Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
BELGIUM
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	$ 36	$ 22
BRAZIL
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	106	0
FRANCE
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	123	0
CHINA
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	215	713
RUSSIAN FEDERATION
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	94	85
GERMANY
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	31	13
ITALY
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	27	169
KOREA, REPUBLIC OF
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	82	240
SINGAPORE
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	32	82
TAIWAN, PROVINCE OF CHINA
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	101	0
UNITED KINGDOM
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	261	0
Other Countries [Member]
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	315	441
Foreign Revenue [Member]
Segment Information (Details) - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Line Items]
Revenues	$ 1,423	$ 1,765