Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Stock-based compensation
Vesting of early exercised options (in shares)	4,670		14,745
Unvested early exercises of stock options	$ 100		$ 100
Future awards under the 2021 Employee Stock Purchase Plan
Stock-based compensation
Stock authorized for issuance (in shares)	1,153,675		839,539
Exercise of outstanding stock options
Stock-based compensation
Weighted-average grant-date fair value of stock options granted (in dollars per share)	$ 9.66	$ 9.19
Unrecognized compensation cost	$ 17,200
Unrecognized compensation cost, weighted-average period for recognition	2 years 10 days
Vesting of outstanding restricted stock units
Stock-based compensation
Unrecognized compensation cost	$ 24,900
Unrecognized compensation cost, weighted-average period for recognition	2 years 11 months 15 days
Performance Shares (PSUs)
Stock-based compensation
Granted (in shares)	438,500
Granted (in dollars per share)	$ 14.86
Outstanding (in shares)	438,500
Vested (in shares)	0
Stock-based compensation expense	$ 0
Future awards under the 2021 Stock Option and Incentive Plan
Stock-based compensation
Stock authorized for issuance (in shares)	7,339,182		6,336,068
2016 Stock Plan
Stock-based compensation
Stock authorized for issuance (in shares)	1,813,811		2,044,585