Avinger (AVGR) 10-Q 8 Aug 19 2019 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Aug. 08, 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)		6,424,965
Entity Shell Company	false
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Title of 12(b) Security	Common Stock

Condensed Balance Sheets (Curre

Condensed Balance Sheets (Current Period Unaudited) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 14,754,000	$ 16,410,000
Accounts receivable, net of allowance for doubtful accounts of $218 and $260 at June 30, 2019 and December 31, 2018, respectively	1,210,000	1,154,000
Inventories	4,105,000	3,422,000
Prepaid expenses and other current assets	764,000	635,000
Total current assets	20,833,000	21,621,000
Right of use asset	5,596,000
Property and equipment, net	2,006,000	2,078,000
Other assets	384,000
Total assets	28,819,000	23,699,000
Current liabilities:
Accounts payable	1,086,000	1,148,000
Accrued compensation	1,439,000	1,197,000
Accrued expenses and other current liabilities	776,000	1,449,000
Leasehold liability	1,063,000
Borrowings	8,201,000	7,486,000
Preferred stock dividends payable	1,790,000	2,918,000
Total current liabilities	14,355,000	14,198,000
Leasehold liability	4,533,000
Other long-term liabilities	11,000	41,000
Total liabilities	18,899,000	14,239,000
Commitments and contingencies (Note 6)
Stockholders’ equity:
Convertible preferred stock issuable in series, par value of $0.001 Shares authorized: 5,000,000 at June 30, 2019 and December 31, 2018 Shares issued and outstanding: 44,923 and 45,671 at June 30, 2019 and December 31, 2018, respectively; aggregate liquidation preference of $46,535 and $44,718 at June 30, 2019 and December 31, 2018, respectively
Common stock, par value of $0.001; Shares authorized: 100,000,000 at June 30, 2019 and December 31, 2018 Shares issued and outstanding: 6,421,317 and 3,492,200 at June 30, 2019 and December 31, 2018, respectively	6,000	3,000
Additional paid-in capital	348,505,000	338,342,000
Accumulated deficit	(338,591,000)	(328,885,000)
Total stockholders’ equity	9,920,000	9,460,000
Total liabilities and stockholders’ equity	$ 28,819,000	$ 23,699,000

Condensed Balance Sheets (Cur_2

Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Allowance for doubtful accounts	$ 218	$ 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	$ 46,535	$ 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)	6,421,317	3,492,200
Common stock, shares outstanding (in shares)	6,421,317	3,492,200

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues	$ 2,319	$ 2,058	$ 4,159	$ 3,867
Cost of revenues	1,599	2,169	3,066	3,584
Gross profit (loss)	720	(111)	1,093	283
Operating expenses:
Research and development	1,335	1,159	2,749	2,936
Selling, general and administrative	4,091	4,444	8,077	8,944
Total operating expenses	5,426	5,603	10,826	11,880
Loss from operations	(4,706)	(5,714)	(9,733)	(11,597)
Interest income	90	50	172	83
Interest expense	(364)	(362)	(714)	(5,034)
Other income (expense), net	329	227	569	468
Net loss and comprehensive loss	(4,651)	(5,799)	(9,706)	(16,080)
Accretion of preferred stock dividends	(895)	(836)	(1,790)	(1,246)
Deemed dividend arising from beneficial conversion feature of convertible preferred stock				(5,216)
Net loss attributable to common stockholders	$ (5,546)	$ (6,635)	$ (11,496)	$ (22,542)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.87)	$ (9.83)	$ (2.16)	$ (51.82)
Weighted average common shares used to compute net loss per share, basic and diluted (in shares)	6,377	675	5,319	435

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	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 B Preferred Stock into Common Stock [Member]	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 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																								83,359
Balance at Dec. 31, 2017																									$ 265,630	$ (301,320)	$ (35,690)
Employee stock-based compensation																									1,259		1,259
Exercises of warrants for common stock (in shares)																								29,050
Exercises of warrants for common stock																									581		581
Conversion of convertible securities (in shares)	(16,278)	813,958			41,800
Conversion of convertible securities		$ 1	$ (1)				$ 41,800		$ 41,800
Accretion of Series A Preferred Stock dividends																									(1,246)		(1,246)
Issuance of common stock to a vendor (in shares)																								8
Issuance of common stock to a vendor																									106		106
Net and comprehensive loss																										(16,080)	(16,080)
Issuance of common stock (in shares)																								4,212
Issuance of common stock																									337		337
Issuance of common stock (in shares)															17,979
Issuance of stock																$ 15,525	$ 15,525
Balance (in shares) at Jun. 30, 2018																							43,501	930,587
Balance at Jun. 30, 2018																								$ 1	323,991	(317,400)	6,592
Balance (in shares) at Mar. 31, 2018																							52,762	438,422
Balance at Mar. 31, 2018																									323,504	(311,601)	11,903
Employee stock-based compensation																									641		641
Exercises of warrants for common stock (in shares)																								29,050
Exercises of warrants for common stock																									581		581
Conversion of convertible securities (in shares)	(9,261)	463,107
Conversion of convertible securities		$ 1	(5)	$ (4)
Accretion of Series A Preferred Stock dividends																									(836)		(836)
Issuance of common stock to a vendor (in shares)																								8
Issuance of common stock to a vendor																									106		106
Net and comprehensive loss																										(5,799)	(5,799)
Balance (in shares) at Jun. 30, 2018																							43,501	930,587
Balance at Jun. 30, 2018																								$ 1	323,991	(317,400)	6,592
Balance (in shares) at Dec. 31, 2018																							45,671	3,492,200
Balance at Dec. 31, 2018																								$ 3	338,342	(328,885)	9,460
Employee stock-based compensation																									1,009		1,009
Exercises of warrants for common stock (in shares)																								1,998,079
Exercises of warrants for common stock																								$ 2	7,991		7,993
Conversion of convertible securities (in shares)	(1,523)	380,750								(2,170)	542,500
Conversion of convertible securities											$ 1	$ (1)
Accretion of Series A Preferred Stock dividends																									(1,790)		(1,790)
Net and comprehensive loss																										(9,706)	(9,706)
Stock Issued During Period, Shares, Employee Stock Purchase Plans																								7,788
Issuance of common stock under officers and directors purchase plan																									36		36
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 Jun. 30, 2019																							44,923	6,421,317
Balance at Jun. 30, 2019																								$ 6	348,505	(338,591)	9,920
Balance (in shares) at Mar. 31, 2019																							44,923	6,005,218
Balance at Mar. 31, 2019																								$ 6	347,213	(333,940)	13,279
Employee stock-based compensation																									516		516
Exercises of warrants for common stock (in shares)																								413,000
Exercises of warrants for common stock																									1,653		1,653
Accretion of Series A Preferred Stock dividends																									(895)		(895)
Net and comprehensive loss																										(4,651)	(4,651)
Stock Issued During Period, Shares, Employee Stock Purchase Plans																								3,099
Issuance of common stock under officers and directors purchase plan																									18		18
Balance (in shares) at Jun. 30, 2019																							44,923	6,421,317
Balance at Jun. 30, 2019																								$ 6	$ 348,505	$ (338,591)	$ 9,920

