Panbela Therapeutics (PBLA) 10-K 22 Mar 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 15, 2019	Jun. 29, 2018
Document Information [Line Items]
Entity Registrant Name	Sun BioPharma, Inc.
Entity Central Index Key	0001029125
Trading Symbol	snbp
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding (in shares)		5,070,341
Entity Public Float			$ 23,751,819
Entity Shell Company	false
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash	$ 1,405,000	$ 152,000
Prepaid expenses and other current assets	110,000	195,000
Income tax receivable	332,000	420,000
Total current assets	1,847,000	767,000
Other noncurrent assets	51,000
Total assets	1,898,000	767,000
Current liabilities:
Accounts payable	1,064,000	1,196,000
Accrued expenses	212,000	1,254,000
Convertible notes payable, net of debt discounts	64,000	1,525,000
Term debt, current portion	286,000	14,000
Accrued interest	4,000	181,000
Total current liabilities	1,630,000	4,170,000
Long-term liabilities:
Term debt, noncurrent portion		286,000
Total long-term liabilities		286,000
Stockholders' equity (deficit):
Preferred stock, $0.001 par value; 10,000,000 authorized; no shares issued or outstanding as of December 31 2018 and 2017	0	0
Common stock, $0.001 par value; 100,000,000 authorized; 5,077,483 and 3,841,652 shares issued and outstanding, as of December 31, 2018 and 2017, respectively	5,000	4,000
Additional paid-in capital	35,038,000	25,625,000
Accumulated deficit	(35,058,000)	(29,153,000)
Accumulated comprehensive income (loss)	283,000	(165,000)
Total stockholders' equity (deficit)	268,000	(3,689,000)
Total liabilities and stockholders' equity (deficit)	$ 1,898,000	$ 767,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	5,077,483	3,841,652
Common stock, shares outstanding (in shares)	5,077,483	3,841,652

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating expenses:
General and administrative	$ 2,108	$ 3,423
Research and development	1,783	2,593
Operating loss	(3,891)	(6,016)
Other income (expense):
Interest income		1
Grant income	54	163
Interest expense	(1,814)	(1,617)
Loss on induced debt conversions		(3,696)
Other (expense) income	(508)	255
Total other expense	(2,268)	(4,894)
Loss before income tax benefit	(6,159)	(10,910)
Income tax benefit	254	536
Net loss	(5,905)	(10,374)
Foreign currency translation adjustment	448	(241)
Comprehensive loss	$ (5,457)	$ (10,615)
Basic and diluted net loss per share (in dollars per share)	$ (1.27)	$ (2.91)
Weighted average shares outstanding - basic and diluted (in shares)	4,662,080	3,566,098

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2016	3,220,000
Balances at Dec. 31, 2016	$ 3	$ 14,058	$ (18,779)	$ 76	$ (4,642)
Conversion of convertible notes payable and accrued interest into common stock (in shares)	385,000
Conversion of convertible notes payable and accrued interest into common stock	$ 1	5,840			5,841
Conversion of demand notes into common stock (in shares)	34,000
Conversion of demand notes into common stock		993			993
Charge for fair market value of beneficial conversion feature		2,954			$ 2,954
Exercise of common stock options (in shares)	22,000				22,000
Exercise of common stock options		28			$ 28
Exercise of stock purchase warrants (in shares)	181,000
Exercise of stock purchase warrants		19			19
Stock based compensation		1,733			1,733
Net loss			(10,374)		(10,374)
Foreign currency translation adjustment				(241)	(241)
Warrants issued with sale of convertible notes payable
Balances (in shares) at Dec. 31, 2017	3,842,000
Balances at Dec. 31, 2017	$ 4	25,625	(29,153)	(165)	(3,689)
Charge for fair market value of beneficial conversion feature		716			$ 716
Exercise of common stock options (in shares)					30,000
Stock based compensation		2,373			$ 2,373
Net loss			(5,905)		(5,905)
Foreign currency translation adjustment				448	448
Sale of common stock and warrants, net and exercise of stock options (in shares)	485,000
Sale of common stock and warrants, net and exercise of stock options		2,328			2,328
Warrants issued with sale of convertible notes payable		739			739
Conversion of convertible notes payable and accrued interest into common stock and warrants (in shares)	751,000
Conversion of convertible notes payable and accrued interest into common stock and warrants	$ 1	3,257			3,258
Balances (in shares) at Dec. 31, 2018	5,078,000
Balances at Dec. 31, 2018	$ 5	$ 35,038	$ (35,058)	$ 283	$ 268

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (5,905,000)	$ (10,374,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on induced debt conversions		3,696,000
Stock-based compensation	1,279,000	1,733,000
Amortization of debt discount	1,732,000	1,387,000
Amortization of debt issuance costs	9,000	56,000
Non-cash interest expense	4,000	162,000
Changes in operating assets and liabilities:
Income tax receivable	50,000	(70,000)
Prepaid expenses and other current assets	25,000	(75,000)
Accounts payable	360,000	(319,000)
Accrued liabilities	59,000	402,000
Net cash used in operating activities	(2,387,000)	(3,402,000)
Cash flows from financing activities:
Proceeds from the sale of convertible promissory notes, net of offering costs of $5 and $16 respectively	1,329,000	3,059,000
Proceeds from sale of common stock and warrants, net of offering costs of $27	2,328,000
Proceeds from the exercise of stock options		28,000
Proceeeds from exercise of stock purchase warrants		19,000
Repayments of term debt	(14,000)
Net cash provided by financing activities	3,643,000	3,106,000
Effect of exchange rate changes on cash	(3,000)	10,000
Net increase in cash	1,253,000	(286,000)
Cash at beginning of period	152,000	438,000
Cash at end of period	1,405,000	152,000
Supplemental disclosure of cash flow information:
Cash paid during period for interest	67,000	11,000
Supplemental disclosure of non-cash transactions:
Conversion of convertible notes payable and accrued interest into common stock		2,888,000
Conversion of convertible notes payable and accrued interest into common stock and warrants	3,258,000
Intrinsic Value of Convertible Debt with Conversion Feature	716,000	2,954,000
Warrants issued with convertible notes	739,000
Conversion of demand notes into common stock		250,000
Options granted in exchange for release from contingent payment obligations	$ 1,094,000

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Proceeds from the sale of convertible promissory notes, offering costs	$ 5	$ 16
Proceeds from issuance of common stock and warrants, issuance costs	$ 27

Note 1 - Business

Note 1 - Business	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. Business Sun BioPharma, Inc. and its wholly-owned subsidiary Sun BioPharma Australia Pty Ltd. (collectively “we,” “us,” “our,” and the “Company”) exist for the primary purpose of advancing the commercial development of a proprietary polyamine analogue for pancreatic cancer and for a second 101, September 21, 2011. May 24, 2013

Note 2 - Risks and Uncertaintie

Note 2 - Risks and Uncertainties	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Nature of Operations [Text Block]	2. Risks and Uncertainties The Company operates in a highly regulated and competitive environment. The development, manufacturing and marketing of pharmaceutical products require approval from, and are subject to ongoing oversight by, the Food and Drug Administration (“FDA”) in the United States, the Therapeutic Goods Administration (“TGA”) in Australia, the European Medicines Agency (“EMA”) in the European Union, and comparable agencies in other countries. Obtaining approval for a new pharmaceutical product is never certain, may We have incurred losses of $35.1 2011. December 31, 2018 $5.9 $2.4 101. December 31, 2018, $1.4 $1.1 $1.3 $0.3 The accompanying Consolidated Financial Statements have been prepared assuming that we will continue as a going concern which contemplates the realization of assets and liquidation of liabilities in the normal course of business and do not 101,

