Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets
Allowance for doubtful accounts	$ 333	$ 214
Stockholders' equity
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	8,000,000	8,000,000
Common stock, shares issued	5,224,911	5,223,245
Common stock, shares outstanding	5,164,324	5,112,825
Treasury shares	40,920	40,920