Consolidated Balance Sheets Parentheticals - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value per share	$ 0.001	$ 0.001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	50,639,926	50,476,042
Common stock, shares outstanding	50,639,926	50,476,042
Treasury stock, shares	1,729,408	1,729,408