Avinger (AVGR) 10-Q 8 May 19 2019 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 06, 2019
Document Information [Line Items]
Entity Registrant Name	Avinger Inc
Entity Central Index Key	0001506928
Trading Symbol	avgr
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Small Business	true
Entity Common Stock, Shares Outstanding (in shares)		64,195,616
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Balance Sheets (Curre

Condensed Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 16,707	$ 16,410
Accounts receivable, net of allowance for doubtful accounts of $232 and $260 at March 31, 2019 and December 31, 2018, respectively	1,112	1,154
Right of use asset	1,313
Inventories	3,955	3,422
Prepaid expenses and other current assets	1,026	635
Total current assets	24,113	21,621
Property and equipment, net	2,140	2,078
Total assets	26,253	23,699
Current liabilities:
Accounts payable	969	1,148
Accrued compensation	1,016	1,197
Accrued expenses and other current liabilities	906	1,449
Leasehold liability	1,313
Borrowings	7,837	7,486
Preferred stock dividends payable	895	2,918
Total current liabilities	12,936	14,198
Other long-term liabilities	38	41
Total liabilities	12,974	14,239
Commitments and contingencies (Note 6)
Stockholders’ equity:
Convertible preferred stock issuable in series, par value of $0.001 Shares authorized: 5,000,000 at March 31, 2019 and December 31, 2018 Shares issued and outstanding: 44,923 and 45,671 at March 31, 2019 and December 31, 2018, respectively; aggregate liquidation preference of $45,640 and $44,718 at March 31, 2019 and December 31, 2018, respectively
Common stock, par value of $0.001; Shares authorized: 100,000,000 at March 31, 2019 and December 31, 2018 Common stock, par value of $0.001, Shares authorized: 100,000,000 at at December 31, 2018 and 2017 Shares issued and outstanding: 60,052,992 and 34,921,999 at March 31, 2019 and December 31, 2018, respectively	59	34
Additional paid-in capital	347,160	338,311
Accumulated deficit	(333,940)	(328,885)
Total stockholders’ equity	13,279	9,460
Total liabilities and stockholders’ equity	$ 26,253	$ 23,699

Condensed Balance Sheets (Cur_2

Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts	$ 232	$ 260
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	44,923	45,671
Preferred stock, shares outstanding (in shares)	44,923	45,671
Preferred stock, liquidation value	$ 45,640	$ 44,718
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)	60,052,992	34,921,999
Common stock, shares outstanding (in shares)	60,052,992	34,921,999

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues	$ 1,840	$ 1,809
Cost of revenues	1,467	1,415
Gross profit	373	394
Operating expenses:
Research and development	1,414	1,777
Selling, general and administrative	3,986	4,500
Total operating expenses	5,400	6,277
Loss from operations	(5,027)	(5,883)
Interest income	82	33
Interest expense	(350)	(4,672)
Other income, net	240	241
Net loss and comprehensive loss	(5,055)	(10,281)
Accretion of preferred stock dividends	(895)	(410)
Deemed dividend arising from beneficial conversion feature of convertible preferred stock		(5,216)
Net loss applicable to common stockholders	$ (5,950)	$ (15,907)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.14)	$ (7.99)
Weighted average common shares used to compute net loss per share, basic and diluted (in shares)	42,481	1,992

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Conversion of CRG into Series A Preferred Stock [Member]Preferred Stock [Member]	Conversion of CRG into Series A Preferred Stock [Member]Common Stock [Member]	Conversion of CRG into Series A Preferred Stock [Member]Additional Paid-in Capital [Member]	Conversion of CRG into Series A Preferred Stock [Member]Retained Earnings [Member]	Conversion of CRG into Series A Preferred Stock [Member]	Conversion of Series B Preferred Stock into Common Stock [Member]Preferred Stock [Member]	Conversion of Series B Preferred Stock into Common Stock [Member]Common Stock [Member]	Conversion of Series B Preferred Stock into Common Stock [Member]Additional Paid-in Capital [Member]	Conversion of Series C Preferred Stock into Common Stock [Member]Preferred Stock [Member]	Conversion of Series C Preferred Stock into Common Stock [Member]Common Stock [Member]	Conversion of Series C Preferred Stock into Common Stock [Member]Additional Paid-in Capital [Member]	Conversion of Series C Preferred Stock into Common Stock [Member]Retained Earnings [Member]	Conversion of Series C Preferred Stock into Common Stock [Member]	Series B Preferred Stock [Member]Preferred Stock [Member]	Series B Preferred Stock [Member]Additional Paid-in Capital [Member]	Series B Preferred Stock [Member]	Series A Preferred Stock [Member]Preferred Stock [Member]	Series A Preferred Stock [Member]Common Stock [Member]	Series A Preferred Stock [Member]Additional Paid-in Capital [Member]	Series A Preferred Stock [Member]Retained Earnings [Member]	Series A Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2017																							833,597
Balance at Dec. 31, 2017																							$ 1	$ 265,636	$ (301,327)	$ (35,690)
Issuance of common stock (in shares)																							42,127
Issuance of common stock																								337		337
Employee stock-based compensation																								618		618
Conversion of converitble securities (in shares)	41,800					(7,017)	3,508,500
Conversion of converitble securities			$ 41,800		$ 41,800		$ 2	$ (2)
Issuance of common stock (in shares)														17,979
Issuance of stock															$ 15,525	$ 15,525
Accretion of Series A Preferred Stock dividends																								(410)		(410)
Net and comprehensive loss																									(10,281)	(10,281)
Balance (in shares) at Mar. 31, 2018																						52,762	4,384,224
Balance at Mar. 31, 2018																							$ 3	323,504	(311,608)	11,899
Balance (in shares) at Dec. 31, 2018																						45,671	34,921,999
Balance at Dec. 31, 2018																							$ 34	338,311	(328,885)	9,460
Employee stock-based compensation																								493		493
Conversion of converitble securities (in shares)						(1,523)	3,807,500		(2,170)	5,425,000
Conversion of converitble securities							$ 4	$ (4)		$ 5	$ (5)
Accretion of Series A Preferred Stock dividends																								(895)		(895)
Net and comprehensive loss																									(5,055)	(5,055)
Stock Issued During Period, Shares, Employee Stock Purchase Plans																							46,888
Issuance of common stock under officers and directors purchase plan																								18		18
Exercises of warrants for common stock (in shares)																							15,851,605
Exercises of warrants for common stock																							$ 16	6,324		6,340
Issuance of Series A preferred stock to pay dividends (in shares)																	2,945
Issuance of Series A preferred stock to pay dividends																			$ 2,918		$ 2,918
Balance (in shares) at Mar. 31, 2019																						44,923	60,052,992
Balance at Mar. 31, 2019																							$ 59	$ 347,160	$ (333,940)	$ 13,279

