During the second half of 2019, the Company initiated a restructuring plan to realign its expense structure with the reduction in revenue experienced in recent years and overall Company objectives. As part of this restructuring plan, the Company announced plans to reduce its overall operating expenses, both in the U.S. and internationally. Management continued to assess the efficiency of operations during 2020 and, in turn, consolidated locations and personnel, among other things, where possible.

In February 2019, the Company announced the restructuring of a certain portion of its workforce predominantly in Germany, which included the closure of the Company’s office location in Munich, Germany accompanied by relocation or severance benefits for the affected employees. Voluntary early retirement was offered to certain other employees and was announced in March 2019 and again in August 2020.

The cumulative amount of restructuring expenses incurred as of December 31, 2020 for the restructuring plans announced in the second half of 2019 and continuing in 2020 was $12.2 million.

In January 2018, the Company announced an early retirement incentive program for employees that met certain defined requirements. The cumulative amount incurred during the year ended December 31, 2018 related to this restructuring program was $7.3 million. We did not incur any additional expenses related to this restructuring program during the year ended December 31, 2019 or 2020.

A reconciliation of the beginning and ending restructuring liability, which is included in accrued wages and benefits in the Consolidated Balance Sheets as of December 31, 2020 and 2019, is as follows:

(In thousands)	2020			2019
Balance at beginning of period	$	1,568		$	185
Plus: Amounts charged to cost and expense		6,229			6,014
Less: Amounts paid		(3,611	)		(4,631	)
Balance at end of period	$	4,186		$	1,568

Restructuring expenses included in the Consolidated Statements of Income (Loss) are for the years ended December 31, 2020, 2019 and 2018:

(In thousands)	2020		2019		2018
Cost of sales	$	455	$	785	$	2,775
Selling, general and administrative expenses		1,832		2,360		2,655
Research and development expenses		3,942		2,869		1,831
Total restructuring expenses	$	6,229	$	6,014	$	7,261

The following table represents the components of restructuring expense by geographic area for the years ended December 31, 2020, 2019 and 2018:

(In thousands)	2020		2019		2018
United States	$	2,234	$	3,336	$	7,120
International		3,995		2,678		141
Total restructuring expenses	$	6,229	$	6,014	$	7,261