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Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		9 Months Ended
	Aug. 18, 2021	Mar. 24, 2021	Mar. 12, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Aug. 01, 2021	Dec. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period			4 years
Unrecognized compensation expense				$ 607,110		$ 607,110
Unrecognized compensation expense related to unvested restricted stock				64,360,347		64,360,347			85,903,970
Weighted average contractual years						1 year 4 months 13 days
share related expenses				$ 69,343	$ 26	$ 188,613	$ 79
IPO [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Percentage of vesting of restricted stock and restricted stock units			25.00%
Share-based compensation arrangement by share-based payment award, award vesting period			1 year
Restricted Stock And Restricted Stock Units [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Percentage of vesting of restricted stock and restricted stock units						25.00%
Share-based compensation arrangement by share-based payment award, award vesting period						5 years
Restricted Stock And Restricted Stock Units [Member] \| Share-based Payment Arrangement, Tranche Two [Member] \| IPO [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period deferred		1 year
Restricted Stock And Restricted Stock Units [Member] \| Maximum [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Percentage of vesting of restricted stock and restricted stock units		20.00%
Share-based compensation arrangement by share-based payment award, award vesting period		4 years
Restricted Stock And Restricted Stock Units [Member] \| Maximum [Member] \| Share-based Payment Arrangement, Tranche Two [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Percentage of vesting of restricted stock and restricted stock units		100.00%
Share-based compensation arrangement by share-based payment award, award vesting period		5 years
Restricted Stock And Restricted Stock Units [Member] \| Maximum [Member] \| Share-based Payment Arrangement, Tranche Three [Member] \| IPO [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		5 years
Restricted Stock And Restricted Stock Units [Member] \| Minimum [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		1 year
Restricted Stock And Restricted Stock Units [Member] \| Minimum [Member] \| Share-based Payment Arrangement, Tranche Two [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Percentage of vesting of restricted stock and restricted stock units		25.00%
Share-based compensation arrangement by share-based payment award, award vesting period		5 years
Restricted Stock And Restricted Stock Units [Member] \| Minimum [Member] \| Share-based Payment Arrangement, Tranche Three [Member] \| IPO [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		1 year
Unvested Restricted Stock And Restricted Stock Units [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized compensation expense related to unvested restricted stock				64,360,347		64,360,347
Performance Shares [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Award, Number of Shares Authorized	1,500,000			1,500,000		1,500,000
Wighted average exercise price				$ 1.95		$ 1.95
share related expenses				$ 86		$ 86
Performance Shares [Member] \| Common Class A [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Issuance of shares	3,000,000
Employee Stock [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Wighted average exercise price								$ 2.16
share related expenses				$ 180		180
Stock Issued under Employee Stock Purchase Plan						10,000
Employee Stock [Member] \| Common Class A [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Maximum Value of Shares Per Employee can purchase under the plan						$ 25,000