Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
ASSETS
Other physical property, accumulated depreciation	$ 365	$ 353
CURRENT ASSETS:
Accounts receivables, reserves	$ 325	$ 305
COMMON STOCKHOLDERS' EQUITY:
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, authorized (in shares)	46,500,000	46,500,000
Common stock, issued (in shares)	12,845,989	12,852,295
Common stock, outstanding (in shares)	12,845,989	12,852,295
Preferred stock, authorized (in shares)	500,000	500,000
Preferred stock, issued (in shares)	0	0