For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13531-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13537-108611

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Revenue - Customer Concentration (Details) - Customer Concentration Risk	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Revenue \| Customer One
Disaggregation of Revenue [Line Items]
Customer concentration risk, percentage	19.00%	26.00%	14.00%
Revenue \| Customer Two
Disaggregation of Revenue [Line Items]
Customer concentration risk, percentage	12.00%	10.00%	12.00%
Accounts Receivable \| Customer One
Disaggregation of Revenue [Line Items]
Customer concentration risk, percentage	18.00%	33.00%
Accounts Receivable \| Customer Two
Disaggregation of Revenue [Line Items]
Customer concentration risk, percentage	14.00%	19.00%
Accounts Receivable \| Customer Three
Disaggregation of Revenue [Line Items]
Customer concentration risk, percentage	14.00%	15.00%
Accounts Receivable \| Customer Four
Disaggregation of Revenue [Line Items]
Customer concentration risk, percentage	11.00%