Note 2 - Cash, Cash Equivalents and Short-term Investments
 3 Months Ended
Nov. 30, 2011
Cash and Cash Equivalents Disclosure [Text Block]
Note 2 — Cash, Cash Equivalents and Short-term Investments

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.

Foreign government and foreign government guaranteed securities – We invest in foreign government and foreign government guaranteed securities that are publicly traded and valued.

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. Losses in this category are due primarily to market liquidity.

At November 30, 2011, 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
  $ 514,815     $ —     $ —     $ 514,815     $ 514,815     $ —  
Money market mutual funds
    122,231       —       —       122,231       122,231       —  
Certificates of deposit
    205,611       —       —       205,611       —       205,611  
Available-for-sale securities:
                                               
Bond mutual funds
    20,000       36       —       20,036       —       20,036  
Corporate bonds
    12,095       5       (144 )     11,956       —       11,956  
Trading securities:
                                               
Equity investments
    4,998       —       (7 )     4,991       —       4,991  
Total
  $ 879,750     $ 41     $ (151 )   $ 879,640     $ 637,046     $ 242,594  

At August 31, 2011, the components of our cash, cash equivalents, and short-term investments were as follows (in thousands):

   
Cost
Basis
   
Unrealized
Gain
   
Unrealized (Loss)
   
Recorded
Basis
   
Cash and Cash Equivalents
   
Short-term
Investments
 
                                     
Cash
  $ 653,979     $ —     $ —     $ 653,979     $ 653,979     $ —  
Money market mutual funds
    17,350       —       —       17,350       17,350       —  
Certificates of deposit
    211,910       —       —       211,910       2,751       209,159  
Available-for-sale securities:
                                               
Corporate bonds
    17,853       40       (116 )     17,777       —       17,777  
Total
  $ 901,092     $ 40     $ (116 )   $ 901,016     $ 674,080     $ 226,936  

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, 2011 and 2010, the proceeds and realized gains and losses were as follows (in thousands):

   
2011
   
2010
 
Proceeds
  $ 5,617     $ 25,624  
Realized gains
  $ 1     $ 73  
Realized losses
  $ —     $ —  

There were no transfers of securities between available for sale and trading classifications during the three months ending November 30, 2011.

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, 2011 or 2010.

Gross unrealized losses on investment securities and the fair value of those securities that have been in a continuous loss position for which we have not recognized an impairment charge at November 30, 2011, were as follows (in thousands):

   
Less than 12 Months
 
   
Fair
Value
   
Unrealized
Loss
 
Available-for-sale:
           
Corporate bonds
    1,874       (29 )
Total
  $ 1,874     $ (29 )

At November 30, 2011, maturities of debt securities classified as available-for-sale were as follows (in thousands):

   
Cost
Basis
   
Estimated
Fair Value
 
Due in one year or less
  $ 12,095     $ 11,956  
Due in one to two years
    —       —  
Total
  $ 12,095     $ 11,956