Share-Based Payments (Tables)

9 Months Ended

Sep. 30, 2023

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,
	2023		2022		2023		2022
	(unaudited)				(unaudited)
Research and development	$	1,254	$	825	$	3,458	$	2,284
Selling, general and administrative	6,666		4,160		16,856		11,023
Total	$	7,920	$	4,985	$	20,314	$	13,307

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		Weighted Average Remaining Contractual Term (in years)
Outstanding, December 31, 2022	5,797,569	$	26.99	6.11
Granted	1,148,143	$	38.28
Exercised	(228,628)	$	17.50
Forfeited	(91,986)	$	33.24
Outstanding, September 30, 2023 (unaudited)	6,625,098	$	29.17	6.14
As of September 30, 2023 (unaudited):
Vested and expected to vest	6,625,098	$	29.17	6.14
Exercisable	4,116,000	$	26.44	4.65
As of December 31, 2022:
Vested and expected to vest	5,797,569	$	26.99	6.11
Exercisable	3,541,395	$	25.08	4.68

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, 2022	131,960	$	32.17
Granted	227,980	$	38.60
Vested	(47,049)	$	32.18
Forfeited	(6,375)	$	34.63
Nonvested, September 30, 2023 (unaudited)	306,516	$	36.90

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, 2022	181,750	$	29.07	20,000	$	28.63	201,750	$	29.03
Granted	205,000	$	34.00	—	$	—	205,000	$	34.00
Vested	(102,520)	$	31.04	—	$	—	(102,520)	$	31.04
Forfeited	(3,000)	$	28.93	—	$	—	(3,000)	$	28.93
Nonvested, September 30, 2023 (unaudited)	281,230	$	31.95	20,000	$	28.63	301,230	$	31.73