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net loss	$ (9,706,000)	$ (16,080,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	428,000	518,000
Amortization of debt issuance costs and debt discount	86,000	57,000
Stock-based compensation	1,009,000	1,260,000
Noncash interest expense and other charges	724,000	5,037,000
Common stock to be issued for services		106,000
Provision for doubtful accounts receivable		45,000
Provision for excess and obsolete inventories	97,000	528,000
Changes in operating assets and liabilities:
Accounts receivable	(56,000)	(593,000)
Other long-term assets	219,000
Inventories	(1,066,000)	575,000
Prepaid expenses and other current assets	(334,000)	(439,000)
Other assets		104,000
Accounts payable	(62,000)	(301,000)
Accrued compensation	242,000	334,000
Leasehold liability	(492,000)
Accrued expenses and other current liabilities	(673,000)	(2,383,000)
Other long-term liabilities and accrued interest	(30,000)	(114,000)
Net cash used in operating activities	(9,615,000)	(11,346,000)
Cash flows from investing activities
Purchase of property and equipment	(88,000)	(125,000)
Proceed from sale of property and equipment	18,000
Net cash used in investing activities	(70,000)	(125,000)
Cash flows from financing activities
Proceeds from the issuance of convertible preferred stock, net of issuance costs		15,534,000
Proceeds from the issuance of common stock related to warrant exercises	7,993,000	581,000
Proceeds from the issuance of common stock in public offerings, net of issuance costs		326,000
Proceeds from the issuance of common stock under officers and directors purchase plan	36,000
Payment of debt discount in connection with loan amendment		(155,000)
Payment of accrued interest included in borrowings		(60,000)
Net cash provided by financing activities	8,029,000	16,226,000
Net change in cash and cash equivalents	(1,656,000)	4,755,000
Cash and cash equivalents, beginning of period	16,410,000	5,389,000
Cash and cash equivalents, end of period	14,754,000	10,144,000
Supplemental disclosure of cash flow information
Cash paid for interest		60,000
Noncash investing and financing activities:
Conversion of CRG loan principal into Series A Preferred Stock		38,000,000
Accretion of Series A Preferred Stock dividends	1,790,000	1,246,000
Issuance of Series A Preferred Stock to pay dividends	2,918,000
Reclassification of right of use asset to prepaid rent	179,000
Increase to right of use asset and leasehold liability arising from lease amendment	4,680,000
Transfers between inventory and property and equipment	287,000
Deemed dividend arising from beneficial conversion feature of convertible preferred stock		$ 5,216,000

Note 1 - Organization

Note 1 - Organization	6 Months Ended
	Jun. 30, 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 June 30, 2019, $338.6 $14.8 June 30, 2019 fourth 2019. $10.2 November 2018 $15.5 February 2018 six June 30, 2019 $8.0 $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 June 30, 2019 2018 not Public Offerings On February 16, 2018, 17,979 1,797,900 $15.5 $0.001 no no not one 1 seventh 50 one 2 seventh 60th 50 60 seven 41,800 $38.0 $41.8 2,090,000 On July 12, 2018, 216,618 $16.425 one two 108,309 July 16, 2018, $3.0 February 2018 $1.58 $15.80 may January 17, 2019 July 16, 2021. On November 1, 2018, 728,500 8,586 $10.2 $0.001 no

