Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Allowances on accounts receivable	$ 8,252	$ 5,897
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock authorized	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	150,000	150,000
Common stock, shares issued	116,257	112,360
Common stock, shares outstanding	116,257	112,360