Note 3 - Liquidity and Manageme

Note 3 - Liquidity and Management Plans	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Substantial Doubt about Going Concern [Text Block]	3. Liquidity and Management Plans We will need to seek additional sources of funds to support our current business plans. We may no not If we are unable to obtain additional financing when needed, we would need to scale back our operations taking actions that may 101 third 101 Between March 1, 2016 September 30, 2017, $10 December 31, 2017, $1.1 February 27, 2018, 7, On February 20, 2018, March 16, 2018 May 16, 2018 “2018 468,200 2018 three $5.00 $2.3 2018 $125,000 On May 16, 2018, $2.0 2017 $3.1 $183,000 104,463 646,279 one To preserve funds, effective November 1, 2018 October 31, 2018, December 31, 2018 $179,000. On December 21, 2018, December 31, 2018 January 2019. $2.2 “2018 1,243,498 December 31, 2018 $59,000 Our future success is dependent upon our ability to obtain additional financing, the success of our development efforts, our ability to demonstrate clinical progress for our SBP- 101 101 not not There can be no

Note 4 - Summary of Significant

Note 4 - Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Significant Accounting Policies [Text Block]	4. Summary of Significant Accounting Policies Basis of p resentation We have prepared the accompanying Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Our fiscal year ends on December 31. Principles of consolidation The accompanying Consolidated Financial Statements include the assets, liabilities and expenses of Sun BioPharma, Inc. and our wholly-owned subsidiary. All significant intercompany transactions and balances have been eliminated in consolidation. Use of estimates The preparation of Consolidated Financial Statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amount of revenues and expenses during the reporting period. Actual results could differ from those estimates. Concentration of c redit r isk Financial instruments that potentially subject the company to significant concentrations of credit risk consist primarily of cash. Cash is deposited in demand accounts at commercial banks. At times, such deposits may not Beneficial conversion feature For convertible debt where the rate of conversion is below fair market value for our common stock, the Company records a charge for the beneficial conversion feature (“BCF”) and related debt discount which is presented as a direct deduction from the carrying amount of the related debt. The discount is amortized to interest expense over the life of the debt. Debt issuance costs Costs associated with the issuance of debt instruments are capitalized. These costs are amortized on a straight-line basis, which approximates the effective interest method, over the term of the debt agreements and are included in interest expense. The unamortized balance of debt issuance costs is presented as a direct reduction of the carrying amount of the related debt. Research and development costs Research and development costs include expenses incurred in the conduct of our Phase 1 third 101 101 We charge research and development costs, including clinical trial costs, to expense when incurred. Our human clinical trials are performed at clinical trial sites and are administered jointly by us with assistance from contract research organizations (“CROs”). Costs of setting up clinical trial sites are accrued upon execution of the study agreement. Expenses related to the performance of clinical trials generally are accrued based on contracted amounts and the achievement of agreed upon milestones, such as patient enrollment, patient follow-up, etc. We monitor levels of performance under each significant contract, including the extent of patient enrollment and other activities through communications with the clinical trial sites and CROs, and adjust the estimates, if required, on a quarterly basis so that clinical expenses reflect the actual effort expended at each clinical trial site and by each CRO. We expense costs associated with obtaining licenses for patented technologies when it is determined there is no S tock -based compensation In accounting for stock-based incentive awards we measure and recognize the cost of employee and non-employee services received in exchange for awards of equity instruments based on the grant date fair value of those awards. Compensation cost is recognized ratably using the straight-line attribution method over the vesting period, which is considered to be the requisite service period. We record forfeitures in the periods in which they occur. The compensation expense for performance-based stock option awards is recognized when “performance” has occurred or is probable of occurring. The fair value of stock-based awards is estimated at the date of grant using the Black-Scholes option pricing model. The determination of the fair value of stock-based awards is affected by our stock price, as well as assumptions regarding a number of complex and subjective variables. Risk free interest rates are based upon U.S. Treasury rates appropriate for the expected term of each award. Expected volatility rates are based primarily on the volatility rates of a set of guideline companies, which consist of public and recently public biotechnology companies. The assumed dividend yield is zero, as we do not Income taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the Consolidated Financial Statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry-forwards. Deferred tax assets and liabilities are measured using enacted rates, for each of the jurisdictions in which the Company operates, expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. Valuation allowances are established when necessary to reduce deferred tax assets to the amount that is more likely than not December 31, 2018 2017. Foreign c urrency t ranslation The functional currency of Sun BioPharma Australia Pty Ltd is the Australian Dollar (“AUD”). Accordingly, assets and liabilities, and equity transactions of Sun BioPharma Australia Pty Ltd are translated into U.S. dollars at period-end exchange rates. Expenses are translated at the average exchange rate in effect for the period. The resulting translation gains and losses are recorded as a component of accumulated comprehensive gain (loss) in the Consolidated Statements of Operations and Comprehensive Loss. During the years ended December 31, 2018 2017, Grant Income Grant income is derived from a one $225,000 101 December 31, 2018 Comprehensive l oss Comprehensive loss consists of our net loss and the effects of foreign currency translation. Net l oss per s hare We compute net loss per share by dividing our net loss (the numerator) by the weighted-average number of common shares outstanding (the denominator) during the period. Shares issued during the period and shares reacquired during the period, if any, are weighted for the portion of the period that they were outstanding. The computation of diluted earnings per share, or EPS, is similar to the computation of basic EPS except that the denominator is increased to include the number of additional common shares that would have been outstanding if the dilutive potential common shares had been issued. Our diluted EPS is the same as basic EPS due to common equivalent shares being excluded from the calculation, as their effect is anti-dilutive. The following outstanding potential common shares were not not December 31, 2018 2017 Employee and non-employee stock options 1,032,211 733,960 Estimated common shares issuable upon conversion of notes payable and accrued interest 383,947 319,193 Common stock issable under common stock purchase warrants 2,035,197 151,500 3,451,355 1,204,653 Recently Adopted Accounting Pronouncement s In May 2014, 2014 09, 605, five no In April 2016, 2016 10, 606 2016 10 December 15, 2017. no In July 2017, No. 2017 11, 260 480 815 no no December 15, 2018, January 1,2018 No. 2017 11, No. 2017 11 2018 2017 11, 2018 not Recently Issued Accounting Pronouncement s In February 2016, 2016 02, 842 12 not 2019, not In June 2018, 2018 07, 718 2018 07 December 15, 2018. not

Note 5 - Accrued Expenses

Note 5 - Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Accrued Liabilities [Text Block]	5 . Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, 2018 2017 Deferred payroll and related expenses $ - $ 1,094 Clinical trial and related expenses 42 95 Professional services 157 61 Other 13 4 Total accrued liabilities $ 212 $ 1,254

