CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Cumulative effect, period of adoption, adjustment	Cumulative effect, period of adoption, adjustment Accumulated Deficit
Beginning balance (in shares) at Mar. 31, 2019		96,119,888
Beginning balance at Mar. 31, 2019	$ 249,390	$ 96	$ 506,949	$ (7,353)	$ (250,302)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans, less withholding (in shares)		451,308
Issuance of common stock under stock plans, less withholding	1,494	$ 1	1,493
Stock-based compensation expense	14,059		14,059
Unrealized investment gain/loss	121			121
Foreign currency translation adjustment	(652)			(652)
Net loss	(34,265)				(34,265)
Ending balance (in shares) at Jun. 30, 2019		96,571,196
Ending balance at Jun. 30, 2019	230,147	$ 97	522,501	(7,884)	(284,567)
Beginning balance (in shares) at Mar. 31, 2019		96,119,888
Beginning balance at Mar. 31, 2019	249,390	$ 96	506,949	(7,353)	(250,302)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized investment gain/loss	106
Foreign currency translation adjustment	682
Net loss	(122,268)
Ending balance (in shares) at Dec. 31, 2019		100,784,960
Ending balance at Dec. 31, 2019	219,491	$ 101	598,525	(6,565)	(372,570)
Beginning balance (in shares) at Jun. 30, 2019		96,571,196
Beginning balance at Jun. 30, 2019	230,147	$ 97	522,501	(7,884)	(284,567)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans, less withholding (in shares)		1,761,483
Issuance of common stock under stock plans, less withholding	(788)	$ 2	(790)
Stock-based compensation expense	17,867		17,867
Issuance of common stock related to acquisitions (in shares)		1,476,009
Issuance of common stock related to acquisition	35,839	$ 1	35,838
Unrealized investment gain/loss	(3)			(3)
Foreign currency translation adjustment	(3,253)			(3,253)
Net loss	(40,932)				(40,932)
Ending balance (in shares) at Sep. 30, 2019		99,808,688
Ending balance at Sep. 30, 2019	238,877	$ 100	575,416	(11,140)	(325,499)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans, less withholding (in shares)		976,272
Issuance of common stock under stock plans, less withholding	140	$ 1	139
Stock-based compensation expense	19,881		19,881
Equity component of convertible senior notes, net of issuance costs	3,089		3,089
Unrealized investment gain/loss	(12)			(12)
Foreign currency translation adjustment	4,587			4,587
Net loss	(47,071)				(47,071)
Ending balance (in shares) at Dec. 31, 2019		100,784,960
Ending balance at Dec. 31, 2019	219,491	$ 101	598,525	(6,565)	(372,570)
Beginning balance (in shares) at Mar. 31, 2020		103,178,621
Beginning balance at Mar. 31, 2020	190,731	$ 103	625,474	(12,176)	(422,670)	$ (2,800)	$ (2,800)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans, less withholding (in shares)		688,414
Issuance of common stock under stock plans, less withholding	(66)	$ 1	(67)
Stock-based compensation expense	23,118		23,118
Issuance of common stock related to acquisition	8,489		8,489
Unrealized investment gain/loss	422			422
Foreign currency translation adjustment	885			885
Net loss	(41,913)				(41,913)
Ending balance (in shares) at Jun. 30, 2020		103,867,035
Ending balance at Jun. 30, 2020	178,866	$ 104	657,014	(10,869)	(467,383)
Beginning balance (in shares) at Mar. 31, 2020		103,178,621
Beginning balance at Mar. 31, 2020	190,731	$ 103	625,474	(12,176)	(422,670)	$ (2,800)	$ (2,800)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized investment gain/loss	306
Foreign currency translation adjustment	8,367
Net loss	(120,551)
Ending balance (in shares) at Dec. 31, 2020		107,135,983
Ending balance at Dec. 31, 2020	167,403	$ 107	716,820	(3,503)	(546,021)
Beginning balance (in shares) at Jun. 30, 2020		103,867,035
Beginning balance at Jun. 30, 2020	178,866	$ 104	657,014	(10,869)	(467,383)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans, less withholding (in shares)		2,119,196
Issuance of common stock under stock plans, less withholding	4,708	$ 2	4,706
Stock-based compensation expense	26,396		26,396
Unrealized investment gain/loss	(43)			(43)
Foreign currency translation adjustment	2,945			2,945
Net loss	(38,413)				(38,413)
Ending balance (in shares) at Sep. 30, 2020		105,986,231
Ending balance at Sep. 30, 2020	174,459	$ 106	688,116	(7,967)	(505,796)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans, less withholding (in shares)		1,149,752
Issuance of common stock under stock plans, less withholding	1,347	$ 1	1,346
Stock-based compensation expense	27,358		27,358
Unrealized investment gain/loss	(73)			(73)
Foreign currency translation adjustment	4,537			4,537
Net loss	(40,225)				(40,225)
Ending balance (in shares) at Dec. 31, 2020		107,135,983
Ending balance at Dec. 31, 2020	$ 167,403	$ 107	$ 716,820	$ (3,503)	$ (546,021)