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Equity Incentive Plans (Tables)
 3 Months Ended
Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]  
Schedule of Activity Related to Stock Option Awards A summary of the activity related to stock option awards during the three months ended March 31, 2023 is as follows:  
Shares
Subject to
Options
Weighted-Average
Exercise
Price per
Share
Weighted-Average
Remaining
Contractual
Term
(in years)
Aggregate
Intrinsic
Value (in
thousands)
Outstanding at January 1, 20233,673,208 $32.04 6.28$18,686 
Granted1,091,455 $23.25 
Exercises(55,158)$22.16 
Forfeitures and cancellations(424,238)$27.87 
Outstanding at March 31, 20234,285,267 $30.34 7.42$5,390 
Exercisable at March 31, 20232,000,802 $36.07 5.42$4,553 
Schedule of Time-based Restricted Stock Units Activity
Number of Restricted Stock UnitsWeighted-Average Grant Date Fair Value
Weighted-Average
Remaining
Contractual
Term
(in years)
Aggregate
Intrinsic
Value (in
thousands)
Outstanding at January 1, 20231,028,843 $26.14 1.17$31,884 
Granted394,825 $23.24 
Released(39,300)$24.10 
Forfeitures and cancellations(16,845)$23.50 
Outstanding at March 31, 20231,367,523 $25.39 1.31$29,757 
RSU expected to vest at March 31, 20231,367,523 $25.39 1.31$29,757 
Schedule of Weighted Average Assumptions used to Estimate Fair Value The
estimated fair values of stock option awards granted to employees were determined on the date of grant using the Black-Scholes option valuation model with the following weighted-average assumptions:
Three Months Ended
March 31,
20232022
Risk-free interest rate3.7%2.0%
Expected volatility86.5%88.5%
Expected dividend yield— %— %
Expected term (in years)5.656.18
Weighted-average grant date fair value per share$16.88$22.63
Schedule of Non-cash Stock-based Compensation Expense
Total non-cash stock-based compensation expense for all stock awards that was recognized in the consolidated statements of operations and comprehensive loss is as follows:
Three Months Ended
March 31,
(in thousands)20232022
Research and development$2,770 $1,656 
General and administrative6,090 6,086 
Total$8,860 $7,742