Accounts Receivable (Tables)

12 Months Ended

Oct. 31, 2019

Receivables [Abstract]

Activity in allowance for doubtful accounts

The following table summarizes the activity in Ciena’s allowance for doubtful accounts for the fiscal years indicated (in thousands):

Year ended	Beginning				Net		Ending
October 31,	Balance		Provisions		Deductions		Balance
2017	$	3,963	$	18,221	$	4,604	$	17,580
2018	$	17,580	$	2,700	$	2,902	$	17,378
2019	$	17,378	$	6,740	$	4,017	$	20,101