CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts receivable, allowances	$ 270	$ 387
Debt instrument unamortized discount and debt issuance costs, current	$ 60	$ 25
Preferred stock, par value	$ 0.001
Preferred stock, shares authorized	10,000,000
Preferred stock, outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	17,931,000	17,004,000
Common stock, shares outstanding	16,786,000	15,967,000
Treasury stock, shares	1,145,000	1,047,000
Series B 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