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (5,055)	$ (10,281)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	200	277
Amortization of debt issuance costs and debt discount	43	(128)
Stock-based compensation	493	619
Noncash interest expense and other charges	308	4,705
Provision for doubtful accounts receivable		(6)
Provision for excess and obsolete inventories	46	(79)
Changes in operating assets and liabilities:
Accounts receivable	42	(221)
Inventories	(776)	563
Prepaid expenses and other current assets	(391)	(523)
Other assets		98
Accounts payable	(179)	486
Accrued compensation	(181)	92
Accrued expenses and other current liabilities	(543)	(2,288)
Other long-term liabilities and accrued interest	(3)	(191)
Net cash used in operating activities	(5,996)	(6,877)
Cash flows from investing activities
Purchase of property and equipment	(83)
Proceed from sale of property and equipment	18	46
Net cash provided by (used in) investing activities	(65)	46
Cash flows from financing activities
Proceeds from the issuance of convertible preferred stock, net of issuance costs		15,534
Proceeds from the issuance of common stock related to warrant exercises	6,340
Proceeds from the issuance of common stock under officers and directors purchase plan	18
Proceeds from the issuance of common stock in public offerings, net		326
Net cash provided by financing activities	6,358	15,860
Net change in cash and cash equivalents	297	9,029
Cash and cash equivalents, beginning of period	16,410	5,389
Cash and cash equivalents, end of period	16,707	14,418
Supplemental disclosure of cash flow information
Cash paid for interest
Noncash investing and financing activities:
Conversion of CRG loan principal into Series A Preferred Stock		38,000
Accretion of Series A Preferred Stock dividends	895	410
Issuance of Series A Preferred Stock to pay dividends	2,918
Transfers between inventory and property and equipment	198
Deemed dividend arising from beneficial conversion feature of convertible preferred stock		$ 5,216

Note 1 - Organization

Note 1 - Organization	3 Months Ended
	Mar. 31, 2019
Notes to Financial Statements
Nature of Operations [Text Block]	1. Organization, Nature of Business Avinger, Inc. (the “Company”), a Delaware corporation, was incorporated in March 2007. “OCT”) March 2016, 510 May 2018, 510 April 2019, Liquidity Matters The accompanying financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2014 15, Presentation of Financial Statements - Going Concern (Subtopic 205 40 one In the course of its activities, the Company has incurred losses and negative cash flows from operations since its inception. As of March 31, 2019, $333.9 $16.7 March 31, 2019 fourth 2019. $10.2 November 2018 $15.5 February 2018 February March 2019 $6.3 $3.0 July 2018 twelve may no not twelve no may one not Additionally, due to the substantial doubt about the Company’s ability to continue operating as a going concern and the material adverse change clause in the Loan Agreement with CRG, the entire amount of borrowings at March 31, 2019 2018 not Public Offerings On February 16, 2018, 17,979 17,979,000 $15.5 one seventh 500 1 one seventh 60th 500 60 seven 2 41,800 $38.0 $41.8 20,900,000 On July 12, 2018, 2,166,180 $1.6425 one two 1,083,091 July 16, 2018, $3.0 February 2018 $1.58 $1.58 may January 17, 2019 July 16, 2021. On November 1, 2018, 7,285,000 8,586 $10.2 $0.001 no

Note 2 - Summary of Significant

Note 2 - Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Notes to Financial Statements
Basis of Presentation and Significant Accounting Policies [Text Block]	2. Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) and pursuant to the rules and regulations of the SEC. The accompanying unaudited condensed interim financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial information. The results for the three March 31, 2019 not December 31, 2019, December 31, 2018 10 December 31, 2018, March 6, 2019. 2 10 December 31, 2018. On January 30, 2018, 1 40 not January 30, 2018. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements. Management uses significant judgment when making estimates related to its common stock valuation and related stock-based compensation, the valuation of the common stock warrants, the valuation of compound embedded derivatives, provisions for doubtful accounts receivable and excess and obsolete inventories, clinical trial accruals, and its reserves for sales returns and warranty costs. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not may may Fair Value of Financial Instruments The Company has evaluated the estimated fair value of its financial instruments as of March 31, 2019 December 31, 2018. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three 1 March 31, 2019 December 31, 2018, no March 31, 2019 December 31, 2018. Concentration of Credit Risk, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents and accounts receivable to the extent of the amounts recorded on the balance sheets. The Company’s policy is to invest in cash and cash equivalents, consisting of money market funds. These financial instruments are held in Company accounts at one The Company provides for uncollectible amounts when specific credit problems arise. Management’s estimates for uncollectible amounts have been adequate, and management believes that all significant credit risks have been identified at March 31, 2019 December 31, 2018. The Company’s accounts receivable are due from a variety of healthcare organizations in the United States and select international markets. At March 31, 2019 December 31, 2018, no 10% three March 31, 2019 2018, no 10% The Company manufactures its commercial products in-house, including Pantheris and the Ocelot family of catheters. Certain of the Company’s product components and sub-assemblies continue to be manufactured by sole suppliers. Disruption in component or sub-assembly supply from these manufacturers or from in-house production would have a negative impact on the Company’s financial position and results of operations. The Company is subject to certain risks, including that its devices may not no not third Existing or future devices developed by the Company may may may Revenue Recognition The Company’s revenues are derived from ( 1 2 3 1. Lightbox sales: The Company sells its products directly to hospitals and medical centers. Provided all other criteria for revenue recognition have been met, the Company recognizes revenue for Lightbox sales directly to end customers when delivery and acceptance occurs, which is defined as receipt by the Company of an executed form by the customer acknowledging that the training and installation process is complete. 2. Sales of disposables: Disposable revenues consist of sales of the Company’s catheters and accessories and are recognized when the product has shipped, risk of loss and title has passed to the customer and collectability is reasonably assured. 3. Service revenue: Service contract revenue is recognized ratably over the term of the service period and maintenance contract revenue is recognized as work is performed. To date, service revenue has been insignificant. The Company offers its customers the ability to purchase or lease its Lightbox. In addition, the Company provides a Lightbox under a limited commercial evaluation program to allow certain strategic accounts to install and utilize the Lightbox for a limited trial period of three six The Company evaluates its lease and commercial evaluation program agreements and accounts for these contracts under the guidance in Accounting Standards Codification (“ASC”) 840, Leases No. 2014 09, Revenue from Contracts with Customers (Topic 606 third The Company assessed whether the embedded lease is an operating lease or sales-type lease. Based on the Company’s assessment of the guidance and given that any payments under the lease agreements are dependent upon contingent future sales, it was determined that collectability of the minimum lease payments is not not For sales through distributors, the Company recognizes revenue when title to the product and the risk of loss transfers from the Company to the distributor. The distributors are responsible for all marketing, sales, training and warranty in their respective territories. The standard terms and conditions contained in the Company’s distribution agreements do not not The Company estimates reductions in revenue for potential returns of products by customers. In making such estimates, management analyzes historical returns, current economic trends and changes in customer demand and acceptance of its products. The Company expenses shipping and handling costs as incurred and includes them in the cost of revenues. In those cases where the Company bills shipping and handling costs to customers, it will classify the amounts billed as a component of revenue. Cost of Revenues Cost of revenues consists primarily of manufacturing overhead costs, material costs and direct labor. A significant portion of the Company’s cost of revenues currently consists of manufacturing overhead costs. These overhead costs include the cost of quality assurance, material procurement, inventory control, facilities, equipment and operations supervision and management. Cost of revenues also includes depreciation expense for the Lightboxes under lease agreements and certain direct costs such as shipping costs. Product Warranty Costs The Company typically offers a one Balance at December 31, 2018 $ 271,651 Warranty provision 2,068 Usage/Release (67,638 ) Balance at March 31, 2019 $ 206,081 Common Stock Valuation and Stock-Based Compensation Stock-based compensation for the Company includes amortization related to all stock options and restricted stock units (“RSUs”), based on the grant-date estimated fair value. The fair value of stock options is estimated on the date of grant using the Black-Scholes option pricing model and recognized as expense on a straight-line basis over the vesting period of the award. The Company measures the fair value of RSUs using the closing stock price of a share of the Company’s common stock on the grant date and is recognized as expense on a straight-line basis over the vesting period of the award. Because noncash stock-based compensation expense is based on awards ultimately expected to vest, it is reduced by an estimate for future forfeitures. The Company estimates a forfeiture rate for its stock options and RSUs based on an analysis of its actual forfeiture experience and other factors. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates. Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period, without consideration for potential dilutive common shares. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock and dilutive potential shares of common stock outstanding during the period. Any common stock shares subject to repurchase are excluded from the calculations as the continued vesting of such shares is contingent upon the holders’ continued service to the Company. As of March 31, 2019 December 31, 2018, no Net loss per share attributable to common stockholders was determined as follows (in thousands, except per share data): Three Months Ended March 31, 2019 2018 Net loss attributable to common stockholders $ (5,950 ) $ (15,907 ) Weighted average common stock outstanding 42,481 1,992 Net loss per share attributable to common stockholders, basic and diluted $ (0.14 ) $ (7.99 ) The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted average shares outstanding because such securities have an anti-dilutive impact due to losses reported: Three Months Ended March 31, 2019 2018 Common stock warrants 45,036,182 18,032,715 Common stock options 77,619 55,862 Convertible preferred stock 45,297 52,762 Unvested restricted stock units 2,893,542 3,457 48,052,640 18,144,796 Segment and Geographical Information The Company operates and manages its business as one three March 31, 2019 2018, 91% 92%, Recent Accounting Pronouncements Adopted: In May 2014, No. 2014 09 , Revenue from Contracts with Customers (Topic 606 605, August 2015, No. 2015 14, 606 one December 15, 2017. In March 2016, No. 2016 08, Revenue from Contracts with Customers (Topic 606 ) In April 2016, No. 2016 10, Revenue from Contracts with Customers (Topic 606 ) Identifying Performance Obligations and Licensing In May 2016, No. 2016 12, Revenue from Contracts with Customers (Topic 606 ) Narrow-Scope Improvements and Practical Expedients The Company adopted ASC 606 January 1, 2018, not In May 2017, No. 2017 09, Compensation—Stock Compensation (Topic 718 ) 718. January 1, 2018 not In August 2016, No. 2016 15, Statement of Cash Flows (Topic 230 ): Classification of Certain Cash Receipts and Cash Payments December 15, 2017, January 1, 2018 not In February 2016, No. 2016 02 Leases (Topic 842 ). 842 one July, 842 No. 2018 10, 842 , Leases No. 2018 11, Leases (Topic 842 ): Targeted Improvements first 2019 January 1, 2019. $1.8 no $240,000 three March 31, 2018 In June 2018, No. 2018 07, Compensation-Stock Compensation (Topic 718 ): Improvements to Nonemployee Share-Based Payment Accounting, 718 718 not 1 2 606. December 15, 2018, no 606. January 1, 2019 not

