CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Accounts receivable, allowances for doubtful accounts	$ 659	$ 776
Class A common stock
Common Stock, par value	$ 0.0001	$ 0.0001
Common Stock, Authorized	139,500	139,500
Common Stock, Issued	54,923	43,783
Common Stock, outstanding	54,923	43,783
Class B common stock
Common Stock, par value	$ 0.0001	$ 0.0001
Common Stock, Authorized	40,500	40,500
Common Stock, Issued	11,113	20,961
Common Stock, outstanding	11,113	20,961