CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (shares) at Mar. 31, 2018		92,847,354
Beginning balance at Mar. 31, 2018	$ 218,774	$ 93	$ 425,790	$ (5,645)	$ (201,464)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans, less withholding (shares)		403,377
Issuance of common stock under stock plans, less withholding	777		777
Stock-based compensation expense	9,304		9,304
Unrealized investment gain	113			113
Foreign currency translation adjustment	(1,672)			(1,672)
Net loss	(15,355)				(15,355)
Ending balance (shares) at Jun. 30, 2018		93,250,731
Ending balance at Jun. 30, 2018	251,842	$ 93	435,871	(7,204)	(176,918)
Beginning balance (shares) at Mar. 31, 2018		92,847,354
Beginning balance at Mar. 31, 2018	218,774	$ 93	425,790	(5,645)	(201,464)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	(2,051)
Net loss	(36,837)
Ending balance (shares) at Sep. 30, 2018		95,091,118
Ending balance at Sep. 30, 2018	239,364	$ 94	445,104	(7,434)	(198,400)
Beginning balance (shares) at Jun. 30, 2018		93,250,731
Beginning balance at Jun. 30, 2018	251,842	$ 93	435,871	(7,204)	(176,918)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans, less withholding (shares)		1,840,387
Issuance of common stock under stock plans, less withholding	(595)	$ 1	(596)
Stock-based compensation expense	9,829		9,829
Unrealized investment gain	149			149
Foreign currency translation adjustment	(379)			(379)
Net loss	(21,482)				(21,482)
Ending balance (shares) at Sep. 30, 2018		95,091,118
Ending balance at Sep. 30, 2018	239,364	$ 94	445,104	(7,434)	(198,400)
Beginning balance (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 (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	121			121
Foreign currency translation adjustment	(652)			(652)
Net loss	(34,265)				(34,265)
Ending balance (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 (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]
Foreign currency translation adjustment	(3,905)
Net loss	(75,197)
Ending balance (shares) at Sep. 30, 2019		99,808,688
Ending balance at Sep. 30, 2019	238,877	$ 100	575,416	(11,140)	(325,499)
Beginning balance (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 (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 (shares)		1,476,009
Issuance of common stock related to acquisitions	35,839	$ 1	35,838
Unrealized investment gain	(3)			(3)
Foreign currency translation adjustment	(3,253)			(3,253)
Net loss	(40,932)				(40,932)
Ending balance (shares) at Sep. 30, 2019		99,808,688
Ending balance at Sep. 30, 2019	$ 238,877	$ 100	$ 575,416	$ (11,140)	$ (325,499)