Note 3 - Fair Value Measurement

Note 3 - Fair Value Measurements	3 Months Ended
	Mar. 31, 2019
Notes to Financial Statements
Fair Value Disclosures [Text Block]	3. The Company measures certain financial assets and liabilities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three Level 1—Quoted Level 2—Inputs 1 not Level 3—Unobservable no As of March 31, 2019 December 31, 2018, 1 March 31, 2019 December 31, 2018, no 2 3. no three March 31, 2019.

Note 4 - Inventories

Note 4 - Inventories	3 Months Ended
	Mar. 31, 2019
Notes to Financial Statements
Inventory Disclosure [Text Block]	4. Inventories consisted of the following (in thousands): March 31 , December 31, 201 9 201 8 Raw materials $ 1,018 $ 2,102 Work-in-process 703 158 Finished products 2,234 1,162 Total inventories $ 3,955 $ 3,422

Note 5 - Borrowings

Note 5 - Borrowings	3 Months Ended
	Mar. 31, 2019
Notes to Financial Statements
Debt Disclosure [Text Block]	5. CRG On September 22, 2015, $50,000,000 March 29, 2017. $30,000,000 September 22, 2015. $10,000,000 June 15, 2016 On October 28, 2016, 2016 $18,000,000. February 14, 2018, $38,000,000 $3,800,000 7, three March 31, 2018, $3,800,000 Under the Loan Agreement, as amended, no first 2020. first 2020 not 12.5%. third 2021, $1.2 $2.4 2021, $4.8 2022 $2.4 2023. The Company may 5.0% 1.0% no fifth 1.5% 7.0% The Loan Agreement requires that the Company adheres to certain affirmative and negative covenants, including financial reporting requirements, certain minimum financial covenants for pre-specified liquidity and revenue requirements and a prohibition against the incurrence of indebtedness, or creation of additional liens, other than as specifically permitted by the terms of the Loan Agreement. In particular, the covenants of the original Loan Agreement included a covenant that the Company maintain a minimum of $5,000,000 $7,000,000 2015, $23,000,000 2016, $40,000,000 2017, $50,000,000 2018, $60,000,000 2019 $70,000,000 2020 October 28, 2016, 2016 $18,000,000. 2.0 may On February 14, 2018, No. 2 ● extend the interest only payment period and the period during which the Company may June 30, 2021; ● provide for a 15% ● permit the Company to make the entire interest payment for payment dates in 2018 2019 no ● extend the maturity date to June 30, 2023; ● modify certain of the covenants, including the indebtedness covenant, lien covenant and restricted payments covenant, to eliminate or modify permitted exceptions to the restrictions in those covenants; ● modify the financial covenants to reduce the minimum liquidity requirement to $3,500,000 2018 2019, $15,000,000 2020, $20,000,000 2021 $25,000,000 2022; ● provide CRG with board observer rights. As of March 31, 2019, As of March 31, 2019, Period Ending December 31 , 2019 (remaining nine months of the year) $ 196 2020 804 2021 4,637 2022 5,371 2023 2,697 13,705 Less: Amount of PIK additions and final facility fee to be incurred subsequent to March 31, 2019 (5,154 ) Less: Amount representing debt financing costs (714 ) Borrowings, as of March 31, 2019 $ 7,837 In connection with drawdowns under the Loan Agreement, the Company recorded aggregate debt discounts of $1.3 March 31, 2019 December 31, 2018, $714,000 $757,000, $43,000 $26,000 three March 31, 2019 2018, three March 31, 2019 2018, $350,000 $4.7 Due to the substantial doubt about the Company’s ability to continue operating as a going concern and the material adverse change clause in the Loan Agreement with CRG, the entire amount of borrowings at March 31, 2019 2018 not

