Avinger (AVGR) 10-Q 10 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	May 01, 2017
Document and Entity Information
Entity Registrant Name	Avinger Inc
Entity Central Index Key	1,506,928
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		23,913,359
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 23,034	$ 36,096
Accounts receivable, net of allowance for doubtful accounts of $114 at March 31, 2017 and $21 at December 31, 2016	2,089	3,570
Inventories	8,352	8,462
Prepaid expenses and other current assets	1,359	662
Total current assets	34,834	48,790
Property and equipment, net	4,175	4,555
Other assets	211	212
Total assets	39,220	53,557
Current liabilities:
Accounts payable	1,161	1,607
Accrued compensation	2,188	2,807
Accrued expenses and other current liabilities	3,053	3,067
Borrowings	41,882	41,289
Total current liabilities	48,284	48,770
Other long-term liabilities	257	546
Total liabilities	48,541	49,316
Commitments and contingencies (Note 7)
Stockholders' equity (deficit):
Common stock, par value of $0.001; Shares authorized: 100,000,000 at March 31, 2017 and December 31, 2016; Shares issued and outstanding: 23,913,359 at March 31, 2017 and 23,776,033 at December 31, 2016	24	24
Additional paid-in capital	258,590	256,606
Accumulated deficit	(267,935)	(252,389)
Total stockholders' equity (deficit)	(9,321)	4,241
Total liabilities and stockholders' equity (deficit)	$ 39,220	$ 53,557

CONDENSED BALANCE SHEETS (Paren

CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
CONDENSED BALANCE SHEETS
Allowance for doubtful accounts (in dollars)	$ 114	$ 21
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	23,913,359	23,776,033
Common stock, shares outstanding	23,913,359	23,776,033

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Revenues	$ 3,491	$ 4,539
Cost of revenues	4,075	3,360
Gross profit (loss)	(584)	1,179
Operating expenses:
Research and development	3,923	4,047
Selling, general and administrative	9,318	12,161
Total operating expenses	13,241	16,208
Loss from operations	(13,825)	(15,029)
Interest income	32	33
Interest expense	(1,550)	(1,172)
Other income (expense), net	3	1
Net loss and comprehensive loss	$ (15,340)	$ (16,167)
Net loss per share, basic and diluted (in dollars per share)	$ (0.64)	$ (1.28)
Weighted average common shares used to compute net loss per share, basic and diluted	23,820	12,669

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities
Net loss	$ (15,340)	$ (16,167)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	428	336
Amortization of debt issuance costs and debt discount	62	47
Stock-based compensation	1,542	1,978
Noncash interest expense and other charges	536	371
Provision for doubtful accounts receivable	94
Provision for excess and obsolete inventories	1,257	294
Changes in operating assets and liabilities:
Accounts receivable	1,387	(1,976)
Inventories	(1,165)	(1,794)
Prepaid expenses and other current assets	(697)	(516)
Other assets		(135)
Accounts payable	(446)	1,145
Accrued compensation	(619)	267
Accrued expenses and other current liabilities	(8)	136
Other long-term liabilities and accrued interest	(294)	(179)
Net cash used in operating activities	(13,263)	(16,193)
Cash flows from investing activities
Purchase of property and equipment	(29)	(301)
Net cash used in investing activities	(29)	(301)
Cash flows from financing activities
Principal paydown of capital lease obligations	(6)	(9)
Payments on deferred offering costs		(93)
Proceeds from the issuance of common stock	236	419
Net cash provided by financing activities	230	317
Net change in cash and cash equivalents	(13,062)	(16,177)
Cash and cash equivalents, beginning of period	36,096	43,059
Cash and cash equivalents, end of period	23,034	26,882
Supplemental disclosure of cash flow information
Cash paid for interest	1,193	957
Noncash investing and financing activities:
Accounts payable for purchases of property and equipment		54
Transfer between inventory and property and equipment	$ 93	$ 365

