Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Summary of net sales to significant customers as a percentage of total net sales

Our net sales to significant customers as a percentage of total net sales were as follows:

	Years Ended December 31,
	2019	2018	2017
Cummins Inc.	16.1%	15.2%	13.4%
Honda Motor Co.	11.6%	10.5%	11.2%
Toyota Motor Corporation	9.6%	10.5%	10.2%

We sell parts to these three transportation customers for certain vehicle platforms under purchase agreements that have no volume commitments and are subject to purchase orders issued on a periodic basis.

No other customer accounted for 10% or more of total net sales during these periods.

Summary of Molds, Dies and Other Tools

We occasionally enter into agreements with our customers whereby we receive a contractual guarantee to be reimbursed the costs we incur to construct molds, dies, and other tools that are used to make many of the products we sell. The costs we incur are included in other current assets on the Consolidated Balance Sheets until reimbursement is received from the customer. Reimbursements received from customers are netted against such costs and included in our Consolidated Statements of Earnings if the amount received is in excess of the costs that we incur. The following is a summary of amounts to be received from customers as of December 31, 2019, and 2018:

	As of December 31,
	2019		2018
Cost of molds, dies and other tools included in other current assets	$	7,690	$	5,388

Fair Value Measurements, Recurring and Nonrecurring

We estimate the fair value of our financial instruments as follows:

Instrument	Method for determining fair value
Cash, cash equivalents, accounts receivable and accounts payable	Cost, approximates fair value due to the short-term nature of these instruments.
Revolving credit facility	The fair value of long-term debt approximates carrying value and was determined by valuing a similar hypothetical coupon bond and attributing that value to our credit facility.
Interest rate swaps and forward contracts	The fair value of our interest rate swaps and forward contracts are measured using a market approach which uses current industry information.

Summary of antidilutive stock options

Our antidilutive securities consist of the following:

	Years Ended December 31,
(units)	2019	2018	2017
Antidilutive securities	22,040	18,138	22,110

Summary of foreign currency gain (loss) recorded in the statement of operations

Foreign currency (losses) gains recorded in the Consolidated Statement of Earnings includes the following:

	Years Ended December 31,
	2019			2018			2017
Foreign currency (losses) gains	$	(1,797	)	$	(2,619	)	$	3,052