Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

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

Schedule of stock option activity

The following table summarizes the activity for stock options, RSUs and PSOs for the three months ended March 31, 2019 (in thousands):

	Stock Options		RSUs	PSOs
Equity awards outstanding, beginning of year	4,757		15	538
Changes during the year:
Granted	1,238		—	260
Exercised	(1,063	)	—	—
Expired or forfeited	(498	)	—	(273	)
Equity awards outstanding, end of period	4,434		15	525

Schedule of RSU and PSU activity

The following table summarizes the activity for stock options, RSUs and PSOs for the three months ended March 31, 2019 (in thousands):

	Stock Options		RSUs	PSOs
Equity awards outstanding, beginning of year	4,757		15	538
Changes during the year:
Granted	1,238		—	260
Exercised	(1,063	)	—	—
Expired or forfeited	(498	)	—	(273	)
Equity awards outstanding, end of period	4,434		15	525

Schedule of compensation cost related to unvested awards

As of March 31, 2019, total compensation cost related to unvested awards not yet recognized and the weighted-average periods over which the awards are expected to be recognized were as follows ($ in thousands):

	Stock Options		RSUs		PSOs
Unrecognized compensation cost	$	36,921	$	1	$	3,737
Expected weighted-average period in years of compensation cost to be recognized	3.3		—		1.8