Organization

Organization	3 Months Ended
	Mar. 31, 2017
Organization
Organization	1. Organization Organization, Nature of Business Avinger, Inc. (the “Company”), a Delaware corporation, was founded in March 2007 by cardiologist and medical device entrepreneur Dr. John B. Simpson. The Company designs, manufactures and sells image-guided, catheter-based systems that are used by physicians to treat patients with peripheral artery disease (“PAD”). Patients with PAD have a build-up of plaque in the arteries that supply blood to areas away from the heart, particularly the pelvis and legs. The Company manufactures and sells a suite of products in the United States (“U.S.”) and in select international markets. The Company has developed its Lumivascular platform, which integrates optical coherence tomography (“OCT”) visualization with interventional catheters and is the industry’s only system that provides real-time intravascular imaging during the treatment portion of PAD procedures. The Company’s Lumivascular platform consists of a capital component, Lightbox, as well as a variety of disposable catheter products. The Company’s current products include its non-imaging catheters, Wildcat and Kittycat, as well as its Lumivascular platform products, Ocelot, Ocelot PIXL and Ocelot MVRX, all of which are designed to allow physicians to penetrate a total blockage in an artery, known as a chronic total occlusion (“CTO”). In March 2016, the Company also received 510(k) clearance from the U.S. Food and Drug Administration (“FDA”) for commercialization of Pantheris, the Company’s image-guided atherectomy system, designed to allow physicians to precisely remove arterial plaque in PAD patients. The Company commenced sales of Pantheris in the U.S. and select international markets promptly thereafter. The Company is located in Redwood City, California. 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. In the course of its activities, the Company has incurred losses and negative cash flows from operations since its inception. As of March 31, 2017, the Company had an accumulated deficit of $267,935,000. The Company expects to incur losses for the foreseeable future. The Company believes that its cash and cash equivalents of $23,034,000 at March 31, 2017 and expected revenues will be sufficient to allow the Company to fund its current operations until approximately December 31, 2017. The Company will seek additional sources of funding in the form of debt financing or equity issuances. However, there can be no assurance that the Company will be successful in acquiring additional funding at levels sufficient to fund its operations. These conditions raise substantial doubt about the Company’s ability to continue as a going concern. If the Company is unable to raise additional capital in sufficient amounts or on terms acceptable to it, the Company may have to significantly reduce its operations or delay, scale back or discontinue the development of one or more of its products. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. The Company’s ultimate success will largely depend on its continued development of innovative medical technologies, its ability to successfully commercialize its products and its ability to raise significant additional funding. 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 Term Loan Agreement with CRG Partners III L.P. and certain of its affiliated funds (collectively “CRG”), the entire amount of borrowings at March 31, 2017 and December 31, 2016 has been classified as current in these financial statements. CRG has not invoked the material adverse change clause. Public Offerings In January 2015, the Company issued and sold 5,000,000 shares of its common stock in its initial public offering (“IPO”) at a public offering price of $13.00 per share, for net proceeds of approximately $56,897,000 after deducting underwriting discounts and commissions of approximately $4,550,000 and expenses of approximately $3,553,000. Upon the closing of the IPO, all shares of convertible preferred stock then outstanding converted into an aggregate of 6,967,925 shares of common stock resulting in the reclassification of $137,626,000 from outside of stockholders’ equity to additional paid-in capital. On February 3, 2016, the Company filed a universal shelf registration statement to offer up to $150,000,000 of its securities and entered into an “at-the-market” program pursuant to a Sales Agreement with Cowen and Company (“Cowen”), through which it may, from time to time, issue and sell shares of common stock having an aggregate offering value of up to $50,000,000. The shelf registration statement also covers the resale of the shares sold to CRG in September 2015. The registration statement was declared effective by the SEC on March 8, 2016. During the three months ended March 31, 2017 and 2016, the Company sold no shares of common stock under the “at-the-market” program. During the year ended December 31, 2016, the Company sold 1,095,378 shares of common stock under the “at-the-market” program at an average price of $4.87 and raised net proceeds of $5,171,000, after payment of $160,000 in commissions and fees to Cowen. In August 2016, the Company issued and sold 9,857,800 shares of its common stock in its follow-on public offering, which includes the exercise in full by the underwriters of their option to purchase 1,285,800 shares of common stock, at a public offering price of $3.50 per share. Net proceeds from the follow-on public offering were approximately $31,549,000 after deducting underwriting discounts and commissions of approximately $2,415,000 and expenses of approximately $538,000.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies 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 United States Securities and Exchange Commission (“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 months ended March 31, 2017, are not necessarily indicative of results to be expected for the year ending December 31, 2017, or for any other interim period or for any future year. The December 31, 2016 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, 2016, which was filed with the SEC on March 14, 2017. The Company’s significant accounting policies are more fully described in Note 2 of the Notes to the Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. 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, provisions for doubtful accounts receivable and excess and obsolete inventories, the determination of useful lives and impairment of assets, 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 March 31, 2017 and December 31, 2016. 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 its borrowings approximate 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 March 31, 2017 and December 31, 2016, 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 March 31, 2017 and December 31, 2016. 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 March 31, 2017 and December 31, 2016. The Company’s accounts receivable are due from a variety of health-care organizations in the United States and select European markets. At March 31, 2017 and December 31, 2016, there were no customers that represented 10% or more of the Company’s accounts receivable. For the three months ended March 31, 2017 and 2016, there were no customers that represented 10% or more of revenues. Disruption of sales orders or a deterioration of financial condition 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 its Lightbox (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 recognizes revenue in accordance with Accounting Standards Codification (“ASC”) 605-10, Revenue Recognition, when persuasive evidence of an arrangement exists, the fee is fixed or determinable, collection of the fee is probable and delivery has occurred. 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 revenue is recognized ratably over the term of the service period. 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 ASC 840, Leases and ASC 605-25, Revenue Recognition—Multiple Element Arrangements . 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. The Company expenses all warranty costs and inventory provisions to cost of revenues. The Company records adjustments to its inventory valuation for estimated excess, obsolete and non-sellable inventories based on assumptions about future demand, past usage, changes to manufacturing processes and overall market conditions. Cost of revenues also includes depreciation expense for the Lightboxes under lease and commercial evaluation program 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. The warranty liability is included within accrued liabilities on the balance sheet.Warranty provisions and claims are summarized as follows (in thousands): Amount Balance at December 31, 2016 $ Warranty provision Usage/Release ) Balance at March 31, 2017 $ Net Loss per Share Basic net loss per share is computed by dividing the net loss 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 is computed by dividing the net loss 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. For the computation of net loss per share, there were no common stock shares subject to repurchase excluded from the calculations as of March 31, 2017 and 2016. Since the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share as the inclusion of all potentially dilutive common shares would have been anti-dilutive. Net loss per share was determined as follows (in thousands, except per share data): Three Months Ended March 31, 2017 2016 Net loss $ ) $ ) Weighted average common stock outstanding Net loss per share, basic and diluted $ ) $ ) 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: March 31, 2017 2016 Common stock options Unvested restricted stock units Common stock warrants Comprehensive Loss For the three months ended March 31, 2017 and 2016, there was no difference between comprehensive loss and the Company’s net loss. 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 March 31, 2017 and 2016, 96% and 99% of the Company’s revenues were in the United States, respectively, based on the shipping location of the external customer. Accounting Pronouncements Adopted in 2017 In March 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-09, Compensation — Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for employee share-based payments, including income tax consequences, application of award forfeitures to expense, classification on the statement of cash flows, and classification of awards as either equity or liabilities. This guidance is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. As a result of adopting ASU 2016-09, the Company has made an accounting policy election to account for forfeitures as they occur. This change has been applied on a modified retrospective basis, resulting in a cumulative-effect adjustment to increase accumulated deficit by $206,000 as of January 1, 2017, the date of adoption. The adoption of ASU 2016-09 also requires that excess tax benefits and tax deficiencies be recorded in the statement of operations as opposed to additional paid-in capital when the awards vest or are settled. The adoption of ASU 2016-09 as it relates to the accounting for excess tax benefits and tax deficiencies has no impact on the Company’s current financial statements or on any prior period financial statements presented. ASU 2016-09 also requires excess tax benefits to be classified as an operating activity, consistent with other income tax cash flows, and may be applied either on a retrospective or prospective basis. The Company has elected to apply this amendment on a prospective basis, as there is no impact to its prior period statements of cash flows. As such, prior periods have not been adjusted. In July 2015, the FASB issued an accounting standard which applies to all inventory that is measured using methods other than last-in, first-out or the retail inventory method, including inventory that is measured using first-in, first-out or average cost. The standard requires entities to measure inventory at the lower of cost and net realizable value, defined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The guidance is effective for public entities for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. The Company’s elected to adopt this standard as of January 1, 2017, on a prospective basis. The adoption had no impact on its financial statements. In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740) — Balance sheet Classification of Deferred Taxes, which requires entities to present its deferred tax assets and deferred tax liabilities as noncurrent in its financial statements. The guidance is effective for public entities for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. The Company’s elected to adopt this standard as of January 1, 2017, on a prospective basis. The adoption of this new guidance does not create any impact to the Company’s financial statements due to the fact that no deferred tax assets or liabilities have been reported in its financial statements. This will likely remain the case if the Company continues to incur additional losses, which requires it to maintain a full valuation allowance as it will be more-likely-than-not that its deferred tax assets are not realizable. Recent Accounting Pronouncements In May 2014, the FASB, jointly with the International Accounting Standards Board, issued a comprehensive new standard on revenue recognition from contracts with customers. The standard’s core principle is that a reporting entity will recognize revenue when it transfers promised 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 standard will become effective for the Company beginning in the first quarter of 2018. Early application would be permitted in 2017. Entities would have the option of using either a full retrospective or a modified retrospective approach to adopt this new guidance. The Company has preliminarily decided to adopt this accounting standard in the first quarter of fiscal year 2018 using the modified retrospective approach, with the cumulative effect being recorded within accumulated deficit on January 1, 2018; however, the final determination will depend on a number of factors including finalizing our assessment of the impact to the Company’s financial results as well as assessing the impacts of any additional disclosure requirements. The guidance requires an entity to recognize revenue in an amount that reflects the consideration to which an entity expects to be entitled in exchange for the transfer of goods or services. The guidance also requires expanded disclosures relating to the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. Additionally, qualitative and quantitative disclosures are required about customer contracts, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The Company has not completed its assessment of the adoption on its financial statements.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
Fair Value Measurements
Fair Value Measurements	3. Fair Value Measurements 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-tier fair value hierarchy is established as a basis for considering such assumptions and for inputs used in the valuation methodologies in measuring fair value: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Inputs other than quoted prices included within Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. As of March 31, 2017 and December 31, 2016, cash equivalents were all categorized as Level 1 and consisted of money market funds. As of March 31, 2017 and December 31, 2016, there were no financial assets and liabilities categorized as Level 2 or 3. There were no transfers between fair value hierarchy levels during the three months ended March 31, 2017 and 2016.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2017
Inventories
Inventories	4. Inventories Inventories consisted of the following (in thousands): March 31, December 31, 2017 2016 Raw materials $ $ Work-in-process — Finished products Total inventories $ $

