Equity-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Apr. 30, 2019
Other disclosures
Equity-based compensation	$ 1,395	$ 404
Selling, general and administrative expenses
Other disclosures
Equity-based compensation	$ 1,200	$ 300
Stock Options
Number of Options
Outstanding, beginning of the period (in shares)	2,080
Options granted (in shares)	85	0
Options exercised (in shares)	(9)
Options forfeited (in shares)	(6)
Outstanding, end of the period (in shares)	2,150		2,080
Exercisable at end of period (in shares)	1,645
Vested and expected to vest at end of period (in shares)	2,144
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)	$ 16.34
Options granted (in dollars per share)	18.04
Options exercised (in dollars per share)	14.77
Options forfeited (in dollars per share)	37.49
Outstanding, end of the period (in dollars per share)	16.36		$ 16.34
Exercisable at end of period (in dollars per share)	13.70
Vested and expected to vest at end of period (in dollars per share)	$ 16.33
Other disclosures
Weighted Average Remaining Contractual Life, Outstanding (in years)	6 years 14 days		6 years 1 month 24 days
Weighted Average Remaining Contractual Life, Exercisable at end of period (in years)	5 years 1 month 28 days
Weighted Average Remaining Contractual Life, Vested and expected to vest at end of period (in years)	6 years 10 days
Aggregate Intrinsic Value, Outstanding	$ 15,284		$ 7,615
Aggregate Intrinsic Value, Exercisable at end of period	14,902
Aggregate Intrinsic Value, Vested and expected to vest at end of period	15,284
Intrinsic value of options exercised	100	$ 500
Unrecognized compensation cost	$ 3,200
Weighted-average period for recognition of unrecognized compensation expense (in years)	2 years 1 month 6 days