Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
OTHER PHYSICAL PROPERTY:
Other physical property, accumulated depreciation	$ 226	$ 219
CURRENT ASSETS:
Receivables, reserves	$ 315	$ 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)	12,950,755	12,918,633
Common stock, outstanding (in shares)	12,950,755	12,918,633
Preferred stock, authorized (in shares)	500,000	500,000
Preferred stock, issued (in shares)	0	0