Antidilutive securities excluded from computation of earnings per share amount subject to adjustment.

No definition available.

Name:	bill_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmountSubjectToAdjustment
Namespace Prefix:	bill_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

+ Details

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6031898-161870

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=bill_ConvertibleSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=bill_TwoThousandTwentySevenConvertibleSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=bill_TwoThousandTwentyFiveConvertibleSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=bill_SharesUnderConversionOptionInNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Net Loss Per Share Attributable To Common Stockholders - Additional Information (Details) - $ / shares shares in Thousands	3 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 24, 2021	Nov. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Number of shares not considered in calculation of diluted net loss per share	8,657	9,089
Notes \| Maximum
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Number of shares subject to adjustment	12,700
2027 Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Conversion price per share			$ 414.80
2027 Notes \| Common Stock \| Maximum
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Conversion price per share	$ 414.80
2025 Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Conversion price per share				$ 160.88
2025 Notes \| Common Stock \| Maximum
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Conversion price per share	$ 160.88
Shares Underlying Conversion Option in Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Number of shares not considered in calculation of diluted net loss per share	8,500