CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounts receivable, allowances	$ 361	$ 299
Debt instrument debt issuance costs, current	$ 235	$ 41
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	19,320,000	18,209,000
Common stock, shares outstanding	17,966,000	16,986,000
Treasury stock, shares	1,354,000	1,223,000
Series B convertible preferred stock
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, issued	5,000,000	5,000,000
Preferred stock, outstanding	5,000,000	5,000,000