Other Current Liabilities

3 Months Ended

Mar. 27, 2020

Accrued Liabilities, Current [Abstract]

Components of other current liabilities were (in thousands):



	March 27, 2020		December 27, 2019
Accrued self-insurance retentions	$	7,600	$	7,570
Accrued warranty and service liabilities	12,759		12,785
Accrued trade promotions	6,654		8,390
Payable for employee stock purchases	2,976		13,722
Customer advances and deferred revenue	42,515		33,138
Income taxes payable	12,803		8,706
Right of return refund liability	13,788		13,791
Operating lease liability, current	9,116		7,690
Other	32,866		37,145
Total	$	141,077	$	142,937

A liability is established for estimated future warranty and service claims that relate to current and prior period sales. The Company estimates warranty costs based on historical claim experience and other factors including evaluating specific product warranty issues. Following is a summary of activity in accrued warranty and service liabilities (in thousands):



Balance, December 27, 2019	$	12,785
Charged to expense	1,897
Margin on parts sales reversed	741
Reductions for claims settled	(2,664		)
Balance, March 27, 2020	$	12,759

Deferred Revenue

Revenue is deferred when cash payments are received or due in advance of performance, including amounts which are refundable. This is also the case for services associated with certain product sales. The balance in the deferred revenue and customer advances was $42.5 million as of March 27, 2020 and $33.1 million as of December 27, 2019. Net sales for the year to date included $11.3 million in 2020 and $19.7 million in 2019 that related to deferred revenue as of the beginning of each period.