Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares
Sep. 30, 2016
Dec. 31, 2015
Statement of Financial Position [Abstract]    
Preferred stock, par value (in dollars per share) $ 0.001 $ 0.001
Preferred stock, authorized (in shares) 5,000,000 5,000,000
Preferred stock, issued (in shares) 0 0
Preferred stock, outstanding (in shares) 0 0
Common stock, par value (in dollars per share) $ 0.001 $ 0.001
Common stock, authorized (in shares) 100,000,000 100,000,000
Common stock, issued (in shares) 57,418,432 56,954,830
Common stock, outstanding (in shares) 57,418,432 56,954,830