Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Convertible Preferred Stock	Series D convertible preferred stock	Series D1 convertible preferred stock	Common Class A	Common Class A Common Stock	Common Class A Additional Paid-in Capital	Common Class B	Common Class B Common Stock	Common Class B Additional Paid-in Capital
Beginning balance of temporary equity (in shares) at Dec. 31, 2017						59,730,213
Beginning balance of temporary equity at Dec. 31, 2017						$ 158,414
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of convertible preferred stock, net of issuance costs (in shares)							5,224,658	2,749,407
Issuance of convertible preferred stock, net of issuance costs							$ 49,878	$ 34,952
Ending balance of temporary equity (in shares) at Dec. 31, 2018						67,704,278
Ending balance of temporary equity at Dec. 31, 2018						$ 243,244
Beginning balance (in shares) at Dec. 31, 2017		12,883,930
Beginning balance at Dec. 31, 2017	$ (112,509)	$ 1	$ 6,136	$ (118,631)	$ (15)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock upon exercise of options (in shares)										1,508,762
Issuance of Class A common stock upon exercise of options									$ 1,173		$ 1,173
Issuance of Class A common stock for in-process research and development (in shares)										157,109
Issuance of Class A common stock for in-process research and development									792		792
Vesting of shares subject to repurchase, including early exercised options	256		256
Issuance of warrants to purchase Class A common stock									150		150
Stock-based compensation	2,658		2,658
Net loss	(112,485)			(112,485)
Other comprehensive loss	(22)				(22)
Ending balance (in shares) at Dec. 31, 2018		14,549,801
Ending balance at Dec. 31, 2018	(219,987)	$ 1	11,165	(231,116)	(37)
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of convertible preferred stock into Class B common stock (in shares)												(67,704,278)
Conversion of convertible preferred stock into Class B common stock												$ (243,244)
Ending balance of temporary equity (in shares) at Dec. 31, 2019						0
Ending balance of temporary equity at Dec. 31, 2019						$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock upon exercise of options (in shares)										2,226,493
Issuance of Class A common stock upon exercise of options									3,435		3,435
Conversion of convertible preferred stock into Class B common stock (in shares)													67,704,278
Conversion of convertible preferred stock into Class B common stock												$ 243,244	$ 1	$ 243,243
Issuance of Class A common stock upon initial public offering, net of issuance costs (in shares)										11,500,000
Issuance of Class A common stock upon initial public offering, net of issuance costs									410,824		410,824
Issuance of Class A common stock for in-process research and development (in shares)										261,024
Vesting of shares subject to repurchase, including early exercised options	494		494
Stock-based compensation	13,333		13,333
Net loss	(31,251)			(31,251)
Other comprehensive loss	(9)				(9)
Ending balance (in shares) at Dec. 31, 2019		96,241,596
Ending balance at Dec. 31, 2019	420,083	$ 2	682,494	(262,367)	(46)
Ending balance of temporary equity (in shares) at Dec. 31, 2020						0
Ending balance of temporary equity at Dec. 31, 2020						$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock related to equity awards (in shares)										5,742,931
Issuance of Class A common stock related to equity awards									23,743		23,743
Issuance of Class A common stock upon initial public offering, net of issuance costs (in shares)										4,600,000
Issuance of Class A common stock upon initial public offering, net of issuance costs									482,267		482,267
Issuance of Class A common stock for asset acquisition (in shares)										1,901,382
Issuance of Class A common stock for asset acquisition									$ 306,000		$ 306,000
Vesting of shares subject to repurchase, including early exercised options	247		247
Stock-based compensation	49,467		49,467
Net loss	(542,731)			(542,731)
Other comprehensive loss	(4)				(4)
Ending balance (in shares) at Dec. 31, 2020		108,485,909
Ending balance at Dec. 31, 2020	$ 739,072	$ 2	$ 1,544,218	$ (805,098)	$ (50)