Corindus Vascular Robotics (CVRS) 10-K 18 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Mar. 12, 2019	Jun. 30, 2018
Document And Entity Information
Entity Registrant Name	Corindus Vascular Robotics, Inc.
Entity Central Index Key	0001528557
Document Type	10-K
Trading Symbol	CVRS
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known seasoned issuer	No
Entity Voluntary Filer	No
Entity's Reporting Status Current	Yes
Entity Small Business	true
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 75,526,354
Entity Common Stock, Shares Outstanding		206,212,607
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2018

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 23,849	$ 17,458
Accounts receivable	4,599	2,863
Inventories, net	2,508	2,103
Prepaid expenses and other current assets	447	539
Total current assets	31,403	22,963
Property and equipment, net	1,779	1,452
Deposits and other assets	343	151
Total assets	33,525	24,566
Current Liabilities:
Accounts payable	3,591	2,416
Accrued expenses	3,292	3,637
Customer deposits		93
Deferred revenue	662	339
Current portion of capital lease obligation	56	49
Current portion of long-term debt	1,011
Total current liabilities	8,612	6,534
Long-term Liabilities
Deferred revenue, net of current portion	285	342
Long-term capital lease obligation, net of current portion	46	102
Other liabilities	62	73
Long-term debt	10,774
Total long-term liabilities	11,167	517
Total liabilities	19,779	7,051
Commitments and Contingencies (Note 12)
Preferred stock:
Total preferred stock, Series A convertible preferred stock, $0.0001 par value; 1,000,000 shares designated, issued and outstanding at December 31, 2018 and none designated, issued or outstanding at December 31, 2017; Series A-1 convertible preferred stock, $0.0001 par value; 1,000,000 shares designated and 70,400 shares issued and outstanding at December 31, 2018 and none designated, issued or outstanding at December 31, 2017	22,952
Stockholders' (deficit) equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; 2,000,000 shares designated at December 31, 2018 and none designated, issued or outstanding at December 31, 2017
Common stock, $0.0001 par value; 350,000,000 and 250,000,000 shares authorized; 191,731,152 and 188,764,851 shares issued and outstanding at December 31, 2018 and 2017, respectively	19	19
Additional paid-in capital	206,165	198,337
Accumulated deficit	(215,390)	(180,841)
Total stockholders' (deficit) equity	(9,206)	17,515
Total liabilities, preferred stock and stockholders' (deficit) equity	33,525	$ 24,566
Series A Preferred Stock [Member]
Preferred stock:
Total preferred stock, Series A convertible preferred stock, $0.0001 par value; 1,000,000 shares designated, issued and outstanding at December 31, 2018 and none designated, issued or outstanding at December 31, 2017; Series A-1 convertible preferred stock, $0.0001 par value; 1,000,000 shares designated and 70,400 shares issued and outstanding at December 31, 2018 and none designated, issued or outstanding at December 31, 2017	20,564
Series A-1 Preferred Stock [Member]
Preferred stock:
Total preferred stock, Series A convertible preferred stock, $0.0001 par value; 1,000,000 shares designated, issued and outstanding at December 31, 2018 and none designated, issued or outstanding at December 31, 2017; Series A-1 convertible preferred stock, $0.0001 par value; 1,000,000 shares designated and 70,400 shares issued and outstanding at December 31, 2018 and none designated, issued or outstanding at December 31, 2017	$ 2,388

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized shares	10,000,000	10,000,000
Preferred stock, designated shares	2,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, authorized shares	350,000,000	250,000,000
Common stock, issued shares	191,731,152	188,764,851
Common stock, outstanding shares	191,731,152	188,764,851
Series A Preferred Stock [Member]
Series Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Series Preferred stock, issued shares	1,000,000
Series Preferred stock, outstanding shares	1,000,000
Preferred stock, designated shares	1,000,000
Series A-1 Preferred Stock [Member]
Series Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Series Preferred stock, issued shares	70,400
Series Preferred stock, outstanding shares	70,400
Preferred stock, designated shares	1,000,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue	$ 10,781	$ 9,650
Cost of revenue	8,673	9,265
Gross profit	2,108	385
Operating expenses:
Research and development	8,769	9,517
Selling, general and administrative	27,300	24,777
Restructuring charge	346
Total operating expense	36,415	34,294
Operating loss	(34,307)	(33,909)
Other income (expense):
Warrant revaluation	120
Interest, net	(884)	(208)
Other, net	82	(6)
Total other income (expense), net	(682)	(214)
Net loss	(34,989)	(34,123)
Accretion of beneficial conversion feature of Series A preferred stock	(5,266)
Dividends on preferred stock	(2,388)
Net loss attributable to common stockholders	$ (42,643)	$ (34,123)
Net loss per share attributable to common stockholders--basic and diluted (in dollars per share)	$ (0.22)	$ (0.2)
Weighted-average common shares used in computing net loss per share attributable to common stockholders--basic and diluted (in shares)	189,619,507	173,925,450
Comprehensive loss	$ (34,989)	$ (34,123)

CONSOLIDATED STATEMENT OF PREFE

CONSOLIDATED STATEMENT OF PREFERRED STOCK AND STOCKHOLDERS' (DEFICIT) EQUITY - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
Beginning balance at Dec. 31, 2016		$ 12	$ 150,776	$ (146,718)	$ 4,070
Beginning balance, (in shares) at Dec. 31, 2016		119,025,221
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense			2,892		2,892
Issuance of stock in connection with private placement, net of issuance costs		$ 7	44,604		44,611
Issuance of stock in connection with private placement, net of issuance costs (in shares)		68,055,700
Issuance of common stock upon vesting of restricted stock units (in shares)		26,362
Issuance of common stock upon exercise of stock options			65		65
Issuance of common stock upon exercise of stock options (in shares)		261,670
Issuance of common stock upon exercise of warrants,(in shares)		1,393,605
Issuance of common stock (in shares)		2,293
Net loss				(34,123)	(34,123)
Ending balance at Dec. 31, 2017		$ 19	198,337	(180,841)	$ 17,515
Ending balance, (in shares) at Dec. 31, 2017		188,764,851			188,764,851
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of a change in accounting principles				440	$ 440
Stock-based compensation expense			3,204		3,204
Issuance of stock in connection with private placement, net of issuance costs	$ 20,564
Issuance of stock in connection with private placement, net of issuance costs (in shares)	1,000,000
Issuance of warrants in connection with private placement			4,108		$ 4,108
Beneficial conversion feature of Series A and Series A-1 preferred stock	$ (5,266)		5,266		5,266
Accretion of beneficial conversion feature of Series A and Series A-1 preferred stock	5,266		(5,266)		(5,266)
Accrued dividends on Series A preferred stock	628		(628)		(628)
Issuance of Series A-1 preferred stock as dividends on Series A preferred stock	$ 1,760		(1,760)		(1,760)
Issuance of Series A-1 preferred stock as dividends on Series A preferred stock (in shares)	70,400
Issuance of common stock in connection with at-the-market offering, net of issuance costs			2,688		2,688
Issuance of common stock in connection with at-the-market offering, net of issuance costs (in shares)		2,569,159
Issuance of common stock upon vesting of restricted stock units
Issuance of common stock upon vesting of restricted stock units (in shares)		197,589
Issuance of common stock upon exercise of stock options			108		108
Issuance of common stock upon exercise of stock options (in shares)		180,587
Common stock withheld to pay statutory minimum withholding taxes on exercise of stock options			(13)		(13)
Common stock withheld to pay statutory minimum withholding taxes on exercise of stock options (in shares)		(12,048)
Issuance of common stock to non-employee directors			31		31
Issuance of common stock to non-employee directors (in shares)		31,014
Reclassification of warrant liability			90		90
Net loss				(34,989)	(34,989)
Ending balance at Dec. 31, 2018	$ 22,952	$ 19	$ 206,165	$ (215,390)	$ (9,206)
Ending balance, (in shares) at Dec. 31, 2018	1,070,400	191,731,152			191,731,152

CONSOLIDATED STATEMENT OF PRE_2

CONSOLIDATED STATEMENT OF PREFERRED STOCK AND STOCKHOLDERS' (DEFICIT) EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Issuance costs	$ 375
Private Placement [Member]
Issuance costs	$ 329	$ 415

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net loss	$ (34,989)	$ (34,123)
Adjustments to reconcile net loss to net cash flows used in operating activities:
Depreciation and amortization	853	723
Stock-based compensation expense	3,235	2,892
Accretion of interest expense	328	101
Write down of inventories	268	268
Warrant liability revaluation	(120)
Loss on disposal of property and equipment	62	28
Changes in operating assets and liabilities:
Accounts receivable	(1,736)	(2,479)
Due from related party		250
Prepaid expenses and other current assets	130	(91)
Inventories	(1,026)	(1,638)
Deposits and other assets	18	(1)
Accounts payable, accrued expenses and other liabilities	689	1,817
Customer deposits	(93)	93
Deferred revenue	347	(198)
Net cash used in operating activities	(32,034)	(32,358)
Investing activities
Purchase of property and equipment	(736)	(245)
Collection of notes receivable		71
Net cash used in investing activities	(736)	(174)
Financing activities
Proceeds from issuance of Series A preferred stock and warrants, net of issuance costs	24,671
Proceeds from issuance of long term debt and warrants, net of deferred financing costs and discounts	11,626
Proceeds from issuance of common stock, net of issuance costs	2,818	44,611
Proceeds from exercise of stock options	108	65
Payments for withholding taxes on stock option exercises	(13)
Payments on debt		(3,856)
Payments on capital lease obligation	(49)	(13)
Net cash provided by financing activities	39,161	40,807
Net increase in cash and cash equivalents	6,391	8,275
Cash and cash equivalents at beginning of period	17,458	9,183
Cash and cash equivalents at end of period	23,849	17,458
Supplemental Cash Flow Information
Fair value of warrants issued with Series A preferred stock	4,162
Fair value of warrants issued with long-term debt	210
Accrued dividends on Series A preferred stock	628
Issuance of Series A-1 preferred stock as dividends on Series A preferred stock	1,760
Financing costs included in account payable and accrued expenses	130
Transfer from inventories to property and equipment in the field	425	812
Interest paid	$ 878	157
Assets acquired under capital lease		$ 164

