We operate in one reportable industry segment: developing and manufacturing products primarily for medical applications and have no foreign operating subsidiaries.  We have other product lines which include pressure relief valves and inflation systems, which are sold primarily to the aviation and marine industries. Due to the similarities in product technologies and manufacturing processes, these products are managed as part of our medical products segment. Our revenues from sales to customers outside the United States totaled approximately 35 percent of our net revenues in 2015, and 42 percent in each of 2014 and 2013.  In 2015, we saw a shift in the percentage of our international sales that was driven in large part by a customer's decision to build its new facility in the United States. We have no assets located outside the United States.

A summary of revenues by geographic area, based on shipping destination, for 2015, 2014 and 2013 is as follows (in thousands):

A summary of revenues by product line for 2015, 2014 and 2013 is as follows (in thousands):