Note 6 - Indebtedness

Note 6 - Indebtedness	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Debt Disclosure [Text Block]	6 . Indebtedness 2018 Convertible notes payable On December 21 31, 2018, “2018 $1.3 2018 June 30, 2019 10.0% may 2018 2018 1 June 30, 2019 2 $6.0 2018 $3.50 2018 two $3.50 2018 762,076 December $4.50 5 June 30, 2019. $1.7 2018 $0.6 2018 2018 2017 Convertible notes payable In 2017 “2017 $3.1 2017 December 1, 2018 5.0% 2017 2017 $2.0 2017 2017 $10.10 2017 $3.0 2017 2017 On May 16, 2018, $2.0 2017 $3.1 $183,000 104,463 646,279 one 2018 3 9 no $121,000 $1.0 2013 Convertible notes payable In 2013, “2013 $3.1 2013 5% $11.25 December 2018. In March 2017, 2013 March 31, 2017 $7.50 $3.75, 33.3%, 2013 $11.25 $2,750,000 2013 March 31, 2017 385,000 2013 $138,000 $11.5 $8.5 $3.0 10% $700,000 2013 $35,000 98,000 3 9 no At December 21, 2018 one 2013 not 2017 $25,000 January 4, 2019. Demand notes payable In September 2015, $250,000 $7.50 no $250,000 March 31, 2017 33,332 $1.0 $700,000. 3 9 no The following table sets forth the changes in convertible and demand notes payable during the year ended December 31, 2018 ( Convertible Notes Payable Principal Accrued Interest Principal value at December 31, 2017 $ 3,101 $ 126 Accrued Interest on 2017 notes 57 Aggregate principal value of 2017 notes and accrued interest converted into common stock and warrants (3,076 ) (183 ) Aggregate principal value of 2018 notes sold 1,334 - Accrued interest on 2018 notes - 2 Principal value at December 31, 2018 $ 1,359 $ 2 T erm debt On October 26, 2012, $300,000 4.125%. No October 26, 2017, October 26, 2017, May 1, 2019 $10,000 May 1, 2018 May 1, 2019. first December 31, 2018 $286,000. D eferred financing costs The following table summarizes the deferred financing costs which are presented as a direct reduction of the carrying amount of their related debt liabilities (in thousands): December 31, 2018 December 31, 2017 Convertible Notes Payable Term Debt Convertible Notes Payable Term Debt Loan principal Amount $ 1,359 $ 286 $ 3,101 $ 300 Deferred Financing Costs 5 37 16 37 Accumulated Amortization - (37 ) (7 ) (37 ) Unamortized balance 5 - 9 - Discount on Debt 1,334 - 2,954 - Accumulated Amortization (44 ) - (1,387 ) - Unamortized balance 1,290 - 1,567 - Loan carrying amounts, net $ 64 $ 286 $ 1,525 $ 300 We recorded amortization of deferred financing costs of $9,000 $56,000 December 31, 2018 2017,

Note 7 - Employment Agreement A

Note 7 - Employment Agreement Amendments and Waiver of Contingent Payment Rights	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Employment Agreement Amendments and Waiver of Contingent Payment Rights [Text Block]	7 Employment agreement amendments and waiver of contingent payment rights Effective February 27, 2018, third For each of the Employees, the Amendments waived the contingent cash payment and/or equity payments that had been established by the amendments to the Agreements dated October 1, 2017, June 30, 2018. $1.1 100,000 50,000 25,000 95,000 10 2016 February 27, 2018 $1.3

Note 8 - Commitments and Contin

Note 8 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	8 . Commitments and Contingencies License agreement On December 22, 2011, 2.5% 5% ten 10 first ● $50,000 270 first ● $100,000 first first ● $100,000 second first ● $300,000 third first In addition, the company is subject to five ● $300,000 first 2 ● $3,000,000 ● $2,000,000 one ● $1,000,000 first $100,000,000; ● $3,000,000 first $500,000,000. The license agreement is subject to customary and usual termination provisions. The Company must also pay an annual license maintenance fee of $10,000. $10,000 2018 2017

Note 9 - Stockholders' Equity (

Note 9 - Stockholders' Equity (Deficit)	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	9 . Stockholder s’ Equity ( Deficit ) 2018 Private placement On February 20, 2018, “2018 two March May 2018, 468,200 2018 three $5.00 $2.3 2018 $125,000 December 31, 2018, 468,200 Shares r eserved Shares of common stock reserved for future issuance are as follows: Shares of common stock reserved for future issuance were as follows as of December 31, 2018: Stock options outstanding 1,032,211 Shares available for grant under equity incentive plan 732,149 Estimated common shares issuable upon conversion of notes payable and accrued interest 383,947 Common shares issuable under outstanding commons stock purchase warrants 2,035,197 4,183,504

Note 10 - Stock-based Compensat

Note 10 - Stock-based Compensation	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	10 . Stock- B ased Compensation 2016 Stock-based awards are granted under the Sun BioPharma, Inc. 2016 “2016 March 2016 May 2016. March 1, 2018, 2016 1 1 10 2 162 1986 no 2017 3 162 2016 2016 no 2016 ten 1,500,000 2016 December 31, 2018, 767,851 2016 2011 Prior to approval of the 2016 2011 “2011 September 2011 January 2012. 2016 2011 2011 2011 ten zero two December 31, 2018, 264,360 2011 We recognize stock-based compensation based on the fair value of each award as estimated using the Black-Scholes option valuation model. Ultimately, the actual expense recognized over the vesting period will only be for those shares that actually vest. A summary of option activity is as follows: Shares Available for Grant Shares Underlying Options Weighted Average Exercise Price Per Share Aggregate Intrinsic Value Balance at January 1, 2017 1,114,400 701,960 $ 9.50 $ 3,896,235 Granted (54,000 ) 54,000 10.00 Exercised - (22,000 ) 1.25 Cancelled - - - Balance at December 31, 2017 1,060,400 733,960 $ 9.79 $ 2,121,985 Granted (404,000 ) 404,000 7.49 Exercised (30,000 ) 2.20 Cancelled - - - Forfeitures 75,749 (75,749 ) 7.34 Balance at December 31, 2018 732,149 1,032,211 $ 8.90 $ 169,495 A summary of the status of our unvested shares during the year ended and as of December 31, 2018 Shares Under Option Weighted Average Grant Date Fair Value Unvested at December 31, 2017 135,200 $ 9.31 Granted 404,000 3.69 Vested (468,751 ) 9.43 Forefeitures (27,949 ) 9.68 Unvested at December 31, 2018 42,500 $ 4.83 Information about stock options outstanding, vested and expected to vest as of December 31, 2018, Outstanding, Vested and Expected to Vest Options Vested and Excercisable Per Share Exercise Price Shares Weighted Average Remaining Contractual Life (Years) Weighted Average Exercise Price Options Excercisable Weighted Average Remaining Contractual Life (Years) $0.875 - $1.10 26,360 4.00 $ 1.029 26,360 4.00 $2.275 - $2.50 38,000 5.12 $ 2.464 38,000 5.12 $3.175 200,000 6.17 $ 3.175 200,000 6.17 $5.75 - $8.10 379,000 8.24 $ 7.488 349,000 8.15 $10.00 - $10.10 54,000 8.55 $ 10.007 52,000 8.76 $15.10 334,851 7.44 $ 15.100 324,351 7.58 Totals 1,032,211 7.37 $ 8.904 989,711 7.37 The cumulative grant date fair value of options vested during the years ended December 31, 2018 2017 $2.3 $1.9 December 31, 2018, 30,000 9,747 As of December 31, 2018, not $85,000 2.53 The assumptions used in calculating the fair value under the Black-Scholes option valuation model are set forth in the following table for options issued by the Company for the years ended December 31, 2018 2017: 2018 2017 Common stock fair value $3.50 - $8.10 $10.00 - $29.80 Risk-free interest rate 2.30% - 2.94% 1.43% - 1.93% Expected dividend yield 0 0 Expected Option life (years) 1.25 - 5.75 2.25 - 5 Expected stock price volatility 72% 75.0% - 78.0% Nonemployee s tock- b ased c ompensation We account for stock options granted to nonemployees in accordance with FASB ASC 505. $263,000 $495,000 December 31, 2018 2017,

