2. Summary of Significant Accounting Policies (Details - Useful life)	9 Months Ended
Jan. 31, 2021
Leasehold Improvements [Member]
Useful lives of property and equipment	Shorter of estimated useful life or lease term
Laboratory and Manufacturing Equipment [Member]
Useful lives of property and equipment	5-10 years
Computer equipment and software [Member]
Useful lives of property and equipment	3-5 years
Furniture, fixtures and office equipment [Member]
Useful lives of property and equipment	5-10 years

Describes the periods of time over which an entity anticipates to receive utility from its property, plant and equipment (that is, the periods of time over which an entity allocates the initial cost of its property, plant and equipment).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 35
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68071081&loc=d3e1205-110223

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration