Quarterly report pursuant to Section 13 or 15(d)

Composition of Certain Financial Statement Captions (Details 2)

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Composition of Certain Financial Statement Captions (Details 2) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Apr. 30, 2013
item
Jan. 31, 2013
Available-for-sale securities    
Adjusted Cost $ 56,315 $ 66,272
Unrealized Losses (1) (3)
Fair Value 56,314 66,269
Number of owned securities that were in an unrealized loss position 4  
Portion of the unrealized losses deemed to be other-than-temporary 0  
Available-for-sale securities having an unrealized loss position for 12 months or more 0  
Money market funds
   
Available-for-sale securities    
Adjusted Cost 28,080 32,522
Fair Value 28,080 32,522
Commercial paper
   
Available-for-sale securities    
Adjusted Cost 21,845 24,093
Unrealized Losses   (1)
Fair Value 21,845 24,092
Corporate debt securities
   
Available-for-sale securities    
Adjusted Cost 6,390 9,657
Unrealized Losses (1) (2)
Fair Value $ 6,389 $ 9,655