CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for doubtful accounts	$ 4,135	$ 2,524
Preferred stock, shares authorized	500	500
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	40,353,000	40,207,000
Common stock, shares outstanding	40,353,000	40,207,000
Treasury stock, at cost	250	0