8. Warranty

Intevac provides for the estimated cost of warranty when revenue is recognized. Intevac’s warranty is per contract terms and for its HDD manufacturing, DCP manufacturing and solar cell manufacturing the warranty typically ranges between 12 and 24 months from customer acceptance. During this warranty period any defective non-consumable parts are replaced and installed at no charge to the customer. Intevac uses estimated repair or replacement costs along with its historical warranty experience to determine its warranty obligation. The provision for the estimated future costs of warranty is based upon historical cost and product performance experience. Intevac exercises judgment in determining the underlying estimates.

On the condensed consolidated balance sheets, the short-term portion of the warranty provision is included in other accrued liabilities, while the long-term portion is included in other long-term liabilities. The expense associated with product warranties issued or adjusted is included in cost of net revenues on the condensed consolidated statements of operations.

The following table displays the activity in the warranty provision account for the three-month periods ended March 31, 2018 and April 1, 2017:


	Three Months Ended
	March 31, 2018			April 1, 2017
	(In thousands)
Opening balance	$	994		$	1,007
Expenditures incurred under warranties		(236	)		(142	)
Accruals for product warranties issued during the reporting period		104			250
Adjustments to previously existing warranty accruals		4			(9	)

Closing balance	$	866		$	1,106

The following table displays the balance sheet classification of the warranty provision account at March 31, 2018 and at December 30, 2017:


	March 31,		December 30,
	2018		2017
	(In thousands)
Other accrued liabilities	$	646	$	757
Other long-term liabilities		220		237

Total warranty provision	$	866	$	994