CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Redeemable Convertible Preferred Stock, shares outstanding	22,000	22,000
Redeemable Convertible Preferred Stock, liquidation preference	$ 22,000	$ 22,000
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized	200,000,000	200,000,000
Common Stock, shares issued	18,709,078	18,596,774
Common Stock, shares outstanding	16,338,914	16,726,610
Treasury Stock, shares at cost	2,370,164	1,870,164
Redeemable Convertible Preferred Stock [Member]
Redeemable Convertible Preferred Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Redeemable Convertible Preferred Stock, shares authorized	100,000,000	100,000,000
Redeemable Convertible Preferred Stock, shares outstanding	10,552,941	10,552,941
Redeemable Convertible Preferred Stock, liquidation preference	$ 51,170	$ 51,170