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	1. Nature of Operations The Company Corindus Vascular Robotics, Inc. (the “Company”), formerly named Your Internet Defender, Inc. (“YIDI”), acquired Corindus, Inc., a privately-held company, in a reverse acquisition on August 12, 2014 (the “Acquisition”). The Company was previously a Nevada corporation, but effective June 28, 2016, the Company changed its state of incorporation from the State of Nevada to the State of Delaware. The Company has its corporate headquarters, manufacturing and a research and development facility in Waltham, Massachusetts and the Company is engaged in the design, manufacture and sales of precision vascular robotic-assisted systems (the “CorPath System”) for use in interventional vascular procedures. Since its inception on March 21, 2002, the Company has devoted its efforts principally to research and development and business development activities. In July 2012, the Company received 510(k) clearance from the United States Food and Drug Administration (“FDA”) for the CorPath 200 System and initiated a limited commercial launch in the United States. In 2013, the Company moved into the growth stage, investing in sales and marketing in order to build the customer base. While the Company’s device is initially cleared for and targeting percutaneous coronary intervention (“PCI”) and peripheral vascular procedures, the Company believes its technology platform has the capability to be developed in the future for other segments of the vascular intervention market, including neurointerventional and other more complex cardiac interventions such as structural heart procedures. In October 2015, the Company received 510(k) clearance from the FDA for its robotic-assisted CorPath 200 System to be used during PCI procedures performed via radial access. The 510(k) clearance was based on results of a clinical trial conducted at Spectrum Health, Grand Rapids, Michigan, and St. Joseph’s Hospital Health Center, Syracuse, New York. In March 2016, the Company received 510(k) clearance from the FDA for its robotic-assisted CorPath 200 System for use in peripheral vascular interventions. The 510(k) clearance for peripheral intervention was based on results of a clinical trial conducted at Medical University of Graz in Graz, Austria. In October 2016, the Company received 510(k) clearance from the FDA for its CorPath GRX, the second generation of its CorPath System and in February 2018, the Company received 510(k) clearance from the FDA for CorPath GRX to be used during peripheral vascular interventions. In March 2018, the Company received 510(k) clearance from the FDA for the first automated robotic movement designed for the CorPath GRX platform. The CorPath GRX System is intended for use in the remote delivery and manipulation of guidewires and rapid exchange catheters, and remote manipulation of guide catheters during percutaneous coronary and vascular procedures. The Company began commercial shipment of the CorPath GRX in late January 2017. The Company’s future capital requirements will depend upon many factors, including progress with developing, manufacturing and marketing its technologies, the time and costs involved in preparing, filing, prosecuting, maintaining and enforcing patent claims and other proprietary rights, its ability to establish collaborative arrangements, marketing activities and competing technological and market developments, including regulatory changes affecting medical procedure reimbursement, and overall economic conditions in the Company’s target markets. Liquidity On March 16, 2018, the Company completed a financing arrangement with two lenders which provided for borrowings of up to $26,000 in the form of up to $23,000 in term loans and up to a $3,000 revolving line-of-credit through March 2022. As of December 31, 2018, we had $12,000 in principal outstanding under the term loan facility and no principal outstanding under the revolving loan facility. The Company will begin making the monthly $400 principal payments on October 1, 2019. As of December 31, 2018, the Company had not achieved the gross profit or equity financing milestones required to draw on the additional $11,000 potentially available under the term loan facility. The revolving line-of-credit also has various covenants which restrict its availability and for which the Company currently does not meet such restrictions. On March 14, 2019, the Company amended its financing arrangement with its two lenders to add an additional term loan of $2,750, all of which was outstanding principal as of March 14, 2019. The $2,750 term loan is interest only through April 1, 2020 after which the principal will be due in twenty-four consecutive monthly payments. On August 31, 2018, the Company entered into a Common Stock Sales Agreement with Cowen and Company, LLC. See Note 8 for additional details. During the year ended December 31, 2018, the Company received net proceeds of $2,688 under the Sales Agreement through the sale of its common stock. In the first quarter of 2019, the Company closed a private placement with a large institutional investor and existing stockholders consisting of the sale of 14,384,840 shares of the Company’s common stock, at a price of $1.3796 per share for gross proceeds of approximately $19,800 and net proceeds of approximately $19,500. The shares sold in the private placement are subject to a contractual six-month lock-up. The Company has incurred losses since inception and has funded its cash flow deficits primarily through the issuance of capital stock and debt. As of December 31, 2018, the Company had an accumulated deficit of $215,390. As of December 31, 2018, the Company had cash and cash equivalents of $23,849 and working capital of $22,791. The Company has evaluated whether or not its cash and cash equivalents on hand and the cash proceeds from the financing activities described above would be sufficient to sustain projected operating activities through March 18, 2020 as required by Accounting Standards Codification (ASC) 205-40 Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern. Based on the Company’s current forecast of annual cash flow deficits the Company will not have sufficient resources to meet its cash requirements through March 18, 2020. Management has considered its plans to alleviate its projected cash deficit at March 18, 2020 and the probability and effectiveness of such plans eliminating its cash deficit at March 18, 2020. In the event the Company does not achieve the Company’s year to date plan revenue by the third quarter of 2019 or obtain anticipated financing, the Company will undertake the following activities to reduce its cash flow deficits: ● Eliminate or defer the 2019 discretionary bonus payouts for all bonus eligible employees, including executive management; ● Reduce spending on prototypes and clinical trials; ● Eliminate planned headcount additions in research and development, marketing and medical affairs; ● Defer or limit some or all spending on capital equipment planned for 2019; and ● Reduce employee travel and entertainment expenses, external consulting resources and its presence at tradeshows. It is probable that the above activities can be effectively implemented by management and it is probable that the plans will eliminate the cash deficit at March 18, 2020 such that the Company has the ability to continue as a going concern one year from March 18, 2019. As a result, management believes its plans can be effectively implemented, if required. As the Company continues to incur losses and cash flow deficits, its transition to profitability is dependent upon achieving a level of revenues adequate to support its cost structure, but the Company will otherwise rely on additional capital funding until such time as that is achieved. The Company may never achieve profitability, and unless and until doing so, the Company intends to fund future operations through additional non-dilutive or dilutive financings. There can be no assurances, however, that additional funding will be available on terms acceptable to the Company, if at all.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Corindus, Inc. and Corindus Security Corporation. All intercompany transactions and balances have been eliminated in consolidation. The functional currency of both wholly-owned subsidiaries is the U.S. dollar and, therefore, the Company has not recorded any currency translation adjustments. In the fourth quarter of 2014, the Company participated in the formation of a not-for-profit, which was established to generate awareness of the health risks linked to the use of fluoroscopy in hospital catheterization. As of December 31, 2018, the Company’s Chief Executive Officer and one of its senior executives represented two of the three voting members of the board of directors of the entity. As a result, under the voting model used for the consolidation of related parties which are controlled by a company, the Company has consolidated the financial statements of the entity and recognized expenses of $24 and $36 for the years ended December 31, 2018 and 2017, respectively and other income of $40 and $0 for the years ended December 31, 2018 and 2017, respectively. The entity had assets and liabilities of $33 and $1, respectively, on its balance sheet at December 31, 2018 and had assets and liabilities of $15 and $7, respectively, on its balance sheet at December 31, 2017. Segment Information The Company operates in one business segment, which is the design, manufacture and sale of precision vascular robotic-assisted systems for use in interventional vascular procedures. Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. To date, the chief operating decision-maker has made such decisions and assessed performance at the Company level, as one segment. The Company’s chief operating decision-maker is the Chief Executive Officer. Use of Estimates The process of preparing financial statements in conformity with the United States Generally Accepted Accounting Principles (the “U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the financial statements. Such management estimates include those relating to revenue recognition, inventory valuation, assumptions used in the valuation of the Company’s preferred stock and warrants, valuation of stock-based awards, and valuation allowances against deferred income tax assets. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers money market funds and other highly liquid short-term investments with original maturity dates of three months or less at the purchase date, to be cash equivalents. From time to time, the Company’s cash balances may exceed federal deposit insurance limits. Fair Value Measurements In accordance with ASC 820, Fair Value Measurements and Disclosures ● Level 1 – ● Level 2 – ● Level 3 – During 2018, the Company had two items, cash equivalents and warrant liability, measured at fair value on a recurring basis. The warrant liability was reclassed to equity as of December 31, 2018 as described in Note 6. The Company had cash equivalents (measured at fair value on a recurring basis) totaling $23,849 and $0 at December 31, 2018 and 2017, respectively, which were valued based on Level l inputs. The warrant liability relates to warrants to purchase shares of the Company’s common stock that were issued to the Company’s lenders in connection with a debt financing arrangement executed on March 16, 2018. See Note 8 for additional details. The fair value of these warrants was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. In order to determine the fair value of these warrants, the Company utilized a Monte-Carlo simulation in combination with a Black-Scholes-Merton option pricing model (“Black-Scholes Model”). Estimates and assumptions impacting the fair value measurement include the fair value of the underlying shares of common stock, the remaining contractual term of the warrant, risk-free interest rate, expected dividend yield, expected volatility of the price of the underlying preferred stock and management’s assessment of the probability of additional borrowing on the credit facility. Due to the available public market information for the Company’s common stock for only a limited period of time, the Company estimates its expected stock volatility based on a blended approach utilizing the Company’s historical volatility of its common stock and the historical volatility of publicly traded guideline companies for a term equal to the estimated remaining contractual term of the warrants. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the warrants. The Company estimated no expected dividend yield based on the fact that the Company has never paid or declared dividends on its common stock and does not intend to do so in the foreseeable future. The Company also estimated the number of shares issuable under the warrant based upon its assessment of the timing and amounts of future advances drawn under the financing arrangement. The assumptions that the Company used to determine the fair value of these warrants are as follows: March 16, 2018 December 31, Volatility 75.0% to 83.0% 81.0 % Risk-free interest rate 2.8 % 2.7 % Estimated term (in years) 8.5 to 10.0 9.2 The following table sets forth a summary of changes in fair value of the Company’s common stock warrant based on Level 3 inputs: Balance at December 31, 2017 $ — Issuance of warrants in connection with debt financing arrangements 210 Revaluation of warrants (120 ) Reclass to equity (90 ) Balance at December 31, 2018 $ — The Company’s financial instruments of deposits and other assets are carried at cost and approximate their fair values given the liquid nature of such items. The fair value of the Company’s long-term debt and capital lease obligation approximates their carrying values due to their recent negotiation and variable market rate for the long-term debt. Concentrations of Credit Risk and Significant Customers The Company had the following customers that accounted for greater than 10.0% of its revenues for the years ended December 31, 2018 and 2017, respectively: For the Year ended December 31, Customer 2018 2017 A 20 % 20 % B 14 % 8 % Customer A accounted for 15% of the Company’s account receivable balance at December 31, 2018. Additionally, the Company had four other customers that together accounted for 60% of its accounts receivable balance at December 31, 2018, but none of these customers exceeded 10% of its revenues in 2018. Given the current revenue levels, in a period in which the Company sells a system, the customer is likely to represent a significant customer. The Company had five other customers that together accounted for 84% of the Company’s accounts receivable balance at December 31, 2017, but none of these customers exceeded 10% of its revenues in 2017. Revenues from domestic customers were $7,050 and $6,694 for the years ending December 31, 2018 and 2017, respectively. Revenues from international customers were $3,731 and $2,956 for the years ending December 31, 2018 and 2017, respectively. Off-Balance Sheet Arrangements The Company has no significant off-balance sheet risk such as foreign exchange contracts, option contracts, or other hedging arrangements. Allowance for Doubtful Accounts The Company evaluates the collectability of accounts receivable on a regular basis. The allowance for doubtful accounts, if any, is based upon various factors including the financial condition and payment history of customers, an overall review of collections experience on other accounts and economic factors or events expected to affect future collections experience. The Company’s accounts receivable consist primarily of amounts due from large, well-capitalized customers and while the Company reviews their creditworthiness, collectability is generally not an issue. The Company records an allowance for doubtful accounts, when necessary, based on the potential for collectability issues within the customer base. The Company’s allowance for doubtful accounts was $0 at December 31, 2018 and 2017. Product Warranty Customers are permitted to return defective products under the Company’s standard product warranty program. For CorPath Systems, the Company’s standard one-year warranty provides for the repair of any product that malfunctions. Return and replacement can only occur if a material breach of the warranty remains uncured for 30 days. The warranty liability is included within accrued expenses on the consolidated balance sheets. A roll-forward of the Company’s warranty liability is as follows: Balance at December 31, 2016 $ 57 Provision for warranty obligations 352 Settlements (113 ) Balance at December 31, 2017 296 Provision for warranty obligations 122 Settlements (181 ) Balance at December 31, 2018 $ 237 Inventories Inventories are valued at the lower of cost or net realizable value using the first-in, first-out (FIFO) method. The Company routinely monitors the recoverability of its inventory and records the lower of cost or net realizable value reserves based on current selling prices and reserves for excess and obsolete inventory based on historical and forecasted usage, as required. Scrap and excess manufacturing costs are charged to cost of revenue as incurred and not capitalized as part of inventories. The Company only capitalizes pre-launch inventories when purchased for commercial use and it deems regulatory approval to be probable. Customer Deposits Customer deposits represent cash received from customers for whom related products have not been delivered or services have not yet been performed. Property and Equipment Property and equipment is carried at cost. Major items and betterments are capitalized; maintenance and repairs are charged to expense as incurred. The Company capitalizes certain costs incurred in connection with developing or obtaining internal-use software. Software costs that do not meet capitalization criteria are expensed as incurred. Demonstration equipment represents internally manufactured capital equipment that is used on-site at trade shows and at customer locations to demonstrate the CorPath System. Field equipment represents internally manufactured capital equipment placed at customer locations under programs that involve the customer’s agreement to provide their facility as a training/show site for other potential customers while purchasing cassettes for their cases performed. As of December 31, 2018, the Company had placed two CorPath GRX field equipment units and one CorPath GRX for customer’s evaluation purposes. Depreciation on the demonstration equipment is charged to selling, general and administrative and the depreciation on the field equipment is charged to cost of revenue. Depreciation is computed under the straight-line method over the estimated useful lives of the respective assets. Depreciation is provided over the following estimated asset lives: Machinery and equipment 5 years Computer equipment 3 years Office furniture and equipment 5 years Leasehold improvements Shorter of life of lease or useful life Vendor tooling 1.5 - 3.0 years, based on planned usage Software 4 years Demonstration equipment 3 years Field equipment 3 years Impairment of Long-Lived Assets An impairment loss is recognized when expected cash flows are less than an asset’s carrying value. The Company’s policy is to record an impairment loss when it is determined that the carrying amount of the asset may not be recoverable. The Company’s long-lived assets principally consist of property and equipment. The Company continually monitors events and changes in circumstances that could indicate carrying amounts of long-lived assets may not be recoverable. Accordingly, when indicators of impairment are present, the Company evaluates the carrying value of such assets in relation to the operating performance and estimated future undiscounted cash flows of the underlying assets. There were no impairment charges or indicators of impairment for the years ended December 31, 2018 and 2017. Revenue from Contracts with Customers Adoption of ASC 606, Revenue from Contracts with Customers The Company adopted ASC 606 on January 1, 2018, using the modified retrospective method for all contracts not completed as of the date of adoption. The reported results for 2018 reflect the application of ASC 606 guidance while the reported results for 2017 were prepared under the guidance of ASC 605, Revenue Recognition Financial Statement Impact of Adopting ASC 606 The cumulative effect of applying the new guidance to all contracts with customers that were not completed as of December 31, 2017, was recorded as an adjustment to accumulated deficit as of the adoption date. As a result of applying the modified retrospective method to adopt the new revenue guidance, the following adjustments were made to accounts on the consolidated balance sheet as of January 1, 2018: As Reported at Adjustments Balance at Assets: Prepaid expenses and other current assets $ 539 $ 38 $ 577 Deposits and other assets $ 151 $ 321 $ 472 Liabilities: Deferred revenue $ 339 $ (68 ) $ 271 Deferred revenue, net of current portion $ 342 $ (13 ) $ 329 Stockholders’ (deficit) equity: Accumulated deficit $ (180,841 ) $ 440 $ (180,401 ) The following tables compare the reported consolidated balance sheets and statements of operations, as of and for the year ended December 31, 2018, to the pro-forma amounts as if the previous guidance had been in effect: As of December 31, 2018 Balance Sheet As Reported Pro-forma as if Assets: Prepaid expenses and other current assets $ 447 $ 319 Deposits and other assets $ 343 $ 191 Liabilities: Deferred revenue $ 662 $ 756 Deferred revenue, net of current portion $ 285 $ 284 Stockholders’ (deficit) equity: Accumulated deficit $ (215,390 ) $ (215,764 ) Year Ended December 31, 2018 Statement of Operations As Reported Pro-forma as if Revenue $ 10,781 $ 10,824 Selling, general and administrative 27,300 27,277 Net loss $ (34,989 ) $ (34,923 ) Net loss attributable to common stockholders $ (42,643 ) $ (42,577 ) Net loss per share attributable to common $ (0.22 ) $ (0.22 ) The most significant impact was the recognition pattern for promised goods and services related to the Company’s service plans. The new standard requires revenues to be estimated and recognized upon transfer of the promised goods and services, which resulted in a cumulative adjustment of approximately $353. Under the new standard, the Company is able to recognize revenues upon delivery of certain promised goods, prior to the customers being invoiced based on the contractual arrangement with the Company. Specifically, the Company sells certain extended service plans which may include a specified upgrade or an unspecified upgrade right. Under legacy GAAP, the Company recognized revenue for service plans ratably over the term of the services to be provided. Under the new standard, the Company concluded that the service plans and upgrade rights were distinct performance obligations, and therefore would be recognized as the individual components of the service were delivered. The Company determined that the service component of the plans would continue to be recognized ratably over the term of the agreement, whereas the unspecified upgrade component would be recognized ratably over the term of the unspecified upgrade right, and the specified upgrade component would be recognized at a point in time upon delivery. The change in the timing of revenue recognition is primarily related to the impact associated with the accelerated recognition of specified upgrades. Another impact relates to the requirement to capitalize incremental costs to acquire new contracts, which consist of sales commissions. During previous periods, these costs were expensed as incurred. Adoption of the new standard resulted in the capitalization of $87 of such incremental costs as of January 1, 2018. Revenue Recognition The Company generates revenues primarily from the sale of the CorPath System, CorPath Cassettes, accessories and service contracts. Revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of the new revenue recognition accounting standard, the Company performs the following five steps: (i) identifies the contract with a customer; (ii) identifies the performance obligations in the contract; (iii) determines the transaction price; (iv) allocates the transaction price to the performance obligations in the contract; and (v) recognizes revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, the Company assesses the goods or services promised within each contract, and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Revenue is measured as the amount of consideration the Company expects to receive in exchange for transferring products or services to a customer. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price utilizing the expected value method to which it expects to be entitled. Variable consideration is included in the transaction price if, in the Company’s judgment, it is probable that a significant future reversal of cumulative revenue under the contract will not occur. Estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of the Company’s anticipated performance and all information (historical, current and forecasted) that is reasonably available. Sales, value add, and other taxes collected on behalf of third parties are excluded from revenue. When determining the transaction price of a contract, an adjustment is made if payment from a customer occurs either significantly before or significantly after performance, resulting in a significant financing component. The Company does not assess whether a significant financing component exists if the period between when it performs its obligations under the contract and when the customer pays is one year or less. For contracts where the period between performance and payment is greater than one year, the Company assesses whether a significant financing component exists, by applying a discount rate to the expected cash collections. If this difference is significant, the Company will conclude that a significant financing component exists. The Company identified a small number of contracts where the period between performance and payment was greater than one year; however, none of the Company’s contracts contained a significant financing component as of December 31, 2018. Contracts that are modified to account for changes in contract specifications and requirements are assessed to determine if the modification either creates new or changes the existing enforceable rights and obligations. Generally, contract modifications are for products or services that are not distinct from the existing contract due to the inability to use, consume or sell the products or services on their own to generate economic benefits and are accounted for as if they were part of that existing contract. The effect of a contract modification on the transaction price and measure of progress for the performance obligation to which it relates, is recognized as an adjustment to revenue (either as an increase in or a reduction of revenue) on a cumulative catch-up basis. Revenue is generally recognized when the customer obtains control of the Company’s product, which occurs at a point in time, and may be upon shipment or upon delivery based on the contractual shipping terms of a contract, or upon installation when the combined performance obligation is not distinct within the context of the contract. Service revenue is generally recognized over time as the services are delivered to the customer based on the extent of progress towards completion of the performance obligation. The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services to be provided. Services are expected to be delivered to the customer throughout the term of the contract and the Company believes recognizing revenue ratably over the term of the contract best depicts the transfer of value to the customer. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. The Company enters into certain contracts that have multiple performance obligations, one or more of which may be delivered subsequent to the delivery of other performance obligations. These performance obligations may include installation, training, maintenance and support services, cassettes, and accessories. The Company allocates the transaction price based on the estimated relative standalone selling prices of the promised products or services underlying each performance obligation. The Company determines standalone selling prices based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price considering available information such as market conditions and internally approved pricing guidelines related to the performance obligations. Revenue is then allocated to the performance obligations using the relative selling prices of each of the performance obligations in the contract. For all performance obligations, the Company determines the revenue for each deliverable based on its relative selling price in the contract and recognizes revenue upon delivery of the product or service, assuming all other revenue recognition criteria have been met. Revenue for equipment is recognized when the equipment has been delivered, and installation and training have been completed. Revenue for cassettes and optional equipment is recognized when the goods have been delivered. Revenue for maintenance and support services is recognized ratably over the term of the service contract. Contract Assets Contract assets include unbilled amounts primarily for maintenance and support service and future cassette purchases where revenue recognized exceeds the amount billed to the customer, and the Company’s right to bill is not until the maintenance and support service period commence or the cassettes are delivered. Amounts may not exceed their net realizable value. Short-term contract assets are included in prepaid expenses and other current assets on the Company’s consolidated balance sheet as of December 31, 2018. Long-term contract assets are included in deposits and other assets on the Company’s consolidated balance sheets as of December 31, 2018. Deferred Contract Costs The Company’s incremental direct costs of obtaining a contract, which generally consist of sales commissions, are deferred and amortized over the period of contract performance. Applying the practical expedient, the Company recognizes sales commission expense when incurred if the amortization period of the assets that it otherwise would have recognized is one year or less. At December 31, 2018 and January 1, 2018, the Company had $64 and $87 of deferred sales commissions, respectively, which are included in deposits and other assets on the Company’s consolidated balance sheet. At times, the Company has other incremental costs associated with obtaining a contract which are deferred until the revenues from the related contract are recognized. Other deferred contract costs would be included in prepaid expenses and other current assets and/or deposits and other assets on the Company’s consolidated balance sheets. The Company had $34 and $119, respectively, of amortization of deferred commissions and other deferred contract costs during the year ended December 31, 2018. These costs are included in selling, general and administrative expenses on the Company’s consolidated statement of operations. Contract Liabilities The Company’s contract liabilities consist of advance payments and billings in excess of revenue recognized (deferred revenues and customer deposits). The Company’s contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. The Company classifies deferred revenue as current or noncurrent based on the timing of when it expects to recognize revenue. In order to determine revenue recognized in the period from contract liabilities, the Company first allocates revenue to the individual contract liability balance outstanding at the beginning of the period until the revenue exceeds that balance. If additional advances are received on those contracts in subsequent periods, the Company assumes all revenue recognized in the reporting period first applies to the beginning contract liability as opposed to a portion applying to the new advances for the period. Disaggregation of Revenue The following table summarizes revenue by revenue source for the year ended December 31, 2018: Major Products/Service Lines Product revenue $ 10,250 Service revenue 531 Total $ 10,781 Timing of Revenue Recognition Products transferred at a point in time $ 10,250 Services transferred over time 500 Services transferred at a point in time 31 Total $ 10,781 Product Revenue The Company generates revenue through the commercial, non-commercial and pre-commercial production and sale of precision vascular robotic-assisted systems, and the single use accessories used in conjunction with such systems. Revenue from the sale of products is recognized at a point in time when the customer obtains control of the product. The Company recognizes system revenue when the CorPath Systems are delivered and installed and accepted by the end user customer. The Company recognizes cassette revenue when the related cassettes have been shipped or delivered to the end customer based on the terms of the arrangement or contract. All costs related to product sales are recognized at time of delivery. The Company does not provide for rights of return to customers on product sales and, therefore, does not record a provision for returns. Service Revenue Revenue generated from maintenance and support service contracts is typically recognized ratably over the term of the service contract. Deferred Revenues The Company records deferred revenues when cash payments are received or due in advance of performance. Amounts received prior to satisfying the related performance obligations are recorded as deferred revenues in the accompanying balance sheets. Transaction Price Allocated to Future Performance Obligations ASC 606 requires that the Company disclose the aggregate amount of transaction price that is allocated to performance obligations that have not yet been satisfied as of December 31, 2018. The following table includes estimated revenues expected to be recognized in the future related to performance obligations that are unsatisfied (or partially satisfied) as of December 31, 2018. Less than 1 year Greater than 1 year Total Product revenue $ 376 $ 551 $ $927 Service revenue 604 459 1,063 Total $ 980 $ 1,010 $ $1,990 Contract Balances from Contracts with Customers Contract assets consist of unbilled amounts at the reporting date and are transferred to accounts receivable when the rights become unconditional. Contract liabilities consist of deferred revenues. The following table presents changes in contract assets and contract liabilities during the year ended December 31, 2018: Balance at Beginning of Period Additions Subtractions Balance at Contract assets $ 272 $ 106 $ (173 ) $ 205 Contract acquisitions and fulfillment costs: Deferred contract costs $ 87 $ 130 $ (153 ) $ 64 Contract liabilities: Deferred revenue $ 693 $ 864 $ (610 ) $ 947 During the year ended December 31, 2018, the Company recognized the following revenues as a result of changes in the contract asset and the contract liability balances in the respective periods: Revenue recognized in the period from: Amounts included in the contract liability at the beginning of the period $ 321 Performance obligations satisfied in previous periods $ 45 The timing of revenue recognition, billings and cash collections results in billed receivables, contract assets and contract liabilities on the consolidated balance sheet. When consideration is received, or such consideration is unconditionally due, from a customer prior to transferring goods or services to the customer under the terms of a contract, a contract liability is recorded. Contract liabilities are recognized as revenue after control of the goods or services is transferred to the customer and all revenue recognition criteria have been met. Costs to Obtain or Fulfill a Customer Contract Prior to the adoption of ASC 606, the Company expensed incremental commissions paid to sales representatives for obtaining product sales as well as service contracts. Under ASC 606, the Company currently capitalizes these incremental costs of obtaining customer contracts unless the capitalization and amortization of such costs are not expected to have a material impact on the financial statements. Capitalized commissions are amortized based on the transfer of the products or services to which the assets relate. Applying the practical expedient in paragraph ASC 340-40-25-4, the Company recognizes the incremental costs of obtaining contracts as an expense when incurred if the amortization period of the assets that the Company otherwise would have recognized is one year or less. These costs are included in selling, general, and administrative expenses. The Company accounts for shipping and handling activities related to contracts with customers as costs to fulfill the promise to transfer the associated products. Warrants to Purchase Common Stock The Company reviews the terms of warrants issued in connection with the applicable accounting guidance and classifies warrants as a long-term liability on the consolidated balance sheets if the warrants do not meet the equity criteria when the number of shares issuable are variable. Warrants to purchase shares of common stock issued in connection with the Company’s long-term debt agreement initially met these criteria because the number of shares would vary with additional draws on the debt and therefore required liability classification. Liability-classified warrants are subject to re-measurement at each balance sheet date, and any change in fair value is recognized as a component of other income (expense), net in the consolidated statements of operations. The Company estimated the fair value of these warrants at issuance and each balance sheet date thereafter using a Monte-Carlo simulation in combination with the Black-Scholes Model based on the estimated market value of the underlying common stock at the valuation measurement date, the remaining contractual term of the warrant, risk-free interest rates, expected dividends and expected volatility of the price of the underlying common stock. The warrant liability was reclassed to equity as of December 31, 2018 for reasons described in Note 6. The Company classifies warrants within stockholders’ (deficit) equity on the consolidated balance sheets if the warrants are considered to be indexed to the Company’s own capital stock, and otherwise would be recorded in