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2017
Credit Agreement
Borrowings
Borrowings	5. Borrowings CRG On September 22, 2015, the Company entered into a Term Loan Agreement (the “Loan Agreement”) with CRG under which, subject to certain conditions, the Company may borrow up to $50,000,000 in principal amount from CRG on or before March 29, 2017. The Company borrowed $30,000,000 on September 22, 2015. The Company borrowed an additional $10,000,000 on June 15, 2016 under the Loan Agreement. The Company would have been eligible to borrow an additional $10,000,000, on or prior to March 29, 2017, upon achievement of certain revenue milestones, among other conditions, but those milestones were not achieved. Under the Loan Agreement, the first sixteen quarterly payments are interest only payments, and the last eight quarterly payments will be equal installments in which interest and principal amounts are paid. Interest is calculated at a fixed rate of 12.5% per annum. The Company makes quarterly payments of interest only in arrears commencing on September 30, 2015. During the interest only period, the Company may elect to make the 12.5% interest payment by making a cash payment for 8.5% per annum of interest and making a payment-in-kind (“PIK”) for the remaining amount, for which the 4.0% per annum of interest would be added to the outstanding principal amount of the borrowings. To date, the Company has elected the PIK interest option to the extent available and has made a cash payment for the remaining amount. Principal is repayable in eight equal quarterly installments during the final two years of the term. All unpaid principal, and accrued and unpaid interest, is due and payable in full on September 30, 2021. The Company may voluntarily prepay the borrowings in full, with a prepayment premium beginning at 5.0% and declining by 1.0% annually thereafter, with no premium being payable if prepayment occurs after the fifth year of the loan. Each tranche of borrowing requires the payment, on the borrowing date, of a financing fee equal to 1.5% of the borrowed loan principal, which is recorded as a discount to the debt. In addition, a facility fee equal to 7.0% of the amounts borrowed plus any PIK is payable at the end of the term or when the borrowings are repaid in full. A long-term liability is being accreted using the effective interest method for the facility fee over the term of the Loan Agreement with a corresponding discount to the debt. The borrowings are collateralized by a security interest in substantially all of the Company’s assets. 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 Loan Agreement, as amended, include a covenant that the Company maintain a minimum of $5,000,000 of cash and certain cash equivalents, and the Company had to achieve minimum revenue of $7,000,000 in 2015 and $18,000,000 in 2016, and must achieve minimum revenue of $40,000,000 in 2017, $50,000,000 in 2018, $60,000,000 in 2019 and $70,000,000 in 2020 and in each year thereafter, as applicable. If the Company fails to meet the applicable minimum revenue target in any calendar year, the Loan Agreement provides the Company with a cure right if it prepays a portion of the outstanding principal equal to 2.0 times the revenue shortfall. In addition, the Loan Agreement prohibits the payment of cash dividends on the Company’s capital stock and also places restrictions on mergers, sales of assets, investments, incurrence of liens, incurrence of indebtedness and transactions with affiliates. CRG may accelerate the payment terms of the Loan Agreement upon the occurrence of certain events of default set forth therein, which include the failure of the Company to make timely payments of amounts due under the Loan Agreement, the failure of the Company to adhere to the covenants set forth in the Loan Agreement, the insolvency of the Company or upon the occurrence of a material adverse change. As of March 31, 2017, the Company was in compliance with all applicable covenants. As of March 31, 2017, principal and PIK payments under the Loan Agreement follows (in thousands): Period Ending December 31, Principal and PIK 2017 $ — 2018 — 2019 2020 2021 Add: Accretion of closing fees Add: PIK Less: Amount representing debt financing costs ) Borrowings $ Contemporaneous with the execution of the Loan Agreement, the Company entered into a Securities Purchase Agreement (the “Securities Purchase Agreement”) with CRG which allowed it to purchase up to $5,000,000 of the Company’s common stock. CRG purchased 348,262 shares of common stock on September 22, 2015 at a price of $14.357 per share, which is the 10-day average of closing prices of the Company’s common stock ending on September 21, 2015. The closing price on September 22, 2015 was $13.97 yielding a $0.387 per share premium. Both the premium and the issuance costs were allocated to the borrowings under Loan Agreement and the common stock purchase under the Securities Purchase Agreement based on the relative fair values of each security. The portion of the premium allocated to the borrowings is being amortized over the term of the Loan Agreement. Pursuant to the Securities Purchase Agreement, the Company filed a shelf registration statement covering, among other things, the resale of the shares sold to CRG and must comply with certain affirmative covenants during the time that such registration statement remains in effect. In connection with the initial drawdown under the Loan Agreement, the Company recorded a debt discount of $876,000. The debt discount comprised financing fees of $450,000, paid directly to CRG, and an allocation of the other costs directly attributable to the Loan Agreement and Securities Purchase Agreement with CRG of $541,000 net of the common stock premium of $115,000 based on the relative fair values of each security. In connection with the June 2016 drawdown under the Loan Agreement, the Company recorded a debt discount of $275,000 which comprised financing fees of $150,000, paid directly to CRG, and other costs directly attributable to the Loan Agreement with CRG of $125,000. The debt discount is being amortized as non-cash interest expense using the effective interest method over the term of the Loan Agreement. As of March 31, 2017, the balance of the aggregate debt discount was $862,000. As noted in Note 1 to these financial statements, 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 CRG Loan Agreement, the entire amount of borrowings at March 31, 2017 and December 31, 2016 has been classified as current in these financial statements. CRG has not invoked the material adverse change clause. PDL BioPharma On April 18, 2013, the Company entered into a Credit Agreement (“Agreement”) with PDL BioPharma, Inc. (“PDL”) whereby PDL agreed to loan up to $40,000,000. Contemporaneous with the execution of the Agreement the Company borrowed an initial $20,000,000 (“Term Note”). The Term Note was scheduled to mature April 18, 2018, had a stated interest rate of 12.0% per annum and could be prepaid by the Company at any time. The Company paid interest-only through the first ten quarters and, thereafter, repayment of principal in equal installments including accrued and unpaid interest, payable each quarter. As provided under the terms of the Agreement, for the first eight quarterly interest payments, or through 2015, on the Term Note the Company elected to convert an amount of interest, up to 1.5% per annum, into additional loans, referred to as PIK loans. The PIK loans accrued interest and were added to the aggregate principal balance of the Term Note. In September 2015, in connection with the consummation of the Loan Agreement with CRG, the Company repaid all amounts outstanding under the Agreement. The payoff amount of $21,363,000 included accrued interest through the repayment date of $563,000 and $200,000 as an end-of-term final payment fee. In addition to the interest and principal payments, the Company also paid a royalty, referred to as Assigned Interests, equal to 1.8% of the Company’s quarterly net revenues. Upon the prepayment of the Term Note, the Company’s obligations relating to Assigned Interests continue, and are payable through the maturity date at a reduced rate of 0.9% of the quarterly net revenues, subject to certain quarterly minimum mandatory amounts, which are payable monthly. The ongoing obligation was determined to be an embedded element of the Agreement and cannot be bifurcated from the Term Note for accounting purposes. Accordingly, the Company continued to account for the Assigned Interest obligation relating to future royalties as a debt instrument by applying the retrospective approach and reviews its estimate of forecasted Assigned Interests payable annually. Under the retrospective method, the Company computes a new effective interest rate based on the original carrying amount, actual cash flows to date, and remaining estimated cash flows over the maturity date. The new effective interest rate, 20.4% as of December 31, 2016, is used to adjust the carrying amount to the present value of the revised estimated cash flows, discounted at the new effective interest rate. At the time of the repayment the resulting increase in the carrying value of the Assigned Interests, of $942,000, was recognized as a component of other income (expense), net, on the statements of operations and comprehensive loss. The Company has an aggregate accrual for its Assigned Interests obligations of $1,227,000 and $1,463,000, representing the net present value of the future minimum royalty obligation as of March 31, 2017 and December 31, 2016, respectively. The Assigned Interest liability was included within accrued expenses and other current liabilities and within other long-term liabilities as of March 31, 2017 and December 31, 2016, on the balance sheet. Prior to the repayment of the Term Note, the Assigned Interests liability was included within borrowings and borrowings, net of current portion, on the balance sheet. Additionally, until there are no further obligations to periodically pay PDL a percentage of its net revenue in April 2018, the Company must comply with certain affirmative covenants and negative covenants limiting its ability to, among other things, undergo a change in control or dispose of assets, in each case subject to certain exceptions. The Company is in compliance with the covenants under the Agreement.

