10. Significant Risk Concentrations

Significant Customer

Honeywell International, Inc. and affiliated entities (“Honeywell”) accounted for $2.6 million, or 13% of total revenue, for the three months ended March 31, 2018, and $3.3 million, or 15% of total revenue, for the three months ended March 31, 2017. PACCAR Inc. and affiliated entities accounted for $3.0 million, or 13% of total revenue for the three months ended March 31, 2017. No other customers accounted for 10% or more of our total revenue for the three months ended March 31, 2018 or 2017.

Honeywell had accounts receivable balances of $9.1 million, or approximately 54% of total accounts receivable, at March 31, 2018, and $8.7 million, or approximately 48% of total accounts receivable, at December 31, 2017. No other customer accounted for 10% or more of the total accounts receivable at March 31, 2018 or December 31, 2017.

Significant Supplier

We have OEM Distribution Agreements (“ODAs”) with Microsoft Corporation (“Microsoft”) which enable us to sell Microsoft Windows Embedded operating systems on a non-exclusive basis to our customers in the United States, Canada, Argentina, Brazil, Chile, Columbia, Mexico, Peru, Puerto Rico, the Caribbean (excluding Cuba), the European Union, the European Free Trade Association, Turkey and Africa, which expire on June 30, 2018. We also have ODAs with Microsoft which allow us to sell Microsoft Windows Mobile operating systems in the Americas (excluding Cuba), Japan, Taiwan, Europe, the Middle East, and Africa, which also expire on June 30, 2018.

Software sales under these agreements constitute a significant portion of our software revenue and total revenue. These agreements are typically renewed bi-annually, annually or semi-annually; however, there is no automatic renewal provision in any of these agreements. Further, these agreements can be terminated unilaterally by Microsoft at any time. Microsoft currently offers a rebate program to sell Microsoft Windows Embedded operating systems pursuant to which we earn money for achieving certain predefined objectives. In accordance with Microsoft rebate program rules, we allocate 30% of rebate values to reduce cost of sales, with the remaining 70% to offset qualified marketing expenses in the period the expenditures are incurred.

Under this rebate program, we recorded rebate credits as follows (in thousands):

	Three Months Ended March 31,
	2018		2017
Reductions to cost of revenue	$	260	$	110
Reductions to marketing expense	$	266	$	155

There was a balance of approximately $607,000 in outstanding rebate credits for which we qualified at March 31, 2018, which will be accounted for as a reduction in marketing expense in the period in which qualified program expenditures are made.