The Company’s Fabrication Technology segment formulates, develops, manufactures and supplies consumable products and equipment. Substantially all revenue from the Fabrication Technology business is recognized at a point in time. The Company disaggregates its Fabrication Technology revenue into the following product groups:

The Company’s Medical Technology segment provides products and services spanning the full continuum of patient care, from injury prevention to rehabilitation. While the Company’s Medical Technology sales are primarily derived from three sales channels including dealers and distributors, insurance, and direct to consumers and hospitals, substantially all its revenue is recognized at a point in time.

(1) For the periods presented, the Prevention & Recovery product group includes bone growth stimulation products, which were previously classified as part of the Reconstructive product group.

Given the nature of the Fabrication Technology and Medical Technology businesses, the total amount of unsatisfied performance obligations with an original contract duration of greater than one year as of April 2, 2021 is immaterial.

The nature of the Company’s contracts gives rise to certain types of variable consideration, including rebates, implicit price concessions, and other discounts. The Company includes estimated amounts of variable consideration in the transaction price to the extent that it is probable there will not be a significant reversal of revenue.

In some circumstances, customers are billed in advance of revenue recognition, resulting in contract liabilities. As of December 31, 2020 and 2019, total contract liabilities were $36.6 million and $14.8 million, respectively. During the three months ended April 2, 2021 and April 3, 2020, revenue recognized that was included in the contract liability balance at the beginning of the year was $14.3 million and $4.9 million, respectively. As of April 2, 2021 and April 3, 2020, total contract liabilities were $40.0 million and $17.0 million, respectively, and were included in Accrued liabilities on the Company’s Condensed Consolidated Balance Sheets. The contract liabilities as of April 2, 2021 and December 31, 2020 include $11.8 million of certain one-time advance payments in the Medical Technology business.

The Company’s estimate of current expected credit losses on trade receivables considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. In calculating and applying its current expected credit losses, the Company disaggregates trade receivables into business segments due to risk characteristics unique to each segment given the individual lines of business and market. The business segments are further disaggregated based on either geography or product type.

The Company uses a loss rate methodology in calculating its current expected credit losses, leveraging historical write-offs over a defined lookback period in deriving a historical loss rate. The expected credit loss model further considers current conditions and reasonable and supportable forecasts using an adjustment for current and projected macroeconomic factors. Management identified appropriate macroeconomic indicators based on tangible correlation to historical losses considering the location and risks associated with the Company.

A summary of the activity in the Company’s allowance for credit losses included within Trade receivables in the Condensed Consolidated Balance Sheets is as follows:


	Three Months Ended April 2, 2021
	Balance at Beginning of Period		Charged to Expense, net		Write-Offs and Deductions		Foreign Currency Translation		Balance at End of Period
	(In thousands)
Allowance for credit losses	$	37,666	$	239	$	(1,062)	$	(1,283)	$	35,560