Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock:	Accumulated other comprehensive income (loss):	Additional paid-in capital:	Accumulated deficit:	Restatement adjustment Additional paid-in capital:
Balance, beginning of period at Dec. 31, 2018		$ 8	$ (5)	$ 678,548	$ (516,712)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued		2		204,024
Unrealized income (loss) on available-for-sale marketable securities, net of tax	$ 5		5
Common stock issued on exercise of stock options, net				2,985
Common stock issued pursuant to exercises of warrants				171
Common stock issued pursuant to employee stock purchase plan				2,578
Common stock issued or issuable pursuant to business combinations				95,220
Equity component of convertible senior notes, net				75,488
Stock-based compensation expense				26,629
Net loss	(165,060)
Balance, end of period at Sep. 30, 2019	403,881	10	0	1,085,643	(681,772)
Balance, beginning of period at Jun. 30, 2019		9	0	944,559	(603,065)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued		1		19,534
Unrealized income (loss) on available-for-sale marketable securities, net of tax	0
Common stock issued on exercise of stock options, net				553
Common stock issued pursuant to exercises of warrants				58
Common stock issued or issuable pursuant to business combinations				35,778
Equity component of convertible senior notes, net				75,488
Stock-based compensation expense				9,673
Net loss	(78,707)				(78,707)
Balance, end of period at Sep. 30, 2019	403,881	10	0	1,085,643	(681,772)
Balance, beginning of period at Dec. 31, 2019	379,640	10	(9)	1,138,316	(758,677)
Balance, beginning of period (Immaterial error related to classification of Indemnification from acquisition) at Dec. 31, 2019						$ (10,387)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued		3		217,486
Unrealized income (loss) on available-for-sale marketable securities, net of tax	208		208
Common stock issued on exercise of stock options, net				4,163
Common stock issued pursuant to exercises of warrants				386
Common stock issued pursuant to employee stock purchase plan				4,527
Common stock issued or issuable pursuant to business combinations				134,445
Stock-based compensation expense				53,912
Net loss	(367,832)
Balance, end of period at Sep. 30, 2020	416,551	13	199	1,542,848	(1,126,509)
Balance, beginning of period at Jun. 30, 2020		13	572	1,487,217	(1,023,607)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized income (loss) on available-for-sale marketable securities, net of tax	(373)		(373)
Common stock issued on exercise of stock options, net				1,992
Common stock issued pursuant to exercises of warrants				324
Common stock issued or issuable pursuant to business combinations				31,939
Stock-based compensation expense				21,376
Net loss	(102,902)				(102,902)
Balance, end of period at Sep. 30, 2020	$ 416,551	$ 13	$ 199	$ 1,542,848	$ (1,126,509)