Share-Based Payments (Tables)

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement [Abstract]

Schedule of share-based compensation expense

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

Summary of stock options and SAR activities

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