Fair Value Measurements (Details 1) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Oct. 31, 2011	Oct. 31, 2010
Level 1 [Member]
Assets are presented on Ciena's Condensed Consolidated Balance Sheet
Prepaid expenses and other		$ 0
Long-term investments	50,264
Other long-term assets	0	0
Total assets measured at fair value	50,264	0
Level 2 [Member]
Assets are presented on Ciena's Condensed Consolidated Balance Sheet
Prepaid expenses and other		0
Long-term investments	0
Other long-term assets	0	0
Total assets measured at fair value	0	0
Level 3 [Member]
Assets are presented on Ciena's Condensed Consolidated Balance Sheet
Prepaid expenses and other		30,195
Long-term investments	0
Other long-term assets	7,020	4,220
Total assets measured at fair value	7,020	34,415
Total [Member]
Assets are presented on Ciena's Condensed Consolidated Balance Sheet
Prepaid expenses and other		30,195
Long-term investments	50,264
Other long-term assets	7,020	4,220
Total assets measured at fair value	$ 57,284	$ 34,415