CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2012	Dec. 31, 2011
CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	91,220,944	90,818,248
Common stock, shares outstanding	91,220,944	90,818,248