Inventories

Inventories	12 Months Ended
	Dec. 31, 2018
Inventory Disclosure [Abstract]
Inventories	3. Inventories Inventories are valued at the lower of cost or net realizable value using the FIFO method and consist of the following: December 31, 2018 2017 Raw material $ 1,036 $ 945 Work in progress 348 310 Finished goods 1,124 848 Total $ 2,508 $ 2,103 The Company wrote down inventories by $268 during the year ended December 31, 2018 to properly state amounts at the lower of cost or net realizable value.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property and Equipment	4. Property and Equipment Property and equipment are stated at cost and are being depreciated using the straight-line method over the assets’ estimated useful lives. Depreciation and amortization expense related to property and equipment was $700 and $723 for the fiscal years 2018 and 2017, respectively. Property and equipment consist of the following: December 31, 2018 2017 Machinery and equipment $ 849 $ 546 Computer equipment 172 147 Office furniture and equipment 340 320 Leasehold improvements 62 62 Vendor tooling 910 898 Software 813 658 Demonstration equipment 914 593 Field equipment 551 819 Construction in progress 83 — 4,694 4,043 Less accumulated depreciation and amortization (2,915 ) (2,591 ) Property and equipment net $ 1,779 $ 1,452 Construction in progress at December 31, 2018 relates to vendor tooling that is currently in the design and testing stage which will be used in the Company’s production process.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consist of the following: December 31, 2018 2017 Payroll and benefits $ 1,715 $ 1,764 Commissions 570 542 Professional and consultant fees 484 579 Warranty 237 296 Travel expense 86 242 Sales tax payable 59 83 Interest 43 — Other 98 131 Total $ 3,292 $ 3,637

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt	6. Long-Term Debt On March 16, 2018, the Company completed a financing arrangement with two lenders which provides for borrowings of up to $26,000 in the form of up to $23,000 in term loans and up to a $3,000 revolving line-of-credit through March 2022. Term Loan As of December 31, 2018, the Company had $12,000 in principal outstanding under the term loan facility and zero outstanding under the revolving loan facility. The initial term loan was made on March 16, 2018 in the amount of $12,000 (Term A Loan) and is repayable in equal monthly installments of principal and interest over 30 months beginning on October 1, 2019. Prior to October 1, 2019, the Company is required to make interest only payments. Term A Loan bears interest at a rate equal to the greater of (a) the ICE Benchmark LIBOR Rate plus 7.25% or (b) 8.83%. The interest rate in effect on Term A Loan was 9.6% at December 31, 2018. As of December 31, 2018, the Company had not achieved the gross profit or equity financing milestones required to draw on the additional $11,000 potentially available under the term loan facility. Both loan facilities are secured by substantially all of the Company’s personal property other than the Company’s intellectual property. Both loan facilities include customary affirmative and negative covenants. Upon the earlier of the second advance under the term loan facility or the first advance under the revolving loan facility, the Company must also achieve minimum revenue on a monthly basis measured against a percentage of the Company’s Board of Directors-approved projections for the applicable fiscal year. The Company’s failure to satisfy the revenue, or any other, covenant could result in an event of default under the loan facilities. At the Company’s option, the Company may prepay the outstanding principal balance of any term loan in whole but not in part, subject to a prepayment fee of 2.5% of any amount prepaid if the prepayment occurs through and including the first anniversary of the term loan being issued, 1.5% of the amount prepaid if the prepayment occurs after the first anniversary of the term loan being issued through and including the second anniversary of the term loan being issued, or 1.0% of the amount prepaid if the prepayment occurs after the second anniversary of the Effective Date through and including the third anniversary of the term loan being issued. The Company is also required to make a final payment of $720 to the lenders equal to 6.0% of the original principal amount of term loans funded. The Company recognizes the final payment using the effective interest method over the term of each term loan. The final payment is included within long term debt on the consolidated balance sheet. As of December 31, 2018, $183 of the discount on the final payment has been accreted. Revolving Loan Facility. The Company also has a revolving line-of-credit with the lenders, pursuant to which the lenders agreed to make a revolving line-of-credit available to the Company in an aggregate amount of up to the lesser of (i) $3,000 or (ii) a borrowing base equal to 80% of the Company’s eligible accounts receivable. The revolving line-of-credit also has various clauses which restrict its availability and, as such, the Company is not currently eligible to draw down on the revolving line-of-credit. Proceeds from the revolving line-of-credit may be used for working capital and general business purposes. The principal amount outstanding under the revolving line bears interest at a floating rate per annum equal to the greater of (i) 5.0% and (ii) the sum of (a) the “prime rate,” as reported in The Wall Street Journal, plus (b) 0.5%, which interest is payable monthly. Principal amounts borrowed under the revolving line-of-credit may be repaid and, prior to the maturity date, re-borrowed, subject to the terms and conditions set forth in the Revolving Loan Facility. The revolving line terminates, and all unpaid principal and accrued and unpaid interest with respect thereto is due and payable in full, on March 1, 2022. The Company is also required to pay an annual facility fee on the revolving line of $15 on each anniversary of the Effective Date, a termination fee of $22 if the revolving line is terminated prior to the maturity date for any reason, and an unused revolving line facility fee in an amount equal to 0.5% per annum of the average unused portion of the revolving line payable monthly. Both loan facilities also include other events of default, the occurrence and continuation of which could cause interest to be charged at the rate that is otherwise applicable plus 5.0% and would provide the collateral agent under the term loan facility or the lender under the revolving loan facility, as applicable, with the right to exercise remedies against the Company and the collateral securing the loan facilities. These events of default include, among other things, any failure by the Company to pay principal or interest due under the loan facilities, a breach of certain covenants under the loan facilities, the Company’s insolvency, a material adverse change, the occurrence of any default under certain other indebtedness in an amount greater than $250, one or more judgments against the Company in an amount greater than $250 individually or in the aggregate, and any default under the other loan facility. The Company was not in default on any conditions of the loan facilities at December 31, 2018. In connection with Term A Loan, the Company issued the lenders warrants to purchase 141,287 shares of the Company’s common stock at an exercise price of $1.27 per share. The fair value of the warrants issued was determined to be $210 at the date of issuance and the balance was remeasured at December 31, 2018 (see Note 2), and were reclassified to equity in the accompanying consolidated balance sheet. The Company also incurred costs of $373 related to the issuance of the credit facility. After allocating the costs between the Term Loan and the revolving line-of-credit the Company recorded a debt discount of $532 to the Term loan which is being amortized to interest expense using the effective interest method and $51 of costs allocated to the revolving line-of-credit were recorded in other assets and are being recognized as interest expense on a straight-line basis. Future principal payments under the term loan facility as of December 31, 2018 are as follows: Year Ending December 31, Amount 2019 $ 1,200 2020 4,800 2021 4,800 2022 1,200 $ 12,000

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes There was no federal or state provision for income taxes for the years ended December 31, 2018 or 2017 due to the Company’s operating losses and a full valuation allowance on deferred income tax assets for all periods since inception. All of the Company’s losses before provision for income taxes are attributable to its United States operations. The Company’s effective income tax rate differs from the statutory federal income tax rate as follows: Years ended December 31, 2018 2017 Statutory U.S. federal rate 21.0 % 34.0 % State income tax 2.2 2.6 Permanent items ( 0.1 ) 0.3 Other (0.9 ) 1.0 Change in state tax rate (0.2 ) 0.1 Deferred federal rate reduction (Effect of US tax reform) — (58.9 ) Federal R&D credit 0.9 1.0 State R&D and other credits 0.5 0.5 Change in valuation allowance (23.4 ) 19.4 Total expense (benefit) —% —% Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and the related valuation allowance were as follows: Years ended December 31, 2018 2017 Deferred income tax assets: Operating loss carryforward $ 43,428 $ 35,950 Start-up expenditures 1,237 1,404 Property and equipment 1 40 Intangibles 1,142 — Stock-based compensation expense 1,733 1,420 R&D investment tax credit carryforwards 3,434 2,928 Accrued expenses and other 778 628 Total deferred income tax assets 51,753 42,370 Deferred income tax liabilities: Deferred commissions (15 ) — Total deferred income tax liabilities (15 ) — Net deferred income tax assets before valuation allowance 51,738 42,370 Valuation allowance (51,738 ) (42,370 ) Net deferred income tax assets $ — $ — On December 22, 2017, the SEC staff issued SAB 118 which allows the recording of provisional amounts during a measurement period not to extend beyond one year of the enactment date. The Company has completed its analysis consistent with the guidance provided in SAB 118 and the final impact did not result in any material change from the original estimate. In 2016, the FASB issued ASU No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”), which removes the previous exception in GAAP prohibiting an entity from recognizing current and deferred income tax expenses or benefits related to the transfer of assets, other than inventory, within the consolidated entity. The exception to defer the recognition of any tax impact on the transfer of inventory within the consolidated entity until it is sold to a third party remains unaffected. ASU 2016-16 became effective January 1, 2018. In 2018, upon adoption of ASU 2016-16, the Company recorded a deferred tax asset and corresponding full valuation allowance of $1,296 million equal to the unamortized cost of intellectual property rights transferred to the United States in 2010 multiplied by an appropriate statutory rate. There was no cumulative effect adjustment to “Accumulated deficit” using the modified-retrospective adoption method. The Company has provided a full valuation allowance against the deferred income tax assets, since it has a history of losses, which are all attributable to the U.S. and currently does not have enough positive evidence required under U.S. GAAP to reverse its valuation allowance. Management does not believe it is more likely than not that its deferred tax assets relating to the loss carryforwards and other temporary differences will be realized in the future. For the year ended December 31, 2017, the valuation allowance decreased by $6,338, resulting principally from the change in deferred federal tax rate from 34% to 21% due to the U.S. tax reform. For the year ended December 31, 2018, the valuation allowance increased by $9,368, resulting principally from an increase in operating loss carryforwards. As a result of passage of the 2017 U.S. Tax Reform (“TCJA”), net operating losses generated in years ending after December 31, 2018 will be carried forward indefinitely and can no longer be carried back, and net operating losses generated in years beginning after December 31, 2017, can only reduce taxable income by 80% when utilized in a future period. The exact ramifications of the legislation are subject to interpretation and could have a material impact on the Company’s financial position and/or results of operations. The TCJA is complex and far-reaching, and its effect, whether adverse or favorable, may not become evident for some period of time. Due to cumulative losses, the Company continues to maintain a full valuation allowance against deferred tax assets. At December 31, 2018, the Company had U.S. federal and state net operating loss carryforwards of approximately $180,780 and $103,703, respectively, that can be carried forward and offset against future taxable income. The federal NOL carryforward will begin to expire in 2028. In 2018, the Company generated a federal NOL of $32,182, which can be carried forward indefinitely. The state NOL carryforward will expire in various amounts, but none before 2022. The Company also had federal and state tax credits of approximately $2,254 and $1,493 at December 31, 2018, respectively, which may be used to offset future tax liabilities. These tax credit carryforwards will expire at various times beginning in 2029 for federal purposes and 2019 for state purposes. Utilization of net operating losses and tax credit carryforwards may be subject to a substantial annual limitation due to the “change in ownership” provisions of the Internal Revenue Code of 1986, and similar state provisions. The annual limitation may result in the expiration of net operating losses before utilization. Through December 31, 2018, the Company had completed several financings since its inception which it believes had not resulted in any changes in ownership as defined by Sections 382 and 383 of the Internal Revenue Code. If the financings caused an “ownership change”, generally defined as a greater than 50 percent change (by value) in its equity ownership over a three-year period, the Company’s attributes may be subject to an annual limitation. Subsequent ownership changes may further affect the limitation in future years. Significant judgment is required in evaluating the Company’s tax positions and in determining the Company’s provision for income taxes. In the ordinary course of business, there are many transactions and calculations for which the ultimate tax determination is uncertain. As of December 31, 2018, the Company was not under audit in any tax jurisdiction. The U.S. statute of limitations will remain open to examination by the tax authorities until the utilization of net operating loss carryforwards. The Company accrues interest and penalties, if any, related to unrecognized tax benefits in income tax expenses.