Capital Leases

Capital Leases	3 Months Ended
	Mar. 31, 2017
Capital Leases
Capital Leases	6. Capital Leases Capital lease obligations consist of leased office equipment. As of March 31, 2017 and December 31, 2016, the aggregate amount of capital leases recorded within property and equipment, net, on the accompanying balance sheet is $33,000 and $39,000, respectively. The current portion of the capital lease obligations is included in accrued liabilities and the balance included within other long-term liabilities represents the long-term portion. The future minimum lease payments as of March 31, 2017, are as follows (in thousands): Future Minimum Period ending December 31, Lease Payments 2017 $ 2018 2019 Total minimum payments Less: Amount representing future interest Present value of minimum lease payments $

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies
Commitments and Contingencies	7. Commitments and Contingencies Lease Commitments The Company’s operating lease obligations primarily consist of leased office, laboratory, and manufacturing space under a non-cancelable operating lease that expires in November 2019. The lease agreement includes a renewal provision allowing the Company to extend this lease for an additional period of three years. In addition to the minimum future lease commitments presented below, the lease requires the Company to pay property taxes, insurance, maintenance, and repair costs. The lease includes a rent holiday concession and escalation clauses for increased rent over the lease term. Rent expense is recognized using the straight-line method over the term of the lease. The Company records deferred rent calculated as the difference between rent expense and the cash rental payments. In March 2016, the Company entered into an additional non-cancelable operating lease for warehouse and storage space that expires in November 2019. Rent expense was $506,000 and $230,000 for the three months ended March 31, 2017 and 2016, respectively. Aggregate future minimum lease payments as of March 31, 2017, are as follows (in thousands): Future Minimum Year ending December 31, Lease Payments 2017 $ 2018 2019 Total minimum lease payments $ Purchase Obligations Purchase obligations consist of agreements to purchase goods and services entered into in the ordinary course of business. The Company had noncancellable commitments to suppliers for purchases totaling $2,976,000 and $3,542,000 as of March 31, 2017 and December 31, 2016, respectively. Indemnification In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and may provide for indemnification of the counterparty. The Company’s exposure under these agreements is unknown because it involves claims that may be made against it in the future, but have not yet been made. To date, the Company has not been subject to any claims or been required to defend any action related to its indemnification obligations. 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 be subject to any proceeding arising out of acts or omissions of such director in such capacity. The maximum amount of potential future indemnification is unlimited; however, the Company currently holds director liability insurance. This insurance allows the transfer of risk associated with the Company’s exposure and may enable it to recover a portion of any future amounts paid. The Company believes that the fair value of these indemnification obligations is minimal. Accordingly, it has not recognized any liabilities relating to these obligations for any period presented. Legal Proceedings The Company was not party to any legal proceedings at March 31, 2017 and December 31, 2016. The Company assesses, in conjunction with its legal counsel, the need to record a liability for litigation and contingencies. Reserve estimates are recorded when and if it is determined that a loss-related matter is both probable and reasonably estimable.

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit)	3 Months Ended
	Mar. 31, 2017
Stockholders' Equity (Deficit)
Stockholders' Equity (Deficit)	8. Stockholders’ Equity (Deficit) Preferred Stock At March 31, 2017, the Company’s certificate of incorporation, as amended and restated, authorizes the Company to issue up to 5,000,000 shares of preferred stock with $0.001 par value per share, of which no shares were issued and outstanding. Common Stock At March 31, 2017, the Company’s certificate of incorporation, as amended and restated, authorizes the Company to issue up to 100,000,000 shares of common stock with $0.001 par value per share, of which 23,913,359 shares were issued and outstanding. Common Stock Warrants In connection with the issuance of the Company’s Series E Convertible Preferred Stock in September 2014 through January 2015, the Company issued, to each investor who purchased shares of Series E Convertible Preferred Stock, warrants to purchase up to the number of shares of common stock equal to 70% of the number of shares of the Company’s Series E Convertible Preferred Stock purchased. The warrants are immediately exercisable, at an exercise price per share of $12.60, and expire upon the earlier of September 2, 2019 or upon the consummation of a change of control of the Company. The Company determined that these common stock warrants meet the requirements for equity classification. The common stock warrants were recorded at their allocated fair value within stockholders’ equity (deficit). As of March 31, 2017 and December 31, 2016, warrants to purchase an aggregate of 2,152,117 shares of common stock were outstanding. Stock Plans In January 2015, the Board of Directors adopted and the Company’s stockholders approved the 2015 Equity Incentive Plan (“2015 Plan”). The 2015 Plan replaced the 2009 Stock Plan (the “2009 Plan”) which was terminated immediately prior to consummation of the Company’s IPO, collectively the “Plans.” The 2015 Plan provides for the grant of incentive stock options (“ISOs”) to employees and for the grant of nonstatutory stock options (“NSOs”), restricted stock, RSUs, stock appreciation rights, performance units and performance shares to employees, directors and consultants. Initially a total of 1,320,000 shares of common stock were reserved for issuance pursuant to the 2015 Plan. The shares reserved for issuance under the 2015 Plan included shares reserved but not issued under the 2009 Plan, plus any share awards granted under the 2009 Plan that expire or terminate without having been exercised in full or that are forfeited or repurchased. In addition, the number of shares available for issuance under the 2015 Plan includes an automatic annual increase on the first day of each fiscal year beginning in fiscal 2016, equal to the lesser of 1,690,000 shares, 5.0% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year or an amount as determined by the Board of Directors. For fiscal 2017, the common stock available for issuance under the 2015 Plan was increased by 1,188,801 shares of common stock. As of March 31, 2017, 1,321,851 shares were available for grant under the 2015 Plan. Pursuant to the Plans, ISOs and NSOs may be granted with exercise prices at not less than 100% of the fair value of the common stock on the date of grant and the exercise price of ISOs granted to a stockholder, who, at the time of grant, owns stock representing more than 10% of the voting power of all classes of the stock of the Company, shall be not less than 110% of the fair market value per share of common stock on the date of grant. The Company’s Board of Directors determines the vesting schedule of the options. Options granted generally vest over four years and expire ten years from the date of grant. Stock option activity under the Plans is set forth below: Options Outstanding Weighted Aggregate Number of Average Intrinsic Value Shares Exercise Price (in thousands) Balance at December 31, 2016 $ $ Options granted $ Options exercised — $ — Options cancelled ) $ Balance at March 31, 2017 $ $ — The weighted-average grant date fair value of stock options granted during the three months ended March 31, 2017 was $1.13 per share. As of March 31, 2017, the aggregate intrinsic value of options outstanding and vested was zero. The aggregate intrinsic value of options exercised was none during the three months ended March 31, 2017. The aggregate intrinsic value was calculated as the difference between the exercise prices of the underlying options and the closing market price of the common stock on the date of exercise. Because of the Company’s net operating losses, the Company did not realize any tax benefits from share-based payment arrangements for the three months ended March 31, 2017 and 2016. At March 31, 2017 and at December 31, 2016, there were 1,946,935 and 1,630,917 shares, respectively, vested with a weighted-average exercise price of $7.72 and $7.40 per share, respectively, and a weighted average contractual life of 7.54 and 7.63 years, respectively. The Company’s RSUs vest annually over four years in equal increments. A summary of all RSU activity for the three months ended March 31, 2017 is presented below: Weighted Average Weighted Average Aggregate Number of Grant Date Remaining Intrinsic Value Shares Fair Value Contractual Term (in thousands) Awards outstanding at December 31, 2016 $ Awarded $ Released ) $ Forfeited ) $ Awards outstanding at March 31, 2017 $ $ As of March 31, 2017, $2,755,000 of total unrecognized compensation expense related to employee RSUs was expected to be recognized over a weighted-average period of 3.04 years. The Company used the closing market price of $1.90 per share at March 31, 2017, to determine the aggregate intrinsic value. 2015 Employee Stock Purchase Plan In January 2015, the Board of Directors adopted and the Company’s stockholders approved the 2015 Employee Stock Purchase Plan (“ESPP”) under which eligible employees are permitted to purchase common stock at a discount through payroll deductions. Initially 500,000 shares of common stock were reserved for issuance, which is subject to an automatic increase on the first day of each fiscal year, commencing in 2016, by an amount equal to the lesser of (i) 493,000 shares (ii) 1.5% of the outstanding shares of common stock as of the last day of the immediately preceding fiscal year; or (iii) an amount as determined by the Board of Directors. For fiscal 2017, the common stock available for issuance under the ESPP was increased by 356,640 shares of common stock. The price of the common stock purchased will be the lower of 85% of the fair market value of the common stock at the beginning of an offering period or at the end of a purchase period. The ESPP is intended to qualify as an “employee stock purchase plan” within the meaning of Section 423 of the Internal Revenue Code of 1986, as amended. The first offering under the ESPP began in February 2015. As of March 31, 2017, approximately 801,318 shares of common stock remained reserved for issuance under the ESPP. The Company incurred $64,000 and $93,000 in stock-based compensation expense related to the ESPP for the three months ended March 31, 2017 and 2016, respectively.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2017
Stock-Based Compensation
Stock-Based Compensation	9. Stock-Based Compensation Stock-based compensation for the Company includes amortization related to all stock options, RSUs and shares issued under the ESPP, based on the grant-date estimated fair value. The Company estimates the fair value of stock options and shares issued under the ESPP on the date of grant using the Black-Scholes option-pricing model. The Black-Scholes model determines the fair value of stock-based payment awards based on the fair market value of the Company’s common stock on the date of grant and is affected by assumptions regarding a number of complex and subjective variables. These variables include, but are not limited to, the fair value of the Company’s common stock, and the volatility over the expected term of the awards. The fair value for the Company’s employee stock options was estimated at the date of grant using the Black-Scholes valuation model with the following weighted average assumptions: Three Months Ended March 31, 2017 2016 Expected term (years) Expected volatility % % Risk-free interest rate % % Dividend rate — — As of March 31, 2017 and December 31, 2016, the total unamortized compensation expense related to stock option awards granted to employees and directors was $10,892,000 and $12,312,000, which is expected to be amortized over the next 2.2 and 2.3 years, respectively. The fair value of the shares to be issued under the Company’s ESPP was estimated using the Black-Scholes valuation model with the following assumptions: Three Months Ended March 31, 2017 2016 Expected term (years) Expected volatility % % Risk-free interest rate % % Dividend rate — — Total stock-based compensation expense related to stock-based awards recognized during the three months ended March 31, 2017 and 2016, is as follows (in thousands): Three Months Ended March 31, 2017 2016 Cost of revenues $ $ Research and development expenses Selling, general and administrative expenses $ $