Note 2 - Summary of Significant

Note 2 - Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 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 and six months ended June 30, 2019 are not necessarily indicative of results to be expected for the year ending December 31, 2019, or for any other interim period or for any future year. The December 31, 2019 condensed balance sheet data has been derived from audited financial statements. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to SEC rules and regulations relating to interim financial statements. These unaudited condensed financial statements and notes should be read in conjunction with the financial statements included in the Company’s Form 10 -K for the fiscal year ended December 31, 2018, which was filed with the SEC on March 6, 2019. The Company’s significant accounting policies are more fully described in Note 2 of the Notes to Financial Statements included in the Company’s Annual Report on Form 10 -K for the year ended December 31, 2018. On January 30, 2018, the Company’s Board of Directors approved an amendment to the Company’s amended and restated certificate of incorporation to effect a 1 -for- 40 reverse stock split of the Company’s common stock. Further, on June 19, 2019 , the Company’s Board of Directors approved an amendment to the Company’s amended and restated certificate of incorporation to effect an additional 1 -for - 10 reverse stock split of the Company’s common stock. The reverse stock split became effective on June 21, 2019. The par value of the common stock and convertible preferred stock was not adjusted as a result of the reverse stock split. All common stock, stock options, and restricted stock units, and per share amounts in the financial statements have been retroactively adjusted for all periods presented to give effect to the reverse stock splits. 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 readily apparent from other sources. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Fair Value of Financial Instruments The Company has evaluated the estimated fair value of its financial instruments as of June 30, 2019 and December 31, 2018. Financial instruments consist of cash and cash equivalents, accounts receivable and payable, and other current liabilities and borrowings. The carrying amounts of cash and cash equivalents, accounts receivable and payable, and other current liabilities approximate their respective fair values because of the short-term nature of those instruments. Based upon the borrowing terms and conditions currently available to the Company, the carrying values of the borrowings approximate their fair value. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the time of purchase to be cash equivalents. Cash equivalents are considered available-for-sale marketable securities and are recorded at fair value, using level 1 inputs, based on quoted market prices. As of June 30, 2019 and December 31, 2018, the Company’s cash equivalents are entirely comprised of investments in money market funds. Any related unrealized gains and losses are recorded in other comprehensive income (loss) and included as a separate component of stockholders’ equity (deficit). There were no unrealized gains and losses as of June 30, 2019 and December 31, 2018. Any realized gains and losses and interest and dividends on available-for-sale securities are included in interest income or expense and computed using the specific identification cost method. 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 financial institution. The counterparties to the agreements relating to the Company’s investments consist of financial institutions of high credit standing. 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 June 30, 2019 and 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 June 30, 2019 and December 31, 2018, there were no customers that represented 10% or more of the Company’s accounts receivable. For the three and six months ended June 30, 2019 and 2018, there were no customers that represented 10% or more of revenues. Disruption of sales orders or a deterioration of financial conditions of its customers would have a negative impact on the Company’s financial position and results of operations. 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 be approved or cleared for marketing by governmental authorities or be successfully marketed. There can be no assurance that the Company’s products will achieve widespread adoption in the marketplace, nor can there be any assurance that existing devices or any future devices can be developed or manufactured at an acceptable cost and with appropriate performance characteristics. The Company is also subject to risks common to companies in the medical device industry, including, but not limited to, new technological innovations, dependence upon third -party payors to provide adequate coverage and reimbursement, dependence on key personnel and suppliers, protection of proprietary technology, product liability claims, and compliance with government regulations. Existing or future devices developed by the Company may require approvals or clearances from the FDA or international regulatory agencies. In addition, in order to continue the Company’s operations, compliance with various federal and state laws is required. If the Company were denied or delayed in receiving such approvals or clearances, it may be necessary to adjust operations to align with the Company’s currently approved portfolio. If clearance for the products in the current portfolio were withdrawn by the FDA, this may have a material adverse impact on the Company. Revenue Recognition The Company’s revenues are derived from ( 1 ) sale of Lightboxes, ( 2 ) sale of disposables, which consist of catheters and accessories, and ( 3 ) sale of customer service contracts. The Company sells its products directly to hospitals and medical centers as well as through distributors. The Company accounts for a contract with a customer when there is a legally enforceable contract between the Company and the customer, the rights of the parties are identified, the contract has commercial substance, and collectability of the contract consideration is probable. The Company’s revenues are measured based on consideration specified in the contract with each customer, net of any sales incentives and taxes collected from customers that are remitted to government authorities. For all sales, the Company uses either a signed agreement or a binding purchase order as evidence of an arrangement. The Company’s revenue recognition policies generally result in revenue recognition at the following points: 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 to six months. When a Lightbox is placed under a lease agreement or under a commercial evaluation program, the Company retains title to the equipment and it remains capitalized on its balance sheet under property and equipment. Depreciation expense on these placed Lightboxes is recorded to cost of revenues on a straight-line basis. The costs to maintain these placed Lightboxes are charged to cost of revenues as incurred. 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 and ASU No. 2014 09, Revenue from Contracts with Customers (Topic 606 ) . The guidance requires arrangement consideration to be allocated between a lease deliverable and a non-lease deliverable based upon the relative selling-price of the deliverables, using a specific hierarchy. The hierarchy is as follows: vendor-specific objective evidence of fair value of the respective elements, third -party evidence of selling price, or best estimate of selling price (“BESP”). The Company allocates arrangement consideration using BESP. 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 reasonably predictable. Accordingly, the Company concluded the embedded lease did not meet the criteria of a sales-type lease and accounts for it as an operating lease. The Company recognizes revenue allocated to the lease as the contingent disposable product purchases are delivered and are included in revenues within the statement of operations and comprehensive loss. 