Marketable Securities (Tables)

6 Months Ended

Apr. 30, 2012

Investments, Debt and Equity Securities [Abstract]

Short-term and long-term investments

As of the dates indicated, short-term and long-term investments are comprised of the following (in thousands):

	April 30, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. government obligations	$	49,960	$	206	$	—	$	50,166
Included in short-term investments	$	49,960	$	206	$	—	$	50,166

	October 31, 2011
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. government obligations	$	49,933	$	331	$	—	$	50,264
Included in long-term investments	$	49,933	$	331	$	—	$	50,264

Legal maturities of debt investments

The following table summarizes final legal maturities of debt investments at April 30, 2012 (in thousands):

	Amortized Cost		Estimated Fair Value
Less than one year	$	49,960	$	50,166
Due in 1-2 years	—		—
	$	49,960	$	50,166