Note 6 - Commitments and Contin

Note 6 - Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	6. Lease Commitments The Company’s operating lease obligations primarily consist of leased office, laboratory, and manufacturing space under a non-cancelable operating lease that expires in November 2019. $369,000 $492,000 $507,000 three March 31, 2019 2018, On October 19, 2017, one December 1, 2017 November 15, 2019 15 $79,950 $82,410 December 1, 2018. Upon the adoption of Topic 842 January 1, 2019, $ 1.8 The future aggregate minimum lease payments as of March 31, 2019, $1.3 December 31, 2019. On April 1, 2019, five November 30, 2019. November 30, 2024. $5.8 November 2024, December 1, 2019. not Purchase Obligations Purchase obligations consist of agreements to purchase goods and services entered into in the ordinary course of business. The Company had non-cancellable commitments to suppliers for purchases totaling approximately $2.1 March 31, 2019. Indemnification In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and may may not not The Company indemnifies each of its directors and officers for certain events or occurrences, subject to certain limits, while the director is or was serving at the Company’s request in such capacity, as permitted under Delaware law and in accordance with its certificate of incorporation and bylaws. The term of the indemnification period lasts as long as a director may may not Legal Proceedings Except as set forth below, we are not may Between May 22, 2017 May 25, 2017, three January 2015 No. 17 02240, No. 17 02284, No. 17 02307. 1933. June 12, 2017, On June 22, 2017, June 23, 2017, July 21, 2017, August 9, 2017, No. 17 02284, September 22, 2017, October 31, 2017, June 20, 2018, On October 11, 2017, November 21, 2017, January 26, 2018. March 19, 2018, January 30, 2015, April 10, 2017. The Company and its directors believe that the foregoing lawsuits were without merit; however, in the interest of avoiding the cost and disruption of continuing to defend against these lawsuits, the Company entered into a settlement of the actions. The settlement is for a total of $5 $1.76 March 2018. October 24, 2018,

Note 7 - Stockholders' Equity (

Note 7 - Stockholders' Equity (Deficit)	3 Months Ended
	Mar. 31, 2019
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	7. Convertible Preferred Stock The Company’s certificate of incorporation, as amended and restated, authorizes the Company to issue up to 5,000,000 $0.001 44,923 March 31, 2019. Series A Convertible Preferred Stock On February 14, 2018, $38.0 $3,800,000 $42.8 20,900,000 8%, no February 14, 2019. January 2019, 2,945 December 31, 2018. March 31, 2019, 44,745 $895,000 three March 31, 2019. Series B Convertible Preferred Stock On February 16, 2018, 17,979 $15.5 $0.001 no no not December 31, 2018, 1,701 three March 31, 2019, 1,523 3,807,500 178 The Company evaluated the Series B convertible preferred stock issuance in accordance with the provisions of ASC 815, Derivatives and Hedging, may $5.2 February 16, 2018. Series C Convertible Preferred Stock On November 1, 2018, 7,285,000 8,586 $10.2 $0.001 no December 31, 2018, 2,170 three March 31, 2019, 2,170 5,425,000 no Common Stock As of March 31, 2019, 100,000,000 $0.001 60,052,992 Common Stock Warrants In connection with the issuance of the Company’s Series E convertible preferred stock in September 2014 January 2015, 50% March 31, 2019 53,803 $504.00 September 2, 2019 On February 16, 2018, two 17,979,000 one $0.40 seventh 500 one seventh 60th 500 60 seven March 31, 2019, 17,688,500 On July 13, 2018, 2,166,180 1,083,091 $1.58 one one third March 31, 2019 1,083,091 On November 1, 2018, 7,285,000 8,586 28,750,000 one one $0.40 5 th one 2,500 December 31, 2018 28,750,000 three March 31, 2019, 15,851,605 $6.3 March 31, 2019, 12,898,395 The Company accounted for the common stock warrants issued during the year ended December 31, 2018 July 2018 November 2018 not February 2018 Expected term (years) 7 Expected volatility 55 % Risk-free interest rate 2 % Dividend rate — As of March 31, 2019 December 31, 2018, 31,723,789 47,575,393 Stock Plans In January 2015, 2015 “2015 2015 2009 “2009 2015 33,000 2015 2015 not 2009 2009 2015 first 2016, 42,250 5.0% 2018, 3,000,000 2015 June 8, 2018. March 31, 2019, 199,201 2015 Pursuant to the Plans, ISOs and NSOs may not 100% 10% not 110% four ten Stock option activity under the Plans is set forth below: Number of (in thousands) Weighted Average Weighted Average Remaining Contractual Life (in years) Intrisic Value (in thousands) Balance at December 31, 2018 79,545 $ 170.73 7.69 $ — Options granted — Options exercised — Options expired (1,054 ) 438.97 Options forfeited (899 ) $ 679.47 Balance at March 31, 2019 77,592 $ 161.19 7.24 $ — Exercisable at March 31, 2019 42,874 $ 245.50 5.78 $ — Vested and expected to vest at March 31, 2019 77,592 $ 161.19 7.24 $ — There were no three March 31, 2019. March 31, 2019, $302,000 1.0 not three March 31, 2019 2018. The Company’s RSUs generally vest annually over three four Number of Shares Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term Awards outstanding at December 31, 2018 2,940,662 $ 1.73 3.09 Awarded — $ — — Released (901 ) $ 220.30 — Forfeited (70,625 ) $ 2.59 — Awards outstanding at March 31, 2019 2,869,136 $ 1.64 2.29 As of March 31, 2019, $3.7 2.3 2.9 $2.7 $0.96 March 31, 2019, three March 31, 2019 2018, $1,000 $1,500, no three March 31, 2019. 2018 On August 22, 2018, may may not 200,000 three March 31, 2019 46,888

Note 8 - Stock-based Compensati

Note 8 - Stock-based Compensation	3 Months Ended
	Mar. 31, 2019
Notes to Financial Statements
Share-based Payment Arrangement [Text Block]	8. Stock-based compensation for the Company includes amortization related to all stock options and RSUs based on the grant-date estimated fair value. The Company estimates the fair value of stock options on the date of grant using the Black-Scholes option-pricing model. The Black-Scholes model determines the fair value of stock-based payment awards based on the fair market value of the Company’s common stock on the date of grant and is affected by assumptions regarding a number of complex and subjective variables. These variables include, but are not not not As noncash stock-based compensation expense recognized in the financial statements is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. The Company recognizes forfeitures when they occur in accordance with ASU 2016 09. Total noncash stock-based compensation expense relating to the Company’s stock options and RSUs recognized during the three March 31, 2019 2018, Three Months Ended March 31, 2019 2018 Cost of revenues $ 48 $ 19 Research and development expenses 101 109 Selling, general and administrative expenses 344 491 $ 493 $ 619