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 provide price protection or stock rotation rights to any of its distributors. In addition, its distributor agreements do not allow the distributor to return or exchange products, and the distributor is obligated to pay the Company upon invoice regardless of its ability to resell the product. 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 -year warranty for parts and labor on its products commencing upon the transfer of title and risk of loss to the customer. The Company accrues for the estimated cost of product warranties upon invoicing its customers, based on historical results. Warranty costs are reflected in the statement of operations and comprehensive loss as a cost of revenues. The warranty obligation is affected by product failure rates, material usage and service delivery costs incurred in correcting a product failure. Should actual product failure rates, material usage or service delivery costs differ from these estimates, revisions to the estimated warranty liability would be required. Periodically the Company assesses the adequacy of its recorded warranty liabilities and adjusts the amounts as necessary. Warranty provisions and claims are summarized as follows (in thousands): Balance at December 31, 2018 $ 272 Warranty provision 36 Usage/Release (93 ) Balance at June 30, 2019 $ 215 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 June 30, 2019 and December 31, 2018, there were no shares subject to repurchase. Since the Company was in a loss position for all periods presented, basic net loss per share attributable to common stockholders is the same as diluted net loss per share attributable to common stockholders as the inclusion of all potentially dilutive common shares would have been anti-dilutive. Net loss per share attributable to common stockholders was determined as follows (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 201 9 201 8 201 9 201 8 Net loss attributable to common stockholders $ (5,546 ) $ (6,635 ) $ (11,496 ) $ (22,542 ) Weighted average common stock outstanding 6,377 675 5,319 435 Net loss per share attributable to common stockholders, basic and diluted $ (0.87 ) $ (9.83 ) $ (2.16 ) $ (51.82 ) 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 June 30, Six Months Ended June 30, 201 9 201 8 201 9 201 8 Common stock warrants 23,845,311 18,032,715 36,458,617 17,742,215 Common stock options 7,492 5,586 7,673 8,484 Convertible preferred stock 44,923 52,762 45,109 43,501 Unvested restricted stock units 287,817 345 288,581 330 24,185,543 18,091,408 36,799,980 17,794,530 Segment and Geographical Information The Company operates and manages its business as one reportable and operating segment. The Company’s chief executive officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. Primarily all of the Company’s long-lived assets are based in the United States. Long-lived assets are comprised of property and equipment. For the three months ended June 30, 2019 and 2018, 92% and 95%, respectively, of the Company’s revenues were in the United States based on the shipping location of the external customer. For the six months ended June 30, 2019 and 2018, 92% and 93%, respectively, of the Company’s revenues were in the United States based on the shipping location of the external customer. Recent Accounting Pronouncements Adopted: In May 2014, the FASB issued ASU No. 2014 - 09 , Revenue from Contracts with Customers (Topic 606 ) , which supersedes the revenue recognition requirements in ASC 605, Revenue Recognition . This ASU is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, FASB issued ASU No. 2015 - 14, Revenue from Contracts with Customers (Topic 606 ): Deferral of the Effective Date , which effectively delayed the adoption date by one year, to an effective date for public entities for annual and interim periods beginning after December 15, 2017. In March 2016, the FASB issued ASU No. 2016 - 08, Revenue from Contracts with Customers (Topic 606 ) : Principal Versus Agent Considerations (Reporting Revenue Gross Versus Net), to clarify certain aspects of the principal-versus-agent guidance in its new revenue recognition standard. In April 2016, the FASB issued ASU No. 2016 - 10, Revenue from Contracts with Customers (Topic 606 ) : Identifying Performance Obligations and Licensing to clarify how to identify the performance obligations and the licensing implementation guidance in its new revenue recognition standard. In May 2016, the FASB issued ASU No. 2016 - 12, Revenue from Contracts with Customers (Topic 606 ) : Narrow-Scope Improvements and Practical Expedients , to address certain issues identified by the Transition Resource Group, (the “TRG”) in the guidance on assessing collectability, presentation of sales tax, noncash consideration, and completed contracts and contracts modifications at transition. The Company adopted ASC 606 and related ASUs on January 1, 2018, using the modified retrospective approach. The adoption did not have a material impact on the Company’s financial statements. In May 2017, the FASB issued ASU No. 2017 - 09, Compensation—Stock Compensation (Topic 718 ) : Scope of Modification Accounting, which provides guidance on determining which changes to the terms and conditions of share-based payment awards require an entity to apply modification accounting under Topic 718. The amendments in this ASU should be applied prospectively to an award modified on or after the adoption date. The Company adopted this guidance on January 1, 2018 and such adoption did not have a material impact on the Company’s financial statements. In August 2016, the FASB issued ASU No. 2016 - 15, Statement of Cash Flows (Topic 230 ): Classification of Certain Cash Receipts and Cash Payments . This update clarifies how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This ASU is effective for public business entities for fiscal years beginning after December 15, 2017, and for interim periods therein with early adoption permitted and must be applied retrospectively to all periods presented. The Company adopted this guidance on January 1, 2018 and such adoption did not have a material impact on the Company’s financial statements. In February 2016, the FASB issued ASU No. 2016 - 02, Leases (Topic 842 ). Topic 842 amends a number of aspects of lease accounting, including requiring lessees to recognize leases with a term greater than one year as a right-of-use asset and corresponding liability, measured at the present value of the lease payments. In July, the FASB issued supplemental adoption guidance and clarification to Topic 842 within ASU No. 2018 - 10, Codification Improvements to Topic 842, Leases and ASU No. 2018 - 11, Leases (Topic 842 ): Targeted Improvements . The guidance became effective for us beginning in the first quarter of 2019 and was required to be adopted using a modified retrospective approach. The Company adopted this guidance on January 1, 2019. This adoption resulted in the recognition of a right of use asset and a corresponding leasehold liability related to the Company’s building lease on the balance sheet of approximately $1.8 million with no material impact on the statements of operations and comprehensive loss. To maintain comparability between periods, the Company reclassified sublease payments received of approximately $240,000 that were netted against rent expense in the three and six months ended June 30, 2018 to other income on the condensed statement of operations and comprehensive loss. In addition, we elected to take advantage of the available practical expedients. In June 2018, the FASB issued ASU No. 2018 - 07, Compensation-Stock Compensation (Topic 718 ): Improvements to Nonemployee Share-Based Payment Accounting, which expands the scope of Topic 718 to include share based payment transactions for acquiring goods and services from nonemployees and applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. Topic 718 does not apply to share-based payments used to effectively provide ( 1 ) financing to the issuer or ( 2 ) awards granted in conjunction with selling goods or services to customers as part of a contract accounted for under Topic 606. This update is effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company adopted this guidance on January 1, 2019 and such adoption did not have a material impact on the Company’s financial statements.

