Equity-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	Apr. 30, 2019
Other disclosures
Equity-based compensation	$ 2,315	$ 1,094	$ 3,710	$ 1,498
Selling, general and administrative expenses
Other disclosures
Equity-based compensation			$ 3,400	1,300
Stock Options
Number of Options
Outstanding, beginning of the period (in shares)			2,080
Options granted (in shares)			380
Options exercised (in shares)			(534)
Options forfeited (in shares)			(102)
Outstanding, end of the period (in shares)	1,824		1,824		2,080
Exercisable at end of period (in shares)	1,242		1,242
Vested and expected to vest at end of period (in shares)	1,816		1,816
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)			$ 16.34
Options granted (in dollars per share)			21.52
Options exercised (in dollars per share)			12.65
Options forfeited (in dollars per share)			25.59
Outstanding, end of the period (in dollars per share)	$ 17.96		17.96		$ 16.34
Exercisable at end of period (in dollars per share)	15.32		15.32
Vested and expected to vest at end of period (in dollars per share)	$ 17.93		$ 17.93
Other disclosures
Weighted Average Remaining Contractual Life, Outstanding (in years)			6 years 6 months 25 days		6 years 1 month 24 days
Weighted Average Remaining Contractual Life, Exercisable at end of period (in years)			5 years 4 months 6 days
Weighted Average Remaining Contractual Life, Vested and expected to vest at end of period (in years)			6 years 6 months 21 days
Aggregate Intrinsic Value, Outstanding	$ 22,326		$ 22,326		$ 7,615
Aggregate Intrinsic Value, Exercisable at end of period	18,354		18,354
Aggregate Intrinsic Value, Vested and expected to vest at end of period	22,272		22,272
Intrinsic value of options exercised			8,600	$ 700
Unrecognized compensation cost	$ 4,600		$ 4,600
Weighted-average period for recognition of unrecognized compensation expense (in years)			2 years 4 months 24 days