Stockholders' (Deficit) Equity

Stockholders' (Deficit) Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Stockholders' (Deficit) Equity	8. Stockholders’ (Deficit) Equity Common Stock On April 10, 2018, the Board of Directors authorized the amendment of the Company’s Certificate of Incorporation to increase the number of authorized shares of common stock from 250,000,000 shares to 350,000,000 shares. This amendment was approved by the Company’s stockholders on May 31, 2018. There was no change in the stated par value of the shares as a result of this amendment. Holders of Common Stock shall be entitled to receive dividends when and if declared by the Board of Directors. No dividends on Common Stock shares have been declared to date. At December 31, 2018, there were 34,801,224 shares of common stock reserved for the potential exercise of warrants (9,246,315), stock options (25,391,173), and restricted stock units (163,736) and 11,128,882 shares that are available for grant under the 2018 Stock Award Plan. Additionally, there were 20,000,000 shares of common stock reserved for the potential conversion of and Series A Preferred Stock and 12,000,000 shares of common stock reserved for the potential conversion of and Series A-1 Preferred stock. On August 31, 2018, the Company entered into a Sales Agreement (the “Sales Agreement”) with Cowen and Company, LLC (“Cowen”) with respect to an at-the-market offering program (the “Offering”) under which the Company may offer and sell, from time to time at its sole discretion, shares of its common stock having an aggregate offering price of up to $30,000 (the “Placement Shares”) through Cowen as its sales agent. Cowen may sell the Placement Shares by any method permitted by law deemed to be an “at the market” offering as defined in Rule 415 of the Securities Act of 1933, as amended. The Company will pay Cowen a commission equal to 3% of the gross sales proceeds of any Placement Shares sold through Cowen under the Sales Agreement. During the twelve months ended December 31, 2018, the Company sold 2,569,159 shares of common stock at a weighted average per share price of $1.19 at the market pursuant to the Sales Agreement for $2,688 in net proceeds. The Company is not obligated to make any sales of common stock under the Sales Agreement and cannot provide any assurances that it will issue any additional shares pursuant to the Sales Agreement. The offering of Placement Shares pursuant to the Sales Agreement will terminate upon the earlier of (i) the sale of all Placement Shares subject to the Sales Agreement or (ii) termination of the Sales Agreement in accordance with its terms. Preferred Stock The Company is authorized to issue 10,000,000 shares, $0.0001 par value per share, preferred stock. Of these shares, 1,000,000 shares of preferred stock have been designated as Series A Preferred Stock and 1,000,000 shares have been designated as Series A-1 Preferred Stock (Series A Preferred Stock and the Series A-1 Preferred Stock are collectively referred to as “Preferred Stock”). On March 16, 2018, the Company issued 1,000,000 shares of Series A Preferred Stock along with warrants to purchase up to 8,750,000 shares of the Company’s common stock at an exercise price per share of $1.40 for proceeds of $24,671, net of issuance costs of $329. The Preferred Stock is classified outside of stockholders’ (deficit) equity because the shares contain certain redemption features which require redemption upon a change in control of the Company. The warrants were determined to be equity classified and are recorded in additional paid-in capital. The Company recorded the Series A Preferred Stock and the warrants at their relative fair values which were $20,838 and $4,162, respectively. The conversion option was determined to have a beneficial conversion feature which was valued at $5,236 and was recorded to additional paid-in capital and as a discount to the Series A Preferred Stock. This resulting discount was immediately amortized as the Series A Preferred Stock has no set redemption date but is currently convertible. The Company estimated the fair value of the warrants at issuance using the Black-Scholes Model based on the estimated market value of the underlying common stock at the valuation measurement date, the remaining contractual term of the warrants, risk-free interest rates, expected dividends and expected volatility of the price of the underlying common stock. The fair value of these warrants was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The Company used the following assumptions for the valuation of these warrants at the issuance date. Risk-free interest rate 2.9 % Dividend yield 0.0 % Expected volatility 61.6 % Expected term (in years) 10.0 The Company estimated the fair value of the Series A Preferred Stock using a Monte Carlo simulation to determine the applicable dividend rate for each respective period based on the financial performance milestone and market condition milestone, as well as to determine the ultimate settlement method of the Series A Preferred Stock. The fair value of the Series A Preferred Stock was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The Company used the following assumptions utilized in the valuation of the Series A Preferred Stock at the issuance date: Expected volatility of future equity 45.9 % Estimated timing of Series A Preferred Stock liquidity event (in years) 3.8 Dividends Voting Rights Rank Liquidation Preference Conversion Forced Conversion As of December 31, 2018, the redemption value and Liquidation Preference of the Preferred Stock was $26,760 and it was convertible into 21,408,000 shares of the Company’s Common Stock. On April 16, 2018, July 16, 2018, October 15, 2018, and January 15, 2019 (the Series A dividend payment dates), the Company issued 10,400, 30,000, 30,000, and 30,000 shares, respectively, of Series A-1 Preferred Stock to the holders of Series A Preferred Stock to fulfill the dividend payment obligation.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation	9. Stock-based Compensation In connection with the Acquisition, Corindus exchanged options to purchase shares of its Common Stock for YIDI’s options to purchase shares of YIDI’s Common Stock (the “Replacement Plan Options”). The 2014 Stock Award Plan is the replacement plan for options previously awarded under the Corindus, Inc. 2006 Umbrella Option Plan and the Corindus, Inc. 2008 Stock Incentive Plan, and is the plan under which all future Company options will be issued. The 2014 Stock Award Plan was limited to award issuances which in the aggregate could not exceed 9,035,016 shares, all of which shares will be used for the issuance of the Company stock-based awards, including options to purchase common stock, restricted stock and restricted stock units. Replacement Plan Options are exercisable for up to ten years from the date of original vesting commencement date of the options. On April 30, 2015, the Company’s Board of Directors and shareholders owning a majority of the Company’s outstanding shares of common stock approved an increase in the authorized shares of common stock under the 2014 Stock Award Plan from 9,035,016 shares to 18,661,856 shares. On June 22, 2017, the stockholders of the Company approved an amendment to the Company’s Amended and Restated 2014 Stock Award Plan to increase the number of shares of common stock available for issuance under the plan by 4,038,144 shares, from 18,661,856 shares to 22,700,000 shares (the “Plan Amendment”). The Plan Amendment was previously adopted by the Company’s Board of Directors, subject to stockholder approval, and became effective upon the receipt of stockholder approval at the Company’s Annual Meeting. On May 31, 2018, the stockholders of the Company approved the 2018 Stock Award Plan at the Company’s 2018 Annual Meeting of Stockholders (the “Annual Meeting”). The 2018 Stock Award Plan was previously adopted by the Company’s Board of Directors, subject to stockholder approval, and became effective upon the receipt of stockholder approval at the Annual Meeting. As a result of the approval, the Amended and Restated 2014 Stock Award Plan was terminated. The 2018 Stock Award plan included 17,500,000 new shares of the Company’s common stock that were available for issuance under the plan, as well as up to 19,558,403 additional shares that may be issued if awards outstanding under the 2014 Stock Award Plan are cancelled or expire on or after the date of the Annual Meeting. During 2018, the Company issued certain stock-based awards that contain both market and service-based vesting conditions. Each of these stock-based awards is contingent on the recipient still providing services to the Company on the date of such achievement. Portions of the awards vest upon the Company’s stock price achieving certain targets for a period of at least 20 consecutive trading days at any time before May 31, 2021. The Company estimated the fair value of these market condition stock-based awards using a Monte Carlo simulation, which involves a series of random scenarios that may take different future price paths over the award’s contractual life. The grant date fair value is determined by taking the average of the grant date fair values under each of many Monte Carlo simulations. The determination of the fair value is affected by the stock price of the Company’s Common Stock, as well as assumptions regarding a number of complex and subjective variables including its expected stock price volatility over the expected term of the awards, and risk-free interest rate. The total number of shares of Common Stock that are subject to issuance under these market condition stock-based awards is 5,183,322 shares. The Company records expenses on these stock-based awards ratably over the expected term of the award. A summary of the activity under the Company’s stock option plans is as follows: Options Weighted Weighted Aggregate Outstanding at December 31, 2017 18,215,932 $ 1.29 7.64 $ 1,830 Granted 10,209,322 $ 0.85 Exercised (168,539 ) $ 0.75 Canceled (2,865,542 ) $ 1.52 Outstanding at December 31, 2018 25,391,173 $ 1.09 7.73 $ 1,460 Exercisable at December 31, 2018 11,413,154 $ 1.19 6.33 $ 864 Vested and expected to vest at December 31, 2018 23,993,371 $ 1.09 7.66 $ 1,432 The fair value of employee options is estimated on the date of each grant using the Black-Scholes Model. The weighted-average grant date fair value of options granted during the year ended December 31, 2018 and 2017 were $0.46 and $0.81, respectively. As of December 31, 2018, there was approximately $6,214 of unrecognized compensation cost related to non-vested stock-based compensation arrangements under the 2018 Stock Award Plan. That cost was expected to be recognized over a weighted-average period of 2.33 years. The total intrinsic value of options exercised in 2018 was $28. Restricted stock units of 334,955 and 68,768 shares of common stock were granted to non-employee directors in 2018 and 2017, respectively. Upon vesting, the Company issues shares of common stock for its restricted stock units. The shares issued have a required holding period of 36 months from the grant date of the restricted stock units. As a result, the Company has valued the restricted stock units based on the closing price of the Company’s common stock on the date of grant less a discount of 18% for lack of marketability during the holding period. The 18% discount was calculated based on various studies quantifying discounts for lack of marketability with similar metrics to the Company. The factors considered in the discount for lack of marketability analysis include market value of equity, holding period, total revenue, total assets, volatility, total shareholders’ equity, and net income. Restricted stock studies are a source of public information on the discount for lack of marketability as the focus of these studies is the purchase of restricted securities. Restricted securities are shares issued and sold by a publicly traded company without prior registration with the Securities and Exchange Commission. Because of the restriction on the marketability of the securities, companies purchase the securities at prices lower than the price of a registered security of the same company. The difference between the two prices represents the discount for the lack of marketability. The related compensation expense is being amortized over the twelve-month vesting period. Compensation costs recognized related to these awards totaled $149 and $27 in 2018 and 2017, respectively, and were included in selling, general and administrative in the accompanying consolidated statement of operations. The following table summarizes the activities for the Company’s unvested restricted stock units for the year ended December 31, 2018: Unvested Restricted Stock Units Number of Shares Weighted- average Grant Date Fair Value Unvested as of December 31, 2017 42,406 $ 0.87 Granted 334,955 $ 0.65 Vested (197,589 ) $ 0.69 Forfeited/Cancelled (16,036 ) $ 0.87 Unvested as of December 31, 2018 163,736 $ 0.63 There were awards of 31,014 and 2,293 shares of common stock granted to non-employee directors in 2018 and 2017, respectively, that were valued at the closing price of the Company’s common stock at the date of grant and were fully vested on the date of grant. Stock-based compensation expenses were allocated based on the employees’ or non-employees’ functions as follows: Years ended December 31, 2018 2017 Cost of revenue $ 137 — Research and development 282 258 Selling, general and administrative 2,816 2,634 Total $ 3,235 $ 2,892

Warrants to Purchase Common Sto

Warrants to Purchase Common Stock	12 Months Ended
	Dec. 31, 2018
Warrants To Purchase Common Stock
Warrants to Purchase Common Stock	10. Warrants to Purchase Common Stock The table below is a roll-forward of the Company’s warrants activity for the year ended December 31, 2018: Number of Weighted- Outstanding at December 31, 2017 355,028 $ 1.41 Granted 8,891,287 $ 1.40 Exercised — $ — Expired — $ — Outstanding at December 31, 2018 9,246,315 $ 1.40 The Company has the following warrants outstanding as December 31, 2018: Exercise Price Date of Number of $ 1.41 May 28, 2020 355,028 $ 1.40 March 15, 2028 8,750,000 $ 1.27 March 15, 2028 141,287 9,246,315

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	11. Related Party Transactions Philips Medical Systems, Nederland B.V. On January 21, 2011, the Company entered into a distributor agreement with Philips appointing Philips to be the sole distributor for the promotion and sale of the Company’s CorPath System. The agreement was terminated on August 7, 2014. The Company may continue to sell CorPath Systems through Philips on a sale by sale basis under a non-exclusive arrangement under mutually agreeable terms, which may include a continued level of discounted pricing, until such time the Company either executes a new distribution arrangement with Philips or the Company no longer does business with Philips. There were no revenues from or shipments to Philips during the years ended December 31, 2018 or 2017. At December 31, 2018 and 2017, there were no amounts outstanding from Philips resulting from the selling activities under the agreement. On October 11, 2017, a warrant to purchase 4,728,191 shares of common stock held by Philips was automatically exercised on a net exercise basis in connection with its expiration. Upon expiration of the warrant, Philips paid the exercise price of $1.06 per share through the Company’s withholding of 3,334,586 of the warrant shares to pay the exercise price and issuing 1,393,605 shares of common stock to Philips. The shares were issued in reliance on an exemption from registration under Section 4(a)(2) of the Securities Act of 1933, as amended. Private Placement On March 16, 2018, the Company closed on a private placement of convertible preferred stock for gross proceeds of $24,671. The preferred stock is convertible into an aggregate of 20,000,000 shares of common stock and is entitled to receive non-compounding dividends in additional shares of preferred stock, at the rate of 12.0% per annum, subject to reduction in the event certain milestones are achieved. The preferred stock purchasers were also issued warrants to purchase an aggregate of 8,750,000 shares of common stock at an exercise price of $1.40 per share, exercisable either for cash or on a cashless basis. Existing investors who participated in this financing included HEC Master Fund LP and BioStar Ventures III, LP. Additionally, a new investor whose participation in this financing resulted in beneficial ownership of greater than 5% of the Company's common stock was Heritage Medical Systems. On March 15, 2017, the Company closed on a private placement for the sale of an aggregate of 68,055,700 shares of its common stock at $0.6616 per share, for an aggregate purchase price of approximately $45,026 before deducting offering expenses of approximately $415. The financing round involved a syndicate of top-tier healthcare investors. Existing key investors who participated in this financing included HealthCor Partners Management, the Company’s largest shareholder, Royal Philips, an affiliate of Philips, and Energy Capital. New investors whose participation in this financing resulted in beneficial ownership of greater than 5% of the Company’s common stock included Consonance Capital and HEC Master Fund LP.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies The Company has an operating lease for approximately 26,402 square feet at its corporate headquarters and manufacturing plant in Waltham, Massachusetts, which expires in January 2021. The lease terms include escalating rent payments over the life of the lease and rent expense are recognized over the life of the lease on a straight-line basis. The difference between the amounts expensed and actual rent payments is recorded as deferred rents included within other liabilities in the consolidated balance sheets. In connection with the lease, the Company is required to maintain a security deposit with its landlord. The security deposit is approximately $134 at December 31, 2018 and 2017 and is included in deposits and other assets in the accompanying consolidated balance sheets. The Company has a capital lease covering office furniture and carpeting, which expires in November 2020. Total rent expense was $632 and $661 for the years ended December 31, 2018 and 2017, respectively. At December 31, 2018, the Company’s future minimum lease payments are indicated below: For the Year Ended December 31, Operating Capital 2019 $ 648 $ 67 2020 664 48 2021 55 — $ 1,367 115 Less amount representing interest 13 Minimum lease payments 102 Less current portion of obligation under capital lease 56 Long-term obligation under capital lease $ 46 Assets held under the capital lease arrangement and the related accumulated amortization totaled $164 and $55, respectively, at December 31, 2018. Amortization of properties under the capital lease is included in depreciation and amortization in the accompanying financial statements.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Net Loss per Share	13. Net Loss per Share The following common stock equivalents were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: As of December 31, 2018 2017 Options to purchase common stock 25,391,173 18,215,932 Warrants to purchase common stock 9,246,315 355,028 Restricted stock units 163,736 42,406 Series A Preferred Stock 20,000,000 — Series A-1 Preferred Stock 1,408,000 —

Restructuring Charge

Restructuring Charge	12 Months Ended
	Dec. 31, 2018
Restructuring and Related Activities [Abstract]
Restructuring Charge	14. Restructuring Charge In May 2018, the Company undertook cost cutting initiatives which included a reduction in force from each functional area of the Company’s operations. In the second quarter of 2018, the Company recorded a restructuring charge of approximately $349 relating to severance-related costs. As of December 31, 2018, $346 of this amount had been paid and $3 of previously accrued restructuring charges was reversed.

401(k) Plan

401(k) Plan	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
401(k) Plan	15. 401(k) Plan The Company has a tax-qualified employee savings and retirement 401(k) plan, covering all qualified employees. Participants may elect a salary deferral up to the statutorily-prescribed annual limit for tax-deferred contributions. The Company matches 100% of the participant’s first 3% of eligible contributions plus 50% of the participant’s next 2% of contributions. Amounts expensed related to this plan totaled $459 and $392 in 2018 and 2017, respectively.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	16. Selected Quarterly Financial Data (Unaudited) The following table presents unaudited operating results for each of the Company’s quarters in the years ended December 31, 2018 and 2017: Fiscal Year 2018 Quarters First Second Third Fourth Year Revenue $ 1,485 $ 1,665 $ 2,958 $ 4,673 $ 10,781 Cost of revenue 1,929 2,151 1,834 2,759 8,673 Gross profit (loss) (444 ) (486 ) 1,124 1,914 2,108 Total operating expense 9,590 9,223 8,403 9,199 36,415 Operating loss (10,034 ) (9,709 ) (7,279 ) (7,285 ) (34,307 ) Total other income (expense), net (16 ) (200 ) (316 ) (150 ) (682 ) Net loss (10,050 ) (9,909 ) (7,595 ) (7,435 ) (34,989 ) Accretion of beneficial conversion feature of Series A and Series A-1 preferred stock (5,236 ) — — (30 ) (5,266 ) Dividends on preferred stock (125 ) (753 ) (758 ) (752 ) (2,388 ) Net loss attributable to common stockholders $ (15,411 ) $ (10,662 ) $ (8,353 ) $ (8,217 ) $ (42,643 ) Net loss per share attributable to common stockholders – basic and diluted $ (0.08 ) $ (0.06 ) $ (0.04 ) $ (0.04 ) $ (0.22 ) Fiscal Year 2017 Quarters First Second Third Fourth Year Revenue $ 777 $ 2,258 $ 2,425 $ 4,190 $ 9,650 Cost of revenue 1,892 2,200 2,183 2,990 9,265 Gross profit (loss) (1,115 ) 58 242 1,200 385 Total operating expense 8,636 8,395 8,081 9,182 34,294 Operating loss (9,751 ) (8,337 ) (7,839 ) (7,982 ) (33,909 ) Total other income (expense), net (134 ) (77 ) (14 ) 11 (214 ) Net loss attributable to common stockholders $ (9,885 ) $ (8,414 ) $ (7,853 ) $ (7,971 ) $ (34,123 ) Net loss per share attributable to common stockholders – basic and diluted $ (0.07 ) $ (0.04 ) $ (0.04 ) $ (0.04 ) $ (0.20 ) Note: Quarterly amount of net loss per share attributable to common stockholders – basic and diluted may not sum to the amount for the year due to rounding .

