Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Trade and other accounts receivable, allowance for doubtful accounts	$ 36	$ 26
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	37,199,519	32,135,029
Common stock, shares outstanding	37,199,519	32,135,029