| Cover Page | Oct. 03, 2019 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Oct. 3, 2019 |
| Entity Registrant Name | Ciena Corp |
| Entity File Number | 001-36250 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 23-2725311 |
| Entity Address, Address Line One | 7035 Ridge Road |
| Entity Address, City or Town | Hanover |
| Entity Address, State or Province | MD |
| Entity Address, Postal Zip Code | 21076 |
| City Area Code | 410 |
| Local Phone Number | 694-5700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $0.01 par value |
| Trading Symbol | CIEN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000936395 |
| Amendment Flag | false |
