Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Stock-based Compensation

Summary of the stock-based compensation activity

	Quarter ended June 30,				Six months ended June 30,
	2020		2019		2020		2019
	(in thousands)
Grants:
Units:
Performance-based RSUs		—		—		422		665
Stock options		—		—		273		344
Time-based RSUs		5		—		310		330
Grant date fair value:
Performance-based RSUs	$	—	$	—	$	14,788	$	15,253
Stock options		—		—		2,770		2,965
Time-based RSUs		150		—		10,823		7,545
Total	$	150	$	—	$	28,381	$	25,763
Vestings and exercises:
Performance-based RSUs vested		—		—		603		648
Stock options exercised		144		29		324		118
Time-based RSUs vested		—		—		348		291
Compensation expense	$	6,757	$	5,652	$	19,125	$	10,183