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	17. Subsequent Events On February 26, 2019, the Company consummated a private placement offering with a large institutional investor consisting of the sale of 10,872,716 shares of the Company’s common stock, at a price of $1.3796 per share (the “Private Placement”). On March 12, 2019, the Company consummated a second closing to the Private Placement with certain existing stockholders entitled to preemptive rights in connection with the initial closing of the Private Placement, consisting of the sale of 3,512,124 shares of the Company’s common stock, at the same price and on the same terms as the initial closing of the Private Placement, through the exercise of such preemptive rights and the purchase of certain additional shares. The aggregate gross proceeds from both closings of the Private Placement was approximately $19,800 and the aggregate net proceeds was approximately $19,500. The investors included HEC Master Fund LP, an affiliate of Douglas L. Braunstein and BioStar Ventures III-XF, L.P., an affiliate of Louis A. Cannon M.D., both of whom are directors of the Company. The shares sold in the private placement are subject to a contractual six-month lock-up. The Company is required to register the shares sold in the Private Placement for resale and is required to prepare and file a registration statement with the Securities and Exchange Commission within 90 days of each closing of the Private Placement, and to use commercially reasonable efforts to have such registration statement declared effective within 180 days of such closing. On March 14, 2019, the Company entered into the first amendment (the “Amendment”) to the loan and security agreement (the “Loan Agreement”) by and among Silicon Valley Bank (“SVB”), as collateral agent, and the lenders party thereto from time to time, including Solar Capital Ltd. and SVB, dated March 16, 2018 (the “Effective Date”). The Amendment provides the Company with an additional term loan of $2,750 (the “New Term Loan”), all of which was outstanding principal as of March 14, 2019. The New Term Loan bears interest at a floating rate per annum equal to the greater of (i) 8.83% and (ii) the sum of (a) the one month ICE Benchmark LIBOR based on U.S. Dollar deposits, plus (b) 7.25%. Proceeds from the New Term Loan may be used for working capital and general business purposes. The New Term Loan is secured by substantially all of the Company’s personal property, other than its intellectual property. The New Term Loan restricts the Company’s ability to grant any interest in its intellectual property other than certain permitted licenses and permitted encumbrances set forth in the Loan Agreement. The Company is required to make monthly interest-only payments on the New Term Loan commencing on April 1, 2019, and continuing on the first calendar day of each calendar month thereafter through March 31, 2020. Commencing on April 1, 2020, and continuing on the first calendar day of each calendar month thereafter, the Company is required to make consecutive equal monthly payments of principal, together with applicable interest, in arrears to each lender, calculated pursuant to the Loan Agreement. All unpaid principal and accrued and unpaid interest with respect to the New Term Loan is due and payable in full on March 1, 2022. Upon repayment of the New Term Loan, the Company is also required to make a final payment to the lenders equal to 6.0% of the original principal amount of the New Term Loan. At the Company’s option, the Company may prepay the outstanding principal balance of the New Term Loan in whole but not in part, subject to a prepayment fee of 2.5% of any amount prepaid prior to the first anniversary of the Effective Date, 1.5% of the amount prepaid if the prepayment occurs after the first anniversary of the Effective Date through and including the second anniversary of the Effective Date, or 1.0% of the amount prepaid if the prepayment occurs after the second anniversary of the Effective Date through and including the third anniversary of the Effective Date. Except as amended by the Amendment, all other the terms, conditions, representations, warranties, covenants and agreements set forth in the Loan Agreement and other loan documents remain in full force and effect. In connection with the Amendment, the Company issued the lenders warrants (the “Warrants”) to purchase an aggregate of 300,000 shares of the Company’s common stock, at an exercise price of $1.3796, subject to adjustment for stock splits, stock dividends, combinations or similar events. The Warrants may be exercised for cash or on a cashless basis.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Corindus, Inc. and Corindus Security Corporation. All intercompany transactions and balances have been eliminated in consolidation. The functional currency of both wholly-owned subsidiaries is the U.S. dollar and, therefore, the Company has not recorded any currency translation adjustments. In the fourth quarter of 2014, the Company participated in the formation of a not-for-profit, which was established to generate awareness of the health risks linked to the use of fluoroscopy in hospital catheterization. As of December 31, 2018, the Company’s Chief Executive Officer and one of its senior executives represented two of the three voting members of the board of directors of the entity. As a result, under the voting model used for the consolidation of related parties which are controlled by a company, the Company has consolidated the financial statements of the entity and recognized expenses of $24 and $36 for the years ended December 31, 2018 and 2017, respectively and other income of $40 and $0 for the years ended December 31, 2018 and 2017, respectively. The entity had assets and liabilities of $33 and $1, respectively, on its balance sheet at December 31, 2018 and had assets and liabilities of $15 and $7, respectively, on its balance sheet at December 31, 2017.
Segment Information	Segment Information The Company operates in one business segment, which is the design, manufacture and sale of precision vascular robotic-assisted systems for use in interventional vascular procedures. Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. To date, the chief operating decision-maker has made such decisions and assessed performance at the Company level, as one segment. The Company’s chief operating decision-maker is the Chief Executive Officer.
Use of Estimates	Use of Estimates The process of preparing financial statements in conformity with the United States Generally Accepted Accounting Principles (the “U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the financial statements. Such management estimates include those relating to revenue recognition, inventory valuation, assumptions used in the valuation of the Company’s preferred stock and warrants, valuation of stock-based awards, and valuation allowances against deferred income tax assets. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers money market funds and other highly liquid short-term investments with original maturity dates of three months or less at the purchase date, to be cash equivalents. From time to time, the Company’s cash balances may exceed federal deposit insurance limits.
Fair Value Measurements	Fair Value Measurements In accordance with ASC 820, Fair Value Measurements and Disclosures ● Level 1 – ● Level 2 – ● Level 3 – During 2018, the Company had two items, cash equivalents and warrant liability, measured at fair value on a recurring basis. The warrant liability was reclassed to equity as of December 31, 2018 as described in Note 6. The Company had cash equivalents (measured at fair value on a recurring basis) totaling $23,849 and $0 at December 31, 2018 and 2017, respectively, which were valued based on Level l inputs. The warrant liability relates to warrants to purchase shares of the Company’s common stock that were issued to the Company’s lenders in connection with a debt financing arrangement executed on March 16, 2018. See Note 8 for additional details. The fair value of these warrants was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. In order to determine the fair value of these warrants, the Company utilized a Monte-Carlo simulation in combination with a Black-Scholes-Merton option pricing model (“Black-Scholes Model”). Estimates and assumptions impacting the fair value measurement include the fair value of the underlying shares of common stock, the remaining contractual term of the warrant, risk-free interest rate, expected dividend yield, expected volatility of the price of the underlying preferred stock and management’s assessment of the probability of additional borrowing on the credit facility. Due to the available public market information for the Company’s common stock for only a limited period of time, the Company estimates its expected stock volatility based on a blended approach utilizing the Company’s historical volatility and the historical volatility of publicly traded guideline companies for a term equal to the estimated remaining contractual term of the warrants. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the warrants. The Company estimated no expected dividend yield based on the fact that the Company has never paid or declared dividends on its common stock and does not intend to do so in the foreseeable future. The Company also estimated the number of shares issuable under the warrant based upon its assessment of the timing and amounts of future advances drawn under the financing arrangement. The assumptions that the Company used to determine the fair value of these warrants are as follows: March 16, 2018 December 31, Volatility 75.0% to 83.0% 81.0 % Risk-free interest rate 2.8 % 2.7 % Estimated term (in years) 8.5 to 10.0 9.2 The following table sets forth a summary of changes in fair value of the Company’s common stock warrant based on Level 3 inputs: Balance at December 31, 2017 $ — Issuance of warrants in connection with debt financing arrangements 210 Revaluation of warrants (120 ) Reclass to equity (90 ) Balance at December 31, 2018 $ — The Company’s financial instruments of deposits and other assets are carried at cost and approximate their fair values given the liquid nature of such items. The fair value of the Company’s long-term debt and capital lease obligation approximates their carrying values due to their recent negotiation and variable market rate for the long-term debt.
Concentrations of Credit Risk and Significant Customers	Concentrations of Credit Risk and Significant Customers The Company had the following customers that accounted for greater than 10.0% of its revenues for the years ended December 31, 2018 and 2017, respectively: For the Year ended December 31, Customer 2018 2017 A 20 % 20 % B 14 % 8 % Customer A accounted for 15% of the Company’s account receivable balance at December 31, 2018. Additionally, the Company had four other customers that together accounted for 60% of its accounts receivable balance at December 31, 2018, but none of these customers exceeded 10% of its revenues in 2018. Given the current revenue levels, in a period in which the Company sells a system, the customer is likely to represent a significant customer. The Company had five other customers that together accounted for 84% of the Company’s accounts receivable balance at December 31, 2017, but none of these customers exceeded 10% of its revenues in 2017. Revenues from domestic customers were $7,050 and $6,694 for the years ending December 31, 2018 and 2017, respectively. Revenues from international customers were $3,731 and $2,956 for the years ending December 31, 2018 and 2017, respectively.
Off-Balance Sheet Arrangements	Off-Balance Sheet Arrangements The Company has no significant off-balance sheet risk such as foreign exchange contracts, option contracts, or other hedging arrangements.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company evaluates the collectability of accounts receivable on a regular basis. The allowance for doubtful accounts, if any, is based upon various factors including the financial condition and payment history of customers, an overall review of collections experience on other accounts and economic factors or events expected to affect future collections experience. The Company’s accounts receivable consist primarily of amounts due from large, well-capitalized customers and while the Company reviews their creditworthiness, collectability is generally not an issue. The Company records an allowance for doubtful accounts, when necessary, based on the potential for collectability issues within the customer base. The Company’s allowance for doubtful accounts was $0 at December 31, 2018 and 2017.
Product Warranty	Product Warranty Customers are permitted to return defective products under the Company’s standard product warranty program. For CorPath Systems, the Company’s standard one-year warranty provides for the repair of any product that malfunctions. Return and replacement can only occur if a material breach of the warranty remains uncured for 30 days. The warranty liability is included within accrued expenses on the consolidated balance sheets. A roll-forward of the Company’s warranty liability is as follows: Balance at December 31, 2016 $ 57 Provision for warranty obligations 352 Settlements (113 ) Balance at December 31, 2017 296 Provision for warranty obligations 122 Settlements (181 ) Balance at December 31, 2018 $ 237
Inventories	Inventories Inventories are valued at the lower of cost or net realizable value using the first-in, first-out (FIFO) method. The Company routinely monitors the recoverability of its inventory and records the lower of cost or net realizable value reserves based on current selling prices and reserves for excess and obsolete inventory based on historical and forecasted usage, as required. Scrap and excess manufacturing costs are charged to cost of revenue as incurred and not capitalized as part of inventories. The Company only capitalizes pre-launch inventories when purchased for commercial use and it deems regulatory approval to be probable.
Customer Deposits	Customer Deposits Customer deposits represent cash received from customers for whom related products have not been delivered or services have not yet been performed.
Property and Equipment	Property and Equipment Property and equipment is carried at cost. Major items and betterments are capitalized; maintenance and repairs are charged to expense as incurred. The Company capitalizes certain costs incurred in connection with developing or obtaining internal-use software. Software costs that do not meet capitalization criteria are expensed as incurred. Demonstration equipment represents internally manufactured capital equipment that is used on-site at trade shows and at customer locations to demonstrate the CorPath System. Field equipment represents internally manufactured capital equipment placed at customer locations under programs that involve the customer’s agreement to provide their facility as a training/show site for other potential customers while purchasing cassettes for their cases performed. As of December 31, 2018, the Company had placed two CorPath GRX field equipment units and one CorPath GRX for customer’s evaluation purposes. Depreciation on the demonstration equipment is charged to selling, general and administrative and the depreciation on the field equipment is charged to cost of revenue. Depreciation is computed under the straight-line method over the estimated useful lives of the respective assets. Depreciation is provided over the following estimated asset lives: Machinery and equipment 5 years Computer equipment 3 years Office furniture and equipment 5 years Leasehold improvements Shorter of life of lease or useful life Vendor tooling 1.5 - 3.0 years, based on planned usage Software 4 years Demonstration equipment 3 years Field equipment 3 years
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets An impairment loss is recognized when expected cash flows are less than an asset’s carrying value. The Company’s policy is to record an impairment loss when it is determined that the carrying amount of the asset may not be recoverable. The Company’s long-lived assets principally consist of property and equipment. The Company continually monitors events and changes in circumstances that could indicate carrying amounts of long-lived assets may not be recoverable. Accordingly, when indicators of impairment are present, the Company evaluates the carrying value of such assets in relation to the operating performance and estimated future undiscounted cash flows of the underlying assets. There were no impairment charges or indicators of impairment for the years ended December 31, 2018 and 2017.
Revenue from Contracts with Customers	Revenue from Contracts with Customers Adoption of ASC 606, Revenue from Contracts with Customers The Company adopted ASC 606 on January 1, 2018, using the modified retrospective method for all contracts not completed as of the date of adoption. The reported results for 2018 reflect the application of ASC 606 guidance while the reported results for 2017 were prepared under the guidance of ASC 605, Revenue Recognition Financial Statement Impact of Adopting ASC 606 The cumulative effect of applying the new guidance to all contracts with customers that were not completed as of December 31, 2017, was recorded as an adjustment to accumulated deficit as of the adoption date. As a result of applying the modified retrospective method to adopt the new revenue guidance, the following adjustments were made to accounts on the consolidated balance sheet as of January 1, 2018: As Reported at Adjustments Balance at Assets: Prepaid expenses and other current assets $ 539 $ 38 $ 577 Deposits and other assets $ 151 $ 321 $ 472 Liabilities: Deferred revenue $ 339 $ (68 ) $ 271 Deferred revenue, net of current portion $ 342 $ (13 ) $ 329 Stockholders’ (deficit) equity: Accumulated deficit $ (180,841 ) $ 440 $ (180,401 ) The following tables compare the reported consolidated balance sheets and statements of operations, as of and for the year ended December 31, 2018, to the pro-forma amounts as if the previous guidance had been in effect: As of December 31, 2018 Balance Sheet As Reported Pro-forma as if Assets: Prepaid expenses and other current assets $ 447 $ 319 Deposits and other assets $ 343 $ 191 Liabilities: Deferred revenue $ 662 $ 756 Deferred revenue, net of current portion $ 285 $ 284 Stockholders’ (deficit) equity: Accumulated deficit $ (215,390 ) $ (215,764 ) Year Ended December 31, 2018 Statement of Operations As Reported Pro-forma as if Revenue $ 10,781 $ 10,824 Selling, general and administrative 27,300 27,277 Net loss $ (34,989 ) $ (34,923 ) Net loss attributable to common stockholders $ (42,643 ) $ (42,577 ) Net loss per share attributable to common $ (0.22 ) $ (0.22 ) The most significant impact was the recognition pattern for promised goods and services related to the Company’s service plans. The new standard requires revenues to be estimated and recognized upon transfer of the promised goods and services, which resulted in a cumulative adjustment of approximately $353. Under the new standard, the Company is able to recognize revenues upon delivery of certain promised goods, prior to the customers being invoiced based on the contractual arrangement with the Company. Specifically, the Company sells certain extended service plans which may include a specified upgrade or an unspecified upgrade right. Under legacy GAAP, the Company recognized revenue for service plans ratably over the term of the services to be provided. Under the new standard, the Company concluded that the service plans and upgrade rights were distinct performance obligations, and therefore would be recognized as the individual components of the service were delivered. The Company determined that the service component of the plans would continue to be recognized ratably over the term of the agreement, whereas the unspecified upgrade component would be recognized ratably over the term of the unspecified upgrade right, and the specified upgrade component would be recognized at a point in time upon delivery. The change in the timing of revenue recognition is primarily related to the impact associated with the accelerated recognition of specified upgrades. Another impact relates to the requirement to capitalize incremental costs to acquire new contracts, which consist of sales commissions. During previous periods, these costs were expensed as incurred. Adoption of the new standard resulted in the capitalization of $87 of such incremental costs as of January 1, 2018. Revenue Recognition The Company generates revenues primarily from the sale of the CorPath System, CorPath Cassettes, accessories and service contracts. Revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of the new revenue recognition accounting standard, the Company performs the following five steps: (i) identifies the contract with a customer; (ii) identifies the performance obligations in the contract; (iii) determines the transaction price; (iv) allocates the transaction price to the performance obligations in the contract; and (v) recognizes revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, the Company assesses the goods or services promised within each contract, and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Revenue is measured as the amount of consideration the Company expects to receive in exchange for transferring products or services to a customer. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price utilizing the expected value method to which it expects to be entitled. Variable consideration is included in the transaction price if, in the Company’s judgment, it is probable that a significant future reversal of cumulative revenue under the contract will not occur. Estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of the Company’s anticipated performance and all information (historical, current and forecasted) that is reasonably available. Sales, value add, and other taxes collected on behalf of third parties are excluded from revenue. When determining the transaction price of a contract, an adjustment is made if payment from a customer occurs either significantly before or significantly after performance, resulting in a significant financing component. The Company does not assess whether a significant financing component exists if the period between when it performs its obligations under the contract and when the customer pays is one year or less. For contracts where the period between performance and payment is greater than one year, the Company assesses whether a significant financing component exists, by applying a discount rate to the expected cash collections. If this difference is significant, the Company will conclude that a significant financing component exists. The Company identified a small number of contracts where the period between performance and payment was greater than one year; however, none of the Company’s contracts contained a significant financing component as of December 31, 2018. Contracts that are modified to account for changes in contract specifications and requirements are assessed to determine if the modification either creates new or changes the existing enforceable rights and obligations. Generally, contract modifications are for products or services that are not distinct from the existing contract due to the inability to use, consume or sell the products or services on their own to generate economic benefits and are accounted for as if they were part of that existing contract. The effect of a contract modification on the transaction price and measure of progress for the performance obligation to which it relates, is recognized as an adjustment to revenue (either as an increase in or a reduction of revenue) on a cumulative catch-up basis. Revenue is generally recognized when the customer obtains control of the Company’s product, which occurs at a point in time, and may be upon shipment or upon delivery based on the contractual shipping terms of a contract, or upon installation when the combined performance obligation is not distinct within the context of the contract. Service revenue is generally recognized over time as the services are delivered to the customer based on the extent of progress towards completion of the performance obligation. The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services to be provided. Services are expected to be delivered to the customer throughout the term of the contract and the Company believes recognizing revenue ratably over the term of the contract best depicts the transfer of value to the customer. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. The Company enters into certain contracts that have multiple performance obligations, one or more of which may be delivered subsequent to the delivery of other performance obligations. These performance obligations may include installation, training, maintenance and support services, cassettes, and accessories. The Company allocates the transaction price based on the estimated relative standalone selling prices of the promised products or services underlying each performance obligation. The Company determines standalone selling prices based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price considering available information such as market conditions and internally approved pricing guidelines related to the performance obligations. Revenue is then allocated to the performance obligations using the relative selling prices of each of the performance obligations in the contract. For all performance obligations, the Company determines the revenue for each deliverable based on its relative selling price in the contract and recognizes revenue upon delivery of the product or service, assuming all other revenue recognition criteria have been met. Revenue for equipment is recognized when the equipment has been delivered, and installation and training have been completed. Revenue for cassettes and optional equipment is recognized when the goods have been delivered. Revenue for maintenance and support services is recognized ratably over the term of the service contract.
Contract Assets	Contract Assets Contract assets include unbilled amounts primarily for maintenance and support service and future cassette purchases where revenue recognized exceeds the amount billed to the customer, and the Company’s right to bill is not until the maintenance and support service period commence or the cassettes are delivered. Amounts may not exceed their net realizable value. Short-term contract assets are included in prepaid expenses and other current assets on the Company’s consolidated balance sheet as of December 31, 2018. Long-term contract assets are included in deposits and other assets on the Company’s consolidated balance sheets as of December 31, 2018.
Deferred Contract Costs	Deferred Contract Costs The Company’s incremental direct costs of obtaining a contract, which generally consist of sales commissions, are deferred and amortized over the period of contract performance. Applying the practical expedient, the Company recognizes sales commission expense when incurred if the amortization period of the assets that it otherwise would have recognized is one year or less. At December 31, 2018 and January 1, 2018, the Company had $64 and $87 of deferred sales commissions, respectively, which are included in deposits and other assets on the Company’s consolidated balance sheet. At times, the Company has other incremental costs associated with obtaining a contract which are deferred until the revenues from the related contract are recognized. Other deferred contract costs would be included in prepaid expenses and other current assets and/or deposits and other assets on the Company’s consolidated balance sheets. The Company had $34 and $119, respectively, of amortization of deferred commissions and other deferred contract costs during the year ended December 31, 2018. These costs are included in selling, general and administrative expenses on the Company’s consolidated statement of operations.
Contract Liabilities	Contract Liabilities The Company’s contract liabilities consist of advance payments and billings in excess of revenue recognized (deferred revenues and customer deposits). The Company’s contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. The Company classifies deferred revenue as current or noncurrent based on the timing of when it expects to recognize revenue. In order to determine revenue recognized in the period from contract liabilities, the Company first allocates revenue to the individual contract liability balance outstanding at the beginning of the period until the revenue exceeds that balance. If additional advances are received on those contracts in subsequent periods, the Company assumes all revenue recognized in the reporting period first applies to the beginning contract liability as opposed to a portion applying to the new advances for the period.
Disaggregation of Revenue	Disaggregation of Revenue The following table summarizes revenue by revenue source for the year ended December 31, 2018: Major Products/Service Lines Product revenue $ 10,250 Service revenue 531 Total $ 10,781 Timing of Revenue Recognition Products transferred at a point in time $ 10,250 Services transferred over time 500 Services transferred at a point in time 31 Total $ 10,781 Product Revenue The Company generates revenue through the commercial, non-commercial and pre-commercial production and sale of precision vascular robotic-assisted systems, and the single use accessories used in conjunction with such systems. Revenue from the sale of products is recognized at a point in time when the customer obtains control of the product. The Company recognizes system revenue when the CorPath Systems are delivered and installed and accepted by the end user customer. The Company recognizes cassette revenue when the related cassettes have been shipped or delivered to the end customer based on the terms of the arrangement or contract. All costs related to product sales are recognized at time of delivery. The Company does not provide for rights of return to customers on product sales and, therefore, does not record a provision for returns. Service Revenue Revenue generated from maintenance and support service contracts is typically recognized ratably over the term of the service contract. Deferred Revenues The Company records deferred revenues when cash payments are received or due in advance of performance. Amounts received prior to satisfying the related performance obligations are recorded as deferred revenues in the accompanying balance sheets.
Transaction Price Allocated to Future Performance Obligations	Transaction Price Allocated to Future Performance Obligations ASC 606 requires that the Company disclose the aggregate amount of transaction price that is allocated to performance obligations that have not yet been satisfied as of December 31, 2018. The following table includes estimated revenues expected to be recognized in the future related to performance obligations that are unsatisfied (or partially satisfied) as of December 31, 2018. Less than 1 year Greater than 1 year Total Product revenue $ 376 $ 551 $ $927 Service revenue 604 459 1,063 Total $ 980 $ 1,010 $ $1,990
Contract Balances from Contracts with Customers	Contract Balances from Contracts with Customers Contract assets consist of unbilled amounts at the reporting date and are transferred to accounts receivable when the rights become unconditional. Contract liabilities consist of deferred revenues. The following table presents changes in contract assets and contract liabilities during the year ended December 31, 2018: Balance at Beginning of Period Additions Subtractions Balance at Contract assets $ 272 $ 106 $ (173 ) $ 205 Contract acquisitions and fulfillment costs: Deferred contract costs $ 87 $ 130 $ (153 ) $ 64 Contract liabilities: Deferred revenue $ 693 $ 864 $ (610 ) $ 947 During the year ended December 31, 2018, the Company recognized the following revenues as a result of changes in the contract asset and the contract liability balances in the respective periods: Revenue recognized in the period from: Amounts included in the contract liability at the beginning of the period $ 321 Performance obligations satisfied in previous periods $ 45 The timing of revenue recognition, billings and cash collections results in billed receivables, contract assets and contract liabilities on the consolidated balance sheet. When consideration is received, or such consideration is unconditionally due, from a customer prior to transferring goods or services to the customer under the terms of a contract, a contract liability is recorded. Contract liabilities are recognized as revenue after control of the goods or services is transferred to the customer and all revenue recognition criteria have been met.
Costs to Obtain or Fulfill a Customer Contract	Costs to Obtain or Fulfill a Customer Contract Prior to the adoption of ASC 606, the Company expensed incremental commissions paid to sales representatives for obtaining product sales as well as service contracts. Under ASC 606, the Company currently capitalizes these incremental costs of obtaining customer contracts unless the capitalization and amortization of such costs are not expected to have a material impact on the financial statements. Capitalized commissions are amortized based on the transfer of the products or services to which the assets relate. Applying the practical expedient in paragraph ASC 340-40-25-4, the Company recognizes the incremental costs of obtaining contracts as an expense when incurred if the amortization period of the assets that the Company otherwise would have recognized is one year or less. These costs are included in selling, general, and administrative expenses. The Company accounts for shipping and handling activities related to contracts with customers as costs to fulfill the promise to transfer the associated products.
Warrants to Purchase Common Stock	Warrants to Purchase Common Stock The Company reviews the terms of warrants issued in connection with the applicable accounting guidance and classifies warrants as a long-term liability on the consolidated balance sheets if the warrants do not meet the equity criteria when the number of shares issuable are variable. Warrants to purchase shares of common stock issued in connection with the Company’s long-term debt agreement initially met these criteria because the number of shares would vary with additional draws on the debt and therefore required liability classification. Liability-classified warrants are subject to re-measurement at each balance sheet date, and any change in fair value is recognized as a component of other income (expense), net in the consolidated statements of operations. The Company estimated the fair value of these warrants at issuance and each balance sheet date thereafter using a Monte-Carlo simulation in combination with the Black-Scholes Model based on the estimated market value of the underlying common stock at the valuation measurement date, the remaining contractual term of the warrant, risk-free interest rates, expected dividends and expected volatility of the price of the underlying common stock. The warrant liability was reclassed to equity as of December 31, 2018 for reasons described in Note 6. The Company classifies warrants within stockholders’ (deficit) equity on the consolidated balance sheets if the warrants are considered to be indexed to the Company’s own capital stock, and otherwise would be recorded in stockholders’ (deficit) equity. Warrants to purchase common stock issued in connection with the Company’s private placement of convertible preferred stock met these criteria and, therefore, were equity classified.
Research and Development	Research and Development Costs for research and development are expensed as incurred. Research and development expense consists primarily of salaries, salary-related expenses and costs of contractors and materials. Cash receipts from collaboration agreements accounted for under ASC 808, Collaborative Arrangements
Income Taxes	Income Taxes The Company accounts for income taxes using the liability method, whereby deferred tax asset and liability account balances are determined based on differences between financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates that will be in effect when the differences are expected to reverse. The Company provides a valuation allowance, if necessary, to reduce deferred tax assets to amounts that are realizable. Consistent with all prior periods, the Company did not record any income tax benefits for its operating losses for the twelve months ended December 31, 2018 and 2017 due to the uncertainty regarding future taxable income. The Company accounts for uncertain tax positions using a “more-likely-than-not” threshold for recognizing and resolving uncertain tax positions. The evaluation of uncertain tax positions is based on factors including, but not limited to, changes in tax laws, the measurements of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. The Company evaluates these tax positions on an annual basis. The Company also accrues for potential interests and penalties related to unrecognized tax benefits in income tax expense. The Company recognizes the tax benefits of tax positions to the extent that the benefits will more likely than not be realized. The determination as to whether the tax benefits will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. On December 22, 2017, the Securities and Exchange Commission (the “SEC”) staff issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB 118”), which allows the recording of provisional amounts during a measurement period not to extend beyond one year of the enactment date. The Company has completed its analysis consist with the guidance provided in SAB 118 and the final impact did not result in any material change from the original estimate.
Stock-Based Compensation	Stock-based Compensation Subsequent to the adoption of ASU 2018-07 (as described below), the Company recognizes compensation costs resulting from the issuance of service stock-based awards to employees, non-employees and directors as an expense in the consolidated statements of operations over the requisite service period based on a measurement of fair value for each stock award. The awards issued to date have primarily been stock options with service-based vesting periods over two or four years, restricted stock units with service-based vesting periods of one year, and shares of common stock. Upon vesting of the restricted stock units, the Company issues shares of its common stock which have a required holding period of 36 months from the date of grant of the restricted stock unit. As a result, the Company values the restricted stock units based on the closing price of the Company’s common stock on the date of grant less a discount for lack of marketability during the holding period. The Company’s Common Stock is listed on the NYSE American, where it trades under the symbol “CVRS”. The Company utilizes quoted market prices to calculate fair value of stock-based awards. The following assumptions were used to estimate the fair value of stock options granted using the Black-Scholes Model. For the Year ended December 31, 2018 2017 Risk-free interest rate 2.69-3.10% 1.87-2.38% Expected term in years 6.25-10.00 6.00-10.00 Expected volatility 64-81% 55-67% Expected dividend yield 0% 0% The risk-free interest rate assumption is based upon observed U.S. government treasury interest rates with a term that is consistent with the expected term of the Company’s employee stock options. The expected term is based on the average of the vesting period and contractual term of the Company’s options given the lack of historical data available. The Company does not pay a dividend, and is not expected to pay a dividend in the foreseeable future. Due to a lack of a public market for the Company’s Common Stock for an extended period of time, the Company utilized a combination of the Company’s and comparable public companies’ volatility rates as a proxy of its expected volatility for purposes of the Black-Scholes Model. Stock-based compensation expense is recorded net of estimated forfeitures and is adjusted periodically for actual forfeitures. The Company uses historical data to estimate forfeiture rates. For the years ended December 31, 2018 and 2017, forfeitures were estimated to be 10% and 5%, respectively.
Net Loss per Share	Net Loss per Share Basic net loss per share is computed using the weighted-average number of common shares outstanding during the period. Diluted net loss per share is computed using the sum of the weighted-average number of common shares outstanding during the period and, if dilutive, the weighted-average number of potential common shares, including the assumed exercise of share options. The Company applies the two-class method to calculate its basic and diluted net loss per share attributable to common stockholders, as its Series A and Series A-1 preferred shares are participating securities. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to common stockholders. However, for the periods presented, the two-class method does not impact the net loss per common share as the Company was in a net loss position for each of the periods presented and holders of Series A and Series A-1 preferred shares do not participate in losses. The Company’s Series A and Series A-1 preferred shares contractually entitle the holders of such shares to participate in dividends but do not contractually require the holders of such shares to participate in losses of the Company. Accordingly, for periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.
Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2018, the FASB issued ASU 2018-07, Stock-based Compensation: Improvements to Nonemployee Share-based Payment Accounting In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows Other Recent Accounting Pronouncements not yet Adopted In February 2016, the Financial Accounting Standards Board (the “FASB”) issued ASU 2016-02, Leases Targeted Improvements

