Shareholder Rights Plan

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Shareholder Rights Plan

14. Shareholder Rights Plan

In December 2009, our Board approved and adopted a shareholder rights plan, or Rights Plan, in which one preferred stock purchase right was distributed for each common share held as of the close of business on January 7, 2010. Initially, the rights were not exercisable, and were attached to, and traded with, all of the shares of CTI’s common stock outstanding as of and issued subsequent to January 7, 2010. In 2012, 2015 and 2017, our Board approved certain amendments to the Rights Plan. The Rights Plan expired on December 2, 2018.