Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Summary of unrecorded unconditional purchase obligations

Future purchase obligations under non-cancellable purchase orders and long-term supply agreements as of December 31, 2017 are as follows:

(In thousands)	Fiscal 2018		Fiscal 2019	Fiscal 2020	Fiscal 2021	Fiscal 2022	Thereafter	Total1
Future purchase obligations	$	342,667	224,612	336,490	1,000	1,000	1,000	$	906,769

¹  Total future purchase obligations were composed of $169.2 million related to non-cancellable purchase orders and $737.5 million related to long-term supply agreement. Subsequent to fiscal 2017, the Company entered into a long-term supply agreement totaling $55.6 million with its supplier.

Schedule of estimated utilization of advances from customers

The estimated utilization of advances from customers as of December 31, 2017 is as follows:

(In thousands)	Fiscal 2018		Fiscal 2019	Fiscal 2020	Fiscal 2021	Fiscal 2022	Thereafter	Total
Estimated utilization of advances from customers	$	54,999	37,470	31,592	—	—	—	$	124,061

Schedule of product warranty liability

The following table summarizes accrued warranty activity for fiscal 2017, 2016 and 2015, respectively:

	Fiscal Year
(In thousands)	2017			2016			2015
Balance at the beginning of the period	$	161,209		$	164,127		$	154,648
Accruals for warranties issued during the period	29,689			14,575			25,561
Settlements and adjustments during the period	(9,595		)	(17,493		)	(16,082		)
Balance at the end of the period	$	181,303		$	161,209		$	164,127

Other Commitments [Table Text Block]

The Company is required to provide certain funding under agreements with unconsolidated investees, subject to certain conditions (see Note 10). As of December 31, 2017, the Company has future financing obligations related to these agreements through fiscal 2018 totaling $25.0 million.