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Schedule of assumptions used for fair value warrants	The assumptions that the Company used to determine the fair value of these warrants are as follows: March 16, 2018 December 31, Volatility 75.0% to 83.0% 81.0 % Risk-free interest rate 2.8 % 2.7 % Estimated term (in years) 8.5 to 10.0 9.2
Schedule of fair value common stock warrant based on Level 3 inputs	The following table sets forth a summary of changes in fair value of the Company’s common stock warrant based on Level 3 inputs: Balance at December 31, 2017 $ — Issuance of warrants in connection with debt financing arrangements 210 Revaluation of warrants (120 ) Reclass to equity (90 ) Balance at December 31, 2018 $ —
Schedule of customers that accounted for greater than 10% of revenues	The Company had the following customers that accounted for greater than 10.0% of its revenues for the years ended December 31, 2018 and 2017, respectively: For the Year ended December 31, Customer 2018 2017 A 20 % 20 % B 14 % 8 %
Schedule of roll-forward of the Company's warranty liability	A roll-forward of the Company’s warranty liability is as follows: Balance at December 31, 2016 $ 57 Provision for warranty obligations 352 Settlements (113 ) Balance at December 31, 2017 296 Provision for warranty obligations 122 Settlements (181 ) Balance at December 31, 2018 $ 237
Schedule of depreciation provided over the following estimated asset lives	Depreciation is provided over the following estimated asset lives: Machinery and equipment 5 years Computer equipment 3 years Office furniture and equipment 5 years Leasehold improvements Shorter of life of lease or useful life Vendor tooling 1.5 - 3.0 years, based on planned usage Software 4 years Demonstration equipment 3 years Field equipment 3 years
Schedule of changes for retrospective method to adapt new revenue guidance	As a result of applying the modified retrospective method to adopt the new revenue guidance, the following adjustments were made to accounts on the consolidated balance sheet as of January 1, 2018: As Reported at Adjustments Balance at Assets: Prepaid expenses and other current assets $ 539 $ 38 $ 577 Deposits and other assets $ 151 $ 321 $ 472 Liabilities: Deferred revenue $ 339 $ (68 ) $ 271 Deferred revenue, net of current portion $ 342 $ (13 ) $ 329 Stockholders’ (deficit) equity: Accumulated deficit $ (180,841 ) $ 440 $ (180,401 )
Schedule of pro-forma amounts as if the previous guidance had been in effect	The following tables compare the reported consolidated balance sheets and statements of operations, as of and for the year ended December 31, 2018, to the pro-forma amounts as if the previous guidance had been in effect: As of December 31, 2018 Balance Sheet As Reported Pro-forma as if Assets: Prepaid expenses and other current assets $ 447 $ 319 Deposits and other assets $ 343 $ 191 Liabilities: Deferred revenue $ 662 $ 756 Deferred revenue, net of current portion $ 285 $ 284 Stockholders’ (deficit) equity: Accumulated deficit $ (215,390 ) $ (215,764 ) Year Ended December 31, 2018 Statement of Operations As Reported Pro-forma as if Revenue $ 10,781 $ 10,824 Selling, general and administrative 27,300 27,277 Net loss $ (34,989 ) $ (34,923 ) Net loss attributable to common stockholders $ (42,643 ) $ (42,577 ) Net loss per share attributable to common $ (0.22 ) $ (0.22 )
Schedule of revenue by revenue source	The following table summarizes revenue by revenue source for the year ended December 31, 2018: Major Products/Service Lines Product revenue $ 10,250 Service revenue 531 Total $ 10,781 Timing of Revenue Recognition Products transferred at a point in time $ 10,250 Services transferred over time 500 Services transferred at a point in time 31 Total $ 10,781
Schedule of estimated revenues expected to be recognized in the future related to performance obligations that are unsatisfied (or partially satisfied)	The following table includes estimated revenues expected to be recognized in the future related to performance obligations that are unsatisfied (or partially satisfied) as of December 31, 2018. Less than 1 year Greater than 1 year Total Product revenue $ 376 $ 551 $ $927 Service revenue 604 459 1,063 Total $ 980 $ 1,010 $ $1,990
Schedule of change in contract asstes and contract liabilities	The following table presents changes in contract assets and contract liabilities during the year ended December 31, 2018: Balance at Beginning of Period Additions Subtractions Balance at Contract assets $ 272 $ 106 $ (173 ) $ 205 Contract acquisitions and fulfillment costs: Deferred contract costs $ 87 $ 130 $ (153 ) $ 64 Contract liabilities: Deferred revenue $ 693 $ 864 $ (610 ) $ 947 During the year ended December 31, 2018, the Company recognized the following revenues as a result of changes in the contract asset and the contract liability balances in the respective periods: Revenue recognized in the period from: Amounts included in the contract liability at the beginning of the period $ 321 Performance obligations satisfied in previous periods $ 45
Schedule of the fair value of stock options granted using the Black-Scholes-Merton option-pricing model	The following assumptions were used to estimate the fair value of stock options granted using the Black-Scholes Model. For the Year ended December 31, 2018 2017 Risk-free interest rate 2.69-3.10% 1.87-2.38% Expected term in years 6.25-10.00 6.00-10.00 Expected volatility 64-81% 55-67% Expected dividend yield 0% 0%

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2018
Inventory Disclosure [Abstract]
Schedule of inventories	Inventories are valued at the lower of cost or net realizable value using the FIFO method and consist of the following: December 31, 2018 2017 Raw material $ 1,036 $ 945 Work in progress 348 310 Finished goods 1,124 848 Total $ 2,508 $ 2,103

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Schedule of property and equipment	Property and equipment consist of the following: December 31, 2018 2017 Machinery and equipment $ 849 $ 546 Computer equipment 172 147 Office furniture and equipment 340 320 Leasehold improvements 62 62 Vendor tooling 910 898 Software 813 658 Demonstration equipment 914 593 Field equipment 551 819 Construction in progress 83 — 4,694 4,043 Less accumulated depreciation and amortization (2,915 ) (2,591 ) Property and equipment net $ 1,779 $ 1,452

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Payables and Accruals [Abstract]
Schedule of accrued expenses	Accrued expenses consist of the following: December 31, 2018 2017 Payroll and benefits $ 1,715 $ 1,764 Commissions 570 542 Professional and consultant fees 484 579 Warranty 237 296 Travel expense 86 242 Sales tax payable 59 83 Interest 43 — Other 98 131 Total $ 3,292 $ 3,637

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of future principal payments	Future principal payments under the term loan facility as of December 31, 2018 are as follows: Year Ending December 31, Amount 2019 $ 1,200 2020 4,800 2021 4,800 2022 1,200 $ 12,000

