ACCOUNTS RECEIVABLE	3 Months Ended
ACCOUNTS RECEIVABLE	Jan. 31, 2016
Receivables [Abstract]
ACCOUNTS RECEIVABLE	ACCOUNTS RECEIVABLE As of October 31, 2015, there was one customer that accounted for 10.4% of net accounts receivable. As of January 31, 2016, there was one customer that accounted for 13.2% of net accounts receivable. Ciena has not historically experienced a significant amount of bad debt expense. Allowance for doubtful accounts was $3.0 million and $3.2 million as of October 31, 2015 and January 31, 2016, 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.