Redeemable Convertible Preferred and Common Stock - Narrative (Details)			1 Months Ended										3 Months Ended			9 Months Ended
		Mar. 10, 2021 $ / shares shares	Aug. 31, 2020 USD ($) $ / shares shares	Jul. 31, 2020 USD ($) $ / shares	Jul. 30, 2020 shares	May 31, 2020 USD ($) $ / shares shares	Apr. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Oct. 31, 2017 USD ($) $ / shares shares	Jul. 31, 2016 USD ($) $ / shares shares	May 31, 2016 USD ($) $ / shares shares	Apr. 30, 2016 USD ($) $ / shares shares	Mar. 31, 2021 shares	Sep. 30, 2020 shares	Jun. 30, 2020 shares	Sep. 30, 2020 USD ($)	Sep. 30, 2021 $ / shares shares	Mar. 11, 2021 vote $ / shares shares	Dec. 31, 2020 $ / shares shares	Dec. 21, 2020 $ / shares
Class of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares																	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, par value (in dollars per share) | $ / shares																	$ 0.0001		$ 0.0001
Common stock, shares authorized (in shares) | shares																	1,000,000,000		210,956,516
Preferred stock, shares authorized (in shares) | shares																	100,000,000		0
Common stock, shares outstanding (in shares) | shares																	161,529,449	161,449,205	33,327,294
Warrants outstanding (in shares) | shares																		15,999,996
Common stock, voting rights, number of votes per share | vote																		1
Redeemable convertible preferred stock, shares authorized (in shares) | shares																	0		131,411,372
Redeemable convertible preferred stock, issue price (in dollars per share) | $ / shares																		$ 10.00
Payment of offering costs | $																$ 265,000
OTI
Class of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares		$ 0.00001
Common stock, shares authorized (in shares) | shares		210,956,516
Stock, shares authorized (in shares) | shares		342,367,887
Authorized stock, par value (in dollars per share) | $ / shares		$ 0.00001
Stock issued from conversion of note (in shares) | shares									1,253,556
Convertible notes payable | $									$ 4,600,000
Investor | OTI
Class of Stock [Line Items]
Stock issued from conversion of note (in shares) | shares												44,256
Convertible notes payable | $												$ 45,000
Redeemable convertible preferred stock
Class of Stock [Line Items]
Redeemable convertible preferred stock, shares issued (in shares) | shares	[1]												4,232,947	44,481,892	43,952,862
Redeemable convertible preferred stock | OTI
Class of Stock [Line Items]
Redeemable convertible preferred stock, shares authorized (in shares) | shares		131,411,372
Series Seed Redeemable Convertible Preferred Stock | OTI
Class of Stock [Line Items]
Redeemable convertible preferred stock, shares issued (in shares) | shares										445,942	563,725	1,887,253
Redeemable convertible preferred stock, issue price (in dollars per share) | $ / shares										$ 1.02	$ 1.02	$ 1.02
Proceeds from issuance of redeemable convertible preferred stock, net off issuance cost | $										$ 500,000	$ 600,000	$ 1,800,000
Payment of offering costs | $												$ 100,000
Stock issued during period, conversion of convertible securities (in shares) | shares							2,941,176
Redeemable convertible preferred stock dividends (in dollars per share) | $ / shares		$ 0.0612
Liquidation preference (in dollars per share) | $ / shares		1.02
Convertible preferred stock, conversion price (in dollars per share) | $ / shares		1.02
Series A Redeemable Convertible Preferred Stock | OTI
Class of Stock [Line Items]
Redeemable convertible preferred stock, shares issued (in shares) | shares								715,712	1,324,511
Redeemable convertible preferred stock, issue price (in dollars per share) | $ / shares								$ 11.3158	$ 11.3158
Proceeds from issuance of redeemable convertible preferred stock, net off issuance cost | $								$ 8,100,000	$ 14,800,000
Payment of offering costs | $									$ 200,000
Stock issued during period, conversion of convertible securities (in shares) | shares							3,293,779
Redeemable convertible preferred stock dividends (in dollars per share) | $ / shares		0.6789
Liquidation preference (in dollars per share) | $ / shares		11.3518
Convertible preferred stock, conversion price (in dollars per share) | $ / shares		11.3518
Series B | OTI
Class of Stock [Line Items]
Redeemable convertible preferred stock, shares authorized (in shares) | shares																			131,411,372
Redeemable convertible preferred stock, shares issued (in shares) | shares			25,286,587		37,970,846	17,320,031	45,185,071
Redeemable convertible preferred stock, issue price (in dollars per share) | $ / shares			$ 0.3323	$ 0.3323		$ 0.3323	$ 0.3323												$ 0.33
Proceeds from issuance of redeemable convertible preferred stock, net off issuance cost | $			$ 8,400,000	$ 12,500,000		$ 5,800,000	$ 15,100,000
Payment of offering costs | $			$ 100,000	$ 100,000		$ 100,000	$ 100,000
Redeemable convertible preferred stock dividends (in dollars per share) | $ / shares		0.019938
Liquidation preference (in dollars per share) | $ / shares		0.3323
Convertible preferred stock, conversion price (in dollars per share) | $ / shares		$ 0.3323

[1] The shares of the Company’s common and redeemable convertible preferred stock, prior to the Merger (as defined in Note 1), have been retroactively restated as shares reflecting the exchange ratio of approximately 0.703 established in the Merger as described in Note 1.