The year patents begin to expire.

No definition available.

Name:	bdsi_PatentExpirationYearStart
Namespace Prefix:	bdsi_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Revenue earned during the period arising from products sold or services provided under the terms of a contract, not elsewhere specified in the taxonomy. May include government contracts, construction contracts, and any other contract related to a particular project or product.

+ References

+ Details

Name:	us-gaap_ContractsRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate cost of goods produced and sold and services rendered during the reporting period.

+ 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 210.5-03.2)

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 2

-Article 5

+ Details

Name:	us-gaap_CostOfRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a).Q1 Response)

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

+ Details

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

- Details

Name:	us-gaap_RevenueRecognitionMilestoneMethodLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Revenue earned during the period from the leasing or otherwise lending to a third party the entity's rights or title to certain property. Royalty revenue is derived from a percentage or stated amount of sales proceeds or revenue generated by the third party using the entity's property. Examples of property from which royalties may be derived include patents and oil and mineral rights.

+ 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

Name:	us-gaap_RoyaltyRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_ProductOrServiceAxis=bdsi_OnsolisMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=us-gaap_EuropeanUnionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

License and Development Agreements - Meda License, Development and Supply Agreements - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended		0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2009	Oct. 31, 2012	May 21, 2012
Revenue Recognition, Milestone Method [Line Items]
Patent expiration year	2020
Aggregate milestones and services revenue recognized	$ 22,749,000us-gaap_ContractsRevenue	$ 6,800,000us-gaap_ContractsRevenue	$ 53,446,000us-gaap_ContractsRevenue
Remaining deferred revenue related to the EU Media arrangement milestones	800,000us-gaap_DeferredRevenue	0us-gaap_DeferredRevenue
Product royalty revenues	3,407,000us-gaap_RoyaltyRevenue	1,773,000us-gaap_RoyaltyRevenue	1,083,000us-gaap_RoyaltyRevenue
Cost of product royalties	4,939,000us-gaap_CostOfRevenue	2,082,000us-gaap_CostOfRevenue	1,910,000us-gaap_CostOfRevenue
Onsolis [Member]
Revenue Recognition, Milestone Method [Line Items]
Product royalty revenues	3,400,000	1,800,000	1,100,000
Cost of product royalties	4,900,000	2,100,000	1,900,000
U.S. [Member]
Revenue Recognition, Milestone Method [Line Items]
Aggregate milestones and services revenue recognized				59,700,000
E.U. [Member]
Revenue Recognition, Milestone Method [Line Items]
Aggregate milestones and services revenue recognized					17,500,000
Milestones [Member] \| E.U. [Member]
Revenue Recognition, Milestone Method [Line Items]
Remaining deferred revenue related to the EU Media arrangement milestones	1,100,000
Meda License Development and Supply Agreement [Member] \| E.U. [Member]
Revenue Recognition, Milestone Method [Line Items]
Aggregate milestones and services revenue recognized					2,500,000
Meda License Development and Supply Agreement [Member] \| E.U. [Member] \| Onsolis [Member]
Revenue Recognition, Milestone Method [Line Items]
Aggregate milestones and services revenue recognized						$ 2,500,000