|3 Months Ended|
Mar. 31, 2019
|Disclosure of Compensation Related Costs, Share-based Payments [Abstract]|
A summary of the stock option activity for the three months ended March 31, 2019 is presented below.
There were no new grants during the three months ended March 31, 2019 and 2018. As of March 31, 2019, the aggregate intrinsic value for our outstanding stock options was $77.5 million, and the aggregate intrinsic value for our exercisable stock options was $74.3 million. The aggregate intrinsic value for the exercised stock options during the three months ended March 31, 2019 was $1.4 million. The remaining contractual term for the outstanding and exercisable stock options as of March 31, 2019, was 5.6 years and 5.5 years, respectively. For the three months ended March 31, 2019 and 2018, we recognized $0.2 million and $0.2 million in stock compensation expense related to these stock option awards.
Restricted Stock Units (Non-Vested Stock) and Performance Stock Units
During the three months ended March 31, 2019, we granted a total of 318,332 restricted stock units ("RSUs") to employees, directors and executives pursuant to our Incentive Award Plan ("IAP"). Each RSU represents the right to receive one share of common stock. The fair value of the RSUs is based on the closing share price of our common stock on the date of grant. During the three months ended March 31, 2019 and 2018, the recorded stock compensation expense for all RSUs was $0.9 million and $0.4 million, respectively. As of March 31, 2019 the total unrecognized compensation expense for all RSUs was approximately $11.3 million, and is expected to be recognized over a weighted average period of approximately 2.5 years.
The following table summarizes RSUs activity during the three months ended March 31, 2019:
Effective March 18, 2019, our Board of Directors authorized and granted 199,413 performance stock units ("PSUs") to certain key employees under the IAP. The actual number of shares that may be issued under the PSUs ranges from zero up to a maximum of twice the target number of performance stock unit awards granted to the participant, based on our total shareholder return relative to a designated peer group from January 1, 2019 through December 31, 2021. Compensation expense is recorded ratably over the corresponding requisite service period. The fair value of PSUs is determined using a Monte Carlo probability model. Grant recipients do not have any shareholder rights until performance relative to the peer group has been determined following the completion of the performance period and shares have been issued. During the three months ended March 31, 2019 and 2018, the recorded stock compensation expense for the PSUs was $0.7 million and $0.2 million, respectively.
The following table summarizes information about PSUs activity during the three months ended March 31, 2019:
The total stock compensation expense for the three months ended March 31, 2019 and 2018 for all stock awards was $1.8 million and $0.8 million, respectively. The total unrecognized compensation expense as of March 31, 2019 is approximately $23.1 million, and is expected to be recognized over a weighted average period of approximately 2.4 years.
The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef