Condensed Balance Sheets (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 38	$ 0
Fair value of equity-method investment	21,954	24,355
Unamortized debt issuance costs - current		57
Unamortized debt issuance costs - long-term	$ 280	$ 575
Par value (in dollars per share)	$ 0.001	$ 0.001
Shares authorized	18,000	18,000
Shares issued	14,392	14,220
Shares outstanding	11,347	11,406
Treasury stock (in shares)	3,045	2,814