Share-Based Payments

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement [Abstract]

Share-based compensation expense is as follows (dollars in thousands):


	Three Months ended September 30,				Nine Months ended September 30,
	2020		2019		2020		2019
	(unaudited)				(unaudited)
Research and development	$	777	$	680	$	2,276	$	1,954
Selling, general and administrative	3,713		3,234		11,164		9,269
Total	$	4,490	$	3,914	$	13,440	$	11,223

Stock Option and Stock Appreciation Rights

The following table summarizes stock option and stock appreciation rights (SAR) activities:


	Number of Options	Weighted- Average Exercise Price (per share)		Weighted- Average Remaining Contractual Term (in years)
Outstanding, December 31, 2019	4,606,559	$	23.05	6.66
Granted	1,210,025	$	23.86
Exercised	(56,873)	$	9.93
Forfeited	(50,875)	$	26.51
Outstanding, September 30, 2020 (unaudited)	5,708,836	$	23.32	6.67

As of December 31, 2019:
Vested and expected to vest	4,606,559	$	23.05	6.66
Exercisable	2,598,112	$	15.68	5.48

As of September 30, 2020:
Vested and expected to vest	5,708,836	$	23.32	6.86
Exercisable	3,347,884	$	18.96	5.31

Restricted Stock Units

During the nine months ended September 30, 2020, the Company granted 26,055 RSUs, with a weighted average grant date fair value per share of $23.99. These RSUs generally vest one year from the date of grant.

Performance Stock Units

Performance-Based Awards

During the nine months ended September 30, 2020, the Company granted 31,250 performance-based awards, with a weighted average grant date fair value per share of $21.35. These awards require certain performance targets to be achieved in order to vest. Vesting is also subject to continued service requirements through the date that the achievement of the performance target is certified. As of September 30, 2020, all of the performance-based awards were vested and issued as shares outstanding.

Market-Based Awards

During the nine months ended September 30, 2020, the Company granted 15,625 market-based awards, with a weighted average grant date fair value per share of $23.41. These awards are subject to achievement of market-based performance targets in order to vest.