Note 2 - Cash, Cash Equivalents and Short-term Investments
 3 Months Ended
Nov. 30, 2012
Cash and Cash Equivalents Disclosure [Text Block]
Note 2 — Cash, Cash Equivalents and Short-term Investments

All short-term investments consist of highly liquid investments which can be promptly converted to cash or cash equivalents, without restriction. Our major types of investments are as follows:

Money market mutual funds – We invest in money market funds that seek to maintain a stable net asset value of $1 per share, while limiting overall exposure to credit, market and liquidity risks.

Certificates of deposit – Certificates of deposit are short-term interest-bearing debt instruments issued by various financial institutions with which we have an established banking relationship.

Bond mutual funds – We invest in publicly traded and valued bond funds.

Corporate bonds – We evaluate our corporate debt securities based on a variety of factors including, but not limited to, the credit rating of the issuer. Our corporate debt securities are publicly traded debt rated at least A/A2 or better by S&P and/or Moody's, respectively, with maturities up to two years at the time of purchase. Any losses in this category are primarily due to market liquidity.

At November 30, 2012, the components of our cash, cash equivalents and short-term investments were as follows (in thousands):

                            Balance Sheet Classifications  
                                     
   
Cost
Basis
   
Unrealized
Gain
   
Unrealized
 (Loss)
   
Recorded
Basis
   
Cash and Cash Equivalents
   
Short-term
Investments
 
                                     
Cash
  $ 799,108     $ —     $ —     $ 799,108     $ 799,107     $ —  
Money market mutual funds
    63,327       —       —       63,327       63,327       —  
Certificates of deposit
    293,200       —       (690 )     292,510       78,997       213,514  
Available-for-sale securities:
                                               
Bond mutual funds
    20,863       —       (237 )     20,626       —       20,626  
Corporate bonds
    21,366       86       (1 )     21,451       —       21,451  
Total
  $ 1,197,864     $ 86     $ (928 )   $ 1,197,022     $ 941,431     $ 255,591  

At August 31, 2012, the components of our cash, cash equivalents and short-term investments were as follows (in thousands):

                           
Balance Sheet Classifications
 
                                     
   
Cost
Basis
   
Unrealized
Gain
   
Unrealized
(Loss)
   
Recorded
Basis
   
Cash and Cash Equivalents
   
Short-term
Investments
 
                                     
Cash
  $ 932,628     $ —     $ —     $ 932,628     $ 932,628     $ —  
Money market mutual funds
    154,982       —       —       154,982       154,982       —  
Certificates of deposit
    257,766       —       —       257,766       4,273       253,493  
Available-for-sale securities:
                                               
Bond mutual funds
    20,734       —       (69 )     20,665       —       20,665  
Corporate bonds
    22,537       46       (9 )     22,574       —       22,574  
Total
  $ 1,388,647     $ 46     $ (78 )   $ 1,388,615     $ 1,091,883     $ 296,732  

Gross realized gains and losses from sales of available-for-sale securities are determined using the specific identification method and are included in other income (expense), net. During the three months ended November 30, 2012 and 2011, the proceeds and realized gains and losses were as follows (in thousands):

   
2012
   
2011
 
Proceeds
  $ 1,010     $ 5,617  
Realized gains
  $ 10     $ 1  
Realized losses
  $  —     $  —  

There were no transfers of securities between available-for-sale and trading classifications during the three months ending November 30, 2012.

We evaluate whether unrealized losses on investments in securities are other-than-temporary, and if we believe the unrealized losses are other-than-temporary, we record an impairment charge. There were no other-than-temporary impairment losses recognized during the three months ended November 30, 2012 or 2011.

At November 30, 2012, maturities of corporate bonds classified as available-for-sale were as follows (in thousands):

   
Cost
Basis
   
Estimated
Fair Value
 
Due in one year or less
  $ 12,144     $ 12,161  
Due in one to two years
    9,222       9,290  
Total
  $ 21,366     $ 21,451