

No definition available.

+ Details

Name:	cien_RepaymentsofConvertibleDebtEmbeddedDerivative
Namespace Prefix:	cien_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Stock Issued During Period, Shares, Conversion of Convertible Securities, Embedded Derivative

+ References

No definition available.

+ Details

Name:	cien_StockIssuedDuringPeriodSharesConversionofConvertibleSecuritiesEmbeddedDerivative
Namespace Prefix:	cien_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as a liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=cien_NewNotesThreePointSevenFivePercentConvertibleSeniorNotesDue2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleNotesPayableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Accrued Liabilities and Other Short-Term Obligations - Narrative (Details) - USD ($) shares in Millions		6 Months Ended
	Nov. 15, 2018	Apr. 30, 2019	Apr. 30, 2018	Oct. 31, 2018	Aug. 30, 2018
Debt Instrument [Line Items]
Debt conversion liability		$ 0		$ 164,212,000
Payment for debt conversion liability		$ 111,268,000	$ 0
3.75% Convertible Senior Notes due October 15, 2018 (New)
Debt Instrument [Line Items]
Interest rate on convertible notes (as a percent)				3.75%
Convertible notes payable \| 3.75% Convertible Senior Notes due October 15, 2018 (New)
Debt Instrument [Line Items]
Interest rate on convertible notes (as a percent)					3.75%
Maximum cash settlement					$ 400,000,000
Debt conversion liability					$ 164,200,000
Payment for debt conversion liability	$ 111,300,000
Shares issued for debt conversion liability (in shares)	1.6