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2017
Subsequent Events
Subsequent Events	10. Subsequent Events Restructuring Plan In April 2017, the Company undertook an organizational realignment which included a reduction in force, lowering its total headcount by approximately 33% compared to December 31, 2016, in order to conserve resources. The Company is currently evaluating the potential financial impact of the organizational restructuring and other expense reduction measures on its financial statements.

Summary of Significant Accoun16

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Summary of Significant Accounting Policies
Basis of Presentation	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 United States Securities and Exchange Commission (“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 months ended March 31, 2017, are not necessarily indicative of results to be expected for the year ending December 31, 2017, or for any other interim period or for any future year. The December 31, 2016 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, 2016, which was filed with the SEC on March 14, 2017. The Company’s significant accounting policies are more fully described in Note 2 of the Notes to the Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016.
Use of Estimates	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, provisions for doubtful accounts receivable and excess and obsolete inventories, the determination of useful lives and impairment of assets, 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	Fair Value of Financial Instruments The Company has evaluated the estimated fair value of its financial instruments as of March 31, 2017 and December 31, 2016. 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 its borrowings approximate fair value.
Cash and Cash Equivalents	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 March 31, 2017 and December 31, 2016, 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 March 31, 2017 and December 31, 2016. 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	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 March 31, 2017 and December 31, 2016. The Company’s accounts receivable are due from a variety of health-care organizations in the United States and select European markets. At March 31, 2017 and December 31, 2016, there were no customers that represented 10% or more of the Company’s accounts receivable. For the three months ended March 31, 2017 and 2016, there were no customers that represented 10% or more of revenues. Disruption of sales orders or a deterioration of financial condition 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	Revenue Recognition The Company’s revenues are derived from (1) sale of its Lightbox (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 recognizes revenue in accordance with Accounting Standards Codification (“ASC”) 605-10, Revenue Recognition, when persuasive evidence of an arrangement exists, the fee is fixed or determinable, collection of the fee is probable and delivery has occurred. 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 revenue is recognized ratably over the term of the service period. 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 ASC 840, Leases and ASC 605-25, Revenue Recognition—Multiple Element Arrangements . 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 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. The Company expenses all warranty costs and inventory provisions to cost of revenues. The Company records adjustments to its inventory valuation for estimated excess, obsolete and non-sellable inventories based on assumptions about future demand, past usage, changes to manufacturing processes and overall market conditions. Cost of revenues also includes depreciation expense for the Lightboxes under lease and commercial evaluation program agreements and certain direct costs such as shipping costs.
Product Warranty 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. The warranty liability is included within accrued liabilities on the balance sheet.Warranty provisions and claims are summarized as follows (in thousands): Amount Balance at December 31, 2016 $ Warranty provision Usage/Release ) Balance at March 31, 2017 $
Net Loss per Share	Net Loss per Share Basic net loss per share is computed by dividing the net loss 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 is computed by dividing the net loss 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. For the computation of net loss per share, there were no common stock shares subject to repurchase excluded from the calculations as of March 31, 2017 and 2016. Since the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share as the inclusion of all potentially dilutive common shares would have been anti-dilutive. Net loss per share was determined as follows (in thousands, except per share data): Three Months Ended March 31, 2017 2016 Net loss $ ) $ ) Weighted average common stock outstanding Net loss per share, basic and diluted $ ) $ ) 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: March 31, 2017 2016 Common stock options Unvested restricted stock units Common stock warrants
Comprehensive Loss	Comprehensive Loss For the three months ended March 31, 2017 and 2016, there was no difference between comprehensive loss and the Company’s net loss.
Segment and Geographical Information	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 March 31, 2017 and 2016, 96% and 99% of the Company’s revenues were in the United States, respectively, based on the shipping location of the external customer.
Accounting Pronouncements Adopted in 2017 and Recent Accounting Pronouncements	Accounting Pronouncements Adopted in 2017 In March 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-09, Compensation — Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for employee share-based payments, including income tax consequences, application of award forfeitures to expense, classification on the statement of cash flows, and classification of awards as either equity or liabilities. This guidance is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. As a result of adopting ASU 2016-09, the Company has made an accounting policy election to account for forfeitures as they occur. This change has been applied on a modified retrospective basis, resulting in a cumulative-effect adjustment to increase accumulated deficit by $206,000 as of January 1, 2017, the date of adoption. The adoption of ASU 2016-09 also requires that excess tax benefits and tax deficiencies be recorded in the statement of operations as opposed to additional paid-in capital when the awards vest or are settled. The adoption of ASU 2016-09 as it relates to the accounting for excess tax benefits and tax deficiencies has no impact on the Company’s current financial statements or on any prior period financial statements presented. ASU 2016-09 also requires excess tax benefits to be classified as an operating activity, consistent with other income tax cash flows, and may be applied either on a retrospective or prospective basis. The Company has elected to apply this amendment on a prospective basis, as there is no impact to its prior period statements of cash flows. As such, prior periods have not been adjusted. In July 2015, the FASB issued an accounting standard which applies to all inventory that is measured using methods other than last-in, first-out or the retail inventory method, including inventory that is measured using first-in, first-out or average cost. The standard requires entities to measure inventory at the lower of cost and net realizable value, defined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The guidance is effective for public entities for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. The Company’s elected to adopt this standard as of January 1, 2017, on a prospective basis. The adoption had no impact on its financial statements. In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740) — Balance sheet Classification of Deferred Taxes, which requires entities to present its deferred tax assets and deferred tax liabilities as noncurrent in its financial statements. The guidance is effective for public entities for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. The Company’s elected to adopt this standard as of January 1, 2017, on a prospective basis. The adoption of this new guidance does not create any impact to the Company’s financial statements due to the fact that no deferred tax assets or liabilities have been reported in its financial statements. This will likely remain the case if the Company continues to incur additional losses, which requires it to maintain a full valuation allowance as it will be more-likely-than-not that its deferred tax assets are not realizable. Recent Accounting Pronouncements In May 2014, the FASB, jointly with the International Accounting Standards Board, issued a comprehensive new standard on revenue recognition from contracts with customers. The standard’s core principle is that a reporting entity will recognize revenue when it transfers promised 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 standard will become effective for the Company beginning in the first quarter of 2018. Early application would be permitted in 2017. Entities would have the option of using either a full retrospective or a modified retrospective approach to adopt this new guidance. The Company has preliminarily decided to adopt this accounting standard in the first quarter of fiscal year 2018 using the modified retrospective approach, with the cumulative effect being recorded within accumulated deficit on January 1, 2018; however, the final determination will depend on a number of factors including finalizing our assessment of the impact to the Company’s financial results as well as assessing the impacts of any additional disclosure requirements. The guidance requires an entity to recognize revenue in an amount that reflects the consideration to which an entity expects to be entitled in exchange for the transfer of goods or services. The guidance also requires expanded disclosures relating to the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. Additionally, qualitative and quantitative disclosures are required about customer contracts, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The Company has not completed its assessment of the adoption on its financial statements.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2017
Summary of Significant Accounting Policies
Summary of warranty provisions and claims	Warranty provisions and claims are summarized as follows (in thousands): Amount Balance at December 31, 2016 $ Warranty provision Usage/Release ) Balance at March 31, 2017 $
Schedule of net loss per share attributable to common stockholders	Net loss per share was determined as follows (in thousands, except per share data): Three Months Ended March 31, 2017 2016 Net loss $ ) $ ) Weighted average common stock outstanding Net loss per share, basic and diluted $ ) $ )
Schedule of outstanding securities excluded from the computation due to antidilutive impact	March 31, 2017 2016 Common stock options Unvested restricted stock units Common stock warrants

