Condensed Consolidated Balance Sheets - Unaudited (Parenthetical) - USD ($)
$ in Thousands
Sep. 30, 2017
Dec. 31, 2016
Statement Of Financial Position [Abstract]    
Allowance for doubtful accounts $ 70 $ 263
Preferred stock, par value $ 0.01 $ 0.01
Preferred stock, shares authorized 10,000,000 10,000,000
Preferred stock, shares issued 0 0
Common stock, par value $ 0.01 $ 0.01
Common stock, shares authorized 100,000,000 100,000,000
Common stock, shares issued 39,451,256 31,626,635
Common stock, shares outstanding 38,635,883 30,881,148
Treasury stock, shares 815,373 745,487