Note 11 - Income Taxes

Note 11 - Income Taxes	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Income Tax Disclosure [Text Block]	1 1 . Income Taxes We have incurred net operating losses since inception. We have not Changes in tax laws and rates may December 22, 2017 2017 December 31, 2017. 21%, January 1, 2018, December 22, 2017. December 31, 2017, $1.8 At December 31, 2018 2017, $332,000 $420,000, Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes as well as operating losses and tax credit carryforwards. The significant components of our deferred tax assets and liabilities are as follows (in thousands): December 31, Deferred tax assets (liabilities) 2018 2017 Net operating loss carryforwards $ 4,807 $ 3,440 Research credit carryforwards 235 235 Stock-based compensation 971 530 Other 71 212 Deferred tax assets 6,084 4,417 Valuation allowance (5,801 ) (4,079 ) Deferred tax assets, net of valuation allowance 283 338 Beneficial conversion feature, net (283 ) (338 ) Deferrred tax liablities (283 ) (338 ) Net deferred tax asset $ - $ - Realization of the future tax benefits is dependent on our ability to generate sufficient taxable income within the carry-forward period. Because of our history of operating losses, management believes that the deferred tax assets arising from the above-mentioned future tax benefits are currently not A reconciliation of the statutory tax rates and the effective tax rates is as follows: Year Ended December 31, 2018 2017 Statutory rate 21.0 % 34.0 % Permanent differences 0.1 (13.5 ) Change in effective tax rate 0.6 (17.2 ) Valuation allowance (22.6 ) (6.6 ) Foreign research incentives 5.7 3.8 Deferred true-up - 3.0 Other 0.9 0.3 Effective rate 5.7 % 3.8 % Net operating losses and tax credit carryforwards as of December 31, 2018, Amount (in thousands) Expiration Years Net operating losses--federal 12,958 Beginning 2031 2018 net operating loss -- federal 4,807 No expiration Tax credits--federal 235 Beginning 2041 Utilization of the net operating loss carryforwards and credits may not 382 The Company is subject to taxation in the United States and Australia. Tax returns, since the inception of Sun BioPharma, Inc. in 2011 may December 31, 2013

Note 12 - Subsequent Events

Note 12 - Subsequent Events	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Subsequent Events [Text Block]	1 2 . Subsequent Event s Sale of Convertible Promissory Notes and stock purchase Warrants In January 2019 “2018 $0.8 481,422 2018 $3.50 $3.50 2018 two $3.50 $4.50 June 30, 2019. 5 2018 may Restoration of employee Salaries Effective February 1, 2018 November 2018

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of p resentation We have prepared the accompanying Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Our fiscal year ends on December 31.
Consolidation, Policy [Policy Text Block]	Principles of consolidation The accompanying Consolidated Financial Statements include the assets, liabilities and expenses of Sun BioPharma, Inc. and our wholly-owned subsidiary. All significant intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates, Policy [Policy Text Block]	Use of estimates The preparation of Consolidated Financial Statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amount of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Concentration of c redit r isk Financial instruments that potentially subject the company to significant concentrations of credit risk consist primarily of cash. Cash is deposited in demand accounts at commercial banks. At times, such deposits may not
Beneficial Conversion Feature, Policy [Policy Text Block]	Beneficial conversion feature For convertible debt where the rate of conversion is below fair market value for our common stock, the Company records a charge for the beneficial conversion feature (“BCF”) and related debt discount which is presented as a direct deduction from the carrying amount of the related debt. The discount is amortized to interest expense over the life of the debt.
Debt Issuance Costs [Policy Text Block]	Debt issuance costs Costs associated with the issuance of debt instruments are capitalized. These costs are amortized on a straight-line basis, which approximates the effective interest method, over the term of the debt agreements and are included in interest expense. The unamortized balance of debt issuance costs is presented as a direct reduction of the carrying amount of the related debt.
Research and Development Expense, Policy [Policy Text Block]	Research and development costs Research and development costs include expenses incurred in the conduct of our Phase 1 third 101 101 We charge research and development costs, including clinical trial costs, to expense when incurred. Our human clinical trials are performed at clinical trial sites and are administered jointly by us with assistance from contract research organizations (“CROs”). Costs of setting up clinical trial sites are accrued upon execution of the study agreement. Expenses related to the performance of clinical trials generally are accrued based on contracted amounts and the achievement of agreed upon milestones, such as patient enrollment, patient follow-up, etc. We monitor levels of performance under each significant contract, including the extent of patient enrollment and other activities through communications with the clinical trial sites and CROs, and adjust the estimates, if required, on a quarterly basis so that clinical expenses reflect the actual effort expended at each clinical trial site and by each CRO. We expense costs associated with obtaining licenses for patented technologies when it is determined there is no
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	S tock -based compensation In accounting for stock-based incentive awards we measure and recognize the cost of employee and non-employee services received in exchange for awards of equity instruments based on the grant date fair value of those awards. Compensation cost is recognized ratably using the straight-line attribution method over the vesting period, which is considered to be the requisite service period. We record forfeitures in the periods in which they occur. The compensation expense for performance-based stock option awards is recognized when “performance” has occurred or is probable of occurring. The fair value of stock-based awards is estimated at the date of grant using the Black-Scholes option pricing model. The determination of the fair value of stock-based awards is affected by our stock price, as well as assumptions regarding a number of complex and subjective variables. Risk free interest rates are based upon U.S. Treasury rates appropriate for the expected term of each award. Expected volatility rates are based primarily on the volatility rates of a set of guideline companies, which consist of public and recently public biotechnology companies. The assumed dividend yield is zero not
Income Tax, Policy [Policy Text Block]	Income taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the Consolidated Financial Statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry-forwards. Deferred tax assets and liabilities are measured using enacted rates, for each of the jurisdictions in which the Company operates, expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. Valuation allowances are established when necessary to reduce deferred tax assets to the amount that is more likely than not December 31, 2018 2017.
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign c urrency t ranslation The functional currency of Sun BioPharma Australia Pty Ltd is the Australian Dollar (“AUD”). Accordingly, assets and liabilities, and equity transactions of Sun BioPharma Australia Pty Ltd are translated into U.S. dollars at period-end exchange rates. Expenses are translated at the average exchange rate in effect for the period. The resulting translation gains and losses are recorded as a component of accumulated comprehensive gain (loss) in the Consolidated Statements of Operations and Comprehensive Loss. During the years ended December 31, 2018 2017,
Grant Income Policy [Policy Text Block]	Grant Income Grant income is derived from a one $225,000 101 December 31, 2018
Comprehensive Income, Policy [Policy Text Block]	Comprehensive l oss Comprehensive loss consists of our net loss and the effects of foreign currency translation.
Earnings Per Share, Policy [Policy Text Block]	Net l oss per s hare We compute net loss per share by dividing our net loss (the numerator) by the weighted-average number of common shares outstanding (the denominator) during the period. Shares issued during the period and shares reacquired during the period, if any, are weighted for the portion of the period that they were outstanding. The computation of diluted earnings per share, or EPS, is similar to the computation of basic EPS except that the denominator is increased to include the number of additional common shares that would have been outstanding if the dilutive potential common shares had been issued. Our diluted EPS is the same as basic EPS due to common equivalent shares being excluded from the calculation, as their effect is anti-dilutive. The following outstanding potential common shares were not not December 31, 2018 2017 Employee and non-employee stock options 1,032,211 733,960 Estimated common shares issuable upon conversion of notes payable and accrued interest 383,947 319,193 Common stock issable under common stock purchase warrants 2,035,197 151,500 3,451,355 1,204,653
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Accounting Pronouncement s In May 2014, 2014 09, 605, five no In April 2016, 2016 10, 606 2016 10 December 15, 2017. no In July 2017, No. 2017 11, 260 480 815 no no December 15, 2018, January 1,2018 No. 2017 11, No. 2017 11 2018 2017 11, 2018 not Recently Issued Accounting Pronouncement s In February 2016, 2016 02, 842 12 not 2019, not In June 2018, 2018 07, 718 2018 07 December 15, 2018. not

