Acquisitions - Additional Information (Detail) $ in Thousands				3 Months Ended	9 Months Ended	12 Months Ended
	Aug. 16, 2021 USD ($) shares	Dec. 11, 2020 USD ($) shares	Nov. 30, 2020 USD ($) shares	Sep. 30, 2021 USD ($) acquisition	Sep. 30, 2021	Dec. 31, 2020 USD ($)
Series of Individually Immaterial Asset Acquisitions
Business Combination and Asset Acquisition [Line Items]
Asset acquisition, number of asset acquisitions | acquisition				2
Asset acquisition, consideration				$ 8,500
Assembled Workforce | Series of Individually Immaterial Asset Acquisitions
Business Combination and Asset Acquisition [Line Items]
Finite lived intangible assets acquired weighted remaining useful lives				3 years
Finite lived intangible assets acquired				$ 8,500
Guilded
Business Combination and Asset Acquisition [Line Items]
Business combination total consideration transferred value	$ 77,559
Payment of cash to acquire business	46,285
Business combination unrecognized share based combination acquiree	$ 8,500
Business combination unrecognized share based combination acquiree period of recognition	3 years
Guilded | Developed Technology
Business Combination and Asset Acquisition [Line Items]
Finite lived intangible assets acquired weighted remaining useful lives					5 years
Guilded | Common Class A
Business Combination and Asset Acquisition [Line Items]
Business combination equity issued (in shares) | shares	500,000
Business combination fair value of equity issued or issuable	$ 31,300
Loomai
Business Combination and Asset Acquisition [Line Items]
Business combination total consideration transferred value		$ 86,694
Payment of cash to acquire business		45,998
Business combination transaction costs expensed		800
Business combination unrecognized share based combination acquiree		$ 9,200
Business combination unrecognized share based combination acquiree period of recognition		3 years
Business combination goodwill deductible for tax purposes		$ 6,700
Loomai | Developed Technology
Business Combination and Asset Acquisition [Line Items]
Finite lived intangible assets acquired weighted remaining useful lives						5 years
Finite lived intangible assets acquired						$ 29,000
Loomai | Common Class A
Business Combination and Asset Acquisition [Line Items]
Business combination equity issued (in shares) | shares		1,300,000
Business combination fair value of equity issued or issuable		$ 40,700
Imbellus
Business Combination and Asset Acquisition [Line Items]
Payment of cash to acquire business			$ 8,800
Business combination equity issued (in shares) | shares			80,000
Business combination fair value of equity issued or issuable			$ 2,900
Imbellus | Developed Technology
Business Combination and Asset Acquisition [Line Items]
Finite lived intangible assets acquired weighted remaining useful lives						5 years
Finite lived intangible assets acquired						$ 11,700