Note 3 - Fair Value Measurement

Note 3 - Fair Value Measurements	6 Months Ended
	Jun. 30, 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 June 30, 2019 December 31, 2018, 1 June 30, 2019 December 31, 2018, no 2 3. no three six June 30, 2019 2018.

Note 4 - Inventories

Note 4 - Inventories	6 Months Ended
	Jun. 30, 2019
Notes to Financial Statements
Inventory Disclosure [Text Block]	4. Inventories consisted of the following (in thousands): June 3 0 , December 31, 2019 2018 Raw materials $ 1,689 $ 2,102 Work-in-process 695 158 Finished products 1,721 1,162 Total inventories $ 4,105 $ 3,422

Note 5 - Borrowings

Note 5 - Borrowings	6 Months Ended
	Jun. 30, 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 six June 30, 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 June 30, 2019, As of June 30, 2019, Year Ending December 31, 2019 (remaining six months of the year) $ — 2020 799 2021 3,403 2022 5,522 2023 3,981 13,705 Less: Amount of PIK additions and final facility fee to be accreted subsequent to June 30, 2019 (4,832 ) Less: Amount representing debt financing costs (672 ) Borrowings, as of June 30, 2019 $ 8,201 In connection with drawdowns under the Loan Agreement, the Company recorded aggregate debt discounts of $1.3 June 30, 2019 December 31, 2018, $672,000 $757,000, $43,000 $30,000 three June 30, 2019 2018, $85,000 $56,000 six June 30, 2019 2018, three June 30, 2019 2018, $364,000 $362,000, six June 30, 2019 2018, $714,000 $5.0 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 June 30, 2019 December 31, 2018 not

Note 6 - Commitments and Contin

Note 6 - Commitments and Contingencies	6 Months Ended
	Jun. 30, 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 originally were to expire in November 2019. $369,000 On October 19, 2017, one December 1, 2017 November 15, 2019 15 $82,410 Upon the adoption of Topic 842 January 1, 2019, $1.8 On April 1, 2019, five November 30, 2019. November 30, 2024. $5.8 November 2024, December 1, 2019. not In connection with the amendment the Company adjusted its right-of-use asset and lease liability to $6.0 6.5% not For the three June 30, 2019, $314,000. three June 30, 2018 $480,000. six June 30, 2019, $806,000. six June 30, 2018 $960,000. $219,000 six June 30, 2019. $179,000 June 30, 2019. The following table presents the future operating lease payments and lease liability included on the condensed balance sheet related to the Company’s operating lease as of June 30, 2019 ( Year Ending December 31, 2019 (remaining six months of the year) $ 912 2020 1,085 2021 1,123 2022 1,162 2023 1,203 Thereafter 1,138 6,623 Less: Imputed interest (1,027 ) Leasehold liability as of June 30, 2019 $ 5,596 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 $1.9 June 30, 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)	6 Months Ended
	Jun. 30, 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 June 30, 2019. Series A Convertible Preferred Stock On February 14, 2018, $38.0 $3,800,000 $42.8 2,090,000 8%, no February 14, 2019. January 2019, 2,945 December 31, 2018. June 30, 2019, 44,745 $1.8 six June 30, 2019. Series B Convertible Preferred Stock On February 16, 2018, 17,979 $15.5 $0.001 no no not December 31, 2018, 1,701 six June 30, 2019, 1,523 380,750 178 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, 728,500 8,586 $10.2 $0.001 no December 31, 2018, 2,170 six June 30, 2019, 2,170 542,500 no Common Stock As of June 30, 2019, 100,000,000 $0.001 6,421,317 Common Stock Warrants In connection with the issuance of the Company’s Series E convertible preferred stock in September 2014 January 2015, 50% June 30, 2019, 5,380 $5,040.00 September 2, 2019 On February 16, 2018, two 1,797,900 one one $4.00 seventh 50 one seventh 60th 50 60 seven June 30, 2019, 1,768,850 On July 13, 2018, 216,618 108,309 $15.80 one one third June 30, 2019 On November 1, 2018, 728,500 8,586 2,875,000 one one $4.00 5 th one 250 December 31, 2018 28,750,000 six June 30, 2019, 1,998,160 $8.0 June 30, 2019, 876,840 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 June 30, 2019 December 31, 2018, 27,593,789 47,575,393 Stock Plans In January 2015, 2015 “2015 2015 2009 “2009 2015 3,300 2015 2015 not 2009 2009 2015 first 2016, 4,225 5.0% 2018, 300,000 2015 June 8, 2018. June 19, 2019, 800,000 2015 June 30, 2019, 809,453 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 Price Weighted Average Remaining Contractual Life (in years) Intrisic Value (in thousands) Balance at December 31, 2018 7,954 $ 1,707.30 7.7 $ — Options granted — Options exercised — Options expired (371 ) 2,863.83 Options forfeited (103 ) $ 1,876.54 Balance at June 30, 2019 7,480 $ 1,340.79 7.3 $ — Exercisable at June 30, 2019 7,193 $ 1,318.21 7.3 $ — Vested and expected to vest at June 30, 2019 7,480 $ 1,340.79 7.3 $ — There were no six June 30, 2018. June 30, 2019, $221,000 1.0 not three six June 30, 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 294,066 $ 17.34 3.1 Awarded 18,500 $ 5.03 — Released (87 ) $ 2,175.45 — Forfeited (15,072 ) $ 21.90 — Awards outstanding at June 30, 2019 297,407 $ 15.71 2.1 As of June 30, 2019, $3.3 2.1 297,407 $900,000. $3.03 June 30, 2019, June 30, 2019 2018, $565 $1,900, no six June 30, 2018. 2018 On August 22, 2018, may may not 20,000 six June 30, 2019 7,596 June 30, 2019, 8,411

Note 8 - Stock-based Compensati

Note 8 - Stock-based Compensation	6 Months Ended
	Jun. 30, 2019
Notes to Financial Statements
Share-based Payment Arrangement [Text Block]	8. Total noncash stock-based compensation expense relating to the Company’s stock options and RSUs recognized during the three six June 30, 2019 2018, Three Months Ended June 30, Six Months Ended June 30, 201 9 201 8 201 9 201 8 Cost of revenues $ 40 $ 17 $ 87 $ 36 Research and development expenses 116 105 218 216 Selling, general and administrative expenses 360 519 704 1,008 $ 516 $ 641 $ 1,009 $ 1,260