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of reconciliation of effective income tax rate to the statutory federal income tax rate	The Company’s effective income tax rate differs from the statutory federal income tax rate as follows: Years ended December 31, 2018 2017 Statutory U.S. federal rate 21.0 % 34.0 % State income tax 2.2 2.6 Permanent items ( 0.1 ) 0.3 Other (0.9 ) 1.0 Change in state tax rate (0.2 ) 0.1 Deferred federal rate reduction (Effect of US tax reform) — (58.9 ) Federal R&D credit 0.9 1.0 State R&D and other credits 0.5 0.5 Change in valuation allowance (23.4 ) 19.4 Total expense (benefit) —% —%
Schedule of deferred income tax assets and liabilities	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and the related valuation allowance were as follows: Years ended December 31, 2018 2017 Deferred income tax assets: Operating loss carryforward $ 43,428 $ 35,950 Start-up expenditures 1,237 1,404 Property and equipment 1 40 Intangibles 1,142 — Stock-based compensation expense 1,733 1,420 R&D investment tax credit carryforwards 3,434 2,928 Accrued expenses and other 778 628 Total deferred income tax assets 51,753 42,370 Deferred income tax liabilities: Deferred commissions (15 ) — Total deferred income tax liabilities (15 ) — Net deferred income tax assets before valuation allowance 51,738 42,370 Valuation allowance (51,738 ) (42,370 ) Net deferred income tax assets $ — $ —

Stockholders' (Deficit) Equity

Stockholders' (Deficit) Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Schedule of assumptions for fair value	The Company used the following assumptions for the valuation of these warrants at the issuance date. Risk-free interest rate 2.9 % Dividend yield 0.0 % Expected volatility 61.6 % Expected term (in years) 10.0 The Company used the following assumptions utilized in the valuation of the Series A Preferred Stock at the issuance date: Expected volatility of future equity 45.9 % Estimated timing of Series A Preferred Stock liquidity event (in years) 3.8

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of activity under stock option plans	A summary of the activity under the Company’s stock option plans is as follows: Options Weighted Weighted Aggregate Outstanding at December 31, 2017 18,215,932 $ 1.29 7.64 $ 1,830 Granted 10,209,322 $ 0.85 Exercised (168,539 ) $ 0.75 Canceled (2,865,542 ) $ 1.52 Outstanding at December 31, 2018 25,391,173 $ 1.09 7.73 $ 1,460 Exercisable at December 31, 2018 11,413,154 $ 1.19 6.33 $ 864 Vested and expected to vest at December 31, 2018 23,993,371 $ 1.09 7.66 $ 1,432
Schedule of activity unvested restricted stock units	The following table summarizes the activities for the Company’s unvested restricted stock units for the year ended December 31, 2018: Unvested Restricted Stock Units Number of Shares Weighted- average Grant Date Fair Value Unvested as of December 31, 2017 42,406 $ 0.87 Granted 334,955 $ 0.65 Vested (197,589 ) $ 0.69 Forfeited/Cancelled (16,036 ) $ 0.87 Unvested as of December 31, 2018 163,736 $ 0.63
Schedule of stock-based compensation expense	Stock-based compensation expenses were allocated based on the employees’ or non-employees’ functions as follows: Years ended December 31, 2018 2017 Cost of revenue $ 137 — Research and development 282 258 Selling, general and administrative 2,816 2,634 Total $ 3,235 $ 2,892

Warrants to Purchase Common S_2

Warrants to Purchase Common Stock (Tables)	12 Months Ended
	Dec. 31, 2018
Warrants To Purchase Common Stock
Schedule of rollforward of warrant activity	The table below is a roll-forward of the Company’s warrants activity for the year ended December 31, 2018: Number of Weighted- Outstanding at December 31, 2017 355,028 $ 1.41 Granted 8,891,287 $ 1.40 Exercised — $ — Expired — $ — Outstanding at December 31, 2018 9,246,315 $ 1.40
Schedule of warrants outstanding	The Company has the following warrants outstanding as December 31, 2018: Exercise Price Date of Number of $ 1.41 May 28, 2020 355,028 $ 1.40 March 15, 2028 8,750,000 $ 1.27 March 15, 2028 141,287 9,246,315

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum lease payments	At December 31, 2018, the Company’s future minimum lease payments are indicated below: For the Year Ended December 31, Operating Capital 2019 $ 648 $ 67 2020 664 48 2021 55 — $ 1,367 115 Less amount representing interest 13 Minimum lease payments 102 Less current portion of obligation under capital lease 56 Long-term obligation under capital lease $ 46

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Schedule of securities excluded from the calculation of diluted net loss per share	The following common stock equivalents were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: As of December 31, 2018 2017 Options to purchase common stock 25,391,173 18,215,932 Warrants to purchase common stock 9,246,315 355,028 Restricted stock units 163,736 42,406 Series A Preferred Stock 20,000,000 — Series A-1 Preferred Stock 1,408,000 —

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial results	The following table presents unaudited operating results for each of the Company’s quarters in the years ended December 31, 2018 and 2017: Fiscal Year 2018 Quarters First Second Third Fourth Year Revenue $ 1,485 $ 1,665 $ 2,958 $ 4,673 $ 10,781 Cost of revenue 1,929 2,151 1,834 2,759 8,673 Gross profit (loss) (444 ) (486 ) 1,124 1,914 2,108 Total operating expense 9,590 9,223 8,403 9,199 36,415 Operating loss (10,034 ) (9,709 ) (7,279 ) (7,285 ) (34,307 ) Total other income (expense), net (16 ) (200 ) (316 ) (150 ) (682 ) Net loss (10,050 ) (9,909 ) (7,595 ) (7,435 ) (34,989 ) Accretion of beneficial conversion feature of Series A and Series A-1 preferred stock (5,236 ) — — (30 ) (5,266 ) Dividends on preferred stock (125 ) (753 ) (758 ) (752 ) (2,388 ) Net loss attributable to common stockholders $ (15,411 ) $ (10,662 ) $ (8,353 ) $ (8,217 ) $ (42,643 ) Net loss per share attributable to common stockholders – basic and diluted $ (0.08 ) $ (0.06 ) $ (0.04 ) $ (0.04 ) $ (0.22 ) Fiscal Year 2017 Quarters First Second Third Fourth Year Revenue $ 777 $ 2,258 $ 2,425 $ 4,190 $ 9,650 Cost of revenue 1,892 2,200 2,183 2,990 9,265 Gross profit (loss) (1,115 ) 58 242 1,200 385 Total operating expense 8,636 8,395 8,081 9,182 34,294 Operating loss (9,751 ) (8,337 ) (7,839 ) (7,982 ) (33,909 ) Total other income (expense), net (134 ) (77 ) (14 ) 11 (214 ) Net loss attributable to common stockholders $ (9,885 ) $ (8,414 ) $ (7,853 ) $ (7,971 ) $ (34,123 ) Net loss per share attributable to common stockholders – basic and diluted $ (0.07 ) $ (0.04 ) $ (0.04 ) $ (0.04 ) $ (0.20 )

Nature of Operations (Details N

Nature of Operations (Details Narrative) $ / shares in Units, $ in Thousands	Mar. 14, 2019USD ($)Number	Feb. 26, 2019$ / sharesshares	Mar. 16, 2018USD ($)Number	Mar. 12, 2019USD ($)	Dec. 31, 2018USD ($)$ / shares	Dec. 31, 2017USD ($)$ / shares	Jan. 02, 2018USD ($)	Dec. 31, 2016USD ($)
Cash and cash equivalents					$ 23,849	$ 17,458		$ 9,183
Accumulated deficit					(215,390)	$ (180,841)	$ (180,401)
Working capital					$ 22,791
Warrants exercise price (in dollars per share) | $ / shares					$ 1.40	$ 1.41
Net proceeds from sale of common stock					$ 2,818	$ 44,611
Financing Arrangement [Member]
Number of lenders | Number			2
Debt facility maximum capacity			$ 26,000
Financing Arrangement [Member] | Term Loans [Member]
Debt facility maximum capacity			23,000
Additional debt facility capacity available					11,000
Principle amount outstanding					12,000
Principal payment					400
Financing Arrangement [Member] | Revolving Credit Facility [Member]
Debt facility maximum capacity			$ 3,000
Credit facility, expiration year			2022
Basis spread on variable interest rate			0.50%
Description of variable interest rate base			Prime Rate
Principle amount outstanding			$ 0
Financing Arrangement [Member] | Additonal Term Loan [Member] | Subsequent Event [Member]
Number of lenders | Number	2
Basis spread on variable interest rate	7.25%
Description of variable interest rate base	ICE Benchmark LIBOR
Principle amount outstanding	$ 2,750
Sales Agreement [Member] | Cowen and Company, LLC [Member]
Net proceeds from sale of common stock					$ 2,688
Securities Purchase Agreement [Member] | Subsequent Event [Member] | Private Placement [Member]
Gross proceeds from sale of common stock				$ 19,800
Net proceeds from sale of common stock				$ 19,500
Number of stock issued (in shares) | shares		10,872,716
Number of stock issued (in dollars per share) | $ / shares		$ 1.3796
Common stock lock-in period				6 months

Significant Accounting Polici_4

Significant Accounting Policies (Details Narrative) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)Number	Dec. 31, 2017USD ($)	Jan. 02, 2018USD ($)
Number of segments | Number	1
Assets	$ 33,525	$ 24,566
Liabilities	19,779	7,051
Revenue	10,781
Adoption of Topic 606 resulted in a cumulative impact to revenue	353
Adoption of Topic 606 resulted in a cumulative impact to capitalized contract costs	87
Amortization of deferred commissions	34
Deferred commissions	64		$ 87
Other deferred contract costs	119
Allowance for doubtful accounts	$ 0	$ 0
Warranty period of systems sold	1 year
Estimated forfeitures rates	10.00%	5.00%
Fair Value, Level 1 [Member]
Cash equivalents	$ 23,849	$ 0
Collaborative Arrangement [Member] | Research and Development Expense [Member]
Collaborative arrangements	946	0
Domestic Customers [Member]
Revenue	7,050	6,694
International Customers [Member]
Revenue	$ 3,731	$ 2,956
Accounts Receivable [Member] | Customer A [Member]
Concentration percentage	15.00%
Accounts Receivable [Member] | Four Customer [Member]
Concentration percentage	60.00%
Accounts Receivable [Member] | Five Customer [Member]
Concentration percentage		84.00%
Not-For-Profit Subsidiary [Member]
Recognized expenses	$ 24	$ 36
Other income	40	0
Assets	33	15
Liabilities	$ 1	$ 7
Restricted Stock Units [Member]
Vesting period of stock options	36 months

Significant Accounting Polici_5

Significant Accounting Policies (Details) - Warrants [Member]	Dec. 31, 2018	Mar. 16, 2018
Volatility [Member]
Measurement input	0.810	.616
Volatility [Member] | Minimum [Member]
Measurement input		0.75
Volatility [Member] | Maximum [Member]
Measurement input		0.83
Risk-Free Interest Rate [Member]
Measurement input	0.027	0.028
Expected Term [Member]
Estimated term (in years)	9 years 2 months 12 days	10 years
Expected Term [Member] | Minimum [Member]
Estimated term (in years)		8 years 6 months
Expected Term [Member] | Maximum [Member]
Estimated term (in years)		10 years

Significant Accounting Polici_6

Significant Accounting Policies (Details 1) - Warrants [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Beginning Balance	$ 0
Issuance of warrants in connection with debt financing arrangement	210
Revaluation of warrants	(120)
Reclass to equity	(90)
Ending Balance	$ 0

Significant Accounting Polici_7

Significant Accounting Policies (Details 2) - Sales Revenue, Net [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Customer A [Member]
Concentration percentage	20.00%	20.00%
Customer B [Member]
Concentration percentage	14.00%	8.00%

Significant Accounting Polici_8

Significant Accounting Policies (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance, Product warrant liability	$ 296	$ 57
Provision for warranty obligation	122	352
Settlements	(181)	(113)
Ending balance, Product warrant liability	$ 237	$ 296

Significant Accounting Polici_9

Significant Accounting Policies (Details 4)	12 Months Ended
	Dec. 31, 2018
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Vendor Tooling [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	1 year 6 months
Vendor Tooling [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Software [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	4 years
Demonstration Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Field Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years

Significant Accounting Polic_10

Significant Accounting Policies (Details 5) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 02, 2018	Dec. 31, 2017
Assets:
Prepaid expenses and other current assets	$ 447	$ 577	$ 539
Deposits and other assets		472	151
Liabilities:
Deferred revenue	662	271	339
Deferred revenue, net of current portion	285	329	342
Stockholders' (deficit) equity
Accumulated deficit	$ (215,390)	$ (180,401)	(180,841)
Adjustments Due to ASC 606 [Member]
Assets:
Prepaid expenses and other current assets			38
Deposits and other assets			321
Liabilities:
Deferred revenue			(68)
Deferred revenue, net of current portion			(13)
Stockholders' (deficit) equity
Accumulated deficit			$ 440

Significant Accounting Polic_11

Significant Accounting Policies (Details 6) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jan. 02, 2018
Assets:
Prepaid expenses and other current assets	$ 447				$ 539				$ 447	$ 539	$ 577
Deposits and other assets	343				151				343	151
Liabilities:
Deferred revenue	662				339				662	339	271
Deferred revenue, net of current portion	285				342				285	342	329
Stockholders' equity:
Accumulated deficit	(215,390)				(180,841)				(215,390)	(180,841)	$ (180,401)
Revenue									10,781
Selling, general and administrative									27,300	24,777
Net loss	(7,435)	$ (7,595)	$ (9,909)	$ (10,050)					(34,989)	(34,123)
Net loss attributable to common stockholders	(8,217)	$ (8,353)	$ (10,662)	$ (15,411)	$ (7,971)	$ (7,853)	$ (8,414)	$ (9,885)	$ (42,643)	$ (34,123)
Net loss per share attributable to common stockholders--basic and diluted (in dollars per share)									$ (0.22)	$ (0.2)
Pro-forma as if the Previous Accounting Was In Effect [Member]
Assets:
Prepaid expenses and other current assets	319								$ 319
Deposits and other assets	191								191
Liabilities:
Deferred revenue	756								756
Deferred revenue, net of current portion	284								284
Stockholders' equity:
Accumulated deficit	$ (215,764)								(215,764)
Revenue									10,824
Selling, general and administrative									27,277
Net loss									(34,923)
Net loss attributable to common stockholders									$ (42,577)
Net loss per share attributable to common stockholders--basic and diluted (in dollars per share)									$ (0.22)

Significant Accounting Polic_12

Significant Accounting Policies (Details 7) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Revenue	$ 10,781
Products Transferred at Point in Time [Member]
Revenue	10,250
Services Transferred over Time [Member]
Revenue	500
Services Transferred at a point in Time [Member]
Revenue	31
Product Revenue [Member]
Revenue	10,250
Service Revenue [Member]
Revenue	$ 531

Significant Accounting Polic_13

Significant Accounting Policies (Details 8) $ in Thousands	Dec. 31, 2018USD ($)
Estimated revenues	$ 1,990
Less than 1 Year [Member]
Estimated revenues	980
Greater than 1 Year [Member]
Estimated revenues	1,010
Product Revenue [Member]
Estimated revenues	927
Product Revenue [Member] | Less than 1 Year [Member]
Estimated revenues	376
Product Revenue [Member] | Greater than 1 Year [Member]
Estimated revenues	551
Service Revenue [Member]
Estimated revenues	1,063
Service Revenue [Member] | Less than 1 Year [Member]
Estimated revenues	604
Service Revenue [Member] | Greater than 1 Year [Member]
Estimated revenues	$ 459

Significant Accounting Polic_14

Significant Accounting Policies (Details 9) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Change in Contract with Customer, Asset [Abstract]
Balance at Beginning of Period	$ 272
Additions	106
Subtractions	(173)
Balance at End of Period	205
Revenue recognized in the period from:
Amounts included in the contract liability at the beginning of the period	321
Performance obligations satisfied in previous periods	45
Deferred Revenue [Member]
Change in Contract with Customer, Liability [Abstract]
Balance at Beginning of Period	693
Additions	864
Subtractions	(610)
Balance at End of Period	947
Deferred Contract Costs [Member]
Change in Contract with Customer, Asset [Abstract]
Balance at Beginning of Period	87
Additions	130
Subtractions	(153)
Balance at End of Period	$ 64

Significant Accounting Polic_15

Significant Accounting Policies (Details 10) - Stock Options [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate - minimum	2.69%	1.87%
Risk-free interest rate - maximum	3.10%	2.38%
Expected volatility - minimum	64.00%	55.00%
Expected volatility - maximum	81.00%	67.00%
Expected dividend yield	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term in years	6 years 3 months	6 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term in years	10 years	10 years

Inventories (Details Narrative)

Inventories (Details Narrative) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Inventory write-down	$ 268	$ 268

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw material	$ 1,036	$ 945
Work in progress	348	310
Finished goods	1,124	848
Inventories, net	$ 2,508	$ 2,103

Property and Equipment (Details

Property and Equipment (Details Narrative) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 853	$ 723

Property and Equipment (Detai_2

Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 4,694	$ 4,043
Less accumulated depreciation and amortization	(2,915)	(2,591)
Property and equipment, net	1,779	1,452
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	813	658
Vendor Tooling [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	910	898
Demonstration Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	914	593
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	172	147
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	849	546
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	340	320
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	62	62
Field Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	551	$ 819
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 83

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Payroll and benefits	$ 1,715	$ 1,764
Commissions	570	542
Professional and consultant fees	484	579
Warranty	237	296
Travel expense	86	242
Sales tax payable	59	83
Interest	43
Other	98	131
Accrued expenses	$ 3,292	$ 3,637