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2017
Inventories
Schedule of inventories	Inventories consisted of the following (in thousands): March 31, December 31, 2017 2016 Raw materials $ $ Work-in-process — Finished products Total inventories $ $

Borrowings (Tables)

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2017
Borrowings
Schedule of principal and PIK payments under the Loan Agreement	As of March 31, 2017, principal and PIK payments under the Loan Agreement follows (in thousands): Period Ending December 31, Principal and PIK 2017 $ — 2018 — 2019 2020 2021 Add: Accretion of closing fees Add: PIK Less: Amount representing debt financing costs ) Borrowings $

Capital Leases (Tables)

Capital Leases (Tables)	3 Months Ended
	Mar. 31, 2017
Capital Leases
Schedule of future minimum lease payments	The future minimum lease payments as of March 31, 2017, are as follows (in thousands): Future Minimum Period ending December 31, Lease Payments 2017 $ 2018 2019 Total minimum payments Less: Amount representing future interest Present value of minimum lease payments $

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies
Schedule of future minimum lease payments	Aggregate future minimum lease payments as of March 31, 2017, are as follows (in thousands): Future Minimum Year ending December 31, Lease Payments 2017 $ 2018 2019 Total minimum lease payments $

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit) (Tables)	3 Months Ended
	Mar. 31, 2017
Stockholders' Equity (Deficit)
Summary of option activity	Options Outstanding Weighted Aggregate Number of Average Intrinsic Value Shares Exercise Price (in thousands) Balance at December 31, 2016 $ $ Options granted $ Options exercised — $ — Options cancelled ) $ Balance at March 31, 2017 $ $ —
Summary of RSU activity	Weighted Average Weighted Average Aggregate Number of Grant Date Remaining Intrinsic Value Shares Fair Value Contractual Term (in thousands) Awards outstanding at December 31, 2016 $ Awarded $ Released ) $ Forfeited ) $ Awards outstanding at March 31, 2017 $ $

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2017
Stock-Based Compensation
Schedule of fair value of employee stock options estimated at date of grant using the Black-Scholes valuation model	Three Months Ended March 31, 2017 2016 Expected term (years) Expected volatility % % Risk-free interest rate % % Dividend rate — —
Schedule of fair value of shares to be issued under the ESSP estimated using the Black-Scholes valuation model	Three Months Ended March 31, 2017 2016 Expected term (years) Expected volatility % % Risk-free interest rate % % Dividend rate — —
Schedule of stock-based compensation expense related to stock-based awards	Total stock-based compensation expense related to stock-based awards recognized during the three months ended March 31, 2017 and 2016, is as follows (in thousands): Three Months Ended March 31, 2017 2016 Cost of revenues $ $ Research and development expenses Selling, general and administrative expenses $ $

Organization - Liquidity Matter

Organization - Liquidity Matters (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Organization
Accumulated deficit	$ 267,935	$ 252,389
Cash and cash equivalents	$ 23,034	$ 36,096	$ 26,882	$ 43,059

Organization - Public Offerings

Organization - Public Offerings (Details) - USD ($)	1 Months Ended		3 Months Ended		12 Months Ended
	Aug. 31, 2016	Jan. 31, 2015	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Feb. 03, 2016
Common stock and convertible preferred stock
Maximum value of common stock offering under a shelf registration						$ 150,000,000
Conversion of Convertible Preferred Stock into Common Stock upon IPO | Convertible preferred stock outstanding
Common stock and convertible preferred stock
Amount reclassified from outside of stockholders' equity		$ 137,626,000
Common Stock | Conversion of Convertible Preferred Stock into Common Stock upon IPO
Common stock and convertible preferred stock
Number of shares issued for convertible preferred stock		6,967,925
Additional Paid-in Capital | Conversion of Convertible Preferred Stock into Common Stock upon IPO
Common stock and convertible preferred stock
Amount reclassified to additional paid-in-capital		$ 137,626,000
IPO | Common Stock
Common stock and convertible preferred stock
Issuance of stock, net (in shares)		5,000,000
Public offering price (in dollars per share)		$ 13
Net proceeds from initial public offering		$ 56,897,000
Underwriting discounts and commissions		4,550,000
Other offering expenses		$ 3,553,000
Sales Agreement with Cowen
Common stock and convertible preferred stock
Proceeds from public offerings, net of issuance costs					$ 5,171,000
Underwriting discounts and commissions					$ 160,000
Maximum value of common stock offering under a shelf registration						$ 50,000,000
Sales Agreement with Cowen | Common Stock
Common stock and convertible preferred stock
Issuance of stock, net (in shares)			0	0	1,095,378
Public offering price (in dollars per share)					$ 4.87
Follow-On Public Offering | Common Stock
Common stock and convertible preferred stock
Issuance of stock, net (in shares)	9,857,800
Public offering price (in dollars per share)	$ 3.50
Proceeds from public offerings, net of issuance costs	$ 31,549,000
Underwriting discounts and commissions	2,415,000
Other offering expenses	$ 538,000
Underwriters' Option | Common Stock
Common stock and convertible preferred stock
Issuance of stock, net (in shares)	1,285,800

