Short-term and Long-term Investments (Tables)

9 Months Ended

Jul. 31, 2015

Investments, Debt and Equity Securities [Abstract]

Short-term and long-term investments

As of the dates indicated, investments are comprised of the following (in thousands):

	July 31, 2015
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. government obligations:
Included in short-term investments	$	105,041	$	44	—		$	105,085
Included in long-term investments	70,149		12		—		70,161
	$	175,190	$	56	$	—	$	175,246
Commercial paper:
Included in short-term investments	54,982		—		—		54,982
	$	54,982	$	—	$	—	$	54,982

	October 31, 2014
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. government obligations:
Included in short-term investments	$	110,182	$	29	$	—	$	110,211
Included in long-term investments	50,016		41		—		50,057
	$	160,198	$	70	$	—	$	160,268
Commercial paper:
Included in short-term investments	29,994		—		—		29,994
	$	29,994	$	—	$	—	$	29,994

Legal maturities of debt investments

The following table summarizes the final legal maturities of debt investments at July 31, 2015 (in thousands):

	Amortized Cost		Estimated Fair Value
Less than one year	$	160,023	$	160,067
Due in 1-2 years	70,149		70,161
	$	230,172	$	230,228