v3.8.0.1

Note 10 - Commitments and Contingencies (Details Textual) $ in Thousands			1 Months Ended	12 Months Ended
	Jun. 14, 2017 USD ($) a	Oct. 02, 2015 ft² $ / item	May 31, 2014 ft²	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2011 ft²
Rental Rate Per Square Foot | $ / item		2.05
Future Minimum Sublease Rentals, Sale Leaseback Transactions, Next Twelve Months				$ 300
Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Two Years				25
Operating Leases, Rent Expense, Net				$ 600	$ 300	$ 600
Redwood City, California [Member]
Area of Operating Lease | ft²		11,871					13,787
Lessee, Operating Lease, Term of Contract		2 years 60 days
Lease Extended Term [Member]
Area of Operating Lease | ft²			12,106
Lessee, Operating Lease, Renewal Term			1 year 261 days
Lease Agreement, Term			3 years 180 days
Executive Offices in Redwood City, CA [Member] | Metropolitan Life Insurance Company [Member]
Lessee, Operating Lease, Renewal Term	6 years
Area of Real Estate Property | a	25,893
Operating Lease, Annual Rent	$ 1,200
Lessee, Operating Lease, Term for Annual Rent Increase	1 year

X

- Definition

Represents the number of square feet that are leased to the Company under a non-cancelable operating lease.

+ References

No definition available.

+ Details

Name:	acrx_AreaOfOperatingLease
Namespace Prefix:	acrx_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Represents the term of an operating lease agreement.

+ References

No definition available.

+ Details

Name:	acrx_LeaseAgreementTerm
Namespace Prefix:	acrx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Term of lessee's annual rent increase under the operating lease.

+ References

No definition available.

+ Details

Name:	acrx_LesseeOperatingLeaseTermForAnnualRentIncrease
Namespace Prefix:	acrx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Annual rent expense under the operating lease.

+ References

No definition available.

+ Details

Name:	acrx_OperatingLeaseAnnualRent
Namespace Prefix:	acrx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Per square rental rate of leased property.

+ References

No definition available.

+ Details

Name:	acrx_RentalRatePerSquareFoot
Namespace Prefix:	acrx_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Amount of minimum sublease rentals for sale-leaseback transactions accounted for using the deposit method or as a financing to be received by the seller-lessee in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77914019&loc=d3e50824-112756

+ Details

Name:	us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of minimum sublease rentals for sale-leaseback transactions accounted for using the deposit method or as a financing to be received by the seller-lessee in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77914019&loc=d3e50824-112756

+ Details

Name:	us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41499-112717

+ Details

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

X

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=acrx_RedwoodCityCaliforniaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=acrx_LeaseExtendedTermMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=acrx_ExecutiveOfficesInRedwoodCityCAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CounterpartyNameAxis=acrx_MetropolitanLifeInsuranceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: