Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares, issued	44,444,230	31,374,002
Common stock, shares outstanding	44,362,748	31,292,520