Condensed Balance Sheets (Parenthetical) (USD $)
Dec. 31, 2014
Dec. 31, 2013
Condensed Balance Sheets    
Preferred stock, par value (in dollars per share) $ 0.001 $ 0.001
Preferred stock, shares authorized 5,000,000 5,000,000
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 120,000,000 120,000,000
Common stock, shares issued 20,352,876 15,357,413
Common stock, shares outstanding 20,343,325 15,340,710