CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts receivable, allowances	$ 387	$ 306
Debt instrument unamortized discount and debt issuance costs, current	25	404
Debt instrument unamortized discount and debt issuance costs, non-current	$ 0	$ 582
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	17,004,000	15,341,000
Common stock, shares outstanding	15,967,000	14,436,000
Treasury stock, shares	1,047,000	905,000
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	3,000,000
Preferred stock, outstanding	5,000,000	3,000,000