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://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 2: 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=118260190&loc=d3e13531-108611

Reference 3: 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=118260190&loc=d3e13537-108611

Reference 4: 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

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Customers with 10% (or greater) of Net Revenues - Additional information (Detail) - Revenue [Member]	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Customer One [Member]
Concentration Risk [Line Items]
Percentage of concentration	13.40%
Percentage of concentration description		less than 1%
Customer Two [Member]
Concentration Risk [Line Items]
Percentage of concentration	13.20%
Percentage of concentration description		less than 1%
Customer Three [Member]
Concentration Risk [Line Items]
Percentage of concentration		24.70%
Customer Four [Member]
Concentration Risk [Line Items]
Percentage of concentration		22.90%
Customer Five [Member]
Concentration Risk [Line Items]
Percentage of concentration		14.80%
Customer Six [Member]
Concentration Risk [Line Items]
Percentage of concentration		13.70%