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Stock-based Compensation (Tables)
 12 Months Ended
Dec. 31, 2024
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,
 202420232022
Costs of product revenue$429 $354 $452 
Research and development2,928 2,631 3,907 
Selling, general and administrative9,730 6,986 10,172 
Total$13,087 $9,971 $14,531 
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,
 202420232022
Stock options$6,423 $3,962 $4,167 
RSUs and RSAs4,717 4,4474,807
PSUs247 1,649 3,268 
PBOs1,357 $(112)2,289
ESPP343 25 — 
Total$13,087 $9,971 $14,531 
Schedule of 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,
 202420232022
Expected life (years)5.95.85.7
Volatility73.3 %66.2 %62.1 %
Risk-free interest rate3.9 %4.0 %3.1 %
Expected dividend yield0.0 %0.0 %0.0 %
The following summarizes the weighted-average assumptions used to estimate the fair value of 20,000 and 50,000 shares of stock options granted to non-employees for services valued at $44 thousand and $0.1 million during the years ended December 31, 2024 and 2023, respectively:
 Year Ended December 31,
 20242023
Expected life (years)5.85.8
Volatility74.7 %70.1 %
Risk-free interest rate4.4 %4.7 %
Expected dividend yield0.0 %0.0 %
The following summarize the weighted-average assumptions used to estimate the fair value of PBOs granted:
 Year Ended December 31,
2022
Expected life (years)5.6
Volatility54.9 %
Risk-free interest rate1.8 %
Expected dividend yield0.0 %
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, 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 
Granted2,046 $5.23 
Exercised(283)$1.97 
Forfeited/Expired(839)$12.08 
Outstanding at December 31, 20235,174 $7.31 
Granted4,837 $3.08 
Exercised(399)$3.24 
Forfeited/Expired(484)$8.75 
Outstanding at December 31, 20249,128 $5.17 
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, 20249,128 $5.17 6.3$8,497 
Exercisable at December 31, 20242,840 $8.05 4.5$402 
Vested and expected to vest at December 31, 20248,508 $5.27 6.2$7,724 
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, 202180 $17.53 
Granted159 $7.53 
Vested(58)$18.42 
Non-vested balance at December 31, 2022181 $8.45 
Granted277 $2.89 
Vested(133)$9.04 
Non-vested balance at December 31, 2023325 $3.48 
Granted211 $3.32 
Vested(302)$3.31 
Non-vested balance at December 31, 2024234 $3.56 
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, 2021232 $21.83 
Granted518 $17.46 
Vested(106)$21.21 
Forfeited/Expired(126)$19.55 
Non-vested balance at December 31, 2022518 $18.15 
Granted1,049 $5.24 
Vested(204)$18.42 
Forfeited/Expired(343)$9.71 
Non-vested balance at December 31, 20231,020 $7.66 
Granted1,530 $3.08 
Vested(383)$8.96 
Forfeited/Expired(157)$4.66 
Non-vested balance at December 31, 20242,010 $4.16 
Schedule of 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, 2021128 $21.24 
Granted686 $9.55 
Vested(107)$20.52 
Forfeited/Expired(40)$19.93 
Non-vested balance at December 31, 2022667 $9.41 
Vested(315)$11.02 
Forfeited/Expired(75)$12.49 
Other
15 $25.05 
Non-vested balance at December 31, 2023292 $7.69 
Vested(248)$7.69 
Forfeited/Expired(44)$7.69 
Non-vested balance at December 31, 2024— $— 
The following tables summarizes PBOs activities:
Number
of
Shares		Weighted Average
Grant Date Fair Value
Per Share
(In Thousands)
Outstanding at December 31, 20211,840 $4.11 
Granted733 $9.89 
Forfeited/Expired(747)$8.29 
Outstanding at December 31, 20221,826 $4.70 
Forfeited/Expired(178)$9.73 
Outstanding at December 31, 20231,648 $5.64 
Forfeited/Expired(73)$10.23 
Outstanding at December 31, 20241,575 $5.43 

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, 20241,575 $10.62 3.4$114 
Vested and expected to vest at December 31, 20241,575 $10.62 3.4$114 
Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions
The fair value of shares to be issued under the ESPP is computed using the Black-Scholes-Merton option pricing model at the commencement of the offering period. The following summarizes the weighted-average assumptions used to estimate the fair value of ESPP for the initial offering period:
 Year Ended December 31,
20242023
Expected life (years)1.20.4
Volatility89.4 %89.6 %
Risk-free interest rate4.6 %5.3 %
Expected dividend yield0.0 %0.0 %