Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Conversion of Redeemable Convertible Preferred Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Deficit
Redeemable convertible preferred stock, balance (in shares) at Dec. 31, 2016		33,446,250
Redeemable convertible preferred stock, balance at Dec. 31, 2016		$ 200,082
Increase (Decrease) in Redeemable Convertible Preferred Stock [Roll Forward]
Issuance of Series G redeemable convertible preferred stock (in shares)	8,181,957
Issuance of Series G redeemable convertible preferred stock (in shares)	$ 133,936
Redeemable convertible preferred stock, balance (in shares) at Dec. 31, 2017		41,628,207
Redeemable convertible preferred stock, balance at Dec. 31, 2017		$ 334,018
Balance (in shares) at Dec. 31, 2016			0	16,693,380	(188,480)
Balance at Dec. 31, 2016	(149,084)		$ 0	$ 0	$ (488)	$ 51,474	$ (200,070)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				1,401,872
Issuance of common stock upon exercise of stock options	1,767					1,767
Issuance of common stock in acquisitions (in shares)				2,678,189
Issuance of common stock, acquisitions	18,243					18,243
Vesting of early exercised stock options	366					366
Stock-based compensation	11,441					11,441
Net loss	(38,547)						(38,547)
Balance (in shares) at Dec. 31, 2017			0	20,773,441	(188,480)
Balance at Dec. 31, 2017	$ (155,814)		$ 0	$ 0	$ (488)	83,291	(238,617)
Increase (Decrease) in Redeemable Convertible Preferred Stock [Roll Forward]
Automatic conversion of warrants in connection with initial public offering (in shares)		(41,628,207)
Automatic conversion of warrants in connection with initial public offering		$ (334,018)
Redeemable convertible preferred stock, balance (in shares) at Dec. 31, 2018		0
Redeemable convertible preferred stock, balance at Dec. 31, 2018		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	1,727,899			1,727,899
Issuance of common stock upon exercise of stock options	$ 8,108					8,108
Issuance of common stock in acquisitions (in shares)				757,218
Issuance of common stock, acquisitions	8,832					8,832
Issuance of common stock for settlement of RSUs (in shares)				802,900
Issuance of common stock for settlement of RSUs	0
Issuance of common stock in connection with the initial public offering, net of underwriting discounts and commissions (in shares)			11,500,000
Issuance of common stock in connection with the initial public offering, net of underwriting discounts and commissions	245,985					245,985
Conversion of convertible stock (in shares)				42,188,624
Conversion of convertible stock	334,018					334,018
Automatic conversion of warrants in connection with initial public offering (in shares)				997,193
Automatic conversion of warrants in connection with initial public offering	21,465					21,465
Costs related to initial public offering	(5,450)					(5,450)
Issuance of restricted stock awards (in shares)			2,993
Issuance of restricted stock awards	0
Shares withheld related to net share settlement (in shares)				(391,874)
Shares withheld related to net share settlement	(9,013)					(9,013)
Vesting of early exercised stock options	366					366
Stock-based compensation	30,803					30,803
Net loss	(64,078)						(64,078)
Balance (in shares) at Dec. 31, 2018			11,502,993	66,855,401	(188,480)
Balance at Dec. 31, 2018	$ 415,222		$ 0	$ 0	$ (488)	718,405	(302,695)
Redeemable convertible preferred stock, balance (in shares) at Dec. 31, 2019		0
Redeemable convertible preferred stock, balance at Dec. 31, 2019		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	6,465,360		6,209,953	255,407
Issuance of common stock upon exercise of stock options	$ 40,669					40,669
Issuance of common stock for settlement of RSUs (in shares)			353,407
Issuance of common stock for settlement of RSUs	0
Issuance common stock for ESPP Purchase (in shares)			271,294
Issuance of common stock for ESPP Purchase	3,631					3,631
Conversion of convertible stock (in shares)			43,255,565	(43,255,565)
Conversion of convertible stock	0		$ 1			(1)
Issuance of restricted stock awards (in shares)			394,558
Issuance of restricted stock awards	0
Shares withheld related to net share settlement (in shares)			(124,153)
Shares withheld related to net share settlement	(2,821)					(2,821)
Retirement of treasury shares (in shares)					188,480
Retirement of treasury shares	0				$ 488	(488)
Vesting of early exercised stock options	367					367
Stock-based compensation	38,878					38,878
Net loss	(68,760)						(68,760)
Balance (in shares) at Dec. 31, 2019			61,863,617	23,855,243	0
Balance at Dec. 31, 2019	$ 425,815		$ 1	$ 0	$ 0	$ 798,640	$ (372,826)