Subsequent Events	6 Months Ended
Oct. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	(19) Subsequent Events On November 15, 2021, the Company acquired all of the outstanding equity interest of Marine Advanced Robotics, Inc. (“MAR”), a Richmond (San Francisco Bay Area), California-based developer and manufacturer of autonomous surface vehicles (ASVs). The Company paid $11.0 million at closing, consisting of $4.0 million in cash and $7.0 million in common stock (3,330,162 shares). Additional earn-out opportunities for the selling shareholders of MAR exist based on revenue performance through April 2023. The MAR management team and employees have joined the Company and MAR continues to operate under its current brand name as a wholly owned subsidiary of the Company.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

Name:	us-gaap_SubsequentEventsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration