STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

The following table presents stock-based compensation expense:

	Three Months Ended September 30,				Six Months Ended September 30,
	2021		2020		2021		2020
Cost of service revenue	$	2,345	$	2,410	$	4,313	$	4,224
Cost of other revenue	1,203		1,113		2,274		1,900
Research and development	9,458		8,255		18,156		14,800
Sales and marketing	12,724		7,054		27,050		12,793
General and administrative	10,105		6,490		20,629		14,384
Total	$	35,835	$	25,322	$	72,422	$	48,101

Schedule of Stock Option Activity

The following table presents stock option activity (shares in thousands):

	Number of Shares	Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding at March 31, 2021	1,813	$	9.46	2.86 years	$	41,673
Granted	—	—
Exercised	(640)	8.60
Cancelled/Forfeited	(18)	21.94
Outstanding at September 30, 2021	1,155	$	9.74	2.70 years	$	15,770
Vested and expected to vest at September 30, 2021	1,155	$	9.73	2.70 years	$	15,766
Exercisable at September 30, 2021	1,136	$	9.57	2.63 years	$	15,697

Schedule of Nonvested Restricted Stock Units Activity

The following table presents RSU activity (shares in thousands):

	Number of Shares	Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding at March 31, 2021	8,646	$	19.27	1.85 years	$	280,467
Granted	4,119	26.07
Vested and released	(3,099)	18.67
Forfeited	(1,126)	20.13
Outstanding at September 30, 2021	8,539	$	22.66	1.07 years	$	199,726

Schedule of Nonvested Performance-based Units Activity

The following table presents PSU activity (shares in thousands):

	Number of Shares	Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding at March 31, 2021	1,576	$	27.33	1.24 years	$	51,116
Granted	497	30.41
Granted for performance achievement1	20	16.12
Vested and released	(206)	16.12
Cancelled/Forfeited	(605)	22.80
Outstanding at September 30, 2021	1,282	$	33.24	1.32 years	$	29,986

Schedule of Share-based Compensation Arrangements by Share-based Payment Award

The following table presents the per share fair values of the first tranche based on the closing price of the Company's common stock on the grant date:

Per share fair values $24.21 - $25.78

The following table presents the estimated grant date fair values, and valuation assumptions used in the Monte Carlo pricing model, of the second and third tranches:

Second tranche per share fair values	$27.66		-	$33.32
Third tranche per share fair values	$29.59		-	$34.48
Valuation assumptions:
Expected volatility	58.7	%	-	59.7%
Risk-free interest rates	0.3	%	-	0.4%
Dividend rate	—%

The following table presents the estimated fair value on the date of grant of each of the look-back features and the assumptions used in the Black-Scholes pricing model:

Fair value of look-back options	$3.88		-	$8.24
Valuation assumptions:
Expected volatility	58.7%
Risk-free interest rates	0.05	%	-	0.07%
Expected terms (in years)	0.38		-	1.21
Dividend rate	—%