Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Preferred stock, par value (USD per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	36,658,510	36,135,542
Common stock, shares outstanding	36,658,510	36,135,542