Stock Award Plans and Stock-Based Compensation (Tables)

12 Months Ended

Mar. 31, 2020

Stock-Based Compensation Recognized

The following table summarizes stock-based compensation expense by financial statement line item in the Company’s consolidated statements of operations for the fiscal years ended March 31, 2020, 2019 and 2018:

	Fiscal Years Ended March 31,
		2020		2019		2018
	(in $000's)
Cost of revenue	$	2,641	$	2,643	$	1,721
Research and development		5,534		9,312		5,895
Selling, general and administrative		31,606		42,539		32,737
	$	39,781	$	54,494	$	40,353

Components of Stock-Based Compensation

The components of stock-based compensation for the fiscal years ended March 31, 2020, 2019 and 2018 were as follows:

	Fiscal Years Ended March 31,
		2020		2019		2018
	(in $000's)
Restricted stock units	$	28,895	$	45,998	$	34,559
Stock options		9,006		7,445		5,202
Employee stock purchase plan		1,880		1,051		592
	$	39,781	$	54,494	$	40,353

Summary of Stock Option Activity

The following table summarizes stock option activity for the fiscal year ended March 31, 2020:

	Options        (in thousands)			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (in thousands)
Outstanding at beginning of period		853		$	87.14		5.57
Granted		120			257.88
Exercised		(85	)		44.02
Cancelled and expired		(18	)		224.77
Outstanding at end of period		869		$	112.03		5.30	$	60,113
Exercisable at end of period		652		$	64.38		4.23	$	59,445
Options vested and expected to vest at end of period		867		$	112.03		5.29	$	60,049

Summary of Weighted Average Grant-Date Fair Values And Weighted Average Assumptions Used to Calculate Fair Value of Options Granted

The weighted average grant-date fair values and weighted average assumptions used in the calculation of fair value of options granted during the fiscal years ended March 31, 2020, 2019 and 2018 were as follows:

	Fiscal Years Ended March 31,
		2020			2019			2018
Valuation assumptions:
Weighted average grant-date fair value	$	93.05		$	141.47		$	52.34
Risk-free interest rate		1.97	%		2.91	%		1.87	%
Expected option life (years)		4.14			4.04			4.07
Expected volatility		42.3	%		42.8	%		43.5	%

Restricted Stock Units

Summary of Restricted Stock Units Activity

The following table summarizes restricted stock unit activity for the fiscal year ended March 31, 2020:

	Number of Shares			Weighted Average Grant Date Fair Value
	(in thousands)			(per share)
Restricted stock units at beginning of period		620		$	193.53
Granted		161			258.59
Vested		(393	)		144.62
Forfeited		(68	)		304.90
Restricted stock units at end of period		320		$	263.92