Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares shares in Thousands	Jun. 30, 2016	Dec. 31, 2015
Stockholders’ equity:
Preferred stock designated Series A, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock designated Series A, shares authorized	10,000	10,000
Preferred stock designated Series A, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000	500,000
Common stock, shares issued	282,902	282,724
Common stock, shares outstanding	237,141	237,005
Treasury stock, shares	45,761	45,719