Statements of Convertible Preferred Stock and Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock	Series A-1 Convertible Preferred Stock	Series B Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2019	$ (17,102)				$ 1	$ 3,204	$ (20,307)
Beginning balance, shares at Dec. 31, 2019		40,000,000	16,000,000
Beginning balance at Dec. 31, 2019		$ 37,383	$ 19,307
Beginning balance, shares at Dec. 31, 2019					6,390,137
Stock-based compensation expense	123					123
Net loss	(4,848)						(4,848)
Unrealized loss on marketable securities	13							$ 13
Ending balance at Mar. 31, 2020	(21,814)				$ 1	3,327	(25,155)	13
Ending balance, shares at Mar. 31, 2020		40,000,000	16,000,000
Ending balance at Mar. 31, 2020		$ 37,383	$ 19,307
Ending balance, shares at Mar. 31, 2020					6,390,137
Beginning balance at Dec. 31, 2019	(17,102)				$ 1	3,204	(20,307)
Beginning balance, shares at Dec. 31, 2019		40,000,000	16,000,000
Beginning balance at Dec. 31, 2019		$ 37,383	$ 19,307
Beginning balance, shares at Dec. 31, 2019					6,390,137
Net loss	(15,928)
Unrealized loss on marketable securities	8
Ending balance at Sep. 30, 2020	(32,042)				$ 1	4,184	(36,235)	8
Ending balance, shares at Sep. 30, 2020		40,000,000	28,000,000	62,499,993
Ending balance at Sep. 30, 2020		$ 37,383	$ 34,276	$ 114,496
Ending balance, shares at Sep. 30, 2020					6,985,928
Beginning balance at Dec. 31, 2019	(17,102)				$ 1	3,204	(20,307)
Beginning balance, shares at Dec. 31, 2019		40,000,000	16,000,000
Beginning balance at Dec. 31, 2019		$ 37,383	$ 19,307
Beginning balance, shares at Dec. 31, 2019					6,390,137
Net loss	(22,700)
Ending balance at Dec. 31, 2020	(38,147)				$ 1	4,879	(43,014)	(13)
Ending balance, shares at Dec. 31, 2020		40,000,000	28,000,000	62,499,993
Ending balance at Dec. 31, 2020	$ 186,151	$ 37,383	$ 34,272	$ 114,496
Ending balance, shares at Dec. 31, 2020	7,087,130				7,087,130
Beginning balance at Mar. 31, 2020	$ (21,814)				$ 1	3,327	(25,155)	13
Beginning balance, shares at Mar. 31, 2020		40,000,000	16,000,000
Beginning balance at Mar. 31, 2020		$ 37,383	$ 19,307
Beginning balance, shares at Mar. 31, 2020					6,390,137
Issuance of common stock upon exercise of stock options	25					25
Issuance of common stock upon exercise of stock options, shares					26,530
Stock-based compensation expense	119					119
Net loss	(4,663)						(4,663)
Unrealized loss on marketable securities	7							7
Ending balance at Jun. 30, 2020	(26,326)				$ 1	3,471	(29,818)	20
Ending balance, shares at Jun. 30, 2020		40,000,000	16,000,000
Ending balance at Jun. 30, 2020		$ 37,383	$ 19,307
Ending balance, shares at Jun. 30, 2020					6,416,667
Issuance of common stock upon exercise of stock options	526					526
Issuance of common stock upon exercise of stock options, shares					569,261
Issuance of Preferred Stock upon exercise of stock options, net of issuance costs			$ 14,969	$ 114,496
Issuance of Preferred Stock upon exercise of stock options, net of issuance costs, shares			12,000,000
Stock-based compensation expense	187					187
Net loss	(6,417)						(6,417)
Unrealized loss on marketable securities	(12)							(12)
Ending balance at Sep. 30, 2020	(32,042)				$ 1	4,184	(36,235)	8
Ending balance, shares at Sep. 30, 2020		40,000,000	28,000,000	62,499,993
Ending balance at Sep. 30, 2020		$ 37,383	$ 34,276	$ 114,496
Ending balance, shares at Sep. 30, 2020					6,985,928
Issuance of Preferred Stock upon exercise of stock options, net of issuance costs, shares				62,499,993
