ACCOUNTS RECEIVABLE	6 Months Ended
ACCOUNTS RECEIVABLE	Apr. 30, 2016
Receivables [Abstract]
ACCOUNTS RECEIVABLE	ACCOUNTS RECEIVABLE As of April 30, 2016 and October 31, 2015, one customer accounted for 11.2% and 10.4% of Ciena's net accounts receivable, respectively. Ciena has not historically experienced a significant amount of bad debt expense. Allowance for doubtful accounts was $3.4 million and $3.0 million as of April 30, 2016 and October 31, 2015, respectively.

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.