Share-Based Payments (Tables)

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of share-based compensation expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
	(unaudited)				(unaudited)
Research and development	$	808	$	706	$	1,459	$	1,294
Selling, general and administrative	3,489		4,770		6,863		8,553
Total	$	4,297	$	5,476	$	8,322	$	9,847

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, 2021	5,774,076	$	24.15	5.95
Granted	1,006,985	$	31.95
Exercised	(111,363)	$	18.64
Forfeited	(108,949)	$	31.22
Outstanding, June 30, 2022 (unaudited)	6,560,749	$	25.33	6.12
As of December 31, 2021:
Vested and expected to vest	5,774,076	$	24.15	5.95
Exercisable	3,651,824	$	21.29	4.53
As of June 30, 2022 (unaudited):
Vested and expected to vest	6,560,749	$	25.33	6.12
Exercisable	4,202,865	$	22.89	4.60

Summary of restricted stock units

The following table summarizes restricted stock unit (RSU) activities:

	Number of RSUs	Weighted Average Grant Date Fair Value per Share
Nonvested, December 31, 2021	21,110	$	29.61
Granted	132,460	$	32.17
Vested	(21,110)	$	29.61
Nonvested, June 30, 2022 (unaudited)	132,460	$	32.17

There were no forfeited RSU awards during the six months ended June 30, 2022.

Summary of performance stock unit

The following table summarizes performance share unit (PSU) activities:

	Performance-Based Units			Market-Based Units			Total PSUs
	Number of PSUs	Weighted Average Grant Date Fair Value per Share		Number of PSUs	Weighted Average Grant Date Fair Value per Share		Number of PSUs	Weighted Average Grant Date Fair Value per Share
Nonvested, December 31, 2021	53,500	$	29.82	35,625	$	26.34	89,125	$	28.43
Granted	155,000	$	28.93	—	—		155,000	$	28.93
Vested	(21,500)	$	29.67	—	—		(21,500)	$	29.67
Forfeited	(1,500)	$	30.45	—	—		(1,500)	$	30.45
Nonvested, June 30, 2022 (unaudited)	185,500	$	29.09	35,625	$	26.34	221,125	$	28.65