Note 4 - Summary of Significa_2

Note 4 - Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	December 31, 2018 2017 Employee and non-employee stock options 1,032,211 733,960 Estimated common shares issuable upon conversion of notes payable and accrued interest 383,947 319,193 Common stock issable under common stock purchase warrants 2,035,197 151,500 3,451,355 1,204,653

Note 5 - Accrued Expenses (Tabl

Note 5 - Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Accrued Liabilities [Table Text Block]	December 31, 2018 2017 Deferred payroll and related expenses $ - $ 1,094 Clinical trial and related expenses 42 95 Professional services 157 61 Other 13 4 Total accrued liabilities $ 212 $ 1,254

Note 6 - Indebtedness (Tables)

Note 6 - Indebtedness (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Debt Activity [Table Text Block]	Convertible Notes Payable Principal Accrued Interest Principal value at December 31, 2017 $ 3,101 $ 126 Accrued Interest on 2017 notes 57 Aggregate principal value of 2017 notes and accrued interest converted into common stock and warrants (3,076 ) (183 ) Aggregate principal value of 2018 notes sold 1,334 - Accrued interest on 2018 notes - 2 Principal value at December 31, 2018 $ 1,359 $ 2
Schedule of Long-term Debt Instruments [Table Text Block]	December 31, 2018 December 31, 2017 Convertible Notes Payable Term Debt Convertible Notes Payable Term Debt Loan principal Amount $ 1,359 $ 286 $ 3,101 $ 300 Deferred Financing Costs 5 37 16 37 Accumulated Amortization - (37 ) (7 ) (37 ) Unamortized balance 5 - 9 - Discount on Debt 1,334 - 2,954 - Accumulated Amortization (44 ) - (1,387 ) - Unamortized balance 1,290 - 1,567 - Loan carrying amounts, net $ 64 $ 286 $ 1,525 $ 300

Note 9 - Stockholders' Equity_2

Note 9 - Stockholders' Equity (Deficit) (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Common Stock Reserved for Future Issuance [Table Text Block]	Stock options outstanding 1,032,211 Shares available for grant under equity incentive plan 732,149 Estimated common shares issuable upon conversion of notes payable and accrued interest 383,947 Common shares issuable under outstanding commons stock purchase warrants 2,035,197 4,183,504

Note 10 - Stock-based Compens_2

Note 10 - Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Share-based Compensation, Stock Options, Activity [Table Text Block]	Shares Available for Grant Shares Underlying Options Weighted Average Exercise Price Per Share Aggregate Intrinsic Value Balance at January 1, 2017 1,114,400 701,960 $ 9.50 $ 3,896,235 Granted (54,000 ) 54,000 10.00 Exercised - (22,000 ) 1.25 Cancelled - - - Balance at December 31, 2017 1,060,400 733,960 $ 9.79 $ 2,121,985 Granted (404,000 ) 404,000 7.49 Exercised (30,000 ) 2.20 Cancelled - - - Forfeitures 75,749 (75,749 ) 7.34 Balance at December 31, 2018 732,149 1,032,211 $ 8.90 $ 169,495
Schedule of Nonvested Share Activity [Table Text Block]	Shares Under Option Weighted Average Grant Date Fair Value Unvested at December 31, 2017 135,200 $ 9.31 Granted 404,000 3.69 Vested (468,751 ) 9.43 Forefeitures (27,949 ) 9.68 Unvested at December 31, 2018 42,500 $ 4.83
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	Outstanding, Vested and Expected to Vest Options Vested and Excercisable Per Share Exercise Price Shares Weighted Average Remaining Contractual Life (Years) Weighted Average Exercise Price Options Excercisable Weighted Average Remaining Contractual Life (Years) $0.875 - $1.10 26,360 4.00 $ 1.029 26,360 4.00 $2.275 - $2.50 38,000 5.12 $ 2.464 38,000 5.12 $3.175 200,000 6.17 $ 3.175 200,000 6.17 $5.75 - $8.10 379,000 8.24 $ 7.488 349,000 8.15 $10.00 - $10.10 54,000 8.55 $ 10.007 52,000 8.76 $15.10 334,851 7.44 $ 15.100 324,351 7.58 Totals 1,032,211 7.37 $ 8.904 989,711 7.37
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	2018 2017 Common stock fair value $3.50 - $8.10 $10.00 - $29.80 Risk-free interest rate 2.30% - 2.94% 1.43% - 1.93% Expected dividend yield 0 0 Expected Option life (years) 1.25 - 5.75 2.25 - 5 Expected stock price volatility 72% 75.0% - 78.0%

Note 11 - Income Taxes (Tables)

Note 11 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	December 31, Deferred tax assets (liabilities) 2018 2017 Net operating loss carryforwards $ 4,807 $ 3,440 Research credit carryforwards 235 235 Stock-based compensation 971 530 Other 71 212 Deferred tax assets 6,084 4,417 Valuation allowance (5,801 ) (4,079 ) Deferred tax assets, net of valuation allowance 283 338 Beneficial conversion feature, net (283 ) (338 ) Deferrred tax liablities (283 ) (338 ) Net deferred tax asset $ - $ -
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Year Ended December 31, 2018 2017 Statutory rate 21.0 % 34.0 % Permanent differences 0.1 (13.5 ) Change in effective tax rate 0.6 (17.2 ) Valuation allowance (22.6 ) (6.6 ) Foreign research incentives 5.7 3.8 Deferred true-up - 3.0 Other 0.9 0.3 Effective rate 5.7 % 3.8 %
Summary of Operating Loss and Tax Credit Carryforwards [Table Text Block]	Amount (in thousands) Expiration Years Net operating losses--federal 12,958 Beginning 2031 2018 net operating loss -- federal 4,807 No expiration Tax credits--federal 235 Beginning 2041

Note 2 - Risks and Uncertaint_2

Note 2 - Risks and Uncertainties (Details Textual) - USD ($) $ in Thousands	12 Months Ended		96 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2016
Net Income (Loss) Attributable to Parent, Total	$ (5,905)	$ (10,374)	$ 35,100
Net Cash Provided by (Used in) Operating Activities, Total	(2,387)	(3,402)
Cash and Cash Equivalents, at Carrying Value, Ending Balance	1,405	152	1,405	$ 438
Working Capital	(1,100)		(1,100)
Debt Instrument, Unamortized Discount, Total	1,300		1,300
Stockholders' Equity Attributable to Parent, Ending Balance	$ 268	$ (3,689)	$ 268	$ (4,642)

