On May 23, 2019, we implemented a strategic organizational restructuring, to principally align our operations around our vaccine business and significantly curtail further investment in our immuno-oncology business. In connection with the restructuring, we reduced our workforce by approximately 80 positions, or approximately 36%, of U.S.-based personnel. Also in connection with the restructuring, our Chief Executive Officer, also a member of the Board of Directors (the “Board”), submitted notice of his retirement from the Company and the Board, effective August 1, 2019. We expect the restructuring to be substantially complete and the costs incurred and paid by December 31, 2019. We are exploring strategic alternatives for our immuno-oncology business.

The total restructuring cost is estimated to be $9.4 million, of which $5.3 million is related to severance, other termination benefits and outplacement services and $4.1 million is related to stock-based compensation expense as a result of accelerated vesting of stock awards and extension of exercise period of stock options. During the three months ended June 30, 2019, we recognized restructuring charges of $8.8 million and the remaining $0.6 million is expected to be recognized by the end of 2019.

The outstanding restructuring liabilities are included in accrued liabilities on the condensed consolidated balance sheets. As of June 30, 2019, the components of the restructuring liabilities were as follows (in thousands):

	Severance and Other Termination Benefits
Balance at December 31, 2018	$	-
Restructuring charges (a)		4,655
Cash payments or settlements		-
Balance at June 30, 2019	$	4,655