Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	30,632,000	27,895,000
Common stock, shares outstanding	27,497,000	25,432,000
Treasury stock, shares	3,135,000	2,463,000
Series A
Preferred stock, shares issued	127,000	127,000
Preferred stock, shares outstanding	127,000	127,000
Series B
Preferred stock, shares issued	555,000	569,000
Preferred stock, shares outstanding	555,000	569,000