Significant Accounting Policies

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) and pursuant to the rules and regulations of the SEC. The accompanying unaudited condensed interim financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial information. The results for the three March 31, 2019 not December 31, 2019, December 31, 2018 10 December 31, 2018, March 6, 2019. 2 10 December 31, 2018. On January 30, 2018, 1 40 not January 30, 2018.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements. Management uses significant judgment when making estimates related to its common stock valuation and related stock-based compensation, the valuation of the common stock warrants, the valuation of compound embedded derivatives, provisions for doubtful accounts receivable and excess and obsolete inventories, clinical trial accruals, and its reserves for sales returns and warranty costs. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not may may
Fair Value Measurement, Policy [Policy Text Block]	Fair Value of Financial Instruments The Company has evaluated the estimated fair value of its financial instruments as of March 31, 2019 December 31, 2018.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three 1 March 31, 2019 December 31, 2018, no March 31, 2019 December 31, 2018.
Concentration of Credit Risk and Other Risks and Uncertainties [Policy Text Block]	Concentration of Credit Risk, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents and accounts receivable to the extent of the amounts recorded on the balance sheets. The Company’s policy is to invest in cash and cash equivalents, consisting of money market funds. These financial instruments are held in Company accounts at one The Company provides for uncollectible amounts when specific credit problems arise. Management’s estimates for uncollectible amounts have been adequate, and management believes that all significant credit risks have been identified at March 31, 2019 December 31, 2018. The Company’s accounts receivable are due from a variety of healthcare organizations in the United States and select international markets. At March 31, 2019 December 31, 2018, no 10% three March 31, 2019 2018, no 10% The Company manufactures its commercial products in-house, including Pantheris and the Ocelot family of catheters. Certain of the Company’s product components and sub-assemblies continue to be manufactured by sole suppliers. Disruption in component or sub-assembly supply from these manufacturers or from in-house production would have a negative impact on the Company’s financial position and results of operations. The Company is subject to certain risks, including that its devices may not no not third Existing or future devices developed by the Company may may may
Revenue from Contract with Customer [Policy Text Block]	Revenue Recognition The Company’s revenues are derived from ( 1 2 3 1. Lightbox sales: The Company sells its products directly to hospitals and medical centers. Provided all other criteria for revenue recognition have been met, the Company recognizes revenue for Lightbox sales directly to end customers when delivery and acceptance occurs, which is defined as receipt by the Company of an executed form by the customer acknowledging that the training and installation process is complete. 2. Sales of disposables: Disposable revenues consist of sales of the Company’s catheters and accessories and are recognized when the product has shipped, risk of loss and title has passed to the customer and collectability is reasonably assured. 3. Service revenue: Service contract revenue is recognized ratably over the term of the service period and maintenance contract revenue is recognized as work is performed. To date, service revenue has been insignificant. The Company offers its customers the ability to purchase or lease its Lightbox. In addition, the Company provides a Lightbox under a limited commercial evaluation program to allow certain strategic accounts to install and utilize the Lightbox for a limited trial period of three six The Company evaluates its lease and commercial evaluation program agreements and accounts for these contracts under the guidance in Accounting Standards Codification (“ASC”) 840, Leases No. 2014 09, Revenue from Contracts with Customers (Topic 606 third The Company assessed whether the embedded lease is an operating lease or sales-type lease. Based on the Company’s assessment of the guidance and given that any payments under the lease agreements are dependent upon contingent future sales, it was determined that collectability of the minimum lease payments is not not For sales through distributors, the Company recognizes revenue when title to the product and the risk of loss transfers from the Company to the distributor. The distributors are responsible for all marketing, sales, training and warranty in their respective territories. The standard terms and conditions contained in the Company’s distribution agreements do not not The Company estimates reductions in revenue for potential returns of products by customers. In making such estimates, management analyzes historical returns, current economic trends and changes in customer demand and acceptance of its products. The Company expenses shipping and handling costs as incurred and includes them in the cost of revenues. In those cases where the Company bills shipping and handling costs to customers, it will classify the amounts billed as a component of revenue.
Cost of Goods and Service [Policy Text Block]	Cost of Revenues Cost of revenues consists primarily of manufacturing overhead costs, material costs and direct labor. A significant portion of the Company’s cost of revenues currently consists of manufacturing overhead costs. These overhead costs include the cost of quality assurance, material procurement, inventory control, facilities, equipment and operations supervision and management. Cost of revenues also includes depreciation expense for the Lightboxes under lease agreements and certain direct costs such as shipping costs.
Standard Product Warranty, Policy [Policy Text Block]	Product Warranty Costs The Company typically offers a one Balance at December 31, 2018 $ 271,651 Warranty provision 2,068 Usage/Release (67,638 ) Balance at March 31, 2019 $ 206,081
Share-based Payment Arrangement [Policy Text Block]	Common Stock Valuation and Stock-Based Compensation Stock-based compensation for the Company includes amortization related to all stock options and restricted stock units (“RSUs”), based on the grant-date estimated fair value. The fair value of stock options is estimated on the date of grant using the Black-Scholes option pricing model and recognized as expense on a straight-line basis over the vesting period of the award. The Company measures the fair value of RSUs using the closing stock price of a share of the Company’s common stock on the grant date and is recognized as expense on a straight-line basis over the vesting period of the award. Because noncash stock-based compensation expense is based on awards ultimately expected to vest, it is reduced by an estimate for future forfeitures. The Company estimates a forfeiture rate for its stock options and RSUs based on an analysis of its actual forfeiture experience and other factors. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates.
Earnings Per Share, Policy [Policy Text Block]	Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period, without consideration for potential dilutive common shares. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock and dilutive potential shares of common stock outstanding during the period. Any common stock shares subject to repurchase are excluded from the calculations as the continued vesting of such shares is contingent upon the holders’ continued service to the Company. As of March 31, 2019 December 31, 2018, no Net loss per share attributable to common stockholders was determined as follows (in thousands, except per share data): Three Months Ended March 31, 2019 2018 Net loss attributable to common stockholders $ (5,950 ) $ (15,907 ) Weighted average common stock outstanding 42,481 1,992 Net loss per share attributable to common stockholders, basic and diluted $ (0.14 ) $ (7.99 ) The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted average shares outstanding because such securities have an anti-dilutive impact due to losses reported: Three Months Ended March 31, 2019 2018 Common stock warrants 45,036,182 18,032,715 Common stock options 77,619 55,862 Convertible preferred stock 45,297 52,762 Unvested restricted stock units 2,893,542 3,457 48,052,640 18,144,796
Segment Reporting, Policy [Policy Text Block]	Segment and Geographical Information The Company operates and manages its business as one three March 31, 2019 2018, 91% 92%,
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements Adopted: In May 2014, No. 2014 09 , Revenue from Contracts with Customers (Topic 606 605, August 2015, No. 2015 14, 606 one December 15, 2017. In March 2016, No. 2016 08, Revenue from Contracts with Customers (Topic 606 ) In April 2016, No. 2016 10, Revenue from Contracts with Customers (Topic 606 ) Identifying Performance Obligations and Licensing In May 2016, No. 2016 12, Revenue from Contracts with Customers (Topic 606 ) Narrow-Scope Improvements and Practical Expedients The Company adopted ASC 606 January 1, 2018, not In May 2017, No. 2017 09, Compensation—Stock Compensation (Topic 718 ) 718. January 1, 2018 not In August 2016, No. 2016 15, Statement of Cash Flows (Topic 230 ): Classification of Certain Cash Receipts and Cash Payments December 15, 2017, January 1, 2018 not In February 2016, No. 2016 02 Leases (Topic 842 ). 842 one July, 842 No. 2018 10, 842 , Leases No. 2018 11, Leases (Topic 842 ): Targeted Improvements first 2019 January 1, 2019. $1.8 no $240,000 three March 31, 2018 In June 2018, No. 2018 07, Compensation-Stock Compensation (Topic 718 ): Improvements to Nonemployee Share-Based Payment Accounting, 718 718 not 1 2 606. December 15, 2018, no 606. January 1, 2019 not

Note 2 - Summary of Significa_2

Note 2 - Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2019
Notes Tables
Schedule of Product Warranty Liability [Table Text Block]	Balance at December 31, 2018 $ 271,651 Warranty provision 2,068 Usage/Release (67,638 ) Balance at March 31, 2019 $ 206,081
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three Months Ended March 31, 2019 2018 Net loss attributable to common stockholders $ (5,950 ) $ (15,907 ) Weighted average common stock outstanding 42,481 1,992 Net loss per share attributable to common stockholders, basic and diluted $ (0.14 ) $ (7.99 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	Three Months Ended March 31, 2019 2018 Common stock warrants 45,036,182 18,032,715 Common stock options 77,619 55,862 Convertible preferred stock 45,297 52,762 Unvested restricted stock units 2,893,542 3,457 48,052,640 18,144,796

Note 4 - Inventories (Tables)

