Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000	5,000,000
Common stock, par value	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	75,000,000	75,000,000	75,000,000
Common stock, shares issued	25,872,480	25,638,862	25,466,252