Current Liabilities

Deferred Services Income

A portion of our revenue is generated from service contracts. Payments from certain of these service contracts are collected in advance. As such, revenues from these service contracts are deferred and recognized ratably over the contract period for time-based service contracts, or as service hours are delivered for contracts based on a purchased quantity of hours.

Changes in our deferred service revenue were as follows:



	Three Months Ended
(In thousands)	March 29, 2014			March 30, 2013
Balance, beginning of the period	$	5,499		$	6,062
Additions	573			2,303
Revenue recognized	(1,294		)	(1,475		)
Balance, end of the period	$	4,778		$	6,890
Balance sheets classification
Deferred service income-short term	$	3,753		$	5,102
Deferred service income-long term	1,025			1,788
Balance, end of period	$	4,778		$	6,890

Other current liabilities

Other current liabilities consisted of the following:



(In thousands)	March 29, 2014		December 31, 2013
Salaries and benefits	$	6,144	$	8,771
Warranty accrual	1,055		1,142
Advanced billings	1,467		2,522
Other	2,838		2,660
Balance, end of the period	$	11,504	$	15,095

Warranty Accrual

We generally warrant our new and refurbished products for material and labor to repair the product for periods of twelve months and three months, respectively, from the date of system acceptance. Accordingly, an accrual for the estimated cost of the warranty is recorded at the time the product is shipped. Extended warranty terms, if granted, result in deferral of revenue equating to our standard pricing for similar service contracts. Recognition of the related warranty cost is deferred until product revenue is recognized. Factors that affect our warranty liability include the number of installed units, historical and anticipated rates of warranty claims and cost per claim. We periodically assess the adequacy of our recorded warranty liabilities and adjust the amounts as necessary. We believe our warranty accrual as of March 29, 2014 is sufficient to satisfy our outstanding obligations as of that date.

Changes in our warranty accrual were as follows:



	Three Months Ended
(In thousands)	March 29, 2014			March 30, 2013
Balance, beginning of the period	$	1,142		$	2,273
Liabilities accrued for warranties issued	282			518
Warranty claims paid and utilized	(478		)	(668		)
Changes in accrued warranty liabilities	109			(76		)
Balance, end of the period	$	1,055		$	2,047

Advanced Billings

On occasion, we require, or our customers pay, a deposit in advance of order shipment. These amounts are classified as advanced billings until the related order ships. The balance of $1.5 million and $2.5 million of advanced billings was from multiple customers as of March 29, 2014 and December 31, 2013, respectively.