Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,883	$ 1,883
Common stock, par value
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	24,222,000	24,182,000
Common Stock, shares outstanding	24,222,000	24,182,000