Patents and trademarks

12 Months Ended

Dec. 31, 2014

Goodwill and Intangible Assets Disclosure [Abstract]

Patents and trademarks

6. Patents and trademarks

Patents and trademarks as shown in the accompanying balance sheets are net of accumulated amortization of $237 and $232 at December 31, 2014 and 2013, respectively. Amortization expense related to all patents was approximately $5 and $5 for the years ended December 31, 2014 and 2013, respectively. Amortization expense of currently held patents is expected to amount to $5 for each of the years ending December 31, 2015 through 2019, respectively.