Redeemable Convertible Preferred Stock - Additional Information (Details) - USD ($)	1 Months Ended										12 Months Ended
	Oct. 31, 2020	Dec. 31, 2018	Nov. 30, 2018	Oct. 31, 2018	Sep. 30, 2018	Jan. 31, 2018	Dec. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Mar. 31, 2015	Dec. 31, 2021	Jul. 31, 2021	Oct. 30, 2018
Series A Redeemable Convertible Preferred Stock [Member]
Shares offered								14,699,632	8,166,462	9,799,755	32,665,849
Preferred stock purchase price								$ 0.38	$ 0.38	$ 0.38
Proceeds from issuance of redeemable convertible preferred stock											$ 12,200,000
Stock issuance cost											$ 89,000
Repurchase of preferred stock				2,452,270
Preferred stock repurchase, price per share				$ 2.04
Aggregate purchase price of redeemable convertible preferred stock				$ 5,000,000.0
Preferred stock share authorized				30,213,574									32,665,849
Series B Convertible Redeemable Preferred Stock [Member]
Shares offered						6,110,957	9,888,639
Preferred stock purchase price						$ 0.75	$ 0.75
Series C Convertible Redeemable Preferred Stock [Member]
Shares offered		2,084,387	2,501,265		18,717,804
Preferred stock purchase price		$ 2.40	$ 2.40		$ 2.40
Preferred stock share authorized	23,303,456
2018 Eighteen Preferred Stock [Member]
Preferred stock share authorized				70,212,570									72,664,850
Series D Redeemable Convertible Preferred Stock [Member]
Shares offered	17,752,068
Preferred stock purchase price	$ 6.76
Proceeds from issuance of redeemable convertible preferred stock	$ 119,700,000
Redeemable Convertible Preferred Stock
Preferred stock converted into common stock												87,268,694