Condensed Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (unaudited) - USD ($) $ in Thousands	Total	Initial Public Offering	Series A Redeemable Convertible Preferred Stock [Member]	Series A Redeemable Convertible Preferred Stock [Member] Initial Public Offering	Series B Redeemable Convertible Preferred Stock	Series B Redeemable Convertible Preferred Stock Initial Public Offering	Common Stock	Common Stock Initial Public Offering	Common Stock License Agreement with Stanford	Additional Paid in Capital	Additional Paid in Capital Initial Public Offering	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ (2,218)											$ (2,218)
Net loss and comprehensive loss	(141)											(141)
Ending balance at Mar. 31, 2020	(2,359)											(2,359)
Beginning balance at Dec. 31, 2019	(2,218)											(2,218)
Net loss and comprehensive loss	(1,453)
Ending balance at Jun. 30, 2020	(1,445)									$ 2,226		(3,671)
Temporary equity, Ending balance, Shares at Jun. 30, 2020			15,019,945
Temporary equity, Ending balance at Jun. 30, 2020			$ 11,513
Ending balance, Shares at Jun. 30, 2020							9,381,500
Beginning balance at Mar. 31, 2020	(2,359)											(2,359)
Common shares issued to founders and investor							8,548,517
Issuance of restricted common shares, Shares							832,983
Issuance of redeemable convertible preferred stock upon conversion of outstanding related party convertible note and accrued interest			$ 5,020
Issuance of redeemable convertible preferred stock upon conversion of outstanding related party convertible note and accrued interest, Shares			5,019,945
Related party convertible note and accrued interest cancellation	2,225									2,225
Issuance of redeemable convertible preferred stock for cash			$ 6,493
Issuance of redeemable convertible preferred stock for cash, Shares			10,000,000
Stock-based compensation expense	1									1
Net loss and comprehensive loss	(1,312)											(1,312)
Ending balance at Jun. 30, 2020	(1,445)									2,226		(3,671)
Temporary equity, Ending balance, Shares at Jun. 30, 2020			15,019,945
Temporary equity, Ending balance at Jun. 30, 2020			$ 11,513
Ending balance, Shares at Jun. 30, 2020							9,381,500
Beginning balance at Dec. 31, 2020	(65,408)									5,183		(70,591)
Temporary equity, Beginning balance, Shares at Dec. 31, 2020			30,019,945
Temporary equity, Beginning balance at Dec. 31, 2020	55,608		$ 55,608
Beginning balance, Shares at Dec. 31, 2020							10,279,102
Issuance of redeemable convertible preferred stock for cash			$ 14,997		$ 150,524
Issuance of redeemable convertible preferred stock for cash, Shares			15,000,000		29,792,487
Stock-based compensation expense	1,033									1,033
Common stock shares issued upon early exercise, Shares							918,825
Vesting of early exercised stock options	7									7
Reclassification of tranche liability upon settlement			$ 39,403
Net loss and comprehensive loss	(19,709)											(19,709)
Ending balance at Mar. 31, 2021	(84,077)									6,223		(90,300)
Temporary equity, Ending balance, Shares at Mar. 31, 2021			45,019,945		29,792,487
Temporary equity, Ending balance at Mar. 31, 2021			$ 110,008		$ 150,524
Ending balance, Shares at Mar. 31, 2021							11,197,927
Beginning balance at Dec. 31, 2020	(65,408)									5,183		(70,591)
Temporary equity, Beginning balance, Shares at Dec. 31, 2020			30,019,945
Temporary equity, Beginning balance at Dec. 31, 2020	55,608		$ 55,608
Beginning balance, Shares at Dec. 31, 2020							10,279,102
Net loss and comprehensive loss	(37,238)
Ending balance at Jun. 30, 2021	379,184						$ 1			487,012		(107,829)
Temporary equity, Ending balance, Shares at Jun. 30, 2021			0
Ending balance, Shares at Jun. 30, 2021							55,979,002
Beginning balance at Mar. 31, 2021	(84,077)									6,223		(90,300)
Temporary equity, Beginning balance, Shares at Mar. 31, 2021			45,019,945		29,792,487
Temporary equity, Beginning balance at Mar. 31, 2021			$ 110,008		$ 150,524
Beginning balance, Shares at Mar. 31, 2021							11,197,927
Issuance of common stock		$ 218,177									$ 218,177
Issuance of common stock, Shares								14,000,000	640,861
Repurchase of common shares in connection with License Agreement with Stanford, Shares									(624,845)
Conversion of redeemable convertible preferred stock to common stock at closing of initial public offering		$ 260,532						$ 1			$ 260,531
Temporary equity, Conversion of redeemable convertible preferred stock to common stock at closing of initial public offering, Shares				(45,019,945)		(29,792,487)
Temporary equity, Conversion of redeemable convertible preferred stock to common stock at closing of initial public offering				$ (110,008)		$ (150,524)
Conversion of redeemable convertible preferred stock to common stock at closing of initial public offering, Shares								30,761,676
Stock-based compensation expense	2,018									2,018
Common stock shares issued upon early exercise of options	21									21
Common stock shares issued upon early exercise, Shares							3,383
Vesting of early exercised stock options	42									42
Net loss and comprehensive loss	(17,529)											(17,529)
Ending balance at Jun. 30, 2021	$ 379,184						$ 1			$ 487,012		$ (107,829)
Temporary equity, Ending balance, Shares at Jun. 30, 2021			0
Ending balance, Shares at Jun. 30, 2021							55,979,002