Note 3 - Liquidity and Manage_2

Note 3 - Liquidity and Management Plans (Details Textual) - USD ($)	May 16, 2018	Jan. 31, 2019	Jan. 31, 2019	May 16, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 21, 2018	Feb. 27, 2018
Proceeds from Issuance of Private Placement					$ 2,328,000
Debt Instrument, Convertible, Gross Proceeds from Sale of Equity Trigger	$ 2,000,000
Increase (Decrease) in Operating Expense					(179,000)
Proceeds from Convertible Debt					$ 1,329,000	3,059,000
Subsequent Event [Member]
Proceeds from Convertible Debt		$ 800,000	$ 2,200,000
Warrants in Connection with Debt Conversion [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right	1			1
Warrants in Connection with Securities Purchase Agreement [Member]
Class of Warrant or Right, Expiration Term					3 years
Class of Warrant or Right, Exercise Price of Warrants or Rights					$ 5
Class of Warrant or Right, Number of Securities Called by Warrants or Rights							1,243,498
Warrants in Connection with Securities Purchase Agreement [Member] | Subsequent Event [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right		2	2
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		481,422	481,422
Conversion from Debt to Common Stock [Member]
Debt Conversion, Original Debt, Amount	$ 3,100,000
Debt Conversion, Accrued Interest, Amount	$ 183,000
Debt Conversion, Converted Instrument, Shares Issued	104,463
Debt Conversion, Converted Instrument, Units Issued	646,279
Debt Conversion, Common Stock Per Unit	1
Debt Conversion, Class of Warrant or Right Issued Per Unit	1
Conversion from Debt to Units [Member]
Debt Conversion, Converted Instrument, Units Issued	646,279
Conversion from Debt to Common Stock and Units [Member]
Debt Conversion, Common Stock Per Unit	1
Debt Conversion, Class of Warrant or Right Issued Per Unit	1
Officers and Directors [Member]
Proceeds from Convertible Debt					$ 59,000
Private Placement [Member]
Stock Issued During Period, Shares, New Issues				468,200	468,200
Class of Warrant or Right, Expiration Term				3 years
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 5			$ 5
Proceeds from Issuance of Private Placement				$ 2,300,000	$ 2,300,000
Private Placement [Member] | Directors and Officers [Member]
Proceeds from Issuance of Private Placement				$ 125,000
Employment Agreements [Member]
Accrued Salaries						$ 1,100,000		$ 1,100,000

Note 4 - Summary of Significa_3

Note 4 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Grant Agreement, Total Grants	$ 225,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	0.00%	0.00%

Note 4 - Summary of Significa_4

Note 4 - Summary of Significant Accounting Policies - Anti-dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Anti-dilutive securities (in shares)	3,451,355	1,204,653
Stock Compensation Plan [Member]
Anti-dilutive securities (in shares)	1,032,211	733,960
Convertible Debt Securities [Member]
Anti-dilutive securities (in shares)	383,947	319,193
Warrant [Member]
Anti-dilutive securities (in shares)	2,035,197	151,500

Note 5 - Accrued Expenses - Acc

Note 5 - Accrued Expenses - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred payroll and related expenses		$ 1,094
Clinical trial and related expenses	42	95
Professional services	157	61
Other	13	4
Accrued liabilities	$ 212	$ 1,254

Note 6 - Indebtedness (Details

Note 6 - Indebtedness (Details Textual) - USD ($)	Jan. 04, 2019	May 16, 2018	May 01, 2018	Mar. 31, 2017	Mar. 17, 2017	Jan. 31, 2019	Mar. 31, 2017	Sep. 30, 2015	Jan. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2013	Oct. 26, 2012
Proceeds from Convertible Debt										$ 1,329,000	$ 3,059,000
Intrinsic Value of Convertible Debt with Conversion Feature										716,000	2,954,000
Debt Instrument, Convertible, Gross Proceeds from Sale of Equity Trigger		$ 2,000,000
Debt Instrument, Unamortized Discount, Total										1,300,000
Induced Conversion of Convertible Debt Expense											3,696,000
Amortization of Debt Issuance Costs										$ 9,000	56,000
Institute [Member]
Debt Instrument, Interest Rate, Stated Percentage													4.125%
Debt Instrument, Face Amount													$ 300,000
Subsequent Event [Member]
Proceeds from Convertible Debt						$ 800,000			$ 2,200,000
Conversion from Debt to Common Stock [Member]
Debt Conversion, Original Debt, Amount		3,100,000
Debt Conversion, Accrued Interest, Amount		$ 183,000
Debt Conversion, Converted Instrument, Shares Issued		104,463
Debt Conversion, Converted Instrument, Units Issued		646,279
Debt Instrument, Unamortized Discount, Total		$ 121,000
Debt Conversion, Common Stock Per Unit		1
Debt Conversion, Class of Warrant or Right Issued Per Unit		1
Conversion of 2013 Notes into Common Stock [Member]
Debt Conversion, Original Debt, Amount				$ 2,750,000
Debt Conversion, Converted Instrument, Shares Issued				385,000
Debt Conversion, Original Debt, Amount of Accrued but Unpaid Interest				$ 138,000
Debt Conversion, Converted Instrument, Amount				11,500,000
Debt Conversion, Converted Instrument, Initial Agreement Amount				8,500,000			$ 8,500,000
Conversion of 2013 Notes into Common Stock by Stockholder [Member]
Debt Conversion, Original Debt, Amount				$ 700,000
Debt Conversion, Converted Instrument, Shares Issued				98,000
Debt Conversion, Original Debt, Amount of Accrued but Unpaid Interest				$ 35,000
Conversion of Demand Notes into Common Stock [Member]
Debt Conversion, Original Debt, Amount				$ 250,000
Debt Conversion, Converted Instrument, Shares Issued				33,332
Debt Conversion, Converted Instrument, Amount				$ 1,000,000
Debt Conversion, Conversion Price				$ 7.50			$ 7.50
Warrants In Connection with 2018 Convertible Notes Payable [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right										2
Class of Warrant or Right, Number of Securities Called by Warrants or Rights										762,076
Class of Warrant or Right, Exercise Price of Warrants or Rights										$ 4.50
Warrants and Rights Outstanding, Term										5 years
Warrants Upon Issuance, Fair Value										$ 1,700,000
Warrants in Connection with Debt Conversion [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right		1
Convertible Debt [Member]
Debt Instrument, Unamortized Discount, Total										1,290,000	1,567,000
Long-term Debt, Gross										1,359,000	$ 3,101,000
The 2018 Notes [Member]
Proceeds from Convertible Debt										1,300,000
Convertible Debt, Mandatory Conversion Threshold, Gross Proceeds from Sale of Equity Securities										6,000,000
Class of Warrant or Right, Principal Amount of Every Amount Of Notes Purchased										3.50
Intrinsic Value of Convertible Debt with Conversion Feature										$ 600,000
The 2018 Notes [Member] | Subsequent Event [Member]
Debt Instrument, Convertible, Conversion Price						$ 3.50			$ 3.50
Class of Warrant or Right, Principal Amount of Every Amount Of Notes Purchased						$ 3.50			$ 3.50
Class of Warrant or Right, Exercise Price of Warrants or Rights						$ 4.50			$ 4.50
The 2018 Notes [Member] | Convertible Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage										10.00%
Debt Instrument, Convertible, Conversion Price										$ 3.50
The 2017 Notes [Member]
Proceeds from Convertible Debt, Gross					$ 3,100,000
Unamortized Debt Discount Charged to Interest Expense		$ 1,000,000
The 2017 Notes [Member] | Convertible Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage					5.00%
Debt Instrument, Convertible, Conversion Price					$ 10.10
Debt Instrument, Qualified Financing, Minimum Proceeds					$ 2,000,000
Debt Instrument, Convertible, Beneficial Conversion Feature					$ 3,000,000
The 2013 Notes [Member]
Proceeds from Convertible Debt, Gross												$ 3,100,000
The 2013 Notes [Member] | Subsequent Event [Member]
Repayments of Debt	$ 25,000
The 2013 Notes [Member] | Convertible Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage												5.00%
Debt Instrument, Convertible, Conversion Price				$ 11.25			11.25					$ 11.25
Debt Instrument, Debt Default, Settlement Offer Conversion Rate							7.50
Debt Instrument, Convertible, Conversion Price, Discount							$ 3.75
Debt Instrument, Convertible, Conversion Price, Discount rate				33.30%			33.30%
Induced Conversion of Convertible Debt Expense				$ 3,000,000
Demand Notes [Member] | Unsecured Debt [Member]
Induced Conversion of Convertible Debt Expense				$ 700,000
Notes Assumed								$ 250,000
Amended Unsecured Loan Agreement [Member] | Institute [Member]
Debt Instrument, Periodic Payment, Total			$ 10,000
Long-term Debt, Gross										$ 286,000

