The effective date of the Notice of Grant Award.

No definition available.

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- Definition

The total amount of funds for which the grantor is obligated to pay under the Notice of Grant Award agreement if all terms of the agreement are met by the grantee.

+ References

No definition available.

+ Details

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Namespace Prefix:	btx_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Refers to maximum percentage of sublicense revenue in case of a sublicense entered into prior to commencement of a Phase II clinical trial.

+ References

No definition available.

+ Details

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

- Definition

Refers to maximum percentage of sublicense revenue in the case of a sublicense entered into after completion of a Phase III clinical trial.

+ References

No definition available.

+ Details

Name:	btx_MinimumPercentageOfSublicenseRevenueUnderConditionTwo
Namespace Prefix:	btx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The term over which the funds are to be disbursed in accordance with the Notice of Grant Award agreement.

+ References

No definition available.

+ Details

Name:	btx_NoticeOfGrantAwardTerm
Namespace Prefix:	btx_
Data Type:	xbrli:durationItemType
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- Details

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- Definition

Revenue earned during the period from non-repayable sum of money awarded to an entity to carry out a specific purpose as provided in grant agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(e))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=btx_ClinicalTrialAndOptionAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Clinical Trial and Option Agreement and CIRM Grant Award (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Revenue from Grants	$ 3,296,832us-gaap_RevenueFromGrants	$ 1,573,329us-gaap_RevenueFromGrants	$ 2,222,458us-gaap_RevenueFromGrants
CIRM [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Grant Award	14,300,000
Clinical Trial and Option Agreement [Member] \| CRUK and CRT [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Maximum percentage of sublicense revenue prior to commencement of a Phase II clinical trial (in hundredths)	40.00%
Minimum percentage of sublicense revenue after completion of a Phase III clinical trial (in hundredths)	7.50%
Notice of Grant Award [Member] \| CIRM [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Grant Award	14,300,000
Effective Date Of Grant Award Agreement	October 1, 2014
Grant term	4 years
Revenue from Grants	$ 916,554