Segments and Geographic Information

12 Months Ended

Dec. 31, 2017

Effective January 1, 2014, the Company was structured as a single operating (and reportable) segment, a critical communication business. The Chief Executive Officer (who is also the chief operating decision maker as defined by ASC 280) views the business as one operation and assesses performance and allocates resources on the basis of consolidated operations.

The U.S. was the only country that accounted for more than 10% of the Company's total revenue for the years ended December 31, 2017, 2016 and 2015. Revenue by geographic region consisted of the following for the periods stated:



	December 31,
(Dollars in thousands)	2017		2016		2015
Revenue
United States	$	166,790	$	173,852	$	185,741
International	4,385		5,709		3,887
Total revenue	$	171,175	$	179,561	$	189,628

An immaterial amount of long-lived assets were held outside of the United States for the years ended December 31, 2017, 2016 and 2015.