Commitments and Contingencies (Details)		1 Months Ended	3 Months Ended	12 Months Ended
	Jun. 13, 2017 USD ($) Option	Oct. 31, 2015 USD ($)	Oct. 31, 2015 USD ($)	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)	Jul. 01, 2017 USD ($)
Future minimum lease payments under noncancelable operating leases
2018				$ 3,492,000
2019				3,046,000
2020				2,888,000
2021				2,042,000
2022				1,648,000
Thereafter				2,631,000
Total				15,747,000
Future minimum lease payments under non cancellable capital leases
2018				304,000
2019				168,000
Total				472,000
Less: amounts representing interest				(23,000)
Present value of capital lease obligations				449,000
Less: Current portion				(288,000)
Long-term portion of capital lease obligations				161,000	$ 449,000
Rental expense under operating leases				4,612,000	4,820,000	$ 4,350,000
Tenant improvement allowance	$ 420,332
Percentage of increase to base monthly rent	2.50%
Option to extend | Option	2
Years extended	5 years
Letters of credit outstanding				$ 2,070,000	1,080,000
Period of claims				P3Y
Paid Settlement agreement		$ 50,000
Cost of sales				$ 162,763,000	151,995,000	155,130,000
ASBC
Future minimum lease payments under non cancellable capital leases
Cost of sales			$ 3,500,000	3,607,000
UAS
Future minimum lease payments under non cancellable capital leases
Cost of sales				135,937,000	132,209,000	128,233,000
UAS | ASBC
Future minimum lease payments under non cancellable capital leases
Cost of sales				3,203,000,000
EES
Future minimum lease payments under non cancellable capital leases
Cost of sales				26,826,000	$ 19,786,000	$ 26,897,000
EES | ASBC
Future minimum lease payments under non cancellable capital leases
Cost of sales				$ 404,000,000
Expected
Future minimum lease payments under non cancellable capital leases
Base monthly rent							$ 65,200