Net sales include products and shipping and handling charges. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring products. All revenue is recognized when we satisfy our performance obligations under the contract. We recognize revenue by transferring the promised products to the customer, with substantially all revenue recognized at the point in time the customer obtains control of the products. We recognize revenue for shipping and handling charges at the time the products are delivered to or picked up by the customer. The majority of our contracts have a single performance obligation and are short term in nature. Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales.

 

 

The Company allocates sales from external customers to geographic areas based on the location to which the product is transported. Sales outside the United States are principally to countries in the Caribbean, Canada, Central and South America.

 

Our revenues related to the following geographic areas were as follows for the months ended:

 

		December 31, 2018				December 31, 2017
United States		$	18,504,467			$	15,497,661
All other countries			1,584,683				1,369,223
Total Net Sales		$	20,089,150			$	16,866,884

In addition to a proprietary product line designed for the broadband service provider marketplace, Clearfield provides build-to-print services for original equipment manufacturers requiring copper and fiber cable assemblies built to their specification.

 

The percentages of our sales by markets were as follows for the months ended:

 

		December 31, 2018				December 31, 2017
Broadband service providers			94	%			95	%
Build-to-print customers			6	%			5	%
Total Net Sales			100	%			100	%

Credit is extended based on the evaluation of a customer’s financial condition and collateral is generally required. Accounts receivable are stated at their estimated net realizable value. Accounts that are outstanding longer than the contractual payment terms are considered past due. The Company writes off accounts receivable when they become uncollectible; payments subsequently received on such receivables are credited to the allowance for doubtful accounts. As of both and the balance in the allowance for doubtful accounts was

 

See Note “Major Customer Concentration” for further information regarding accounts receivable and net sales.