Condensed Consolidated Statements of Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2018	$ 42,158	$ 30	$ 194,866	$ (147,670)	$ (5,068)
Balance, shares at Dec. 31, 2018		29,700,192
Issuance of common stock, net of cost	138,839	$ 3	138,836
Issuance of common stock, net of cost, shares		2,645,000
Stock-based compensation	7,849		7,849
Vesting of restricted stock units, shares		16,849
Restricted stock units withheld to settle employee tax withholding liability	(333)		(333)
Restricted stock units withheld to settle employee tax withholding liability, shares		(5,301)
Exercise of stock options	8,746		8,746
Exercise of stock options, shares		501,083
Issuance of shares under employee stock purchase plan	1,283		1,283
Issuance of shares under employee stock purchase plan, shares		24,266
Other comprehensive income (loss)	22				22
Net loss	(14,134)			(14,134)
Balance at Mar. 31, 2019	184,430	$ 33	351,247	(161,804)	(5,046)
Balance, shares at Mar. 31, 2019		32,882,089
Balance at Dec. 31, 2018	42,158	$ 30	194,866	(147,670)	(5,068)
Balance, shares at Dec. 31, 2018		29,700,192
Net loss	(39,118)
Balance at Sep. 30, 2019	211,098	$ 34	404,676	(186,788)	(6,824)
Balance, shares at Sep. 30, 2019		33,778,616
Balance at Mar. 31, 2019	184,430	$ 33	351,247	(161,804)	(5,046)
Balance, shares at Mar. 31, 2019		32,882,089
Issuance of common stock, net of cost	(5)		(5)
Stock-based compensation	8,282		8,282
Vesting of restricted stock units, shares		25,720
Restricted stock units withheld to settle employee tax withholding liability	(116)		(116)
Restricted stock units withheld to settle employee tax withholding liability, shares		(1,410)
Exercise of stock options	4,741		4,741
Exercise of stock options, shares		243,920
Other comprehensive income (loss)	271				271
Net loss	(12,063)			(12,063)
Balance at Jun. 30, 2019	185,540	$ 33	364,149	(173,867)	(4,775)
Balance, shares at Jun. 30, 2019		33,150,319
Issuance of common stock in connection with acquisitions	32,838		32,838
Issuance of common stock in connection with acquisition, shares		320,998
Stock-based compensation	8,383		8,383
Vesting of restricted stock units, shares		229,284
Restricted stock units withheld to settle employee tax withholding liability	(4,082)		(4,082)
Restricted stock units withheld to settle employee tax withholding liability, shares		(46,664)
Exercise of stock options	2,335	$ 1	2,334
Exercise of stock options, shares		106,464
Issuance of shares under employee stock purchase plan	1,054		1,054
Issuance of shares under employee stock purchase plan, shares		18,215
Other comprehensive income (loss)	(2,049)				(2,049)
Net loss	(12,921)			(12,921)
Balance at Sep. 30, 2019	211,098	$ 34	404,676	(186,788)	(6,824)
Balance, shares at Sep. 30, 2019		33,778,616
Balance at Dec. 31, 2019	220,312	$ 34	425,945	(199,920)	(5,747)
Balance, shares at Dec. 31, 2019		33,848,627
Issuance of common stock in connection with acquisitions	30,434		30,434
Issuance of common stock in connection with acquisition, shares		301,941
Stock-based compensation	10,368		10,368
Vesting of restricted stock units, shares		44,606
Restricted stock units withheld to settle employee tax withholding liability	(400)		(400)
Restricted stock units withheld to settle employee tax withholding liability, shares		(4,483)
Exercise of stock options	2,989		2,989
Exercise of stock options, shares		126,374
Issuance of shares under employee stock purchase plan	1,710		1,710
Issuance of shares under employee stock purchase plan, shares		30,943
Other comprehensive income (loss)	(6,520)				(6,520)
Net loss	(25,385)			(25,385)
Balance at Mar. 31, 2020	233,508	$ 34	471,046	(225,305)	(12,267)
Balance, shares at Mar. 31, 2020		34,348,008
Balance at Dec. 31, 2019	$ 220,312	$ 34	425,945	(199,920)	(5,747)
Balance, shares at Dec. 31, 2019		33,848,627
Exercise of stock options, shares	275,309
Net loss	$ (68,810)
Balance at Sep. 30, 2020	245,977	$ 35	521,141	(268,730)	(6,469)
Balance, shares at Sep. 30, 2020		34,946,958
Balance at Mar. 31, 2020	233,508	$ 34	471,046	(225,305)	(12,267)
Balance, shares at Mar. 31, 2020		34,348,008
Issuance of common stock in connection with acquisitions	5,074		5,074
Issuance of common stock in connection with acquisition, shares		38,425
Stock-based compensation	11,372		11,372
Vesting of restricted stock units, shares		21,507
Restricted stock units withheld to settle employee tax withholding liability	(527)		(527)
Restricted stock units withheld to settle employee tax withholding liability, shares		(3,980)
Exercise of stock options	1,596		1,596
Exercise of stock options, shares		59,841
Other comprehensive income (loss)	2,343				2,343
Net loss	(19,220)			(19,220)
Balance at Jun. 30, 2020	234,146	$ 34	488,561	(244,525)	(9,924)
Balance, shares at Jun. 30, 2020		34,463,801
Issuance of common stock in connection with acquisitions	17,685		17,685
Issuance of common stock in connection with acquisition, shares		121,858
Stock-based compensation	13,442		13,442
Vesting of restricted stock units, shares		247,669
Restricted stock units withheld to settle employee tax withholding liability	(3,342)		(3,342)
Restricted stock units withheld to settle employee tax withholding liability, shares		(23,618)
Exercise of stock options	2,179	$ 1	2,178
Exercise of stock options, shares		88,974
Issuance of shares under employee stock purchase plan	1,679		1,679
Issuance of shares under employee stock purchase plan, shares		18,376
Settlement of convertible notes due 2022	938		938
Settlement of convertible notes due 2022, shares		29,898
Other comprehensive income (loss)	3,455				3,455
Net loss	(24,205)			(24,205)
Balance at Sep. 30, 2020	$ 245,977	$ 35	$ 521,141	$ (268,730)	$ (6,469)
Balance, shares at Sep. 30, 2020		34,946,958