Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets
Allowance for doubtful accounts - trade receivables	$ 24	$ 14
Allowance for doubtful accounts - long-term trade receivables	$ 0	$ 0
Stockholders equity
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, authorized	25,000,000	25,000,000
Common stock, issued	14,581,484	14,394,113
Common stock, outstanding	14,581,484	14,394,113