Property and Equipment, net Other (Details) - USD ($)	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Depreciation expense	$ 5,676,000	$ 4,939,000	$ 3,799,000
Computer equipment and software
Depreciation expense	201,000	375,000
Property and equipment under capital lease, cost	1,836,000	1,836,000
Accumulated depreciation of asset under capital lease	$ 1,687,000	$ 1,433,000