SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Advertising, Warranty, PPP (Details) - USD ($)	1 Months Ended	12 Months Ended
Apr. 30, 2020	Apr. 30, 2020	Apr. 30, 2019
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Advertising costs		$ 9,000	$ 0
Provided limited warranty period		1 year
Amount of promissory note relating to PPP	$ 1,985,000	$ 1,985,000
Amount of PPP expenses	$ 440,000

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 720
-SubTopic 35
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848

Name:	us-gaap_AdvertisingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration