Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
CURRENT ASSETS:
Allowance for doubtful accounts	$ 48	$ 24
Accumulated amortization	$ 548	$ 548
STOCKHOLDERS' EQUITY:
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0024	$ 0.0024
Common stock, shares authorized (in shares)	25,000,000	25,000,000
Common stock, shares issued (in shares)	10,019,134	9,971,711
Common stock, shares outstanding (in shares)	8,594,758	8,547,335
Treasury stock, shares (in shares)	1,424,376	1,424,376