XML 50 R37.htm IDEA: XBRL DOCUMENT v3.22.1
Share-Based Payments (Tables)
 12 Months Ended
Dec. 31, 2021
Share-based Payment Arrangement [Abstract]  
Schedule of share-based compensation expense Share-based compensation expense is as follows (dollars in thousands):
 Years Ended December 31,
 202120202019
Research and development$2,403 $2,431 $2,599 
Selling, general and administrative15,507 14,130 12,247 
Total$17,910 $16,561 $14,846 
Schedule of assumptions used in estimation of fair value of each award option on the date of grant using Black-Scholes option-pricing model The fair value of each option award is estimated on the date of the grant, using the Black-Scholes option-pricing model and the assumptions in the following table:
 Years Ended December 31,
 202120202019
Fair value of common stock
$25.09 - $30.45
$21.13 - $23.99
$22.99 - $37.78
Expected volatility
60.62% - 61.80%
61.56% - 62.27%
61.36% - 63.28%
Dividend yield0%0%0%
Expected term
5.63 years - 6.56 years
5.72 years - 6.54 years
5.53 years - 6.18 years
Risk-free interest rate
0.72% - 1.30%
0.27% - 1.34%
1.69% - 2.55%
Summary of stock option and SAR activity 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)		Aggregate
Intrinsic Value
(in thousands)
Outstanding , December 31, 20194,606,559 $23.06 6.66$27,716 
Granted1,370,225 $23.55 
Exercised(204,373)$11.47 
Forfeited(320,549)$29.09 
Outstanding, December 31, 20205,451,862 $23.26 6.28$29,877 
Granted1,055,525 $28.93 
Exercised(266,987)$18.47 
Forfeited(466,324)$27.74 
Outstanding, December 31, 20215,774,076 $24.15 5.95$41,530 
As of December 31, 2021
Vested and expected to vest5,774,076 $24.15 5.95$41,530 
Exercisable3,651,824 $21.29 4.53$37,196 
Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity
The following table summarizes restricted stock unit (RSU) activities:
Number of
RSUs		Weighted-
Average
Grant Date Fair Value per Share		Aggregate Intrinsic Value
(in thousands)		Aggregate Fair Value
(in thousands)
Nonvested, December 30, 2019— $— 
Granted26,055 $23.99 
Vested— $— $— $— 
Forfeited— $— 
Nonvested, December 31, 202026,055 $23.99 
Granted21,110 $29.61 
Vested(26,055)$23.99 $146.4 $625.1 
Forfeited— $— 
Nonvested, December 31, 202121,110 $29.61 
Share-based Payment Arrangement, Performance Shares, Activity The following table summarizes performance share unit (PSU) activities:
Performance-Based UnitsMarket-Based UnitsTotal PSUs
Number of PSUsWeighted-
Average
Grant Date Fair Value per Share		Number of PSUsWeighted-
Average
Grant Date Fair Value per Share		Number of PSUsWeighted-
Average
Grant Date Fair Value per Share
Nonvested, December 31, 2019— — — — $— 
Granted31,250 $21.35 15,625 $23.41 46,875 $22.04 
Vested(31,250)$21.35 — $— (31,250)$21.35 
Forfeited— $— — $— — $— 
Nonvested, December 31, 2020— $— 15,625 $23.41 15,625 $23.41 
Granted95,000 $29.74 20,000 $28.63 115,000 $29.55 
Vested(40,000)$29.61 — $— (40,000)$29.61 
Forfeited(1,500)$30.45 — $— (1,500)$30.45 
Nonvested, December 31, 202153,500 $29.82 35,625 $26.34 89,125 $28.43