Significant Accounting Policies

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 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 six June 30, 2019 not December 31, 2019, December 31, 2019 10 December 31, 2018, March 6, 2019. 2 10 December 31, 2018. On January 30, 2018, 1 40 June 19, 2019 , 1 - 10 June 21, 2019. not
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 June 30, 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 June 30, 2019 December 31, 2018, no June 30, 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 June 30, 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 June 30, 2019 December 31, 2018, no 10% three six June 30, 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 $ 272 Warranty provision 36 Usage/Release (93 ) Balance at June 30, 2019 $ 215
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 June 30, 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 June 30, Six Months Ended June 30, 201 9 201 8 201 9 201 8 Net loss attributable to common stockholders $ (5,546 ) $ (6,635 ) $ (11,496 ) $ (22,542 ) Weighted average common stock outstanding 6,377 675 5,319 435 Net loss per share attributable to common stockholders, basic and diluted $ (0.87 ) $ (9.83 ) $ (2.16 ) $ (51.82 ) 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 June 30, Six Months Ended June 30, 201 9 201 8 201 9 201 8 Common stock warrants 23,845,311 18,032,715 36,458,617 17,742,215 Common stock options 7,492 5,586 7,673 8,484 Convertible preferred stock 44,923 52,762 45,109 43,501 Unvested restricted stock units 287,817 345 288,581 330 24,185,543 18,091,408 36,799,980 17,794,530
Segment Reporting, Policy [Policy Text Block]	Segment and Geographical Information The Company operates and manages its business as one three June 30, 2019 2018, 92% 95%, six June 30, 2019 2018, 92% 93%,
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, Revenue Recognition August 2015, No. 2015 14, Revenue from Contracts with Customers (Topic 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, Codification Improvements to Topic 842, Leases No. 2018 11, Leases (Topic 842 ): Targeted Improvements first 2019 January 1, 2019. $1.8 no $240,000 three six June 30, 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)	6 Months Ended
	Jun. 30, 2019
Notes Tables
Schedule of Product Warranty Liability [Table Text Block]	Balance at December 31, 2018 $ 272 Warranty provision 36 Usage/Release (93 ) Balance at June 30, 2019 $ 215
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three Months Ended June 30, Six Months Ended June 30, 201 9 201 8 201 9 201 8 Net loss attributable to common stockholders $ (5,546 ) $ (6,635 ) $ (11,496 ) $ (22,542 ) Weighted average common stock outstanding 6,377 675 5,319 435 Net loss per share attributable to common stockholders, basic and diluted $ (0.87 ) $ (9.83 ) $ (2.16 ) $ (51.82 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	Three Months Ended June 30, Six Months Ended June 30, 201 9 201 8 201 9 201 8 Common stock warrants 23,845,311 18,032,715 36,458,617 17,742,215 Common stock options 7,492 5,586 7,673 8,484 Convertible preferred stock 44,923 52,762 45,109 43,501 Unvested restricted stock units 287,817 345 288,581 330 24,185,543 18,091,408 36,799,980 17,794,530

Note 4 - Inventories (Tables)

Note 4 - Inventories (Tables)	6 Months Ended
	Jun. 30, 2019
Notes Tables
Schedule of Inventory, Current [Table Text Block]	June 3 0 , December 31, 2019 2018 Raw materials $ 1,689 $ 2,102 Work-in-process 695 158 Finished products 1,721 1,162 Total inventories $ 4,105 $ 3,422

Note 5 - Borrowings (Tables)

Note 5 - Borrowings (Tables)	6 Months Ended
	Jun. 30, 2019
Notes Tables
Schedule of Debt [Table Text Block]	Year Ending December 31, 2019 (remaining six months of the year) $ — 2020 799 2021 3,403 2022 5,522 2023 3,981 13,705 Less: Amount of PIK additions and final facility fee to be accreted subsequent to June 30, 2019 (4,832 ) Less: Amount representing debt financing costs (672 ) Borrowings, as of June 30, 2019 $ 8,201

Note 6 - Commitments and Cont_2

Note 6 - Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2019
Notes Tables
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	Year Ending December 31, 2019 (remaining six months of the year) $ 912 2020 1,085 2021 1,123 2022 1,162 2023 1,203 Thereafter 1,138 6,623 Less: Imputed interest (1,027 ) Leasehold liability as of June 30, 2019 $ 5,596

Note 7 - Stockholders' Equity_2

Note 7 - Stockholders' Equity (Deficit) (Tables)	6 Months Ended
	Jun. 30, 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 Price Weighted Average Remaining Contractual Life (in years) Intrisic Value (in thousands) Balance at December 31, 2018 7,954 $ 1,707.30 7.7 $ — Options granted — Options exercised — Options expired (371 ) 2,863.83 Options forfeited (103 ) $ 1,876.54 Balance at June 30, 2019 7,480 $ 1,340.79 7.3 $ — Exercisable at June 30, 2019 7,193 $ 1,318.21 7.3 $ — Vested and expected to vest at June 30, 2019 7,480 $ 1,340.79 7.3 $ —
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 294,066 $ 17.34 3.1 Awarded 18,500 $ 5.03 — Released (87 ) $ 2,175.45 — Forfeited (15,072 ) $ 21.90 — Awards outstanding at June 30, 2019 297,407 $ 15.71 2.1

Note 8 - Stock-based Compensa_2

Note 8 - Stock-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
Notes Tables
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]	Three Months Ended June 30, Six Months Ended June 30, 201 9 201 8 201 9 201 8 Cost of revenues $ 40 $ 17 $ 87 $ 36 Research and development expenses 116 105 218 216 Selling, general and administrative expenses 360 519 704 1,008 $ 516 $ 641 $ 1,009 $ 1,260

