Equity-Based Compensation - (Tables)

9 Months Ended

Jan. 31, 2018

Equity-Based Compensation

Summary of stock option activity

				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Options	Price		Life (years)	Value
	(shares and dollars in thousands)
Outstanding as of May 1, 2017	2,088	$	13.49	7.23	$	47,336
Options granted	63		37.49
Options exercised	(171)		12.56
Options forfeited	—		—
Options expired	—		—
Outstanding as of January 31, 2018	1,980	$	14.34	6.58	$	39,493
Exercisable as of January 31, 2018	1,559	$	12.89	6.33	$	33,339
Vested and expected to vest as of January 31, 2018	1,980	$	14.34	7.52	$	39,493

Schedule of weighted average assumptions used in Black-Scholes option-pricing model

	Nine Months Ended
	January 31,
	2018		2017
Volatility	30.86	%	41.10	%
Expected life (years)	6.0		6.0
Risk-free interest rate	2.18	%	1.53	%
Dividend yield	—	%	—	%