CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Accounts receivable allowance	$ 3,896	$ 3,701
STOCKHOLDERS’ (DEFICIT) EQUITY
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares 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 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)	22,894,000	22,892,000
Treasury stock (in shares)	223,000	225,000