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	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Retained Earnings (Accumulated Deficit), Ending Balance						$ (338,591,000)		$ (328,885,000)
Cash and Cash Equivalents, at Carrying Value, Ending Balance						14,754,000	$ 10,144,000	$ 16,410,000	$ 5,389,000
Proceeds from Issuance or Sale of Equity, Net	$ 10,200,000		$ 3,000,000	$ 15,500,000		$ 8,000,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				1,797,900
Preferred Stock, Par or Stated Value Per Share				$ 0.001		$ 0.001		$ 0.001
Debt Conversion, Original Debt, Amount							$ 38,000,000
Common Stock [Member]
Stock Issued During Period, Shares, New Issues	728,500
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		216,618
Shares Issued, Price Per Share			$ 1.58
November Public Offering [Member] | Common Stock [Member]
Stock Issued During Period, Shares, New Issues	728,500
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, 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				50
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				$ 4
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				50
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]
Stock Issued During Period, Shares, New Issues			216,618
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		108,309	108,309
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right			1
Shares Issued, Price Per Share			$ 16.425
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 15.80	$ 15.80
Common Stock Warrants [Member] | November Public Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	2,875,000					876,840
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	$ 4
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				2,090,000	2,090,000
Series C Preferred Stock [Member]
Proceeds from Issuance or Sale of Equity, Net	$ 10,200,000
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]
Proceeds from Issuance or Sale of Equity, Net	$ 10,200,000
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	Jun. 24, 2019	Jan. 30, 2018	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)shares	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)shares	Apr. 01, 2019USD ($)	Jan. 01, 2019USD ($)
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax, Total			$ 0		$ 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			5,596,000		$ 5,596,000			$ 6,000,000
Number of Operating Segments					1
Operating Lease, Liability, Total			5,596,000		$ 5,596,000			$ 6,000,000
Other Nonoperating Income (Expense), Total			$ 329,000	$ 227,000	$ 569,000	$ 468,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset									$ 1,800,000
Operating Leases, Rent Expense, Sublease Rentals				(240,000)		(240,000)
Operating Lease, Liability, Total									$ 1,800,000
Other Nonoperating Income (Expense), Total				$ 240,000		$ 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	0	0
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | UNITED STATES
Concentration Risk, Percentage			92.00%	95.00%	92.00%	93.00%
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	10	40

Note 2 - Summary of Significa_4

Note 2 - Summary of Significant Accounting Policies - Product Warranty (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Balance	$ 272
Warranty provision	36
Usage/Release	(93)
Balance	$ 215

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net loss attributable to common stockholders	$ (5,546)	$ (6,635)	$ (11,496)	$ (22,542)
Weighted average common shares used to compute net loss per share, basic and diluted (in shares)	6,377	675	5,319	435
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.87)	$ (9.83)	$ (2.16)	$ (51.82)

Note 2 - Summary of Significa_6

Note 2 - Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities (in shares)	24,185,543	18,091,408	36,799,980	17,794,530
Common Stock Warrants [Member]
Antidilutive Securities (in shares)	23,845,311	18,032,715	36,458,617	17,742,215
Common Stock Options [ member]
Antidilutive Securities (in shares)	7,492	5,586	7,673	8,484
Preferred Stock [Member]
Antidilutive Securities (in shares)	44,923	52,762	45,109	43,501
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities (in shares)	287,817	345	288,581	330

Note 3 - Fair Value Measureme_2

Note 3 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Inputs, Level 2 [Member]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ 0	$ 0
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	$ 0	$ 0

Note 4 - Inventories - Schedule

Note 4 - Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Raw materials	$ 1,689	$ 2,102
Work-in-process	695	158
Finished products	1,721	1,162
Total inventories	$ 4,105	$ 3,422

Note 5 - Borrowings (Details Te

Note 5 - Borrowings (Details Textual)	Feb. 14, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2021USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	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		$ 364,000	$ 362,000		714,000	5,034,000
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			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		672,000			672,000				$ 757,000			$ 1,300,000
Amortization of Debt Discount (Premium)		43,000	30,000		85,000	56,000
Interest Expense, Total		$ 364,000	$ 362,000		$ 714,000	$ 5,000,000
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 ($)	Jun. 30, 2019	Dec. 31, 2018	Sep. 22, 2015
Borrowings, as of June 30, 2019	$ 8,201,000	$ 7,486,000
CRG [Member] | Loan Agreement [Member]
2019 (remaining six months of the year)
2020	799,000
2021	3,403,000
2022	5,522,000
2023	3,981,000
	13,705,000
Less: Amount of PIK additions and final facility fee to be accreted subsequent to June 30, 2019	(4,832,000)
Less: Amount representing debt financing costs	(672,000)	$ (757,000)	$ (1,300,000)
Borrowings, as of June 30, 2019	$ 8,201,000

Note 6 - Commitments and Cont_3

Note 6 - Commitments and Contingencies (Details Textual)	Dec. 01, 2017USD ($)	May 25, 2017	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)	Apr. 01, 2019USD ($)	Jan. 01, 2019USD ($)
Operating Lease, Right-of-Use Asset			$ 5,596,000		$ 5,596,000			$ 6,000,000
Lessee, Operating Lease, Term of Contract								5 years
Lessee, Operating Lease, Liability, Payments, Due, Total			6,623,000		6,623,000			$ 5,800,000
Lessee, Operating Lease, Discount Rate								6.50%
Operating Lease, Expense			314,000	$ 480,000	806,000	$ 960,000
Operating Lease, Right-of-Use Asset, Amortization					219,000
Prepaid Rent			179,000		179,000
Purchase Obligation, Total			1,900,000		1,900,000
Operating Lease, Liability, Total			5,596,000		5,596,000			$ 6,000,000
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
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		$ 369,000
Facility Sublease [Member]
Operating Leases Sublease Expiration Prior to Base Lease	15 days
Operating Leases, Monthly Minimum Sublease Rental Payments Receivable Final	$ 82,410