Note 4 - Inventories (Tables)	3 Months Ended
	Mar. 31, 2019
Notes Tables
Schedule of Inventory, Current [Table Text Block]	March 31 , December 31, 201 9 201 8 Raw materials $ 1,018 $ 2,102 Work-in-process 703 158 Finished products 2,234 1,162 Total inventories $ 3,955 $ 3,422

Note 5 - Borrowings (Tables)

Note 5 - Borrowings (Tables)	3 Months Ended
	Mar. 31, 2019
Notes Tables
Schedule of Debt [Table Text Block]	Period Ending December 31 , 2019 (remaining nine months of the year) $ 196 2020 804 2021 4,637 2022 5,371 2023 2,697 13,705 Less: Amount of PIK additions and final facility fee to be incurred subsequent to March 31, 2019 (5,154 ) Less: Amount representing debt financing costs (714 ) Borrowings, as of March 31, 2019 $ 7,837

Note 7 - Stockholders' Equity_2

Note 7 - Stockholders' Equity (Deficit) (Tables)	3 Months Ended
	Mar. 31, 2019
Notes Tables
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]	Expected term (years) 7 Expected volatility 55 % Risk-free interest rate 2 % Dividend rate —
Share-based Payment Arrangement, Option, Activity [Table Text Block]	Number of (in thousands) Weighted Average Weighted Average Remaining Contractual Life (in years) Intrisic Value (in thousands) Balance at December 31, 2018 79,545 $ 170.73 7.69 $ — Options granted — Options exercised — Options expired (1,054 ) 438.97 Options forfeited (899 ) $ 679.47 Balance at March 31, 2019 77,592 $ 161.19 7.24 $ — Exercisable at March 31, 2019 42,874 $ 245.50 5.78 $ — Vested and expected to vest at March 31, 2019 77,592 $ 161.19 7.24 $ —
Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]	Number of Shares Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term Awards outstanding at December 31, 2018 2,940,662 $ 1.73 3.09 Awarded — $ — — Released (901 ) $ 220.30 — Forfeited (70,625 ) $ 2.59 — Awards outstanding at March 31, 2019 2,869,136 $ 1.64 2.29

Note 8 - Stock-based Compensa_2

Note 8 - Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Notes Tables
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]	Three Months Ended March 31, 2019 2018 Cost of revenues $ 48 $ 19 Research and development expenses 101 109 Selling, general and administrative expenses 344 491 $ 493 $ 619

Note 1 - Organization (Details

Note 1 - Organization (Details Textual) - USD ($)	Nov. 01, 2018	Jul. 13, 2018	Jul. 12, 2018	Feb. 16, 2018	Feb. 14, 2018	Mar. 31, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Retained Earnings (Accumulated Deficit), Ending Balance						$ (333,940,000)	$ (333,940,000)		$ (328,885,000)
Cash and Cash Equivalents, at Carrying Value, Ending Balance						16,707,000	16,707,000	$ 14,418,000	$ 16,410,000	$ 5,389,000
Proceeds from Issuance or Sale of Equity, Net	$ 10,200,000		$ 3,000,000	$ 15,500,000		$ 6,300,000
Debt Conversion, Original Debt, Amount								$ 38,000,000
Preferred Stock, Par or Stated Value Per Share						$ 0.001	$ 0.001		$ 0.001
Common Stock [Member]
Stock Issued During Period, Shares, New Issues	7,285,000
Placement Agency Sale - Prospectus Supplement of July 12, 2018 [Member]
Sale of Stock, Consideration Received on Transaction			$ 3,000,000
Placement Agency Sale - Prospectus Supplement of July 12, 2018 [Member] | Common Stock [Member]
Stock Issued During Period, Shares, New Issues		2,166,180	2,166,180
Shares Issued, Price Per Share			$ 1.6425	$ 1.58
November Public Offering [Member] | Common Stock [Member]
Stock Issued During Period, Shares, New Issues	7,285,000
CRG [Member] | Conversion of Principal Amount of Senior Secured Loan to Newly Authorized Series A Preferred Stock [Member]
Debt Conversion, Original Debt, Amount				$ 38,000,000	$ 38,000,000
Debt Conversion, Converted Instrument, Amount				$ 41,800,000	$ 42,800,000
Common Stock Warrants, Issued with Series B Preferred Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				17,979,000		17,688,500	17,688,500
Common Stock Warrants, Issued with Series B Preferred Stock, Warrant One [Member]
Class of Warrant or Right, Number of Warrants Issued for Each Share of Preferred Stock				1
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right				500
Class of Warrant or Right, Contingent Expiration Period Following Initial Exercise Date				7 years
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.40
Common Stock Warrants, Issued with Series B Preferred Stock, Warrant Two [Member]
Class of Warrant or Right, Number of Warrants Issued for Each Share of Preferred Stock				1
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right				500
Class of Warrant or Right, Contingent Expiration Period Following Initial Exercise Date				7 years
Class of Warrant or Right, Expiration Period Following FDA Clearance				60 days
Common Stock Warrants [Member] | Placement Agency Sale - Prospectus Supplement of July 12, 2018 [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		1,083,091	1,083,091			1,083,091	1,083,091
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right			1
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.58	$ 1.58
Common Stock Warrants [Member] | November Public Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	28,750,000
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right	1
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.40
Series B Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues				17,979
Preferred Stock, Par or Stated Value Per Share				$ 0.001
Series A Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues				41,800
Series A Preferred Stock [Member] | Conversion of Principal Amount of Senior Secured Loan to Newly Authorized Series A Preferred Stock [Member]
Convertible Preferred Stock, Shares of Common Stock Issuable on Conversion				20,900,000	20,900,000
Series C Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues	8,586
Preferred Stock, Par or Stated Value Per Share	$ 0.001
Series C Preferred Stock [Member] | November Public Offering [Member]
Stock Issued During Period, Shares, New Issues	8,586

Note 2 - Summary of Significa_3

Note 2 - Summary of Significant Accounting Policies (Details Textual) shares in Thousands	Jan. 30, 2018	Mar. 31, 2019USD ($)shares	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)shares	Jan. 01, 2019USD ($)
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax, Total		$ 0		$ 0
Warranty Period		1 year
Weighted Average Number of Shares, Common Stock Subject to Repurchase or Cancellation | shares		0		0
Number of Reportable Segments				1
Operating Lease, Right-of-Use Asset		$ 1,313,000
Number of Operating Segments		0
Other Nonoperating Income (Expense), Total		$ 240,000	$ 241,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset					$ 1,800,000
Operating Leases, Rent Expense, Sublease Rentals			(240,000)
Operating Lease, Liability, Total					$ 1,800,000
Other Nonoperating Income (Expense), Total			$ 240,000
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Number of Major Customers		0		0
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers		0		0
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | UNITED STATES
Concentration Risk, Percentage		91.00%	92.00%
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	40

Note 2 - Summary of Significa_4

Note 2 - Summary of Significant Accounting Policies - Product Warranty (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Balance	$ 271,651
Warranty provision	2,068
Usage/Release	(67,638)
Balance at March 31, 2019	$ 206,081

Note 2 - Summary of Significa_5

Note 2 - Summary of Significant Accounting Policies - Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net loss attributable to common stockholders	$ (5,950)	$ (15,907)
Weighted average common shares used to compute net loss per share, basic and diluted (in shares)	42,481	1,992
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.14)	$ (7.99)

Note 2 - Summary of Significa_6

Note 2 - Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities (in shares)	48,052,640	18,144,796
Common Stock Warrants [Member]
Antidilutive Securities (in shares)	45,036,182	18,032,715
Common Stock Options [ member]
Antidilutive Securities (in shares)	77,619	55,862
Preferred Stock [Member]
Antidilutive Securities (in shares)	45,297	52,762
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities (in shares)	2,893,542	3,457

