NOTE 6. ACCOUNTS RECEIVABLE AND REVENUES

Amounts billed and due from our customers are classified as accounts receivables on our consolidated balance sheets and require payment on a short-term basis. Invoices are generally issued at the point control transfers and substantially all of our invoices are due within 30 days or less, however certain customers have terms of up to 120 days. For substantially all of our contracts, control of the ordered product(s) transfers at our location. Periodically, we require payment prior to the point in time we recognize revenue. Amounts received from customers prior to revenue recognition on a contract are contract liabilities, are classified as customer prepayments liability on our consolidated balance sheets and are typically applied to an invoice within 30 days of the prepayment. Revenues in 2019 include $0.1 million in unearned revenue as of December 31, 2018, and in 2018 include less than $0.1 million in unearned revenue as of January 1, 2018.

Our accounts receivable potentially subject us to significant concentrations of credit risk. Revenues and accounts receivable from significant customers (customers with revenue or accounts receivable in excess of 10% of consolidated totals) are stated below as a percent of consolidated totals.

	Customer
		A		B		C		D		E
% of revenue, 2019		11	%	9	%	16	%	3	%	2	%
% of revenue, 2018		17	%	14	%	1	%	4	%	-	%

% of accounts receivable, as of December 31, 2019		10	%	8	%	31	%	-	%	10	%
% of accounts receivable, as of December 31, 2018		13	%	-	%	16	%	14	%	-	%

The following table presents revenues by geographic area shipped to (in thousands).

	Year Ended December 31
	2019		2018
United States	$	22,533	$	13,469
Other countries		1,180		1,293
Revenues	$	23,713	$	14,762

The following table presents revenues by product line (in thousands).

	Year Ended December 31
	2019		2018
Food	$	16,957	$	8,600
Animal nutrition		6,756		6,162
Revenues	$	23,713	$	14,762