CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Parenthetical [Abstract]
Allowance for doubtful accounts	$ 100	$ 100
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares issued (in shares)	5,791,000	5,817,000
Common stock, shares outstanding (in shares)	5,791,000	5,817,000