Condensed Statements of Redeemable Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance at Dec. 31, 2019	$ (204,524)		$ 1	$ 5,293	$ 11	$ (209,829)
Temporary Equity, Balance, shares at Dec. 31, 2019		11,066,427
Temporary Equity, Balance at Dec. 31, 2019		$ 120,518
Balance, shares at Dec. 31, 2019			909,486
Issuance of common stock upon exercise of stock options	24			24
Issuance of common stock upon exercise of stock options, shares			57,569
Stock-based compensation expense	150			150
Net Income (Loss)	5,732					5,732
Balance at Mar. 31, 2020	(198,618)		$ 1	5,467	11	(204,097)
Temporary Equity, Balance, shares at Mar. 31, 2020		11,066,427
Temporary Equity, Balance at Mar. 31, 2020		$ 120,518
Balance, shares at Mar. 31, 2020			967,055
Balance at Dec. 31, 2019	(204,524)		$ 1	5,293	11	(209,829)
Temporary Equity, Balance, shares at Dec. 31, 2019		11,066,427
Temporary Equity, Balance at Dec. 31, 2019		$ 120,518
Balance, shares at Dec. 31, 2019			909,486
Net Income (Loss)	(11,892)
Balance at Sep. 30, 2020	(215,571)		$ 1	6,138	11	(221,721)
Temporary Equity, Balance, shares at Sep. 30, 2020		12,397,838
Temporary Equity, Balance at Sep. 30, 2020		$ 123,255
Balance, shares at Sep. 30, 2020			1,012,890
Balance at Mar. 31, 2020	(198,618)		$ 1	5,467	11	(204,097)
Temporary Equity, Balance, shares at Mar. 31, 2020		11,066,427
Temporary Equity, Balance at Mar. 31, 2020		$ 120,518
Balance, shares at Mar. 31, 2020			967,055
Issuance of Series D redeemable convertible preferred stock in connection with business combination		$ 2,737
Issuance of Series D redeemable convertible preferred stock in connection with business combination, shares		1,331,411
Issuance of common stock upon exercise of stock options	42			42
Issuance of common stock upon exercise of stock options, shares			2,977
Stock-based compensation expense	399			399
Net Income (Loss)	(10,300)					(10,300)
Balance at Jun. 30, 2020	(208,477)		$ 1	5,908	11	(214,397)
Temporary Equity, Balance, shares at Jun. 30, 2020		12,397,838
Temporary Equity, Balance at Jun. 30, 2020		$ 123,255
Balance, shares at Jun. 30, 2020			970,032
Issuance of common stock upon exercise of stock options	25			25
Issuance of common stock upon exercise of stock options, shares			42,858
Stock-based compensation expense	205			205
Net Income (Loss)	(7,324)					(7,324)
Balance at Sep. 30, 2020	(215,571)		$ 1	6,138	11	(221,721)
Temporary Equity, Balance, shares at Sep. 30, 2020		12,397,838
Temporary Equity, Balance at Sep. 30, 2020		$ 123,255
Balance, shares at Sep. 30, 2020			1,012,890
Balance at Dec. 31, 2020	$ (221,811)		$ 1	6,269	11	(228,092)
Temporary Equity, Balance, shares at Dec. 31, 2020	12,397,838	12,397,838
Temporary Equity, Balance at Dec. 31, 2020	$ 123,255	$ 123,255
Balance, shares at Dec. 31, 2020			1,192,299
Issuance of common stock upon exercise of stock options	886		$ 2	884
Issuance of common stock upon exercise of stock options, shares			1,828,713
Stock-based compensation expense	131			131
Net Income (Loss)	(14,948)					(14,948)
Balance at Mar. 31, 2021	(235,742)		$ 3	7,284	11	(243,040)
Temporary Equity, Balance, shares at Mar. 31, 2021		12,397,838
Temporary Equity, Balance at Mar. 31, 2021		$ 123,255
Balance, shares at Mar. 31, 2021			3,021,012
Balance at Dec. 31, 2020	$ (221,811)		$ 1	6,269	11	(228,092)
Temporary Equity, Balance, shares at Dec. 31, 2020	12,397,838	12,397,838
Temporary Equity, Balance at Dec. 31, 2020	$ 123,255	$ 123,255
Balance, shares at Dec. 31, 2020			1,192,299
Issuance of common stock upon exercise of stock options, shares	1,957,478
Net Income (Loss)	$ (32,272)
Balance at Sep. 30, 2021	$ (247,382)		$ 3	12,968	11	(260,364)
Temporary Equity, Balance, shares at Sep. 30, 2021	12,397,838	12,397,838
Temporary Equity, Balance at Sep. 30, 2021	$ 123,255	$ 123,255
Balance, shares at Sep. 30, 2021			3,149,777
Balance at Mar. 31, 2021	(235,742)		$ 3	7,284	11	(243,040)
Temporary Equity, Balance, shares at Mar. 31, 2021		12,397,838
Temporary Equity, Balance at Mar. 31, 2021		$ 123,255
Balance, shares at Mar. 31, 2021			3,021,012
Issuance of common stock upon exercise of stock options	40			40
Issuance of common stock upon exercise of stock options, shares			66,288
Vesting of early exercised stock options	15			15
Stock-based compensation expense	4,478			4,478
Net Income (Loss)	(14,099)					(14,099)
Balance at Jun. 30, 2021	(245,308)		$ 3	11,817	11	(257,139)
Temporary Equity, Balance, shares at Jun. 30, 2021		12,397,838
Temporary Equity, Balance at Jun. 30, 2021		$ 123,255
Balance, shares at Jun. 30, 2021			3,087,300
Issuance of common stock upon exercise of stock options	37			37
Issuance of common stock upon exercise of stock options, shares			62,477
Vesting of early exercised stock options	39			39
Stock-based compensation expense	1,075			1,075
Net Income (Loss)	(3,225)					(3,225)
Balance at Sep. 30, 2021	$ (247,382)		$ 3	$ 12,968	$ 11	$ (260,364)
Temporary Equity, Balance, shares at Sep. 30, 2021	12,397,838	12,397,838
Temporary Equity, Balance at Sep. 30, 2021	$ 123,255	$ 123,255
Balance, shares at Sep. 30, 2021			3,149,777