CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Beginning balance (in shares) at Dec. 31, 2018		58,886,000
Beginning balance at Dec. 31, 2018	$ 65,243	$ 6	$ 585,387	$ (520,626)	$ 476
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)		744,000
Issuance of common stock upon the exercise of options	26,973		26,973
Vesting of restricted stock units (in shares)		1,260,000
Vesting of restricted stock units	0
Shares issued under employee stock purchase plan (in shares)		90,000
Shares issued under employee stock purchase plan	3,927		3,927
Repurchase of common stock (in shares)		(254,000)
Repurchase of common stock	(13,530)		(13,530)
Stock-based compensation	59,141		59,141
Net loss	(13,486)			(13,486)
Other comprehensive income, net of tax	2,741				2,741
Ending balance (in shares) at Sep. 30, 2019		60,726,000
Ending balance at Sep. 30, 2019	131,009	$ 6	661,898	(534,112)	3,217
Beginning balance (in shares) at Jun. 30, 2019		59,977,000
Beginning balance at Jun. 30, 2019	106,733	$ 6	637,770	(532,895)	1,852
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)		474,000
Issuance of common stock upon the exercise of options	16,826		16,826
Vesting of restricted stock units (in shares)		529,000
Vesting of restricted stock units	0
Repurchase of common stock (in shares)		(254,000)
Repurchase of common stock	(13,530)		(13,530)
Stock-based compensation	20,832		20,832
Net loss	(1,217)			(1,217)
Other comprehensive income, net of tax	1,365				1,365
Ending balance (in shares) at Sep. 30, 2019		60,726,000
Ending balance at Sep. 30, 2019	131,009	$ 6	661,898	(534,112)	3,217
Beginning balance (in shares) at Dec. 31, 2019		61,038,000
Beginning balance at Dec. 31, 2019	$ 158,482	$ 6	682,717	(524,680)	439
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)	774,000	774,000
Issuance of common stock upon the exercise of options	$ 9,354		9,354
Vesting of restricted stock units (in shares)		1,502,000
Vesting of restricted stock units	0
Shares issued under employee stock purchase plan (in shares)		130,000
Shares issued under employee stock purchase plan	4,370		4,370
Stock-based compensation	60,664		60,664
Common stock issued in acquisition (in shares)		1,110,000
Common stock issued in acquisition	32,889		32,889
Modification of Convertible Notes	18,598		18,598
Net loss	(41,543)			(41,543)
Other comprehensive income, net of tax	1,937				1,937
Ending balance (in shares) at Sep. 30, 2020		64,554,000
Ending balance at Sep. 30, 2020	244,751	$ 6	808,592	(566,223)	2,376
Beginning balance (in shares) at Jun. 30, 2020		64,060,000
Beginning balance at Jun. 30, 2020	241,540	$ 6	788,150	(550,442)	3,826
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)		70,000
Issuance of common stock upon the exercise of options	1,166		1,166
Vesting of restricted stock units (in shares)		424,000
Vesting of restricted stock units	0
Stock-based compensation	19,276		19,276
Net loss	(15,781)			(15,781)
Other comprehensive income, net of tax	(1,450)				(1,450)
Ending balance (in shares) at Sep. 30, 2020		64,554,000
Ending balance at Sep. 30, 2020	$ 244,751	$ 6	$ 808,592	$ (566,223)	$ 2,376