Nature of the Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended						9 Months Ended
	Aug. 03, 2020	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Aug. 04, 2020
Net proceeds from issuance initial public offering	$ 292,000								$ 295,449
Net losses attributable to common stockholders		$ (45,510)	$ (37,588)	$ (30,923)	$ (23,614)	$ (11,632)	$ (9,339)	$ (114,021)	(44,585)
Accumulated deficit		(239,124)						(239,124)		$ (125,103)
Cash and cash equivalents		243,187			$ 142,250			243,187	$ 142,250	122,661
Short-term investments		$ 32,654						$ 32,654		$ 233,663
Convertible Preferred Stock
Preferred stock, shares outstanding											0
Common Stock
Common stock issued and sold					18,687,500
Stock issued upon conversion of preferred stock					39,859,139
IPO
Common stock issued and sold	18,687,500
Public offering price per share	$ 17.00
Gross proceeds from issuance of common stock	$ 317,700
Stock issued upon conversion of preferred stock	39,859,139
IPO | Common Stock
Stock issued upon conversion of preferred stock	39,859,139