Note 7 - Concentration of Revenue (Tables)

9 Months Ended

Sep. 30, 2017

Notes Tables

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	Three Months Ended September 30,						Nine Months Ended September 30,
	201 7			2016			2017			2016
Customer A		15.4	%		10.5	%		10.1	%		15.2	%
Customer B		14.3	%		7.3	%		11.6	%		4.6	%
Customer C		13.1	%		8.0	%		11.8	%		10.4	%
Customer D		7.3	%		43.4	%		27.4	%		27.8	%