Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Treasury stock, shares	8,215	0
Class A Common Stock [Member]
Common stock, par value	0.0001	0.0001
Common stock, shares authorized	0	25,000,000
Common stock, shares issued	0	20,848,847
Common stock, shares outstanding	0	20,848,847
Class B Common Stock [Member]
Common stock, par value	0.0001	0.0001
Common stock, shares authorized	0	6,500,000
Common stock, shares issued	0	6,009,978
Common stock, shares outstanding	0	6,009,978
Common Stock [Member]
Common stock, par value	0.0001	0.0001
Common stock, shares authorized	240,000,000	0
Common stock, shares issued	61,954,576	0
Common stock, shares outstanding	61,946,361	0
Nonvoting Common Stock [Member]
Common stock, par value	0.0001	0.0001
Common stock, shares authorized	50,000,000	0
Common stock, shares issued	10,576,180	0
Common stock, shares outstanding	10,576,180	0