Note 6 - Indebtedness - Changes

Note 6 - Indebtedness - Changes in Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Proceeds from the sale of convertible promissory notes, net of offering costs of $5 and $16 respectively	$ 1,329	$ 3,059
Convertible Debt [Member]
Principal value	3,101
Accrued interest	126
Principal value	1,359	3,101
Accrued interest	2	$ 126
The 2017 Notes [Member]
Accrued Interest	57
Aggregate principal value of 2017 notes converted into common stock and warrants	(3,076)
Accrued interest converted into common stock and warrants	(183)
Convertible Notes Payable 2018 [Member]
Proceeds from the sale of convertible promissory notes, net of offering costs of $5 and $16 respectively	1,334
The 2018 Notes [Member]
Accrued Interest	$ 2

Note 6 - Indebtedness - Deferre

Note 6 - Indebtedness - Deferred Financing Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument, Unamortized Discount, Total	$ 1,300
Convertible Debt [Member]
Long-term Debt, Gross	1,359	$ 3,101
Deferred Financing Costs	5	16
Accumulated Amortization		(7)
Unamortized balance	5	9
Discount on Debt	1,334	2,954
Accumulated Amortization	(44)	(1,387)
Debt Instrument, Unamortized Discount, Total	1,290	1,567
Loan carrying amounts, net	64	1,525
Long-term Debt, Net [Member]
Long-term Debt, Gross	286	300
Deferred Financing Costs	37	37
Accumulated Amortization	(37)	(37)
Unamortized balance
Loan carrying amounts, net	$ 286	$ 300

Note 7 - Employment Agreement_2

Note 7 - Employment Agreement Amendments and Waiver of Contingent Payment Rights (Details Textual) - USD ($)	Feb. 27, 2018	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		404,000	54,000
Allocated Share-based Compensation Expense, Total		$ 263,000	$ 495,000
Sun BioPharma, Inc. 2016 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
Allocated Share-based Compensation Expense, Total	$ 1,300,000
Employment Agreements [Member]
Accrued Salaries	$ 1,100,000		$ 1,100,000
Employment Agreements [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Employment Agreements [Member] | Board of Directors Chairman [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	100,000
Employment Agreements [Member] | Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	50,000
Employment Agreements [Member] | Chief Financial Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	25,000
Employment Agreements [Member] | Chief Medical Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	95,000

Note 8 - Commitments and Cont_2

Note 8 - Commitments and Contingencies (Details Textual) - Licensing Agreement with University of Florida Research Foundation [Member] - USD ($)	Dec. 22, 2011	Dec. 31, 2018	Dec. 31, 2017
Royalty Term	10 years
Minimum Annual Royalties, Due 270 Days After First Commercial Sale	$ 50,000
Minimum Annual Royalties, Due on the First Anniversary Date of the First Payment	100,000
Minimum Annual Royalties, Due on the Second Anniversary Date of the First Payment	100,000
Minimum Annual Royalties, Due on the Third Anniversary Date and Subsequent Anniversary Dates of the First Payment	300,000
Annual License Maintenance Fee	10,000
License Maintenance Fee [Member]
Royalty Expense		$ 10,000	$ 10,000
Milestone Payment Due Upon Enrollment of the First Subject in Phase II Clinical Trial [Member]
Milestone Payments	300,000
Milestone Payments Due Upon Approval of a New Drug Application [Member]
Milestone Payments	3,000,000
Milestone Payments Due Upon Approval to Manufacture and Market in Either European Union or Japan [Member]
Milestone Payments	2,000,000
Milestone Payments Due Upon First Time Annual Net Sales of Licensed Products Reach 100,000,000 [Member]
Milestone Payments	1,000,000
Net Sales Required before Milestone Payments	100,000,000
Milestone Payments Due Upon the First Time Annual Net Sales of Licensed Product Reaches 500,000,000 [Member]
Milestone Payments	3,000,000
Net Sales Required before Milestone Payments	$ 500,000,000
Minimum [Member]
Royalty Fee Percentage of Net Sales	2.50%
Maximum [Member]
Royalty Fee Percentage of Net Sales	5.00%

Note 9 - Stockholders' Equity_3

Note 9 - Stockholders' Equity (Deficit) (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	May 16, 2018	Dec. 31, 2018	Dec. 31, 2017
Proceeds from Issuance of Private Placement		$ 2,328,000
Class of Warrant or Right, Outstanding		2,035,197
Directors and Officers [Member]
Proceeds from Sale of Securities		$ 125,000
Warrants in Connection with Securities Purchase Agreement [Member]
Class of Warrant or Right, Expiration Term		3 years
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 5
Class of Warrant or Right, Outstanding		468,200
Private Placement [Member]
Stock Issued During Period, Shares, New Issues	468,200	468,200
Class of Warrant or Right, Expiration Term	3 years
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 5
Proceeds from Issuance of Private Placement	$ 2,300,000	$ 2,300,000
Private Placement [Member] | Directors and Officers [Member]
Proceeds from Issuance of Private Placement	$ 125,000

Note 9 - Stockholders' Deficit

Note 9 - Stockholders' Deficit - Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock options outstanding (in shares)	1,032,211
Shares available for grant under equity incentive plan (in shares)	732,149	1,060,400	1,114,400
Estimated common shares issuable upon conversion of notes payable and accrued interest (in shares)	383,947
Class of Warrant or Right, Outstanding	2,035,197
(in shares)	4,183,504

Note 10 - Stock-based Compens_3

Note 10 - Stock-based Compensation (Details Textual)	Feb. 27, 2018USD ($)	Dec. 31, 2018USD ($)shares	Dec. 31, 2017USD ($)shares	Dec. 31, 2016shares
Common Stock, Capital Shares Reserved for Future Issuance		4,183,504
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance		1,032,211	733,960	701,960
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		30,000	22,000
Allocated Share-based Compensation Expense, Total | $		$ 263,000	$ 495,000
Employee Stock Option [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options | $		$ 85,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		2 years 193 days
Sun BioPharma, Inc. 2016 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
Common Stock, Capital Shares Reserved for Future Issuance		767,851
Allocated Share-based Compensation Expense, Total | $	$ 1,300,000
Sun BioPharma, Inc. 2016 Omnibus Incentive Plan [Member] | Employee Stock Option [Member]
Common Stock, Capital Shares Reserved for Future Issuance		1,500,000
Sun BioPharma, Inc. 2016 Omnibus Incentive Plan [Member] | Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio		10
Sun BioPharma, Inc. 2011 Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance		264,360
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | $		$ 2,300,000	$ 1,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		30,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures, Total		9,747
Sun BioPharma, Inc. 2011 Stock Option Plan [Member] | Employee Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		0 years
Sun BioPharma, Inc. 2011 Stock Option Plan [Member] | Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		2 years

Note 10 - Stock-based Compens_4

Note 10 - Stock-based Compensation - Summary of Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance, shares available for grant (in shares)	1,060,400	1,114,400
Balance, shares underlying options (in shares)	733,960	701,960
Balance, weighted average exercise price per share (in dollars per share)	$ 8.90	$ 9.79	$ 9.50
Aggregate intrinsic value	$ 169,495	$ 2,121,985	$ 3,896,235
Granted, shares available for grant (in shares)	(404,000)	(54,000)
Granted, shares underlying options (in shares)	404,000	54,000
Granted, weighted average exercise price per share (in dollars per share)	$ 7.49	$ 10
Excercised, shares underlying options (in shares)	(30,000)	(22,000)
Exercised, weighted average exercise price per share (in dollars per share)	$ 2.20	$ 1.25
Forfeitures , shares available for grant (in shares)	75,749
Forfeited, shares underlying options (in shares)	(75,749)
Forfeited, weighted average exercise price per share (in dollars per share)	$ 7.34
Balance, shares available for grant (in shares)	732,149	1,060,400
Balance, shares underlying options (in shares)	1,032,211	733,960