Summary of Significant Accoun26

Summary of Significant Accounting Policies - Reverse Stock Split and Cash Equivalents (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents
Unrealized gains and losses on money market funds	$ 0	$ 0

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Concentration Risk (Details) - Customer Concentration - customer	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Accounts Receivable
Concentration of Credit Risk, and Other Risks and Uncertainties
Number of customers above 10% concentration disclosure threshold	0		0
Revenues
Concentration of Credit Risk, and Other Risks and Uncertainties
Number of customers above 10% concentration disclosure threshold	0	0

Summary of Significant Accoun28

Summary of Significant Accounting Policies - Product Warranty (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Product Warranty Costs
Warranty period	1 year
Changes in warranty provisions
Balance beginning of period	$ 509
Warranty provision	86
Usage/Release	(125)
Balance end of period	$ 470

Summary of Significant Accoun29

Summary of Significant Accounting Policies - Net Loss Per Share (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Summary of Significant Accounting Policies
Common stock shares subject to repurchase, excluded from net loss per share calculations	0	0
Net Loss per Share
Net loss	$ (15,340,000)	$ (16,167,000)
Weighted average common stock outstanding (in shares)	23,820,000	12,669,000
Net loss per share, basic and diluted (in dollars per share)	$ (0.64)	$ (1.28)
Comprehensive Loss
Difference between comprehensive loss and the Company's net loss	$ 0	$ 0

Summary of Significant Accoun30

Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net Loss per Share
Anti-dilutive shares excluded from computations of diluted weighted average shares outstanding	7,087,066	6,268,951
Common stock options
Net Loss per Share
Anti-dilutive shares excluded from computations of diluted weighted average shares outstanding	4,490,346	3,840,226
Unvested restricted stock units
Net Loss per Share
Anti-dilutive shares excluded from computations of diluted weighted average shares outstanding	444,603	276,608
Common stock warrants
Net Loss per Share
Anti-dilutive shares excluded from computations of diluted weighted average shares outstanding	2,152,117	2,152,117

Summary of Significant Accoun31

Summary of Significant Accounting Policies - Segment and Geographical (Details) - segment	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment and Geographical Information
Number of reportable segments	1
Number of operating segments	1
Revenues | Customer Concentration | UNITED STATES
Segment and Geographical Information
Percentage of revenue	96.00%	99.00%

Summary of Significant Accoun32

Summary of Significant Accounting Policies - Accounting Pronouncements Adopted in 2017 (Details)	Jan. 01, 2017USD ($)
Accounting Standards Update 2016-09
Accounting Pronouncements Adopted in 2017
Cumulative-effect adjustment to accumulated deficit	$ 206,000

Fair Value Measurements - Trans

Fair Value Measurements - Transfers (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Fair Value, Assets and Liabilities
Transfer of assets and liabilities between fair value hierarchy levels	$ 0	$ 0
Level 2
Fair Value, Assets and Liabilities
Financial assets	0		$ 0
Financial liabilities	0		0
Level 3
Fair Value, Assets and Liabilities
Financial assets	0		0
Financial liabilities	$ 0		$ 0

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Inventories
Raw materials	$ 3,856	$ 5,706
Work-in-process	1,238
Finished products	3,258	2,756
Total inventories	$ 8,352	$ 8,462

Borrowings - Loan Agreement wit

Borrowings - Loan Agreement with CRG (Details) - Loan Agreement - CRG - USD ($)	Sep. 22, 2015	Mar. 31, 2017	Dec. 31, 2016	Jun. 15, 2016	Dec. 31, 2015
Borrowings
Total borrowing capacity	$ 50,000,000
Amount borrowed		$ 40,000,000
Additional borrowing capacity if revenue milestones are achieved				$ 10,000,000
Period for interest-only payments	4 years
Period for equal quarterly installments of interest and principal	2 years
Fixed interest rate (as a percent)		12.50%
Interest rate, cash payment if electing PIK for the remaining amount (as a percent)		8.50%
Interest rate, eligible for payment-in-kind (as a percent)		4.00%
Beginning prepayment premium (as a percent)		5.00%
Annual decline in prepayment premium (as a percent)		1.00%
Prepayment premium after fifth year of loan (as a percent)		0.00%
Financing fee on each borrowing date (as a percent)		1.50%
Final facility fee (as a percent)		7.00%
Minimum cash and certain cash equivalents required to be maintained		$ 5,000,000
Target minimum revenue in 2015					$ 7,000,000
Target minimum revenue in 2016			$ 18,000,000
Target minimum revenue in 2017		40,000,000
Target minimum revenue in 2018		50,000,000
Target minimum revenue in 2019		60,000,000
Target minimum revenue in 2020 and in each year thereafter		$ 70,000,000
Revenue shortfall multiplier for cure right if minimum revenue targets are not achieved		2
First tranche, borrowed on September 22, 2015
Borrowings
Amount borrowed	$ 30,000,000
Second tranche, borrowed on June 15, 2016
Borrowings
Amount borrowed				$ 10,000,000

Borrowings - Repayment Schedule

Borrowings - Repayment Schedule (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Principal and PIK Loan Repayments
Borrowings	$ 41,882	$ 41,289
Loan Agreement | CRG
Principal and PIK Loan Repayments
2,019	10,000
2,020	20,000
2,021	10,000
Total	40,000
Add: Accretion of closing fees	517
Add: PIK	2,227
Borrowings, before deducting debt financing costs	42,744
Less: Amount representing debt financing costs	(862)
Borrowings	$ 41,882

Borrowings - Securities Purchas

Borrowings - Securities Purchase and Debt Discount (Details)	Sep. 22, 2015USD ($)item$ / sharesshares	Mar. 31, 2017USD ($)$ / shares	Jun. 15, 2016USD ($)
Borrowings
Closing price (in dollars per share) | $ / shares		$ 1.90
Securities Purchase Agreement with CRG | Common Stock
Borrowings
Maximum amount that may be purchase under the agreement	$ 5,000,000
Shares issued during the period | shares	348,262
Price of shares issued (in dollars per share) | $ / shares	$ 14.357
Number of trading days for average closing price to determine price per share | item	10
Closing price (in dollars per share) | $ / shares	$ 13.97
Premium on shares issued (in dollars per share) | $ / shares	$ 0.387
Loan Agreement | CRG
Borrowings
Net debt discount		$ 862,000
Loan Agreement | CRG | First tranche, borrowed on September 22, 2015
Borrowings
Net debt discount	$ 876,000
Direct financing fees	450,000
Other costs included in the debt discount	541,000
Allocation of common stock premium	$ 115,000
Loan Agreement | CRG | Second tranche, borrowed on June 15, 2016
Borrowings
Net debt discount			$ 275,000
Direct financing fees			150,000
Other costs included in the debt discount			$ 125,000

