Class of warrant or rights exercised.

No definition available.

Name:	bntc_ClassOfWarrantOrRightsExercised
Namespace Prefix:	bntc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Weighted average exercise price, number of warrants issued price per share.

No definition available.

Name:	bntc_WeightedAverageExercisePriceNumberOfWarrantsIssuedPricePerShare
Namespace Prefix:	bntc_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

Weighted-average exercise price of class of warrants or rights outstanding.

No definition available.

Name:	bntc_WeightedAverageExercisePriceOfClassOfWarrantsOrRightsOutstanding
Namespace Prefix:	bntc_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

Weighted average exercise price of pre funded warrants issued.

No definition available.

Name:	bntc_WeightedAverageExercisePriceOfPreFundedWarrantsIssued
Namespace Prefix:	bntc_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

Weighted average exercise price of class of warrants or rights exercised.

No definition available.

Name:	bntc_Weightedaverageexercisepriceofclassofwarrantsorrightsexercised
Namespace Prefix:	bntc_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

Number of warrants or rights outstanding.

No definition available.

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

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

No definition available.

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

Name:	us-gaap_ClassOfWarrantOrRightAxis=bntc_SeriesTwoWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ClassOfWarrantOrRightAxis=bntc_CommonWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_SubsidiarySaleOfStockAxis=bntc_PreFundedWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stockholders' equity - Schedule of warrants or rights (Detail) - $ / shares				3 Months Ended
	Mar. 31, 2025	Apr. 22, 2024	Aug. 11, 2023	Dec. 31, 2024	Sep. 30, 2024
Outstanding, beginning of period				26,463,500	34,271,146
Pre-funded warrants issued		5,749,152		6,300
Outstanding, ending of period	21,147,677			20,899,490	26,463,500
Weighted Average Exercise Price, beginning of period				$ 1.57	$ 1.85
Pre-funded warrants issued				178.5
Weighted Average Exercise Price, ending of period				$ 1.08	$ 1.57
Series 2 Warrants [Member]
Pre-funded warrants issued				642,160	857,845
Pre-funded warrants issued				$ 1.9299	$ 1.9299
Common warrants [Member]
Pre-funded warrants exercised				4,309,421	5,181,347
Pre-funded warrants exercised				$ 3.86	$ 3.86
Pre-funded warrants [Member]
Pre-funded warrants issued	300,000		15,126,226	606,129	1,768,454
Pre-funded warrants exercised	51,813
Outstanding, ending of period	21,147,677
Pre-funded warrants issued				$ 0.0001	$ 0.0001
Pre-funded warrants issued March 25, 2025 (Per share)	$ 0.0001
Pre-funded warrants exercised	3.86
Weighted Average Exercise Price, ending of period	$ 1.06