Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
OTHER PHYSICAL PROPERTY:
Other physical property, accumulated depreciation	$ 299	$ 286
CURRENT ASSETS:
Receivables, reserves	$ 358	$ 325
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)	12,882,094	12,830,521
Common stock, outstanding (in shares)	12,882,094	12,830,521
Preferred stock, authorized (in shares)	500,000	500,000
Preferred stock, issued (in shares)	0	0