Note 10 — Restructuring Charges

During 2017, the Company initiated certain restructuring activities related to the Company’s efforts to streamline operations, enhance efficiencies, and reduce costs, as well as reduce the Company’s investments in certain technology development. In addition, during 2017, the Company began the Ultratech acquisition integration process to enhance efficiencies, resulting in reductions in headcount and other facility costs. During the year ended December 31, 2018, additional accruals were recognized and payments were made related to these restructuring initiatives.

During the second quarter of 2018, the Company initiated plans to further reduce excess capacity associated with the manufacture and support of the Company’s advanced packaging lithography and 3D wafer inspection systems by consolidating these operations into its San Jose, California facility. As a result of this and other cost saving initiatives, the Company announced headcount reductions of approximately 40 employees and recorded restructuring charges related to these actions of $2.8 million for the year ended December 31, 2018, consisting principally of personnel severance and related costs. The Company expects the consolidation to be completed in the first quarter of 2019, and expects to incur immaterial additional restructuring costs as this initiative is completed.

During the third quarter of 2018, the Company initiated additional restructuring activities to further reduce costs, including headcount reductions impacting approximately 35 employees and recorded restructuring charges related to these actions of $1.2 million, consisting principally of personnel severance and related costs. This initiative was completed by the end of 2018. Restructuring expense for the year ended December 31, 2018 included non-cash charges of $1.2 million related to accelerated share-based compensation for employee terminations, compared to $1.9 million for the comparable prior year period.

The following table shows the amounts incurred and paid for restructuring activities during the years ended December 31, 2018, 2017, and 2016 and the remaining accrued balance of restructuring costs at December 31, 2018, which is included in “Accrued expenses and other current liabilities” in the Consolidated Balance Sheets:


	Personnel		Facility
	Severance and		Related Costs
	Related Costs		and Other		Total
	(in thousands)
Balance - December 31, 2015	$	824	$	—	$	824
Provision		4,544		1,098		5,642
Changes in estimate		(2)		—		(2)
Payments		(3,570)		(1,098)		(4,668)
Balance - December 31, 2016		1,796		—		1,796
Provision		4,714		5,257		9,971
Payments		(4,990)		(5,257)		(10,247)
Balance - December 31, 2017		1,520		—		1,520
Provision		4,681		2,714		7,395
Payments		(4,058)		(2,644)		(6,702)
Balance - December 31, 2018	$	2,143	$	70	$	2,213