Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Preferred stock, par value (USD per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares outstanding	0	0
Class A Common Stock [Member]
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares outstanding	23,613,835	23,571,221
Class B common stock [Member]
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized	1,000,000	1,000,000
Common stock, shares outstanding	41	41