Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets
Allowance for doubtful accounts and discounts	$ 1,220	$ 1,220
Stockholders' equity
Preferred stock, no par value	$ 0	$ 0
Preferred stock, shares authorized	2,500	2,500
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, no par value	$ 0	$ 0
Common stock, shares authorized	40,000	40,000
Common stock, shares issued	17,274	17,274
Common stock, shares outstanding	15,773	15,814