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)		270,000
Issuance of common stock upon the exercise of options	10,147		10,147
Vesting of restricted stock units (in shares)		731,000
Shares issued under employee stock purchase plan (in shares)		90,000
Shares issued under employee stock purchase plan	3,927		3,927
Stock-based compensation	38,309		38,309
Net loss	(12,269)			(12,269)
Other comprehensive income, net of tax	1,376				1,376
Ending balance (in shares) at Jun. 30, 2019		59,977,000
Ending balance at Jun. 30, 2019	106,733	$ 6	637,770	(532,895)	1,852
Beginning balance (in shares) at Mar. 31, 2019		59,407,000
Beginning balance at Mar. 31, 2019	84,901	$ 6	608,168	(524,090)	817
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)		141,000
Issuance of common stock upon the exercise of options	5,163		5,163
Vesting of restricted stock units (in shares)		339,000
Shares issued under employee stock purchase plan (in shares)		90,000
Shares issued under employee stock purchase plan	3,927		3,927
Stock-based compensation	20,512		20,512
Net loss	(8,805)			(8,805)
Other comprehensive income, net of tax	1,035				1,035
Ending balance (in shares) at Jun. 30, 2019		59,977,000
Ending balance at Jun. 30, 2019	106,733	$ 6	637,770	(532,895)	1,852
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)	704,000	704,000
Issuance of common stock upon the exercise of options	$ 8,188		8,188
Vesting of restricted stock units (in shares)		1,078,000
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	41,388		41,388
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	(25,762)			(25,762)
Other comprehensive income, net of tax	3,387				3,387
Ending balance (in shares) at Jun. 30, 2020		64,060,000
Ending balance at Jun. 30, 2020	241,540	$ 6	788,150	(550,442)	3,826
Beginning balance (in shares) at Mar. 31, 2020		62,512,000
Beginning balance at Mar. 31, 2020	181,258	$ 6	716,158	(538,455)	3,549
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of options (in shares)		5,000
Issuance of common stock upon the exercise of options	107		107
Vesting of restricted stock units (in shares)		303,000
Vesting of restricted stock units	$ 0
Shares issued under employee stock purchase plan (in shares)	130,177	130,000
Shares issued under employee stock purchase plan	$ 4,370		4,370
Stock-based compensation	16,028		16,028
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	(11,987)			(11,987)
Other comprehensive income, net of tax	277				277
Ending balance (in shares) at Jun. 30, 2020		64,060,000
Ending balance at Jun. 30, 2020	$ 241,540	$ 6	$ 788,150	$ (550,442)	$ 3,826