Stock-Based Compensation (Tables)

6 Months Ended

Sep. 30, 2022

Stock-Based Compensation Recognized

The following table summarizes stock-based compensation expense by financial statement line item in the Company’s condensed consolidated statements of operations for each of the three and six months ended September 30, 2022 and 2021:

	For the Three Months Ended September 30,				For the Six Months Ended September 30,
	2022		2021		2022		2021
	(in thousands)
Cost of revenue	$	1,358	$	1,300	$	2,754	$	2,330
Research and development		2,976		2,294		5,774		4,403
Selling, general and administrative		11,680		12,155		20,848		21,624
	$	16,014	$	15,749	$	29,376	$	28,357

Summary of Stock Option Activity

The following table summarizes the stock option activity for the six months ended September 30, 2022:

						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Options			Exercise		Contractual		Value
	(in thousands)			Price		Term (years)		(in thousands)
Outstanding at beginning of period		595		$	178.54		5.55
Granted		5			267.96
Exercised		(21	)		93.07
Cancelled and expired		(3	)		285.00
Outstanding at end of period		576		$	182.01		5.14	$	49,789
Exercisable at end of period		500		$	169.15		4.64	$	49,167
Options vested and expected to vest at end of period		576		$	182.01		5.14	$	49,789

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 were as follows:

	For the Three Months Ended September 30,						For the Six Months Ended September 30,
	2022			2021			2022			2021
Weighted average grant-date fair value	$	118.40		$	115.99		$	119.74		$	103.48
Valuation assumptions:
Risk-free interest rate		3.32	%		0.77	%		3.20	%		0.79	%
Expected option life (years)		5.60			4.14			5.58			4.20
Expected volatility		43.49	%		44.72	%		43.50	%		44.30	%

Restricted Stock Units

Summary of Restricted Stock Units Activity

The following table summarizes activity of restricted stock units for the six months ended September 30, 2022:

				Weighted
				Average
	Number of			Grant Date
	Shares			Fair Value
	(in thousands)			(per share)
Restricted stock units at beginning of period		307		$	274.32
Granted (1)		267			266.68
Vested		(122	)		284.98
Forfeited		(7	)		275.21
Restricted stock units at end of period		445		$	266.72

(1) Includes 19,000 performance-based awards granted due to greater than 100% target vesting.

Summary of Assumptions Used To Value Awards And Estimated Grant-Date Fair Value

The table below sets forth the assumptions used to value the outstanding market-based restricted stock units and the estimated grant-date fair value:

	May 2021			May 2020
Risk-free interest rate		0.3	%		0.2	%
Expected volatility		44.8	%		35.5	%
Dividend yield		—			—
Remaining performance period (years)	2.8				2.9
Estimated fair value per share	$	292.40		$	349.28
Target performance (number of shares)		25,172			15,425