could result in reduced royalty payments from Kadcyla, all of which would result in a reduction of non-cash royalty revenues and the non-cash interest expense over the life of the Royalty Obligation. Conversely, if sales of Kadcyla are more than expected, the non-cash royalty revenues and the non-cash interest expense recorded by the Company would be greater over the term of the Royalty Obligation.
In addition, the royalty purchase agreement grants OMERS the right to receive certain reports and other information relating to the royalties and contains other representations and warranties, covenants, and indemnification obligations that are customary for a transaction of this nature.
2001 Non-Employee Director Stock Plan
During the three and six months ended June 30, 2018, the Company recorded $4,000 and $31,000 in expense related to stock units outstanding under the Company’s 2001 Non-Employee Director Stock Plan, or the 2001 Plan. A market value of $72,000 for the stock units was paid to a retiring director in June 2018, effectively terminating the plan.
Compensation Policy for Non-Employee Directors
During the three and six months ended June 30, 2019, the Company recorded $100,000 and $200,000 in compensation expense, respectively, related to deferred share units issued and outstanding under the Company’s Compensation Policy for Non-Employee Directors, compared to $54,000 and $156,000 in compensation expense recorded during the three and six months ended June 30, 2018, respectively.
Pursuant to the Compensation Policy for Non-Employee Directors, the redemption amount of deferred share units issued will be paid in shares of common stock of the Company on the date a director ceases to be a member of the Board. In February 2018 and June 2018, the Company issued retiring directors 77,012 and 95,497 shares of common stock of the Company to settle outstanding deferred share units. Annual retainers vest quarterly over approximately one year from the date of grant, contingent upon the individual remaining a director of ImmunoGen as of each vesting date. The number of deferred share units awarded is fixed per the plan on the date of the award. All unvested deferred stock awards will automatically vest immediately prior to the occurrence of a change of control.
In addition to the deferred share units, the Non-Employee Directors are also entitled to receive a fixed number of stock options on the date of the annual meeting of shareholders. These options vest quarterly over approximately one year from the date of grant. Any new directors will receive a pro-rated award, depending on their date of election to the Board. The directors received a total of 108,000 and 128,000 options in June 2019 and 2018, respectively, and the related compensation expense for the six months ended June 30, 2019 and 2018 is included in the amounts discussed in the “Stock-Based Compensation” section of Note B above.
G.Restructuring Charges
2019 Corporate Restructuring
On June 26, 2019, the Board of Directors approved a plan to restructure the business to focus resources on continued development of mirvetuximab soravtansine and a select portfolio of three earlier-stage product candidates, resulting in a reduction of our workforce by approximately 220 positions, with a majority of these employees separating from the business by mid-July 2019 and the remaining affected employees transitioning over varying periods of time of up to 12 months. Communication of the plan to the affected employees was substantially completed on June 27, 2019.
As a result of the workforce reduction, during the three months ended June 30, 2019, the Company recorded a $16.0 million charge for severance related to a pre-existing plan in accordance with ASC 712, Compensation-Nonretirement Postemployment Benefits, as such amounts are probable and reasonably estimable. The related cash payments will be substantially paid out by June 30, 2020. In addition, an anticipated charge of $3.7 million is expected to be incurred for incremental retention benefits over the same time period, of which approximately $400,000 was recorded during the three and six months ended June 30, 2019. No payments were made during the three and six months ended June 30, 2019 with respect to this action.
In addition to the termination benefits and other related charges, the Company will seek to sub-lease the majority of the laboratory and office space at 830 Winter Street in Waltham, Massachusetts. The financial impact of these efforts is dependent on the length of time it takes to find a tenant and the terms of the sub-lease. The decision to vacate part of its