Debt instrument reduction in basis spread on variable rate.

No definition available.

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility initiation date.

+ References

No definition available.

+ Details

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Namespace Prefix:	bill_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility maximum borrowing capacity subject to certain conditions.

+ References

No definition available.

+ Details

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Namespace Prefix:	bill_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Balance Type:
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- Details

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- Details

Name:	srt_RangeAxis=srt_MinimumMember
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- Details

Name:	srt_RangeAxis=srt_MaximumMember
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- Details

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- Details

Name:	us-gaap_VariableRateAxis=bill_AlternativeBaseRateMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_LineOfCreditFacilityAxis=bill_SiliconValleyBankMember
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Balance Type:
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- Details

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- Details

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Balance Type:
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
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Bank Borrowings - Additional Information (Details) - USD ($)		6 Months Ended
	Jun. 28, 2019	Dec. 31, 2019	Aug. 15, 2019
Senior Facilities Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, expiration date	Jun. 28, 2022
Line of credit facility, borrowing outstanding		$ 0
Line of credit facility, remaining borrowing capacity		43,100,000
Senior Facilities Agreement \| Eurodollar Rate
Line Of Credit Facility [Line Items]
Debt instrument basis spread on variable rate	1.25%
Senior Facilities Agreement \| Eurodollar Rate \| Minimum
Line Of Credit Facility [Line Items]
Debt instrument basis spread on variable rate	1.75%
Senior Facilities Agreement \| Eurodollar Rate \| Maximum
Line Of Credit Facility [Line Items]
Debt instrument basis spread on variable rate	2.75%
Senior Facilities Agreement \| London Interbank Offered Rate \| Maximum
Line Of Credit Facility [Line Items]
Debt instrument basis spread on variable rate	0.00%
Senior Facilities Agreement \| Alternative Base Rate \| Minimum
Line Of Credit Facility [Line Items]
Debt instrument reduction in basis spread on variable rate	0.25%
Senior Facilities Agreement \| Alternative Base Rate \| Maximum
Line Of Credit Facility [Line Items]
Debt instrument reduction in basis spread on variable rate	1.25%
Senior Facilities Agreement \| Federal Funds Effective Rate
Line Of Credit Facility [Line Items]
Debt instrument basis for effective rate	0.50%
Senior Facilities Agreement \| Silicon Valley Bank
Line Of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 50,000,000
Line of credit facility maximum borrowing capacity subject to certain conditions	$ 25,000,000
Senior Facilities Agreement \| Silicon Valley Bank \| JP Morgan Chase Bank
Line Of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity			$ 20,000,000
Loan Agreement \| Silicon Valley Bank
Line Of Credit Facility [Line Items]
Line of credit facility, expiration date	Jun. 28, 2019
Line of credit facility initiation date	2017-10
Letter of Credit
Line Of Credit Facility [Line Items]
Line of credit facility, utilization		$ 6,900,000