Condensed Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock Series C Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital Series C Redeemable Convertible Preferred Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Series C Redeemable Convertible Preferred Stock	Total
Beginning Balance at Dec. 31, 2019		$ 3		$ 203,492	$ (263,474)			$ (59,979)
Beginning Balance (in shares) at Dec. 31, 2019		34,197,822
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(18,367)			(18,367)
Other comprehensive income						$ 3,856		3,856
Stock-based compensation				672				672
Issuance of Series C redeemable convertible preferred stock			$ 4,714				$ 4,714
Issuance of Series C redeemable convertible preferred stock (in shares)	671,836
Conversion of convertible notes to Series C redeemable convertible preferred stock			1,436				1,436
Conversion of convertible notes to Series C redeemable convertible preferred stock (in shares)	198,750
Vesting of restricted stock awards issued for acquisitions (in shares)		472,141
Issuance of common stock warrants				44				44
Exercise of stock options				1				1
Exercise of stock options (in shares)		8,409
Ending Balance at Mar. 31, 2020		$ 3		210,359	(281,841)	3,856		(67,623)
Ending Balance (in shares) at Mar. 31, 2020		35,548,958
Beginning Balance at Dec. 31, 2019		$ 3		203,492	(263,474)			(59,979)
Beginning Balance (in shares) at Dec. 31, 2019		34,197,822
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss								(33,548)
Ending Balance at Sep. 30, 2020		$ 3		212,999	(296,884)			(83,882)
Ending Balance (in shares) at Sep. 30, 2020		35,973,151
Beginning Balance at Mar. 31, 2020		$ 3		210,359	(281,841)	3,856		(67,623)
Beginning Balance (in shares) at Mar. 31, 2020		35,548,958
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(6,258)			(6,258)
Other comprehensive income						(3,856)		(3,856)
Stock-based compensation				362				362
Issuance of common stock for acquisitions				39				39
Issuance of common stock for acquisitions (in shares)		11,744
Exercise of stock options (in shares)		1,174
Ending Balance at Jun. 30, 2020		$ 3		210,760	(288,099)			(77,336)
Ending Balance (in shares) at Jun. 30, 2020		35,561,876
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(8,923)			(8,923)
Stock-based compensation				507				507
Issuance of Series C redeemable convertible preferred stock			$ 122				$ 122
Issuance of Series C redeemable convertible preferred stock (in shares)	10,703
Repurchase of redeemable convertible stock				(480)				(480)
Repurchase of redeemable convertible stock (in shares)		(75,162)
Issuance of common stock for acquisitions				1,790				1,790
Issuance of common stock for acquisitions (in shares)		396,713
Shareholder contribution				300				300
Exercise of stock options					138			138
Exercise of stock options (in shares)		79,021
Ending Balance at Sep. 30, 2020		$ 3		212,999	(296,884)			(83,882)
Ending Balance (in shares) at Sep. 30, 2020		35,973,151
Beginning Balance at Dec. 31, 2020		$ 8		424,823	(317,506)			107,325
Beginning Balance (in shares) at Dec. 31, 2020		81,669,151
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(65,101)			(65,101)
Stock-based compensation				4,462				4,462
Stock-based compensation - earnout				12,373				12,373
Issuance of common stock for acquisitions				1,169				1,169
Issuance of common stock for acquisitions (in shares)		90,000
Reclassification of earnout liability upon vesting				25,815				25,815
Vesting of restricted stock units (in shares)		2,078,102
Exercise of stock warrants		$ 1		93,007				93,008
Exercise of stock warrants (in shares)		8,087,623
Exercise of stock options				355				355
Exercise of stock options (in shares)		593,106
Income tax withholdings				(16,997)				(16,997)
Income tax withholdings (in shares)		(1,062,250)
Transaction costs				(402)				(402)
Ending Balance at Mar. 31, 2021		$ 9		544,605	(382,607)			162,007
Ending Balance (in shares) at Mar. 31, 2021		91,455,732
Beginning Balance at Dec. 31, 2020		$ 8		424,823	(317,506)			107,325
Beginning Balance (in shares) at Dec. 31, 2020		81,669,151
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss								(86,497)
Ending Balance at Sep. 30, 2021		$ 10		596,156	(404,003)	113		192,276
Ending Balance (in shares) at Sep. 30, 2021		97,332,998
Beginning Balance at Mar. 31, 2021		$ 9		544,605	(382,607)			162,007
Beginning Balance (in shares) at Mar. 31, 2021		91,455,732
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(16,297)			(16,297)
Other comprehensive income						267		267
Stock-based compensation				2,466				2,466
Stock-based compensation - earnout				4,176				4,176
Issuance of common stock for acquisitions				21,687				21,687
Issuance of common stock for acquisitions (in shares)		1,292,441
Contingent consideration for acquisitions				6,685				6,685
Reclassification of private warrant liability upon exercise				16,843				16,843
Vesting of restricted stock units (in shares)		33,182
Exercise of stock warrants		$ 1		33,761				33,762
Exercise of stock warrants (in shares)		2,862,312
Exercise of stock options				2,227				2,227
Exercise of stock options (in shares)		946,392
Income tax withholdings				(5,194)				(5,194)
Income tax withholdings (in shares)		(296,643)
Transaction costs				140				140
Ending Balance at Jun. 30, 2021		$ 10		627,396	(398,904)	267		228,769
Ending Balance (in shares) at Jun. 30, 2021		96,293,416
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(5,099)			(5,099)
Other comprehensive income						(154)		(154)
Stock-based compensation				1,641				1,641
Stock-based compensation - earnout				4,243				4,243
Issuance of common stock for acquisitions				1,937				1,937
Issuance of common stock for acquisitions (in shares)		102,636
Reclassification of private warrant liability upon exercise				14,505				14,505
Vesting of restricted stock units (in shares)		271,432
Exercise of stock warrants (in shares)		557,816
Exercise of stock options				934				934
Exercise of stock options (in shares)		339,150
Income tax withholdings				(1,587)				(1,587)
Income tax withholdings (in shares)		(231,452)
Capped call transactions				(52,913)				(52,913)
Ending Balance at Sep. 30, 2021		$ 10		$ 596,156	$ (404,003)	$ 113		$ 192,276
Ending Balance (in shares) at Sep. 30, 2021		97,332,998