Marketable Debt Securities

12 Months Ended

Oct. 31, 2011

Investments, Debt and Equity Securities [Abstract]

As of October 31, 2010, Ciena had no investments in marketable debt securities. As of October 31, 2011, long-term investments in marketable debt securities are comprised of the following (in thousands):



	October 31, 2011
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
US government obligations	$	49,933	$	331	$	—	$	50,264
	$	49,933	$	331	$	—	$	50,264

Gross unrealized losses related to marketable debt investments, included in short-term investments at October 31, 2009, were immaterial.

The following table summarizes final legal maturities of debt investments at October 31, 2011 (in thousands):



	Amortized Cost		Estimated Fair Value
Less than one year	$	—	$	—
Due in 1-2 years	49,933		50,264
	$	49,933	$	50,264

- Definition

Tabular disclosure of marketable securities. This may consist of investments in certain debt and equity securities, short-term investments and other assets.

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