Name:	bstg_FairValueAssumptionsExpectedDividendRates
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Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	bstg_FairValueAssumptionsExpectedTerms
Namespace Prefix:	bstg_
Data Type:	xbrli:durationItemType
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Period Type:	duration

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

No definition available.

Name:	bstg_FairValueAssumptionsExpectedVolatilityRates
Namespace Prefix:	bstg_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

Risk-free interest rates assumption used in valuing an instrument.

No definition available.

Name:	bstg_FairValueAssumptionsRiskFreeInterestRates
Namespace Prefix:	bstg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The estimated fair value of market value common stock relating to market liability.

No definition available.

Name:	bstg_FairValueAssumptionsWarrantLiabilityMarketValue
Namespace Prefix:	bstg_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

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

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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- References

No definition available.