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, DCP and solar cell manufacturing systems 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 and nine months ended September 29, 2018 and September 30, 2017:


	Three Months Ended						Nine Months Ended
	September 29, 2018			September 30, 2017			September 29, 2018			September 30, 2017
	(In thousands)
Opening balance	$	911		$	1,220		$	994		$	1,007
Expenditures incurred under warranties		(51	)		(360	)		(469	)		(640	)
Accruals for product warranties issued during the reporting period		68			169			347			675
Adjustments to previously existing warranty accruals		(139	)		106			(83	)		93

Closing balance	$	789		$	1,135		$	789		$	1,135

The following table displays the balance sheet classification of the warranty provision account at September 29, 2018 and at December 30, 2017:


	September 29,		December 30,
	2018		2017
	(In thousands)
Other accrued liabilities	$	622	$	757
Other long-term liabilities		167		237

Total warranty provision	$	789	$	994