Share-based Compensation (Tables)
 9 Months Ended
Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]  
Schedule of Share-based Compensation Expense
During the periods presented, the Company recorded the following share-based compensation expense for stock options and restricted stock awards:
Three Months Ended September 30,Nine Months Ended September 30,
2022202120222021
(in thousands)
Sales, general and administrative $2,309$2,396$8,479$5,473
Research and development6126681,6181,904
Total $2,921$3,064$10,097$7,377
Schedule of Stock Options
Stock Options
 Number of Options OutstandingWeighted-Average Exercise PriceWeighted-Average Remaining Contractual Term (in years)Aggregate Intrinsic Value (in thousands)
Balances at December 31, 20212,098,087 $37.49 7.67$67,357 
Granted (weighted-average fair value $37.74 per share)
230,750 63.41 
Exercised(244,896)13.84 
Forfeited/canceled(213,272)61.16 
Balances at September 30, 20221,870,669 $41.08 7.13$38,212 
Schedule of Employee Stock Options Valuation Assumptions
The fair value of stock options granted to employees was estimated using the following assumptions:
Nine Months Ended September 30,
20222021
Volatility
56% - 59%
60%
Risk-free interest rate
1.6% - 3.2%
0.7% - 1.1%
Term (in years)6.256.25
Dividend yield——
The fair value of stock options granted to consultants was estimated using the following assumptions during the following periods presented:
Nine Months Ended September 30,
20222021
Volatility
56% - 58%
60%
Risk-free interest rate
2.4% - 2.9%
1.6%
Term (in years)1010
Dividend yield——
Schedule of Restricted Stock
The following table represents RSU activity for fiscal 2022:
 Restricted Stock Units Weighted-
Average
Grant Date
Fair Value
Outstanding unvested at December 31, 20213,982 $69.05 
Granted171,897 61.94 
Vested(12,542)50.39 
Forfeited/canceled(17,205)65.97 
Outstanding unvested at September 30, 2022146,132 $62.65