Stock-Based Compensation

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

Stock-Based Compensation

Stock-Based Compensation

Aggregate stock-based compensation expense was $2.5 million and $4.2 million for the three months ended March 31, 2020 and 2019, respectively.

Stock-based compensation expense related to stock options was $0.6 million and $0.7 million for the three months ended March 31, 2020 and 2019, respectively.

Expense related to time-based restricted share units was $0.9 million and $2.3 million for the three months ended March 31, 2020 and 2019, respectively.

Stock-based compensation expense related to performance-based restricted share units was $0.9 million and $1.2 million for the three months ended March 31, 2020 and 2019, respectively.

Stock-based compensation expense related to our employee stock purchase plan (“ESPP”) was $0.1 million in the three months ended March 31, 2020. The ESPP was put in place during 2019 with the first offering period beginning on September 1, 2019 through December 31, 2019. As a result, there was no expense for the ESPP in the three months ended March 31, 2019