Financial instruments

Foreign Currency Forward Contracts

The Company uses derivative instruments for risk management purposes. Foreign currency forward contracts designated as cash flows hedges are used to manage foreign currency transaction exposure. Foreign currency forward contracts not designated as hedges for accounting purposes are used to manage exposure related to near term foreign currency denominated monetary assets and liabilities. The Company enters into the non-designated foreign currency forward contracts for periods consistent with its currency translation exposures, which generally approximate one month. For the years ended December 31, 2017 and 2016, the Company recognized a loss related to non-designated foreign currency forward contracts of $2.6 million and $2.3 million, respectively.

The following table presents the locations in the consolidated balance sheets and fair value of derivative instruments as of December 31, 2017 and 2016:



	December 31, 2017		December 31, 2016
	Fair Value
	(Dollars in thousands)
Asset derivatives:
Designated foreign currency forward contracts	$	914	$	667
Non-designated foreign currency forward contracts	307		490
Prepaid expenses and other current assets	1,221		1,157
Total asset derivatives	1,221		1,157
Liability derivatives:
Designated foreign currency forward contracts	1,373		2,139
Non-designated foreign currency forward contracts	53		118
Other current liabilities	1,426		2,257
Total liability derivatives	$	1,426	$	2,257

The total notional amount for all open foreign currency forward contracts designated as cash flow hedges as of December 31, 2017 and 2016 was $88.5 million and $101.8 million, respectively. The total notional amount for all open non-designated foreign currency forward contracts as of December 31, 2017 and 2016 was $110.6 million and $73.4 million, respectively. All open foreign currency forward contracts as of December 31, 2017 have durations of twelve months or less.

See Note 11 for information on the location and amount of gains and losses attributable to derivatives that were reclassified from accumulated other comprehensive income (loss) (“AOCI”) to expense (income), net of tax.

For the years ended December 31, 2017, 2016 and 2015, there was no ineffectiveness related to the Company’s hedging derivatives.

Concentration of Credit Risk

Concentrations of credit risk with respect to trade accounts receivable are generally limited due to the Company’s large number of customers and their diversity across many geographic areas. However, a portion of the Company’s trade accounts receivable outside the United States include sales to government-owned or supported healthcare systems in several countries which are subject to payment delays. Payment is dependent upon the creditworthiness of the healthcare systems in those countries and the financial stability of their economies.

In the ordinary course of business, the Company grants non-interest bearing trade credit to its customers on normal credit terms. In an effort to reduce its credit risk, the Company (i) establishes credit limits for all of its customer relationships, (ii) performs ongoing credit evaluations of its customers’ financial condition, (iii) monitors the payment history and aging of its customers’ receivables, and (iv) monitors open orders against an individual customer’s outstanding receivable balance. An allowance for doubtful accounts is maintained for trade accounts receivable based on expected collectability of accounts receivable, considering the Company's historical collection experience, the length of time an account is outstanding, the financial position of the customer and information provided by credit rating services. The adequacy of this allowance is reviewed each reporting period and adjusted as necessary. The allowance for doubtful accounts was $10.3 million and $8.6 million at December 31, 2017 and 2016, respectively. The current portion of the allowance for doubtful accounts at December 31, 2017 and 2016 of $3.5 million and $2.0 million, respectively, was reported in accounts receivable, net within the consolidated balance sheet. The allowance for doubtful accounts on receivables outstanding for greater than one year at December 31, 2017 and 2016 of $6.8 million and $6.6 million, respectively, is recognized in other assets within the consolidated balance sheet.

Certain of the Company’s customers, particularly in Greece, Italy, Portugal and Spain, have extended or delayed payments for products and services already provided, raising collectability concerns regarding the Company’s trade accounts receivable from these customers. As a result, the Company continues to closely monitor the allowance for doubtful accounts with respect to these customers and uses other risk mitigation strategies such as selling receivables. The aggregate net current and long-term trade accounts receivable for customers in Greece, Italy, Spain and Portugal and the percentage of the Company’s total net current and long-term trade accounts receivable represented by the net current and long-term trade accounts receivable for customers in those countries at December 31, 2017 and 2016 are as follows:



	December 31, 2017			December 31, 2016
	(Dollars in thousands)
Current and long-term trade accounts receivable in Greece, Italy, Spain and Portugal ⁽¹⁾	$	49,054		$	51,098
Percentage of total net current and long-term trade accounts receivables	14.6		%	19.3		%

(1) The long-term portion of trade accounts receivable, net from customers in Greece, Italy, Spain and Portugal at December 31, 2017 and 2016 was $3.3 million and $2.7 million, respectively. In January 2017, the Company sold $16.1 million of receivables outstanding with publicly funded hospitals in Italy for $16.0 million.

For the years ended December 31, 2017, 2016 and 2015, net revenues from customers in Greece, Italy, Spain and Portugal were $129.4 million, $125.3 million and $126.2 million, respectively.