Subsequent Event

9 Months Ended

Sep. 30, 2018

Subsequent Events [Abstract]

Subsequent event

Subsequent event

In October 2018, we established an additional LTIP to provide eligible employees with the opportunity to receive performance-based incentive compensation, which is comprised of restricted stock units. The grant and/or vesting of restricted stock units is contingent upon the achievement of pre-determined regulatory milestones. The estimated value under this LTIP at its inception was approximately $33.4 million. We will record compensation expense related to this LTIP as described in Note 1 under “Long-term incentive plans.”