Organization and Basis of Presentation - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Basis Of Presentation [Line Items]
Common Stock, par value	$ 0.001	$ 0.001
Deferred revenue related to sales	$ 0.9us-gaap_DeferredRevenue	$ 0.1us-gaap_DeferredRevenue
Sales return maximum duration	18 months
Offered period for sales return prior to expiration	6 months
Offered period for sales return subsequent to expiration	12 months
Discount for prompt payment	2.00%bdsi_SalesDiscountsPercentage
Inventory Write down	0.2us-gaap_InventoryWriteDown
Bunavail [Member]
Basis Of Presentation [Line Items]
Deferred cost of sales	$ 0.9	$ 0.7
Minimum [Member]
Basis Of Presentation [Line Items]
Period of payments from customers	30 days
Maximum [Member]
Basis Of Presentation [Line Items]
Period of payments from customers	37 days

Accounts Receivable Collection Period

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- Definition

Offered Period for Sales Return Prior to Expiration

+ References

No definition available.

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- Definition

Offered Period for Sales Return Subsequent to Expiration

+ References

No definition available.

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- Definition

Sales Discounts In Percentages.

+ References

No definition available.

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- Definition

Sales Returns Goods Period

+ References

No definition available.

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- Definition

Face amount or stated value per share of common stock.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 30

-Article 5

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- Definition

Sum of the carrying amounts as of the balance sheet date of deferred costs capitalized at the end of the reporting period that are expected to be charged against earnings within one year or the normal operating cycle, if longer.

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- 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

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

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- Definition

Charge to cost of goods sold that represents the reduction of the carrying amount of inventory, generally attributable to obsolescence or market conditions.

+ 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

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28360613&loc=d3e4542-108314

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