Borrowings - Credit Agreement w

Borrowings - Credit Agreement with PDL (Details) - Credit Agreement - PDL - USD ($)	Sep. 22, 2015	Apr. 18, 2013	Mar. 31, 2017	Dec. 31, 2016
Borrowings
Maximum borrowing capacity		$ 40,000,000
Term Note
Borrowings
Amount borrowed		$ 20,000,000
Stated interest rate (as a percent)		12.00%
Period for interest-only payments		2 years 6 months
Period for convertibility of interest into additional loans		2 years
Interest rate, paid-in-kind (as a percent)				1.50%
Payoff amount	$ 21,363,000
Accrued interest	563,000
Final payment fee	200,000
Assigned Interests (as a percent)		1.80%
Ongoing Assigned Interests
Borrowings
Reduced Assigned Interests upon prepayment (as a percent)			0.90%
Effective interest rate (as a percent)				20.40%
Net present value adjustment	$ 942,000
Aggregate accrual for Assigned Interest obligations			$ 1,227,000	$ 1,463,000

Capital Leases (Details)

Capital Leases (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Capital Leases
Aggregate amount of capital leases recorded within property and equipment, net	$ 33,000	$ 39,000
Future minimum lease payments
2,017	20,000
2,018	13,000
2,019	1,000
Total minimum payments	34,000
Less: Amount representing future interest	1,000
Present value of minimum lease payments	$ 33,000

Commitments and Contingencies -

Commitments and Contingencies - Leases (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Lease Commitments
Rent expense	$ 506,000	$ 230,000
Annual minimum lease payments under non-cancelable future operating lease commitments
2,017	1,482,000
2,018	2,033,000
2,019	1,915,000
Total minimum lease payments	$ 5,430,000
Facility lease
Lease Commitments
Term of renewal provision	3 years

Commitments and Contingencies41

Commitments and Contingencies - Purchase Obligation (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Purchase Obligations
Noncancellable commitments to suppliers for purchases	$ 2,976,000	$ 3,542,000

Stockholders' Equity (Deficit42

Stockholders' Equity (Deficit) - Preferred and Common Stock (Details) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
Stockholders' Equity (Deficit)
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares issued	23,913,359	23,776,033
Common stock, shares outstanding	23,913,359	23,776,033

Stockholders' Equity (Deficit43

Stockholders' Equity (Deficit) - Common Stock Warrants (Details) - $ / shares	Mar. 31, 2017	Dec. 31, 2016	Jan. 31, 2015
Common Stock Warrants
Stockholders' Equity (Deficit)
Number of shares of common stock under warrants outstanding	2,152,117	2,152,117
Common Stock Warrants issued with Series E Convertible Preferred Stock
Stockholders' Equity (Deficit)
Percentage of convertible preferred stock shares for issuance of warrants			70.00%
Exercise price of warrants issued (in dollars per share)			$ 12.60

Stockholders' Equity (Deficit44

Stockholders' Equity (Deficit) - Stock Plan (Details) - 2015 Plan - shares	3 Months Ended
	Mar. 31, 2017	Jan. 31, 2015
Stock Plans
Shares reserved for issuance		1,320,000
Maximum annual increase in shares available for issuance (in shares)	1,690,000
Maximum annual increase in shares available for issuance, percentage of outstanding shares	5.00%
Increase in number of shares authorized for issuance	1,188,801
Shares available for grant (in shares)	1,321,851

Stockholders' Equity (Deficit45

Stockholders' Equity (Deficit) - Stock Options (Details) - Common stock options - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Stock Plans
Vesting period	4 years
Expiration term	10 years
Options outstanding
Balance at the beginning of the period (in shares)	3,708,011
Options granted (in shares)	981,142
Options cancelled (in shares)	(198,807)
Balance at the end of the period (in shares)	4,490,346
Weighted Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 7.86
Granted (in dollars per shares)	2.09
Cancelled (in dollars per share)	8.78
Balance at the end of the period (in dollars per share)	$ 6.56
Aggregate Intrinsic Value (in dollars)		$ 5
Minimum
Stock Plans
Exercise price as percentage of fair value of shares	100.00%
Minimum | Stockholder with more than 10% voting power
Stock Plans
Exercise price as percentage of fair value of shares	110.00%

Stockholders' Equity (Deficit46

Stockholders' Equity (Deficit) - Additional Option Information (Details) - Common stock options - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Stock Plans
Weighted-average grant date fair value of options granted (in dollars per share)	$ 1.13
Aggregate intrinsic value of options outstanding and vested	$ 0
Aggregate intrinsic value of options exercised (in dollars)	$ 0
Additional stock option information
Vested shares outstanding (in shares)	1,946,935	1,630,917
Weighted average exercise price of vested shares outstanding (in dollars per share)	$ 7.72	$ 7.40
Weighted average remaining contractual term of vested shares outstanding	7 years 6 months 15 days	7 years 7 months 17 days

Stockholders' Equity (Deficit47

Stockholders' Equity (Deficit) - RSUs (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Additional information
Closing market price of the Company's common stock (in dollars per share)	$ 1.90
Unvested restricted stock units
Stock Plans
Vesting period	4 years
RSU activity
Awards outstanding at the beginning of the period (in shares)	214,176
Awarded (in shares)	313,665
Released (in shares)	(38,125)
Forfeited (in shares)	(45,113)
Awards outstanding at the end of the period (in shares)	444,603	214,176
Weighted Average Grant Date Fair Value
Awards outstanding at the beginning of the period (in dollars per share)	$ 14.88
Awarded (in dollars per share)	2.05
Released (in dollars per share)	12.98
Forfeited (in dollars per share)	9.37
Awards outstanding at the end of the period (in dollars per share)	$ 6.55	$ 14.88
Additional information
Weighted Average Remaining Contractual Term	3 years 6 months 26 days	3 years 1 month 2 days
Aggregate Intrinsic Value (in dollars)	$ 845,000	$ 792,000
Total unrecognized compensation expense (in dollars)	$ 2,755,000
Expected period for recognition	3 years 15 days

Stockholders' Equity (Deficit48

Stockholders' Equity (Deficit) - ESPP (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Jan. 31, 2015
Stock Plans
Stock-based compensation expense	$ 1,542,000	$ 1,978,000
2015 Employee Stock Purchase Plan
Stock Plans
Shares reserved for issuance				500,000
Maximum annual increase in shares available for issuance (in shares)	493,000
Maximum annual increase in shares available for issuance, percentage of outstanding shares	1.50%
Increase in number of shares authorized for issuance	356,640
Exercise price as percentage of fair market value of shares	85.00%
Common stock remaining reserved for issuance (in shares)	801,318
Stock-based compensation expense	$ 64,000		$ 93,000

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Stock-based compensation expense
Noncash stock-based compensation expense recognized, before taxes	$ 1,542,000	$ 1,978,000
Common stock options
Unamortized compensation
Total unamortized compensation expense	$ 10,892,000		$ 12,312,000
Expected amortization period	2 years 2 months 12 days		2 years 3 months 18 days
Employee stock options
Valuation model average assumptions
Expected term (years)	5 years 10 months 24 days	6 years
Expected volatility	56.50%	49.00%
Risk-free interest rate	2.20%	1.50%
2015 Employee Stock Purchase Plan
Valuation model average assumptions
Expected term (years)	6 months	6 months
Expected volatility	89.20%	61.40%
Risk-free interest rate	0.63%	0.38%
Stock-based compensation expense
Noncash stock-based compensation expense recognized, before taxes	$ 64,000		$ 93,000
Cost of revenues
Stock-based compensation expense
Noncash stock-based compensation expense recognized, before taxes	151,000	$ 132,000
Research and development expenses
Stock-based compensation expense
Noncash stock-based compensation expense recognized, before taxes	541,000	681,000
Selling, general and administrative expenses
Stock-based compensation expense
Noncash stock-based compensation expense recognized, before taxes	$ 850,000	$ 1,165,000

Subsequent Events (Details)

Subsequent Events (Details)	1 Months Ended
	Apr. 30, 2017
Subsequent Event | Organizational realignment
Subsequent Events
Reduction in force (as a percent)	33.00%