Fair Value - Summary of Redeemable Convertible Preferred Stock Warrant Liability (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Redeemable Convertible Preferred Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning fair value	$ 574	$ 624	$ 42	$ 75
Change in fair value	3	(50)	582	(33)
Ending fair value	577	574	624	42
Derivative Liabilities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning fair value	46,147	44,128	38,007	39,499
Recognition				6,848
Change in fair value	(23,383)	2,019	6,121	(8,340)
Ending fair value	22,764	46,147	44,128	38,007
Contingent Consideration Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning fair value	24,584	23,463	23,667
Recognition				23,842
Change in fair value	(137)	1,121	(204)	(175)
Ending fair value	$ 24,447	$ 24,584	$ 23,463	$ 23,667

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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- Definition

Amount of increase (decrease) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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