Note 3 - Fair Value Measureme_2

Note 3 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure	$ 0	$ 0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ 0	$ 0

Note 4 - Inventories - Schedule

Note 4 - Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Raw materials	$ 1,018	$ 2,102
Work-in-process	703	158
Finished products	2,234	1,162
Total inventories	$ 3,955	$ 3,422

Note 5 - Borrowings (Details Te

Note 5 - Borrowings (Details Textual)	Feb. 14, 2018USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2023USD ($)	Dec. 31, 2022USD ($)	Dec. 31, 2018USD ($)	Oct. 28, 2016USD ($)	Jun. 15, 2016USD ($)	Sep. 22, 2015USD ($)
Line of Credit Facility, Maximum Borrowing Capacity										$ 50,000,000
Debt Instrument, Covenant, Compliance Target Minimum Revenue Second Year								$ 18,000,000		$ 23,000,000
Debt Conversion, Original Debt, Amount			$ 38,000,000
Debt Instrument, Redemption Initial Prepayment Premium Percentage										5.00%
Debt Instrument, Redemption Annual Decline in Prepayment Premium Percentage										1.00%
Debt Instrument, Redemption Prepayment Premium Percentage after Fifth Year										0.00%
Debt Instrument, Financing Fee Percentage										1.50%
Debt Instrument, Final Facility Fee Percentage	15.00%									7.00%
Debt Instrument, Covenant Compliance Cash and Certain Cash Equivalents Minimum	$ 3,500,000									$ 5,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue First Year										7,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue Third Year										40,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue Fourth Year										50,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue Fifth Year										60,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue after Year Five										$ 70,000,000
Debt Instrument, Covenant Compliance Prepayment Multiplier for Revenue Shortfall										2
Debt Instrument, Covenant Compliance Target Minimum Revenue Sixth Year	15,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue Seventh Year	20,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue Eighth Year	25,000,000
Interest Expense, Total		350,000	4,672,000
CRG [Member] | Loan Agreement [Member] | Forecast [Member]
Debt Instrument, Periodic Payment, Principal				$ 1,200,000
Debt Instrument, Periodic Payment, Total				$ 2,400,000	$ 2,400,000	$ 4,800,000
CRG [Member] | Loan Agreement [Member] | Series A Preferred Stock Purchase Agreement with CRG [Member]
Debt Conversion, Original Debt, Amount	38,000,000
Debt Conversion, Fees and Prepayment Premium Amount	$ 3,800,000
Interest Expense, Debt, Total			3,800,000
Debt Instrument, Interest Rate, Stated Percentage										12.50%
CRG [Member] | Loan Agreement [Member]
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net, Total		714,000					$ 757,000			$ 1,300,000
Amortization of Debt Discount (Premium)		43,000	26,000
Interest Expense, Total		$ 350,000	$ 4,700,000
CRG [Member] | Loan Agreement [Member] | First Tranche, Borrowed on September 22, 2015 [Member]
Debt Instrument, Face Amount										$ 30,000,000
CRG [Member] | Loan Agreement [Member] | Second Tranche, Borrowed on June 15, 2016 [Member]
Debt Instrument, Face Amount									$ 10,000,000

Note 5 - Borrowings - Schedule

Note 5 - Borrowings - Schedule of Debt (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Sep. 22, 2015
Borrowings, as of March 31, 2019	$ 7,837,000	$ 7,486,000
CRG [Member] | Loan Agreement [Member]
2019 (remaining nine months of the year)	196,000
2020	804,000
2021	4,637,000
2022	5,371,000
2023	2,697,000
	13,705,000
Less: Amount of PIK additions and final facility fee to be incurred subsequent to March 31, 2019	(5,154,000)
Less: Amount representing debt financing costs	(714,000)	$ (757,000)	$ (1,300,000)
Borrowings, as of March 31, 2019	$ 7,837,000

Note 6 - Commitments and Cont_2

Note 6 - Commitments and Contingencies (Details Textual)	Dec. 01, 2017USD ($)	May 25, 2017	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Apr. 01, 2019USD ($)	Jan. 01, 2019USD ($)
Operating Lease, Expense			$ 492,000	$ 507,000
Operating Lease, Right-of-Use Asset			1,313,000
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year			1,300,000
Purchase Obligation, Total			2,100,000
Class Action Lawsuits Related to IPO [Member] | Pending Litigation [Member]
Loss Contingency, New Claims Filed, Number		3
Loss Contingency Accrual, Payments					1,760,000
Class Action Lawsuits Related to IPO [Member] | Settled Litigation [Member]
Litigation Settlement, Amount Awarded to Other Party from All Defendants					$ 5,000,000
Subsequent Event [Member]
Lessee, Operating Lease, Term of Contract						5 years
Lessee, Operating Lease, Liability, Payments, Due, Total						$ 5,800,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset							$ 1,800,000
Operating Lease, Liability, Total							$ 1,800,000
Facility Lease [Member]
Incentive from Lessor			$ 369,000
Facility Sublease [Member]
Operating Leases Sublease Expiration Prior to Base Lease	15 days
Operating Leases, Monthly Minimum Sublease Rental Payments Receivable Base	$ 79,950
Operating Leases, Monthly Minimum Sublease Rental Payments Receivable Final	$ 82,410

