Note 12 - Concentrations

12 Months Ended

Dec. 31, 2018

Notes to Financial Statements

Concentration Risk Disclosure [Text Block]

( 12 ) Concentrations

Most of the Company’s customers are located in the United States. One customer accounted for approximately

29%

of revenue in

2018

and

no

single customer accounted for more than

10%

of revenue in

2017

or

2016.

One customer accounted for

23%

of accounts receivable at

December 31, 2018,

20%

of accounts receivable at

December 31, 2017

and another customer accounted for

29%

of accounts receivable at

December 31, 2016.