CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Restricted cash	$ 200	$ 243
Allowance for doubtful accounts	$ 609	$ 617
Stockholders' equity:
Preferred Stock, par or stated value per share (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred Stock, shares issued (in shares)	0	0
Common Stock, par or stated value per share (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (in shares)	30,000,000	30,000,000
Common Stock, shares issued (in shares)	12,226,782	12,037,966
Treasury stock, shares (in shares)	3,347,020	3,293,223