Note 7 - Stockholders' Equity_3

Note 7 - Stockholders' Equity (Deficit) (Details Textual) - USD ($)	Nov. 01, 2018	Jul. 13, 2018	Jul. 12, 2018	Feb. 16, 2018	Feb. 14, 2018	Mar. 31, 2019	Jan. 31, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Aug. 22, 2018	Jan. 31, 2015
Preferred Stock, Shares Authorized						5,000,000		5,000,000		5,000,000
Preferred Stock, Par or Stated Value Per Share						$ 0.001		$ 0.001		$ 0.001
Preferred Stock, Shares Issued, Total						44,923		44,923		45,671
Debt Conversion, Original Debt, Amount									$ 38,000,000
Preferred Stock, Shares Outstanding, Ending Balance						44,923		44,923		45,671
Proceeds from Issuance or Sale of Equity, Net	$ 10,200,000		$ 3,000,000	$ 15,500,000		$ 6,300,000
Preferred Stock Deemed Dividend Arising from Beneficial Conversion Feature									5,216,000
Common Stock, Shares Authorized						100,000,000		100,000,000		100,000,000
Common Stock, Par or Stated Value Per Share						$ 0.001		$ 0.001		$ 0.001
Common Stock, Shares, Issued, Total						60,052,992		60,052,992		34,921,999
Class of Warrant or Right, Outstanding						31,723,789		31,723,789		47,575,393
Proceeds from Warrant Exercises								$ 6,340,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								4 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period								10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period								0
Share-based Payment Arrangement, Expense, Tax Benefit								$ 0	0
Share Price						$ 0.96		$ 0.96
Common Stock, Value, Outstanding						$ 60,052,992		$ 60,052,992
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total						302,000		$ 302,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition								1 year
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total						$ 3.70		$ 3.70
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition								2 years 109 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance						2,869,136		2,869,136		2,940,662
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Fair Value						$ 2,700,000		$ 2,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value								$ 1,000	$ 1,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period								0
Minimum [Member] | Common Stock Options [ member]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent								100.00%
Minimum [Member] | Common Stock Options [ member] | Stockholder with More than 10% Voting Power [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent								110.00%
Minimum [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								3 years
Maximum [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								4 years
The 2015 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized												33,000
Share-based Compensation Arrangement by Share-based Payment Award, Additional Shares Reserved for Issuance, Annual												42,250
Share-based Compensation Arrangement by Share-based Payment Award, Additional Shares Reserved for Issuance, Percentage on Shares Outstanding												5.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized										3,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant						199,201		199,201
Officer and Director Share Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized											200,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans								46,888
Common Stock Warrants, Issued with Series E Convertible Preferred Stock [Member]
Class of Warrant or Right, Securities Called as Percentage of Convertible Preferred Stock Shares						50.00%		50.00%
Class of Warrant or Right, Outstanding						53,803		53,803
Class of Warrant or Right, Exercise Price of Warrants or Rights						$ 504		$ 504
Common Stock Warrants, Issued with Series B Preferred Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				17,979,000		17,688,500		17,688,500
Common Stock Warrants, Issued with Series B Preferred Stock, Warrant One [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.40
Class of Warrant or Right, Number of Warrants Issued for Each Share of Preferred Stock				1
Class of Warrant or Right, Contingent Expiration Period Following Initial Exercise Date				7 years
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right				500
Common Stock Warrants, Issued with Series B Preferred Stock, Warrant Two [Member]
Class of Warrant or Right, Number of Warrants Issued for Each Share of Preferred Stock				1
Class of Warrant or Right, Contingent Expiration Period Following Initial Exercise Date				7 years
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right				500
Class of Warrant or Right, Expiration Period Following FDA Clearance				60 days
Common Stock Warrants [Member] | Placement Agency Sale - Prospectus Supplement of July 12, 2018 [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.58	$ 1.58
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		1,083,091	1,083,091			1,083,091		1,083,091
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right			1
Common Stock Warrants [Member] | November Public Offering [Member]
Class of Warrant or Right, Outstanding						12,898,395		12,898,395		28,750,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.40
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	28,750,000
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right	1
Preferred Stock Warrants [Member] | November Public Offering [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right	2,500
Common Stock [Member]
Stock Issued During Period, Shares, New Issues	7,285,000
Stock Issued During Period, Shares, Warrants Exercised								15,851,605
Stock Issued During Period, Shares, Employee Stock Purchase Plans								46,888
Common Stock [Member] | Placement Agency Sale - Prospectus Supplement of July 12, 2018 [Member]
Stock Issued During Period, Shares, New Issues		2,166,180	2,166,180
Common Stock [Member] | November Public Offering [Member]
Stock Issued During Period, Shares, New Issues	7,285,000
Conversion of Series B Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Converted								1,523
Conversion of Stock, Shares Issued								3,807,500
Conversion of Series C Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Converted								2,170
Conversion of Stock, Shares Issued								5,425,000
Series A Preferred Stock [Member]
Preferred Stock, Shares Outstanding, Ending Balance						44,745		44,745
Dividends Payable						$ 895,000		$ 895,000
Stock Issued During Period, Shares, New Issues				41,800
Series A Preferred Stock [Member] | CRG [Member]
Preferred Stock Dividends, Shares							2,945
Series B Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share				$ 0.001
Preferred Stock, Shares Outstanding, Ending Balance						178		178		1,701
Stock Issued During Period, Shares, New Issues				17,979
Preferred Stock Deemed Dividend Arising from Beneficial Conversion Feature				$ 5,200,000
Series C Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share	$ 0.001
Preferred Stock, Shares Outstanding, Ending Balance						0		0		2,170
Stock Issued During Period, Shares, New Issues	8,586
Series C Preferred Stock [Member] | November Public Offering [Member]
Stock Issued During Period, Shares, New Issues	8,586
Conversion of Principal Amount of Senior Secured Loan to Newly Authorized Series A Preferred Stock [Member] | Series A Preferred Stock [Member]
Convertible Preferred Stock, Shares of Common Stock Issuable on Conversion				20,900,000	20,900,000
Preferred Stock, Dividend Rate, Percentage					8.00%
CRG [Member] | Conversion of Principal Amount of Senior Secured Loan to Newly Authorized Series A Preferred Stock [Member]
Debt Conversion, Original Debt, Amount				$ 38,000,000	$ 38,000,000
Debt Conversion, Fees and Prepayment Premium Amount					3,800,000
Debt Conversion, Converted Instrument, Amount				$ 41,800,000	$ 42,800,000

Note 7 - Stockholders' Equity_4

Note 7 - Stockholders' Equity (Deficit) - Assumptions Used to Estimate Fair Value (Details)	Feb. 28, 2018
Measurement Input, Expected Term [Member]
Expected term	7
Measurement Input, Price Volatility [Member]
Expected term	0.55
Measurement Input, Risk Free Interest Rate [Member]
Expected term	0.02
Measurement Input, Expected Dividend Rate [Member]
Expected term

Note 7 - Stockholders' Equity_5

Note 7 - Stockholders' Equity (Deficit) - Stock Option Activity (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Options (in shares)	79,545,000
Options, weighted average exercise price (in dollars per share)	$ 170.73
Options, weighted average remaining contractual life (Year)	7 years 87 days	7 years 251 days
Options granted (in shares)
Options granted, weighted average exercise price (in dollars per share)
Options exercised (in shares)	0
Options exercised, weighted average exercise price (in dollars per share)
Options expired (in shares)	(1,054,000)
Options expired, weighted average exercise price (in dollars per share)	$ 438.97
Options forfeited (in shares)	(899,000)
Options forfeited, weighted average exercise price (in dollars per share)	$ 679.47
Options (in shares)	77,592,000	79,545,000
Options, weighted average exercise price (in dollars per share)	$ 161.19	$ 170.73
Exercisable (in shares)	42,874,000
Exercisable, weighted average exercise price (in dollars per share)	$ 245.50
Exercisable, weighted average remaining contractual life (Year)	5 years 284 days
Vested and expected to vest (in shares)	77,592,000
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 161.19
Vested and expected to vest, weighted average remaining contractual life (Year)	7 years 87 days

Note 7 - Stockholders' Equity_6

Note 7 - Stockholders' Equity (Deficit) - Restricted Stock Units Award Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Awards outstanding, Shares (in shares)	2,940,662
Awards outstanding, Weighted grant date fair value (in dollars per share)	$ 1.73
Awards outstanding, Weighted average remaining contractual term (Year)	2 years 105 days	3 years 32 days
Awarded, Shares (in shares)	0
Awarded, Weighted grant date fair value (in dollars per share)
Released, Shares (in shares)	(901)
Released, Weighted grant date fair value (in dollars per share)	$ 220.30
Forfeited, Shares (in shares)	(70,625)
Forfeited, Weighted grant date fair value (in dollars per share)	$ 2.59
Awards outstanding, Shares (in shares)	2,869,136	2,940,662
Awards outstanding, Weighted grant date fair value (in dollars per share)	$ 1.64	$ 1.73

Note 8 - Stock-based Compensa_3

Note 8 - Stock-based Compensation - Noncash Stock-based Compensation Expense Related to Stock Options, ESPP, and RSUs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Allocated Share-based Compensation Expense	$ 493	$ 619
Cost of Sales [Member]
Allocated Share-based Compensation Expense	48	19
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	101	109
Selling, General and Administrative Expenses [Member]
Allocated Share-based Compensation Expense	$ 344	$ 491