Note 5 - Concentrations

12 Months Ended

Dec. 31, 2018

Notes to Financial Statements

Concentration Risk Disclosure [Text Block]

5

. Concentrations

Financial instruments that subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents, investments in marketable securities and trade accounts receivable. The Company extends differing levels of credit to customers and does

not

require collateral deposits. As of

December 

31,

2018

and

2017,

the Company has allowance for doubtful accounts of

$1,152

and

$155,

respectively. As of

December 31, 2018

and

2017,

the Company has allowance for distributors’ price discounts of

$1,634

and

$1,292,

respectively.

The following table summarizes the significant customers’ (including distributors) accounts receivable and revenue as a percentage of total accounts receivable and total revenue, respectively:

	December 31,
Accounts Receivable	201 8			201 7
Customer A		13	%		29	%
Customer B		*			14
Customer C		13			13

	Year Ended December 31,
Revenue	201 8			2017			2016
Customer A		18	%		12	%		*
Customer B		11			*			*
Customer C		*			12			13	%

* Less than 10% of total receivable or total revenue

Customer A is a subcontractor of a direct customer that would be a “Customer D” above. In the aggregate, revenue to Customer A and Customer D as a percentage of total revenue was approximately

18%

and

17%

for the year ended

December 31, 2018

and

2017,

respectively. Customer C is a subcontractor of a direct customer that would be a “Customer E” above. In the aggregate, revenue to Customer C and Customer E as a percentage of total revenue was approximately

14%,

14%

and

16%

for the years ended

December 31, 2018,

2017

and

2016,

respectively. In addition, the Company sells directly and indirectly through subcontractors to what would be a “Customer F” above. The Company believes in the aggregate, revenue to Customer F, including its subcontractors as a percentage of total revenue was approximately

11%,

11%

and

12%

for the years ended

December 31, 2018,

2017

and

2016,

respectively.  Customer B is a distributor who sells to various end customers.