Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts receivable-trade, allowance	$ 97	$ 135
Inventories, allowance	77	78
Redeemable convertible preferred stock, Series A, discount	$ 547	$ 562
Redeemable convertible preferred stock, par value	$ 0.001	$ 0.001
Redeemable convertible preferred stock, shares authorized	1,000,000	1,000,000
Redeemable convertible preferred stock, shares issued	1,000,000	1,000,000
Redeemable convertible preferred stock, shares outstanding	1,000,000	1,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	8,945,404	8,850,532
Common stock, shares outstanding	8,751,429	8,669,650
Treasury stock, shares	193,975	180,882
Equity Method Investments
Accumulated Deficit; accumulated statutory reserves in equity method investments	$ 2,809	$ 2,809