CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ 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, 2020		103,179
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 (in shares)		688
Issuance of common stock under stock plans	(66)	$ 1	(67)
Stock-based compensation expense	23,118		23,118
Issuance of common stock related to acquisition	8,489		8,489
Unrealized investment (loss) gain	422			422
Foreign currency translation adjustment	885			885
Net loss	(41,913)				(41,913)
Ending balance (in shares) at Jun. 30, 2020		103,867
Ending balance at Jun. 30, 2020	178,866	$ 104	657,014	(10,869)	(467,383)
Beginning balance (in shares) at Mar. 31, 2020		103,179
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 (loss) gain	379
Foreign currency translation adjustment	3,830
Net loss	(80,326)
Ending balance (in shares) at Sep. 30, 2020		105,986
Ending balance at Sep. 30, 2020	174,459	$ 106	688,116	(7,967)	(505,796)
Beginning balance (in shares) at Jun. 30, 2020		103,867
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 (in shares)		2,119
Issuance of common stock under stock plans	4,708	$ 2	4,706
Stock-based compensation expense	26,396		26,396
Unrealized investment (loss) gain	(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
Ending balance at Sep. 30, 2020	174,459	$ 106	688,116	(7,967)	(505,796)
Beginning balance (in shares) at Mar. 31, 2021		109,135
Beginning balance at Mar. 31, 2021	160,504	$ 109	755,643	(4,193)	(591,055)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans (in shares)		1,562
Issuance of common stock under stock plans	3,440	$ 2	3,438
Stock-based compensation expense	36,508		36,508
Unrealized investment (loss) gain	(33)			(33)
Foreign currency translation adjustment	283			283
Net loss	(43,906)				(43,906)
Ending balance (in shares) at Jun. 30, 2021		110,697
Ending balance at Jun. 30, 2021	156,796	$ 111	795,589	(3,943)	(634,961)
Beginning balance (in shares) at Mar. 31, 2021		109,135
Beginning balance at Mar. 31, 2021	160,504	$ 109	755,643	(4,193)	(591,055)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized investment (loss) gain	(48)
Foreign currency translation adjustment	(1,866)
Net loss	(86,230)
Ending balance (in shares) at Sep. 30, 2021		113,416
Ending balance at Sep. 30, 2021	152,551	$ 113	835,830	(6,107)	(677,285)
Beginning balance (in shares) at Jun. 30, 2021		110,697
Beginning balance at Jun. 30, 2021	156,796	$ 111	795,589	(3,943)	(634,961)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock plans (in shares)		2,721
Issuance of common stock under stock plans	6,760	$ 2	6,758
Stock-based compensation expense	33,483		33,483
Issuance of common stock related to acquisitions (in shares)		(1)
Issuance of common stock related to acquisition	0
Unrealized investment (loss) gain	(15)
Foreign currency translation adjustment	(2,149)
Net loss	(42,324)
Ending balance (in shares) at Sep. 30, 2021		113,416
Ending balance at Sep. 30, 2021	$ 152,551	$ 113	$ 835,830	$ (6,107)	$ (677,285)