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Stock-based Compensation (Tables)
 12 Months Ended
Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]  
Schedule of Stock-based Compensation Expense
Stock-based compensation expense is included in the consolidated statements of operations as follows (in thousands): 
 Year Ended December 31,
 202220212020
Costs of product revenue$452 $224 $104 
Research and development$3,907 $2,663 $1,843 
Selling, general and administrative10,172 8,706 5,781 
Total$14,531 $11,593 $7,728 
The following table presents total stock-based compensation expense by security type included in the consolidated statements of operations (in thousands):
 Year Ended December 31,
 202220212020
Stock options$4,167 $2,764 $2,381 
RSUs and RSAs4,807 2,7682,231
PSUs3,268 2,333 1,160 
PBOs2,289 3,7281,956
Total$14,531 $11,593 $7,728 
Assumptions Used to Estimate the Fair Value of Option Grants The following summarizes the weighted-average assumptions used to estimate the fair value of employee stock options granted:
 Year Ended December 31,
 202220212020
Expected life (years)5.75.65.3
Volatility62.1 %52.5 %50.4 %
Risk-free interest rate3.1 %0.8 %1.0 %
Expected dividend yield0.0 %0.0 %0.0 %
No stock options were granted to non-employees for services during year ended December 31, 2022. The following summarizes the weighted-average assumptions used to estimate the fair value of 9,000 and 76,000 shares of stock options granted to non-employees for services valued at $0.1 million and $0.4 million during the years ended December 31, 2021 and 2020 respectively:
 Year Ended December 31,
 20212020
Expected life (years)5.65.4
Volatility54.1 %51.6 %
Risk-free interest rate0.9 %0.4 %
Expected dividend yield0.0 %0.0 %
Schedule of Share-based Compensation, Stock Options, Activity
The following tables summarizes stock option activities:
Number
of
Shares		Weighted Average
Exercise Price
Per Share
(In Thousands)
Outstanding at December 31, 20193,147 $6.31 
Granted496 $13.30 
Exercised(210)$6.30 
Forfeited/Expired(48)$16.71 
Outstanding at December 31, 20203,385 $7.19 
Granted286 $26.85 
Exercised(664)$6.96 
Forfeited/Expired(72)$17.99 
Outstanding at December 31, 20212,935 $8.90 
Granted2,000 $8.90 
Exercised(410)$2.33 
Forfeited/Expired(275)$19.01 
Outstanding at December 31, 20224,250 $8.88 
Number
of
Shares		Weighted Average
Exercise Price
Per Share		Weighted Average Remaining Contractual TermAggregate Intrinsic
Value
(In Thousands)(In Years)(In Thousands)
Outstanding at December 31, 20224,250 $8.88 6.2$1,556 
Exercisable at December 31, 20222,162 $8.26 3.1$1,556 
Vested and expected to vest at December 31, 20223,898 $8.91 5.9$1,556 
Schedule of Share-based Compensation, RSA Activity The following table summarizes RSA activities:
Number
of
Shares		Weighted Average
Grant Date Fair Value
Per Share
(In Thousands)
Non-vested balance at December 31, 201935 $17.18 
Granted96 $11.44 
Vested(35)$17.18 
Non-vested balance at December 31, 202096 $11.44 
Granted46 $21.91 
Vested(62)$11.31 
Non-vested balance at December 31, 202180 $17.53 
Granted159 $7.53 
Vested(58)$18.42 
Non-vested balance at December 31, 2022181 $8.45 
Schedule of Share-based Compensation, RSU Activity The following table summarizes RSU activities:
Number
of
Shares		Weighted Average
Grant Date Fair Value
Per Share
(In Thousands)
Non-vested balance at December 31, 2019201 $10.76 
Granted156 $14.22 
Vested(168)$10.05 
Forfeited/Expired(13)$15.16 
Non-vested balance at December 31, 2020176 $14.17 
Granted163 $26.59 
Vested(70)$13.57 
Forfeited/Expired(37)$21.89 
Non-vested balance at December 31, 2021232 $21.83 
Granted518 $17.46 
Vested(106)$21.21 
Forfeited/Expired(126)$19.55 
Non-vested balance at December 31, 2022518 $18.15 
Share-based Compensation, Performance Shares Award Outstanding Activity The following table summarizes PSU activities:
Number
of
Shares		Weighted Average
Grant Date Fair Value
Per Share
(In Thousands)
Non-vested balance at December 31, 2019120 $13.88 
Granted124 $13.59 
Vested(107)$11.28 
Forfeited/Expired(6)$21.80 
Non-vested balance at December 31, 2020131 $15.34 
Granted82 $26.16 
Vested(66)$16.14 
Forfeited/Expired(19)$19.38 
Non-vested balance at December 31, 2021128 $21.24 
Granted686 $9.55 
Vested(107)$20.52 
Forfeited/Expired(40)$19.93 
Non-vested balance at December 31, 2022667 $9.41 
The following tables summarizes PBOs activities:
Number
of
Shares		Weighted Average
Grant Date Fair Value
Per Share
(In Thousands)
Outstanding at December 31, 20191,260 $4.75 
Granted689 $6.37 
Forfeited/Expired(389)$6.42 
Outstanding at December 31, 20201,560 $5.05 
Granted433 $12.23 
Exercised(35)$9.02 
Forfeited/Expired(118)$12.23 
Outstanding at December 31, 20211,840 $4.11 
Granted733 $9.89 
Forfeited/Expired(747)$8.29 
Outstanding at December 31, 20221,826 $4.70 

Number
of
Shares		Weighted Average
Exercise Price
Per Share		Weighted Average
Remaining
Contractual Term		Aggregate Intrinsic
Value
(In Thousands)(In Years)(In Thousands)
Exercisable at December 31, 20221,674 $11.09 5.4$40 
Vested and expected to vest at December 31, 20221,808 $11.85 5.7$40 
Schedule of Assumptions Used The following summarize the weighted-average assumptions used to estimate the fair value of PBOs granted:
 Year Ended December 31,
202220212020
Expected life (years)5.65.55.3
Volatility54.9 %51.9 %49.9 %
Risk-free interest rate1.8 %0.7 %1.3 %
Expected dividend yield0.0 %0.0 %0.0 %