Amount of base rent expense per square foot for leased asset.

No definition available.

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Namespace Prefix:	btx_
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- Definition

Percentage of securities that would be issuable upon the exercise of warrants or rights.

+ References

No definition available.

+ Details

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- Definition

Warrants or rights exercisable term, , in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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Namespace Prefix:	btx_
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Balance Type:	na
Period Type:	duration

- Definition

The amount of property for which lessee committed to purchase.

+ References

No definition available.

+ Details

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Namespace Prefix:	btx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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Namespace Prefix:	btx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Area of leased property under operating lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	btx_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of base rent increase on each anniversary.

+ References

No definition available.

+ Details

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Namespace Prefix:	btx_
Data Type:	dtr-types:percentItemType
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Period Type:	instant

- References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

The amount of unamortized leasehold improvements.

+ References

No definition available.

+ Details

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Namespace Prefix:	btx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21475-112644

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Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

The carrying amount of the asset transferred to a third party to serve as a deposit, which typically serves as security against failure by the transferor to perform under terms of an 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 210.5-02.8,17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
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- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

The number of positions eliminated during the period as a result of restructuring activities.

+ References

No definition available.

+ Details

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

- Definition

The number of positions eliminated during the period as a percentage of total positions eliminated during the period in connection with the restructuring plan(s).

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
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Period Type:	duration

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

+ Details

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

- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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

- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

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Namespace Prefix:
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Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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- Details

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Subsequent Events (Details)	Mar. 31, 2022 ft²	Mar. 06, 2022 USD ($) $ / shares shares	Jan. 03, 2022 USD ($) Employee	Mar. 05, 2022 USD ($)	Dec. 31, 2021 USD ($) ft²	Dec. 31, 2020 USD ($)
Lease Assignment [Abstract]
Security deposit					$ 522,000	$ 453,000
New Lease Agreement [Abstract]
Operating lease area \| ft²					2,700
Subsequent Event [Member]
Reduction in Force [Abstract]
Number of employees terminated in reduction in force \| Employee			8
Percentage of employees terminated in reduction in force			53.00%
Severance and termination-related costs			$ 500,000
Lease Assignment [Abstract]
Commitment to purchase equipment				$ 50,000
Unamortized leasehold improvements				50,000
Security deposit				$ 63,000
New Lease Agreement [Abstract]
Operating lease area \| ft²	5,200
Lease commencement term	62 months
Base rent (per square foot) \| ft²	6.35
Percentage of increase in base rent on each year	3.00%
Extended lease term	5 years
Common Warrants [Member] \| Subsequent Event [Member]
Private Placement of Equity [Abstract]
Warrant exercise price (in dollars per share) \| $ / shares		$ 1.91
Percentage of warrants exercisable		4.99%
Warrant exercisable term		6 months
Pre-funded Warrants [Member] \| Subsequent Event [Member]
Private Placement of Equity [Abstract]
Warrant exercise price (in dollars per share) \| $ / shares		$ 0.005
Percentage of warrants exercisable		9.99%
PIPE Investor [Member] \| Subsequent Event [Member]
Private Placement of Equity [Abstract]
Private placement (in shares) \| shares		6,857,000
Aggregate gross purchase price		$ 12,000,000.0
PIPE Investor [Member] \| Common Warrants [Member] \| Subsequent Event [Member]
Private Placement of Equity [Abstract]
Number of common stock (in shares) \| shares		1
Warrant expiration term		5 years 6 months
PIPE Investor [Member] \| Pre-funded Warrants [Member] \| Subsequent Event [Member]
Private Placement of Equity [Abstract]
Number of common stock (in shares) \| shares		1