Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	15,000,000	15,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	35,850,658	35,011,423
Common stock, shares outstanding (in shares)	35,850,658	35,011,423