Issuance of Preferred Stock upon exercise of stock options, net of issuance costs, shares		40,000,000	28,000,000	62,499,993
Beginning balance at Dec. 31, 2020	(38,147)				$ 1	4,879	(43,014)	(13)
Beginning balance, shares at Dec. 31, 2020		40,000,000	28,000,000	62,499,993
Beginning balance at Dec. 31, 2020	$ 186,151	$ 37,383	$ 34,272	$ 114,496
Beginning balance, shares at Dec. 31, 2020	7,087,130				7,087,130
Issuance of common stock upon exercise of stock options	$ 123					123
Issuance of common stock upon exercise of stock options, shares					117,181
Stock-based compensation expense	835					835
Net loss	(9,299)						(9,299)
Unrealized loss on marketable securities	22							22
Ending balance at Mar. 31, 2021	(46,466)				$ 1	5,837	(52,313)	9
Ending balance, shares at Mar. 31, 2021		40,000,000	28,000,000	62,499,993
Ending balance at Mar. 31, 2021		$ 37,383	$ 34,272	$ 114,496
Ending balance, shares at Mar. 31, 2021					7,204,311
Beginning balance at Dec. 31, 2020	(38,147)				$ 1	4,879	(43,014)	(13)
Beginning balance, shares at Dec. 31, 2020		40,000,000	28,000,000	62,499,993
Beginning balance at Dec. 31, 2020	$ 186,151	$ 37,383	$ 34,272	$ 114,496
Beginning balance, shares at Dec. 31, 2020	7,087,130				7,087,130
Issuance of common stock upon exercise of stock options, shares	65,600
Net loss	$ (33,592)
Unrealized loss on marketable securities	42
Ending balance at Sep. 30, 2021	255,649				$ 4	332,222	(76,606)	29
Ending balance, shares at Sep. 30, 2021		0	0	0
Ending balance, shares at Sep. 30, 2021					40,712,723
Beginning balance at Mar. 31, 2021	(46,466)				$ 1	5,837	(52,313)	9
Beginning balance, shares at Mar. 31, 2021		40,000,000	28,000,000	62,499,993
Beginning balance at Mar. 31, 2021		$ 37,383	$ 34,272	$ 114,496
Beginning balance, shares at Mar. 31, 2021					7,204,311
Issuance of common stock, net of underwriting discounts and issuance costs	137,166				$ 1	137,165
Issuance of common stock, net of underwriting discounts and issuance costs, shares					8,825,000
Conversion of convertible preferred stock to common stock, value		$ (37,383)	$ (34,272)	$ (114,496)
Conversion of convertible preferred stock to common stock, shares		(40,000,000)	(28,000,000)	(62,499,993)
Conversion of convertible preferred stock to common stock, value	186,151				$ 2	186,149
Conversion of convertible preferred stock to common stock, shares					24,392,498
Issuance of contingent common stock, value	831					831
Issuance of contingent common stock, shares					48,889
Issuance of common stock upon exercise of stock options	102					102
Issuance of common stock upon exercise of stock options, shares					100,436
Stock-based compensation expense	896					896
Net loss	(11,352)						(11,352)
Unrealized loss on marketable securities	25							25
Ending balance at Jun. 30, 2021	267,353				$ 4	330,980	(63,665)	34
Ending balance, shares at Jun. 30, 2021					40,571,134
Issuance of common stock upon exercise of stock options	188					188
Issuance of common stock upon exercise of stock options, shares					141,589
Stock-based compensation expense	1,054					1,054
Net loss	(12,941)						(12,941)
Unrealized loss on marketable securities	(5)							(5)
Ending balance at Sep. 30, 2021	$ 255,649				$ 4	$ 332,222	$ (76,606)	$ 29
Ending balance, shares at Sep. 30, 2021		0	0	0
Ending balance, shares at Sep. 30, 2021					40,712,723
Issuance of Preferred Stock upon exercise of stock options, net of issuance costs, shares		0	0	0