Note 6 - Commitments and Cont_4

Note 6 - Commitments and Contingencies - Future Operating Lease Payments (Details) - USD ($)	Jun. 30, 2019	Apr. 01, 2019
2019 (remaining six months of the year)	$ 912,000
2020	1,085,000
2021	1,123,000
2022	1,162,000
2023	1,203,000
Thereafter	1,138,000
	6,623,000	$ 5,800,000
Less: Imputed interest	(1,027,000)
Leasehold liability as of June 30, 2019	$ 5,596,000	$ 6,000,000

Note 7 - Stockholders' Equity_3

Note 7 - Stockholders' Equity (Deficit) (Details Textual) - USD ($)	Jun. 19, 2019	Nov. 01, 2018	Jul. 13, 2018	Jul. 12, 2018	Feb. 16, 2018	Feb. 14, 2018	Jan. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 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		$ 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					$ 8,000,000
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, Outstanding, Ending Balance								6,421,317		6,421,317		3,492,200
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					1,797,900
Class of Warrant or Right, Outstanding								27,593,789		27,593,789		47,575,393
Proceeds from Warrant Exercises										$ 7,993,000	581,000
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	$ 0	0
Share Price								$ 3.03		$ 3.03
Common Stock, Shares, Issued, Total								6,421,317		6,421,317		3,492,200
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total								$ 221,000		$ 221,000
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								$ 3,300,000		$ 3,300,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition										2 years 36 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance								297,407		297,407		294,066
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Fair Value								$ 900,000		$ 900,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value										$ 565,000	$ 1,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period										18,500	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														3,300
Share-based Compensation Arrangement by Share-based Payment Award, Additional Shares Reserved for Issuance, Annual														4,225
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	800,000											300,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant								809,453		809,453
Officer and Director Share Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized													20,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant								8,411		8,411
Stock Issued During Period, Shares, Employee Stock Purchase Plans										7,596
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, Number of Securities Called by Warrants or Rights								5,380		5,380
Class of Warrant or Right, Exercise Price of Warrants or Rights								$ 5,040		$ 5,040
Common Stock Warrants, Issued with Series B Preferred Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					1,797,900			1,768,850		1,768,850
Common Stock Warrants, Issued with Series B Preferred Stock, Warrant One [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights					$ 4
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					50
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					50
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]
Stock Issued During Period, Shares, New Issues				216,618
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			108,309	108,309
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 15.80	$ 15.80
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, Number of Securities Called by Warrants or Rights		2,875,000						876,840		876,840
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 4
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right		1
Class of Warrant or Right, Outstanding												28,750,000
Class of Warrant or Right, Exercised										1,998,160
Proceeds from Warrant Exercises										$ 8,000,000
Preferred Stock Warrants [Member] | November Public Offering [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right		250
Common Stock [Member]
Stock Issued During Period, Shares, New Issues		728,500
Stock Issued During Period, Shares, Employee Stock Purchase Plans								3,099		7,788
Common Stock [Member] | Placement Agency Sale - Prospectus Supplement of July 12, 2018 [Member]
Stock Issued During Period, Shares, New Issues			216,618
Common Stock [Member] | November Public Offering [Member]
Stock Issued During Period, Shares, New Issues		728,500
Conversion of Series B Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Converted										1,523
Conversion of Stock, Shares Issued										380,750
Conversion of Series C Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Converted										2,170
Conversion of Stock, Shares Issued										542,500
Series A Preferred Stock [Member]
Preferred Stock, Shares Outstanding, Ending Balance								44,745		44,745
Dividends Payable								$ 1,800,000		$ 1,800,000
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
Proceeds from Issuance or Sale of Equity, Net		$ 10,200,000
Series C Preferred Stock [Member] | November Public Offering [Member]
Stock Issued During Period, Shares, New Issues		8,586
Proceeds from Issuance or Sale of Equity, Net		$ 10,200,000
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					2,090,000	2,090,000
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	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Options (in shares)	7,954,000
Options, weighted average exercise price (in dollars per share)	$ 1,707.30
Options, weighted average remaining contractual life (Year)	7 years 109 days	7 years 255 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)	(371,000)
Options expired, weighted average exercise price (in dollars per share)	$ 2,863.83
Options forfeited (in shares)	(103,000)
Options forfeited, weighted average exercise price (in dollars per share)	$ 1,876.54
Options (in shares)	7,480,000	7,954,000
Options, weighted average exercise price (in dollars per share)	$ 1,340.79	$ 1,707.30
Exercisable (in shares)	7,193,000
Exercisable, weighted average exercise price (in dollars per share)	$ 1,318.21
Exercisable, weighted average remaining contractual life (Year)	7 years 109 days
Vested and expected to vest (in shares)	7,480,000
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 1,340.79
Vested and expected to vest, weighted average remaining contractual life (Year)	7 years 109 days

Note 7 - Stockholders' Equity_6

Note 7 - Stockholders' Equity (Deficit) - Restricted Stock Units Award Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Awards outstanding, Shares (in shares)	294,066
Awards outstanding, Weighted grant date fair value (in dollars per share)	$ 17.34
Awards outstanding, Weighted average remaining contractual term (Year)	2 years 36 days		3 years 36 days
Awarded, Shares (in shares)	18,500	0
Awarded, Weighted grant date fair value (in dollars per share)	$ 5.03
Released, Shares (in shares)	(87)
Released, Weighted grant date fair value (in dollars per share)	$ 2,175.45
Forfeited, Shares (in shares)	(15,072)
Forfeited, Weighted grant date fair value (in dollars per share)	$ 21.90
Awards outstanding, Shares (in shares)	297,407		294,066
Awards outstanding, Weighted grant date fair value (in dollars per share)	$ 15.71		$ 17.34

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Allocated Share-based Compensation Expense	$ 516	$ 641	$ 1,009	$ 1,260
Cost of Sales [Member]
Allocated Share-based Compensation Expense	40	17	87	36
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	116	105	218	216
Selling, General and Administrative Expenses [Member]
Allocated Share-based Compensation Expense	$ 360	$ 519	$ 704	$ 1,008