Capital Stock	6 Months Ended
Jun. 30, 2018
Capital Stock
Capital Stock	G. Capital Stock 2001 Non-Employee Director Stock Plan During the three and six months ended June 30, 2018, the Company recorded approximately $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, compared to $21,000 and $32,000 recorded during the three and six months ended June 30, 2017. A market value of $72,000 for the stock units was paid to a retiring director in June 2018, effectively closing out the plan. Compensation Policy for Non-Employee Directors During the three and six months ended June 30, 2018, the Company recorded $54,000 and $156,000 in compensation expense, respectively, related to deferred share units issued and outstanding under the Company’s Compensation Policy for Non-Employee Directors compared to $47,000 and $85,000 in compensation expense recorded during the three and six months ended June 30, 2017, respectively. Pursuant to the Compensation Policy for Non-Employee Directors, in June 2018, February 2018 and January 2017, the Company issued retiring directors 95,497, 77,012 and 53,248 shares of common stock of the Company to settle outstanding deferred share units. 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. 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 40,000 options in December 2016, 80,000 options in June 2017, and 128,000 options in June 2018, and the related compensation expense for the six months ended June 30, 2018 and 2017 is included in the amounts discussed in the “Stock-Based Compensation” section of footnote B above.

G. Capital Stock

2001 Non-Employee Director Stock Plan

During the three and six months ended June 30, 2018, the Company recorded approximately $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, compared to $21,000 and $32,000 recorded during the three and six months ended June 30, 2017. A market value of $72,000 for the stock units was paid to a retiring director in June 2018, effectively closing out the plan.

Compensation Policy for Non-Employee Directors

During the three and six months ended June 30, 2018, the Company recorded $54,000 and $156,000 in compensation expense, respectively, related to deferred share units issued and outstanding under the Company’s Compensation Policy for Non-Employee Directors compared to $47,000 and $85,000 in compensation expense recorded during the three and six months ended June 30, 2017, respectively. Pursuant to the Compensation Policy for Non-Employee Directors, in June 2018, February 2018 and January 2017, the Company issued retiring directors 95,497, 77,012 and 53,248 shares of common stock of the Company to settle outstanding deferred share units.

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. 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 40,000 options in December 2016, 80,000 options in June 2017, and 128,000 options in June 2018, and the related compensation expense for the six months ended June 30, 2018 and 2017 is included in the amounts discussed in the “Stock-Based Compensation” section of footnote B above.