In January 2021 and September 2021, the Company announced corporate restructurings to reduce costs, more closely align operating expenses with expected revenue, and focus its resources on Inbrija. As part of the January 2021 restructuring, the Company reduced headcount by approximately 16% through a reduction in force (excluding the employees that transferred to Catalent at the closing of the sale of our Chelsea manufacturing operations). All of the reduction in personnel in connection with the January 2021 restructuring took place during the three-month period ended March 31, 2021. As part of the September 2021 restructuring, the Company reduced headcount by approximately 15% through a reduction in force. Most of this reduction in force took place in September 2021, and it will be nearly complete in the first quarter of 2022.

For the years ended December 31, 2021 and 2020, the Company incurred pre-tax severance and employee separation related expenses of approximately $6.0 million and $0.3 million, respectively, associated with the restructuring. Of the pre-tax severance and employee separation related expenses incurred, $0.6 million and $0.3 million were recorded in research and development expenses and $5.4 million and $0 were recorded in selling, general and administrative expenses for the years ended December 31, 2021 and 2020, respectively.

A summary of the restructuring costs for the years ended December 31, 2021 and 2020 is as follows:

(In thousands)	Restructuring Costs
Restructuring Liability as of December 31, 2019	$	1,264
2020 Restructuring costs		343
2020 Payments		(1,607	)
Restructuring Liability as of December 31, 2020	$	—
2021 Restructuring costs		6,000
2021 Payments		(4,149	)
Restructuring Liability as of December 31, 2021	$	1,851