SHARE-BASED COMPENSATION

6 Months Ended

Jun. 30, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION

Common Stock Awards

We recognized employee share-based compensation expense of $1.4 million and $0.3 million during the three months endedJune 30, 2019 and 2018, respectively. We recognized employee share-based compensation expense of $2.1 million and $2.4 million during the six months endedJune 30, 2019 and 2018, respectively. Our employee share-based awards, including common stock awards, stock option awards and phantom shares, vest in equal installments over a three-year period or which vest in a 40%-60% split respectively over a two-year period. Additionally, we recognized share-based compensation expense related to our outside directors of $0.1 million and $0.2 million during the three months endedJune 30, 2019 and 2018, respectively. We recognized share-based compensation expense related to our outside directors of $0.2 million and $0.5 million during the six months endedJune 30, 2019 and 2018, respectively. The unrecognized compensation cost related to our unvested share-based awards as of June 30, 2019 is estimated to be $5.4 million and is expected to be recognized over a weighted-average period of 1.3 years.

Stock Option Awards

As of June 30, 2019, all outstanding stock options are vested and there are no unrecognized costs related to our stock options.

Phantom Share Plan

We recognized compensation expense related to our phantom shares of negative $0.1 million and $0.5 million during the three months endedJune 30, 2019 and 2018, respectively. We recognized compensation expense related to our phantom shares of less than $0.1 million and $0.8 million during the six months endedJune 30, 2019 and 2018, respectively. The unrecognized compensation cost related to our unvested phantom shares as of June 30, 2019 is estimated to be $0.1 million and is expected to be recognized over a weighted-average period of 1.0 years.