v3.8.0.1

Note 12 - Stock-based Compensation (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2017
Notes Tables |
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] |
|  | December 31, 201 7 |  |  | December 31, 201 6 |  |  | December 31, 201 5 |
Cost of goods sold |  | $ | 324 |  |  | $ | 302 |  |  | $ | 67 |
Research and development |  |  | 1,901 |  |  |  | 2,308 |  |  |  | 2,587 |
General and administrative |  |  | 2,069 |  |  |  | 1,869 |  |  |  | 2,356 |
Total |  | $ | 4,294 |  |  | $ | 4,479 |  |  | $ | 5,010 |
Share-based Compensation, Stock Options, Activity [Table Text Block] |
|  | Number of Stock Options Outstanding |  |  | Weighted- Average Exercise Price |  |  | Weighted- Average Remaining Contractual Life (Years) |  |  | Aggregate Intrinsic Value |
|  |  |  |  |  |  |  |  |  |  |  |  |  | (in thousands) |
December 31, 2016 |  |  | 6,307,756 |  |  | $ | 5.00 |  |  |  |  |  |  |  |  |
Granted |  |  | 3,007,155 |  |  |  | 2.99 |  |  |  |  |  |  |  |  |
Forfeited |  |  | (438,519 | ) |  |  | 4.28 |  |  |  |  |  |  |  |  |
Expired |  |  | (351,922 | ) |  |  | 7.31 |  |  |  |  |  |  |  |  |
Exercised |  |  | (69,372 | ) |  |  | 1.52 |  |  |  |  |  |  |  |  |
December 31, 2017 |  |  | 8,455,098 |  |  | $ | 4.25 |  |  |  | 7.1 |  |  | $ | 13 |
Vested and exercisable options —December 31, 2017 |  |  | 4,529,174 |  |  | $ | 5.11 |  |  |  | 5.56 |  |  | $ | 13 |
Vested and expected to vest —December 31, 2017 |  |  | 8,455,098 |  |  | $ | 4.25 |  |  |  | 7.1 |  |  | $ | 13 |
Schedule of Share-based Compensation, Stock Options Outstanding and Exercisable Activity [Table Text Block] |
|  |  |  | Options Outstanding |  |  | Options Vested and Exercisable |
Exercise Prices |  | Number of Stock Options Outstanding |  |  | Weighted-Average Remaining Contractual Life (Years) |  |  | Weighted-Average Exercise Price per Share |  |  | Shares Subject to Stock Options |  |  | Weighted-Average Exercise Price per Share |
$1.20 | - | $2. 30 |  |  | 105,900 |  |  |  | 8.4 |  |  | $ | 2.13 |  |  |  | 38,400 |  |  | $ | 1.84 |
$2. 40 | - | $3.77 |  |  | 5,592,633 |  |  |  | 7.7 |  |  | $ | 3.10 |  |  |  | 1,948,300 |  |  | $ | 3.17 |
$ 3.92 | - | $6.60 |  |  | 2,060,565 |  |  |  | 5.7 |  |  | $ | 5.45 |  |  |  | 1,880,190 |  |  | $ | 5.36 |
$8.18 | - | $10.55 |  |  | 696,000 |  |  |  | 6.2 |  |  | $ | 10.28 |  |  |  | 662,284 |  |  | $ | 10.28 |
|  |  |  |  | 8,455,098 |  |  |  | 7.1 |  |  | $ | 4.25 |  |  |  | 4,529,174 |  |  | $ | 5.11 |
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] |
|  | Year Ended December 31, |
|  | 201 7 |  |  | 201 6 |  |  | 201 5 |
Expected term (in years) |  | 5.70 |  |  | 5.25 | - | 6.25 |  |  | 5.25 | - | 6.25 |
Risk-free interest rate |  | 1.82% | - | 2.09% |  |  | 1.24% | - | 1.47% |  |  | 1.35% | - | 1.82% |
Expected volatility |  | 73% |  |  | 80% |  |  | 72% |
Expected dividend rate |  | 0% |  |  | 0% |  |  | 0% |

X
- References No definition available. + Details
Name: | acrx_ScheduleOfSharebasedCompensationStockOptionsOutstandingAndExercisableActivityTableTextBlock
Namespace Prefix: | acrx_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the allocation of equity-based compensation costs to a given line item on the balance sheet and income statement for the period. This may include the reporting line for the costs and the amount capitalized and expensed. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 + Details
Name: | us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_TableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration