Share-Based Payments (Tables)

3 Months Ended

Mar. 31, 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 March 31,
	2022		2021
	(unaudited)
Research and development	$	651	$	588
Selling, general and administrative	3,374		3,783
Total	$	4,025	$	4,371

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, 2021	5,774,076	$	24.15	5.95
Granted	929,785	$	32.20
Exercised	(47,601)	$	18.21
Forfeited	(48,036)	$	30.84
Outstanding, March 31, 2022 (unaudited)	6,608,224	$	25.28	6.25
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 March 31, 2022:
Vested and expected to vest	6,608,224	$	25.28	6.25
Exercisable	4,280,012	$	22.87	4.79

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	131,210	$	32.20
Vested	(21,110)	$	29.61
Forfeited	—	$	—
Nonvested, March 31, 2022	131,210	$	32.20

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
Vested	(21,500)	$	29.67	—			(21,500)	$	29.67
Nonvested, March 31, 2022	32,000	$	29.92	35,625	$	26.34	67,625	$	28.04