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Summary Of Significant Accounting Policies (Tables)
 12 Months Ended
Jan. 31, 2012
Summary Of Significant Accounting Policies [Abstract]  
Schedule Of Allowance For Doubtful Accounts
     Balance at
beginning of
year		      Additions      Deductions     Balance at
end of
year		  

Year ended January 31, 2012

    $ 1,015         3,920         (3,321 )    $ 1,614   

Year ended January 31, 2011

    $ 1,284         2,397         (2,666 )    $ 1,015   

Year ended January 31, 2010

    $ 1,229         1,791         (1,736 )    $ 1,284   
Schedule Of Activity Of Sales Returns Reserve
     Balance at
beginning of
year		      Additions      Deductions     Balance at
end of
year		  

Year ended January 31, 2012

    $ 11,367         41,034         (41,434 )    $ 10,967   

Year ended January 31, 2011

    $ 9,912         41,692         (40,237 )    $ 11,367   

Year ended January 31, 2010

    $ 7,547         33,889         (31,524 )    $ 9,912