Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) (USD $) In Thousands, except Per Share data	Apr. 30, 2011	Jan. 31, 2011	Apr. 30, 2010
Current assets:
Allowance for sales returns and doubtful accounts receivable, current	$ 12,450	$ 11,783	$ 11,482
Stockholders' equity:
Preferred Stock, par value	$ 0.01	$ 0.01	$ 0.01
Preferred Stock, shares authorized	2,000	2,000	2,000
Preferred Stock, shares issued	0	0	0
Preferred Stock, shares outstanding	0	0	0
Common Stock, par value	$ 0.01	$ 0.01	$ 0.01
Common Stock, shares authorized	240,000	240,000	240,000
Common Stock, shares issued	127,713	126,969	127,208
Common Stock, shares outstanding	127,713	126,969	127,208