CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Accounts receivable allowance	$ 3,701	$ 3,561
STOCKHOLDERS’ EQUITY
Preferred stock, par or stated value (in dollar per share)	$ 0.001	$ 0.001
Preferred stock authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par or stated value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares, issued (in shares)	23,117,000	23,117,000
Common stock, shares, outstanding (in shares)	22,892,000	22,857,000
Treasury stock (in shares)	225,000	260,000