Note 10 - Stock-based Compens_5

Note 10 - Stock-based Compensation - Nonvested Share Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Unvested, shares under option (in shares)	135,200
Unvested, weighted average grant-date fair value (in dollars per share)	$ 9.31
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	404,000	54,000
Granted, weighted average grant-date fair value (in dollars per share)	$ 3.69
Vested, shares under option (in shares)	(468,751)
Vested, weighted average grant-date fair value (in dollars per share)	$ 9.43
Forfeitures, shares under option (in shares)	(27,949)
Forfeitures, weighted average grant-date fair value (in dollars per share)	$ 9.68
Unvested, shares under option (in shares)	42,500	135,200
Unvested, weighted average grant-date fair value (in dollars per share)	$ 4.83	$ 9.31

Note 10 - Stock-based Compens_6

Note 10 - Stock-based Compensation - Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Options outstanding (in shares) | shares	1,032,211
Options outstanding, weighted average remaining contractual life (Year)	7 years 135 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 8.904
Options excercisable (in shares) | shares	989,711
Options excercisable, weighted average remaining contractual life (Year)	7 years 135 days
Exercise Price Range 1 [Member]
Per share exercise price, lower limit (in dollars per share)	$ 0.875
Per share exercise price, upper limit (in dollars per share)	$ 1.10
Options outstanding (in shares) | shares	26,360
Options outstanding, weighted average remaining contractual life (Year)	4 years
Options outstanding, weighted average exercise price (in dollars per share)	$ 1.029
Options excercisable (in shares) | shares	26,360
Options excercisable, weighted average remaining contractual life (Year)	4 years
Exercise Price Range 2 [Member]
Per share exercise price, lower limit (in dollars per share)	$ 2.275
Per share exercise price, upper limit (in dollars per share)	$ 2.50
Options outstanding (in shares) | shares	38,000
Options outstanding, weighted average remaining contractual life (Year)	5 years 43 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 2.464
Options excercisable (in shares) | shares	38,000
Options excercisable, weighted average remaining contractual life (Year)	5 years 43 days
Exercise Price Range 3 [Member]
Per share exercise price, lower limit (in dollars per share)	$ 3.175
Options outstanding (in shares) | shares	200,000
Options outstanding, weighted average remaining contractual life (Year)	6 years 62 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 3.175
Options excercisable (in shares) | shares	200,000
Options excercisable, weighted average remaining contractual life (Year)	6 years 62 days
Exercise Price Range 4 [Member]
Per share exercise price, lower limit (in dollars per share)	$ 5.75
Per share exercise price, upper limit (in dollars per share)	$ 8.10
Options outstanding (in shares) | shares	379,000
Options outstanding, weighted average remaining contractual life (Year)	8 years 87 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 7.488
Options excercisable (in shares) | shares	349,000
Options excercisable, weighted average remaining contractual life (Year)	8 years 54 days
Exercise Price Range 5 [Member]
Per share exercise price, lower limit (in dollars per share)	$ 10
Per share exercise price, upper limit (in dollars per share)	$ 10.10
Options outstanding (in shares) | shares	54,000
Options outstanding, weighted average remaining contractual life (Year)	8 years 200 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 10.007
Options excercisable (in shares) | shares	52,000
Options excercisable, weighted average remaining contractual life (Year)	8 years 277 days
Exercise Price Range 6 [Member]
Per share exercise price, lower limit (in dollars per share)	$ 15.10
Options outstanding (in shares) | shares	334,851
Options outstanding, weighted average remaining contractual life (Year)	7 years 160 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 15.1
Options excercisable (in shares) | shares	324,351
Options excercisable, weighted average remaining contractual life (Year)	7 years 211 days

Note 10 - Stock-based Compens_7

Note 10 - Stock-based Compensation - Assumptions Used in Calculating Fair Value of Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Expected dividend yield	0.00%	0.00%
Expected stock price volatility	72.00%
Minimum [Member]
Common stock fair value (in dollars per share)	$ 3.50	$ 10
Risk-free interest rate	2.30%	1.43%
Expected option life (Year)	1 year 91 days	2 years 91 days
Expected stock price volatility		75.00%
Maximum [Member]
Common stock fair value (in dollars per share)	$ 8.10	$ 29.80
Risk-free interest rate	2.94%	1.93%
Expected option life (Year)	5 years 273 days	5 years
Expected stock price volatility		78.00%

Note 11 - Income Taxes (Details

Note 11 - Income Taxes (Details Textual) - USD ($)	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	34.00%
Changes in Gross Deferred Tax Assets due to Changes in Enacted Tax Rate	$ (1,800,000)
Income Taxes Receivable, Current	$ 420,000	$ 332,000	$ 420,000
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Open Tax Year		2011 2012 2013 2014 2015 2016 2017 2018
Foreign Tax Authority [Member] | Australian Taxation Office [Member]
Open Tax Year		2013 2014 2015 2016 2017 2018
State and Local Jurisdiction [Member]
Open Tax Year		2011 2012 2013 2014 2015 2016 2017 2018

Note 11 - Income Taxes - Deferr

Note 11 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Net operating loss carryforwards	$ 4,807	$ 3,440
Research credit carryforwards	235	235
Stock-based compensation	971	530
Other	71	212
Deferred tax assets	6,084	4,417
Valuation allowance	(5,801)	(4,079)
Deferred tax assets, net of valuation allowance	283	338
Beneficial conversion feature, net	(283)	(338)
Deferrred tax liablities	(283)	(338)
Net deferred tax asset	$ 0	$ 0

Note 11 - Income Taxes - Income

Note 11 - Income Taxes - Income Tax Reconciliation (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statutory rate	21.00%	34.00%
Permanent differences	0.10%	(13.50%)
Change in effective tax rate	0.60%	(17.20%)
Valuation allowance	(22.60%)	(6.60%)
Foreign research incentives	5.70%	3.80%
Deferred true-up		3.00%
Other	0.90%	0.30%
Effective rate	5.70%	3.80%

Note 11 - Income Taxes - Net Op

Note 11 - Income Taxes - Net Operating Losses and Tax Credit Carryforwards (Details) - Domestic Tax Authority [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Net operating losses--federal	$ 12,958
Tax credits--federal	$ 235
Earliest Tax Year [Member]
Net operating losses--federal	2031
Tax credits--federal	2041
Tax Year 2018 [Member]
Net operating losses--federal	$ 4,807

Note 12 - Subsequent Events (De

Note 12 - Subsequent Events (Details Textual) - USD ($)	1 Months Ended	2 Months Ended	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 21, 2018
Proceeds from Convertible Debt			$ 1,329,000	$ 3,059,000
The 2018 Notes [Member]
Proceeds from Convertible Debt			1,300,000
Class of Warrant or Right, Principal Amount of Every Amount Of Notes Purchased			$ 3.50
Warrants in Connection with Securities Purchase Agreement [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					1,243,498
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 5
Subsequent Event [Member]
Proceeds from Convertible Debt	$ 800,000	$ 2,200,000
Subsequent Event [Member] | The 2018 Notes [Member]
Debt Instrument, Convertible, Conversion Price	$ 3.50	$ 3.50
Class of Warrant or Right, Principal Amount of Every Amount Of Notes Purchased	$ 3.50	$ 3.50
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 4.50	$ 4.50
Subsequent Event [Member] | Warrants in Connection with Securities Purchase Agreement [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	481,422	481,422
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right	2	2
Warrants and Rights Outstanding, Term	5 years	5 years