Long-Term Debt (Details Narrati

Long-Term Debt (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	Mar. 14, 2019	Mar. 16, 2018	Mar. 16, 2018	Dec. 31, 2018	Dec. 31, 2017
Number of warrants issued				$ 1.40
Warrants exercise price (in dollars per share)				$ 1.40	$ 1.41
Financing Arrangement [Member]
Debt facility maximum capacity		$ 26,000	$ 26,000
Default basis spread on variable interest rate			5.00%
Financing Arrangement [Member] | Minimum [Member]
Event of default amount as defined in agreement				$ 250
Financing Arrangement [Member] | Term Loan A [Member]
Principle amount outstanding		12,000	$ 12,000
Basis spread on variable interest rate				7.25%
Description of variable interest rate base				ICE Benchmark LIBOR
Effective interest rate				9.60%
Debt discount		$ 532	532
Financing Arrangement [Member] | Term Loan A [Member] | Warrants [Member]
Number of warrants issued		$ 141,287
Warrants exercise price (in dollars per share)				$ 1.27
Fair value of the warrants		$ 210	210	$ 210
Financing Arrangement [Member] | Term Loans [Member]
Debt facility maximum capacity		$ 23,000	$ 23,000
Principle amount outstanding				12,000
Additional debt facility capacity available				$ 11,000
Debt final payment fee (percent)				6.00%
Debt final payment fee				$ 720
Accretion of debt discount				$ 183
Financing Arrangement [Member] | Term Loans [Member] | Year One of Loan Issuance [Member]
Debt prepayment fee (percent)				2.50%
Financing Arrangement [Member] | Term Loans [Member] | Year 2 of Loan Issuance [Member]
Debt prepayment fee (percent)	1.50%			1.50%
Financing Arrangement [Member] | Term Loans [Member] | Year 3 of Loan Issuance [Member]
Debt prepayment fee (percent)				1.00%
Financing Arrangement [Member] | Term Loans [Member] | Minimum [Member]
Interest rate		8.83%	8.83%
Financing Arrangement [Member] | Revolving Credit Facility [Member]
Debt facility maximum capacity		$ 3,000	$ 3,000
Credit facility, expiration year			2022
Borrowing base of revolving facility (percent)		80.00%	80.00%
Description of borrowing base of revolving facility			Accounts Receivable
Principle amount outstanding		$ 0	$ 0
Basis spread on variable interest rate			0.50%
Description of variable interest rate base			Prime Rate
Annual facility fee			$ 15
Termination fee			$ 22
Unused revolving line facility fee (percent)			0.50%
Deferred financing costs		$ 51	$ 51
Financing costs incurred			$ 373
Financing Arrangement [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Interest rate		5.00%	5.00%

Long-Term Debt (Details)

Long-Term Debt (Details) - Financing Arrangement [Member] - Term Loans [Member] $ in Thousands	Dec. 31, 2018USD ($)
Year Ending December 31,
2019	$ 1,200
2020	4,800
2021	4,800
2022	1,200
Future principal payments under the term loan facility	$ 12,000

Income Taxes (Details Narrative

Income Taxes (Details Narrative) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statutory U.S. federal rate	21.00%	34.00%
Change in valuation allowance	$ 8,226	$ (6,338)
Percentage of reduction on taxable income	80.00%
State [Member]
Net operating loss carryforwards	$ 103,703
Tax credit carryforwards	1,493
Federal [Member]
Net operating loss carryforwards	180,780
Tax credit carryforwards	2,254
Tax Year 2018 [Member]
Net operating loss carryforwards	$ 32,182

Income Taxes (Details)

Income Taxes (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory U.S. federal rate	21.00%	34.00%
State income tax	2.20%	2.60%
Permanent items	(0.10%)	0.30%
Other	(0.90%)	1.00%
Change in state tax rate	(0.20%)	0.10%
Deferred federal rate reduction (Effect of US tax reform)		(58.90%)
Federal R&D credit	0.90%	1.00%
State R&D and other credits	0.50%	0.50%
Change in valuation allowance	(23.40%)	19.40%
Total expense (benefit)	0.00%	0.00%

Income Taxes (Details 1)

Income Taxes (Details 1) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred income tax assets:
Operating loss carryforward	$ 43,428	$ 35,950
Start-up expenditures	1,237	1,404
Property and equipment	1	40
Intangibles	1,142
Stock-based compensation expense	1,733	1,420
R&D investment tax credit carryforwards	3,434	2,928
Accrued expenses and other	778	628
Total deferred income tax assets	51,753	42,370
Deferred income tax liabilities:
Deferred commissions	(15)
Total deferred income tax liabilities	(15)
Net deferred income tax assets before valuation allowance	51,738	42,370
Valuation allowance	(51,738)	(42,370)
Net deferred income tax assets	$ 0	$ 0

Stockholders' (Deficit) Equit_2

Stockholders' (Deficit) Equity (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	Jan. 15, 2019	Oct. 15, 2018	Aug. 31, 2018	Jul. 16, 2018	Apr. 16, 2018	Mar. 16, 2018	Mar. 15, 2017	Dec. 31, 2018	May 31, 2018	Apr. 10, 2018	Dec. 31, 2017
Preferred stock, authorized shares								10,000,000			10,000,000
Preferred stock, par value (in dollars per share)								$ 0.0001			$ 0.0001
Common stock, par value (in dollars per share)								$ 0.0001			$ 0.0001
Common stock, authorized shares								350,000,000	350,000,000	250,000,000	250,000,000
Number of shares issued
Number of warrants issued								$ 1.40
Warrants exercise price (in dollars per share)								$ 1.40			$ 1.41
Common stock reserved for exercise of warrants								9,246,315			355,028
Preferred stock, designated shares								2,000,000
2018 Stock Award Plan [Member]
Common stock reserved for future issuance								34,801,224
Common stock reserved for exercise of warrants								9,246,315
Stock options available for grant								25,391,173
Restricted stock units outstanding								163,736
Stock options outstanding								11,128,882
Private Placement [Member]
Number of shares issued							68,055,700
Private Placement [Member] | Sales Agreement [Member] | Cowen and Company, LLC [Member]
Number of shares sold								2,569,159
Weighted average share price								$ 1.19
Net proceeds			$ 30,000					$ 2,688
Series A-1 Preferred Stock [Member]
Preferred stock, par value (in dollars per share)								$ 0.0001			$ 0.0001
Issuance of shares for dividend payment (shares)		30,000		30,000	10,400
Common stock reserved for future issuance								12,000,000
Preferred stock, designated shares								1,000,000
Series A-1 Preferred Stock [Member] | Subsequent Event [Member]
Issuance of shares for dividend payment (shares)	30,000
Series A Preferred Stock [Member]
Preferred stock, par value (in dollars per share)								$ 0.0001			$ 0.0001
Preferred stock redemption value								$ 26,760
Convertible into common shares								21,408,000
Number of shares issued						1,000,000
Fair value of preferred stock						$ 4,162
Fair value of the warrants						20,838
Beneficial conversion feature						$ 5,236
Percentage of dividend								12.00%
Common stock reserved for future issuance								20,000,000
Preferred stock, designated shares								1,000,000
Series A Preferred Stock [Member] | Private Placement [Member]
Number of warrants issued						$ 8,750,000
Warrants exercise price (in dollars per share)						$ 1.40
Net proceeds from stock issuance						$ 24,671
Percentage of dividend						12.00%
Financing costs incurred						$ 329

Stockholders' (Deficit) Equit_3

Stockholders' (Deficit) Equity (Details)	Mar. 16, 2018	Dec. 31, 2018
Volatility [Member] | Series A Preferred Stock [Member]
Measurement input	0.459
Expected Term [Member] | Series A Preferred Stock [Member]
Preferred stock estimate term (in years)	3 years 9 months 18 days
Warrants [Member] | Risk-Free Interest Rate [Member]
Measurement input	0.028	0.027
Warrants [Member] | Expected Dividend Rate [Member]
Measurement input	0
Warrants [Member] | Volatility [Member]
Measurement input	.616	0.810
Warrants [Member] | Expected Term [Member]
Warrant estimate term (in years)	10 years	9 years 2 months 12 days

Stock-based Compensation (Detai

Stock-based Compensation (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	May 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Jun. 22, 2017	Apr. 30, 2015	Apr. 29, 2015
Stock-based compensation expense		$ 3,235	$ 2,892
Selling General And Administrative Expense [Member]
Stock-based compensation expense		$ 2,816	$ 2,634
Restricted Stock Units [Member] | Non-Employee Directors [Member]
Numbers of option granted		334,955	68,768
Option granted maturity date		36 months
Restricted Stock Units [Member] | Non-Employee Directors [Member] | Selling General And Administrative Expense [Member]
Stock-based compensation expense		$ 149	$ 27
Unrestricted Common Stock [Member] | Non-Employee Directors [Member]
Numbers of option granted		31,014	2,293
2014 Stock Award Plan [Member]
Number of shares authorized under plan				22,700,000	18,661,856	9,035,016
Number of common stock availiable for issurance	19,558,403
2018 Stock Award Plan [Member]
Option weighted-average fair value (in dollars per share)		$ 0.46	$ 0.81
Number of common stock availiable for issurance	17,500,000
Option unrecognized stock-based compensation		$ 6,214
Period stock-based compensation to be recognized		2 years 3 months 29 days
Total intrinsic value of options exercised		$ 28
Minimum [Member]
Option weighted average exercise price (in dollars per share)		$ 0.75	1.17
Maximum [Member]
Option weighted average exercise price (in dollars per share)		$ 1.05	$ 1.85

Stock-Based Compensation (Det_2

Stock-Based Compensation (Details) - Stock Options [Member] $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares
Options
Options outstanding, beginning balance | shares	18,215,932
Options, granted | shares	10,209,322
Options, exercised | shares	(168,539)
Options, cancelled | shares	(2,865,542)
Options outstanding, ending balance | shares	25,391,173
Options, exercisable | shares	11,413,154
Options, vested and expected to vest | shares	23,993,371
Weighted-Average Exercise Price
Options outstanding, beginning balance | $ / shares	$ 1.29
Granted | $ / shares	0.85
Exercised | $ / shares	0.75
Cancelled | $ / shares	1.52
Options outstanding, ending balance | $ / shares	1.09
Options exercisable | $ / shares	1.19
Options vested and expected to vest | $ / shares	$ 1.09
Weighted-Average Remaining Contractual Term in Years, Options outstanding, beginning	7 years 7 months 20 days
Weighted-Average Remaining Contractual Term in Years, Options outstanding, ending	7 years 8 months 23 days
Weighted-Average Remaining Contractual Term in Years, Options exercisable	6 years 3 months 29 days
Weighted-Average Remaining Contractual Term in Years, Options vested and expected to vest	7 years 7 months 28 days
Aggregate Intrinsic Value, Options outstanding,beginning balance | $	$ 1,830
Aggregate Intrinsic Value, Options outstanding, ending balance | $	1,460
Aggregate Intrinsic Value, Options exercisable | $	864
Aggregate Intrinsic Value, Options vested and expected to vest | $	$ 1,432

Stock-based Compensation (Det_3

Stock-based Compensation (Details 1) - Restricted Common Stock [Member]	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Number of shares, Restricted Stock
Unvested Beginning | shares	42,406
Granted | shares	334,955
Vested | shares	(197,589)
Forfeited/Cancelled | shares	(16,036)
Unvested Ending | shares	163,736
Options, Weighted-average Grant-Date Fair Value, Restricted Stock
Unvested Beginning | $ / shares	$ 0.87
Granted | $ / shares	0.65
Vested | $ / shares	0.69
Forfeited/Cancelled | $ / shares	0.87
Unvested Ending | $ / shares	$ 0.63

Stock-based Compensation (Det_4

Stock-based Compensation (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Stock-based compensation expense	$ 3,235	$ 2,892
Cost of revenue [Member]
Stock-based compensation expense	137
Research and Development Expense [Member]
Stock-based compensation expense	282	258
Selling General And Administrative Expense [Member]
Stock-based compensation expense	$ 2,816	$ 2,634

Warrants to Purchase Common S_3

Warrants to Purchase Common Stock (Details)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Warrants, Number of Shares [Rollforward]
Outstanding at beginning | shares	355,028
Granted | shares	8,891,287
Outstanding at ending | shares	9,246,315
Warrants, Weighted-Average Exercise Price [Rollforward]
Outstanding at beginning | $ / shares	$ 1.41
Granted | $ / shares	1.40
Outstanding at ending | $ / shares	$ 1.40

Warrants to Purchase Common S_4

Warrants to Purchase Common Stock (Details 1) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Exercise price	$ 1.40	$ 1.41
Warrants [Member]
Exercise price	$ 1.41
Date of Expiration	May 28, 2020
Number of Warrants	355,028
Warrants [Member]
Exercise price	$ 1.40
Date of Expiration	Mar. 15, 2028
Number of Warrants	8,750,000
Warrants [Member]
Exercise price	$ 1.27
Date of Expiration	Mar. 15, 2028
Number of Warrants	141,287
Warrants [Member]
Number of Warrants	9,246,315

Related Party Transactions (Det

Related Party Transactions (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	Mar. 16, 2018	Oct. 11, 2017	Mar. 15, 2017	Dec. 31, 2018	Dec. 31, 2017
Number of shares issued
Warrant exercise price				$ 1.40	$ 1.41
Convertible Preferred Stock [Member]
Number of shares issued	8,750,000
Shares price (in dollars per share)	$ 1.40
Proceeds from issuance of convertible preferred stock	$ 24,671
Shares issued upon conversion of preferred stock (shares)	20,000,000
Non-compounding dividend rate of preferred stock	12.00%
Convertible Preferred Stock [Member] | Heritak Medical Systems [Member] | Minimum [Member]
Beneficial ownership	5.00%
Philips [Member] | Warrant [Member]
Warrant exercised (shares)		4,728,191
Warrant exercise price		$ 1.06
Issuance of common stock for warrant exercised (shares)		1,393,605
Warrant shares withheld to pay exercise price (shares)		3,334,586
Private Placement [Member]
Number of shares issued			68,055,700
Shares price (in dollars per share)			$ 0.6616
Aggregate purchase price from private placement of common stock			$ 45,026
Offering expenses			$ 415

Commitments and Contingencies_2

Commitments and Contingencies (Details Narrative) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)ft²	Dec. 31, 2017USD ($)
Office and manufacturing lease (square footage) | ft²	26,402
Operating lease expiration date	Jan. 31, 2021
Security deposit	$ 134	$ 134
Rent expense	632	661
Property and equipment, Gross	4,694	4,043
Less accumulated depreciation and amortization	2,915	$ 2,591
Assets Held under Capital Leases [Member]
Property and equipment, Gross	164
Less accumulated depreciation and amortization	$ 55

Commitments and Contingencies_3

Commitments and Contingencies (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Operating Lease
2019	$ 648
2020	664
2021	55
Total Lease Payments	1,367
Capital Lease
2019	67
2020	48
Total Lease Payments	115
Less amount representing interest	13
Minimum lease payments	102
Less current portion of obligation under capital lease	56	$ 49
Long-term obligation under capital lease	$ 46	$ 102

Net Loss per Share (Details)

Net Loss per Share (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Restricted Stock Units [Member]
Number of anti-dilutive securities	163,736	42,406
Series A Preferred Stock [Member]
Number of anti-dilutive securities	20,000,000
Series A-1 Preferred Stock [Member]
Number of anti-dilutive securities	1,408,000
Warrants [Member]
Number of anti-dilutive securities	9,246,315	355,028
Stock Options [Member]
Number of anti-dilutive securities	25,391,173	18,215,932

Restructuring Charge (Details N

Restructuring Charge (Details Narrative) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2018
Restructuring charge - severance costs	$ 349
Payment of restructuring		$ 346
Restructuring Costs [Member]
Accounts payable and accrued expenses		$ 3

401(k) Plan (Details Narrative)

401(k) Plan (Details Narrative) - 401(k) Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Administration expenses	$ 459	$ 392
Company match eligible contributions - first (percent)	100.00%
First eligible contribution	3.00%
Next eligible contribution	2.00%
Company match eligible contributions - second (percent)	50.00%

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 4,673	$ 2,958	$ 1,665	$ 1,485	$ 4,190	$ 2,425	$ 2,258	$ 777	$ 10,781	$ 9,650
Cost of revenue	2,759	1,834	2,151	1,929	2,990	2,183	2,200	1,892	8,673	9,265
Gross profit (loss)	1,914	1,124	(486)	(444)	1,200	242	58	(1,115)	2,108	385
Total operating expense	9,199	8,403	9,223	9,590	9,182	8,081	8,395	8,636	36,415	34,294
Operating loss	(7,285)	(7,279)	(9,709)	(10,034)	(7,982)	(7,839)	(8,337)	(9,751)	(34,307)	(33,909)
Total other income (expense), net	(150)	(316)	(200)	(16)	11	(14)	(77)	(134)	(682)	(214)
Net loss	(7,435)	(7,595)	(9,909)	(10,050)					(34,989)	(34,123)
Accretion of beneficial conversion feature of Series A and Series A-1 preferred stock	(30)			(5,236)					5,266
Dividends on preferred stock	(752)	(758)	(753)	(125)					2,388
Net loss attributable to common stockholders	$ (8,217)	$ (8,353)	$ (10,662)	$ (15,411)	$ (7,971)	$ (7,853)	$ (8,414)	$ (9,885)	$ (42,643)	$ (34,123)
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (0.04)	$ (0.04)	$ (0.06)	$ (0.08)	$ (0.04)	$ (0.04)	$ (0.04)	$ (0.07)	$ (0.22)	$ (0.20)

Subsequent Events (Details Narr

Subsequent Events (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	Mar. 14, 2019	Mar. 12, 2019	Feb. 26, 2019	Mar. 12, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 16, 2018
Net proceeds from sale of common stock					$ 2,818	$ 44,611
Exercise price					$ 1.40	$ 1.41
Financing Arrangement [Member] | Additonal Term Loan [Member] | Year One of Loan Issuance [Member]
Debt prepayment fee (percent)	2.50%
Financing Arrangement [Member] | Additonal Term Loan [Member] | Year 3 of Loan Issuance [Member]
Debt prepayment fee (percent)	1.00%
Financing Arrangement [Member] | Term Loans [Member]
Principle amount outstanding					$ 12,000
Debt final payment fee (percent)					6.00%
Financing Arrangement [Member] | Term Loans [Member] | Year One of Loan Issuance [Member]
Debt prepayment fee (percent)					2.50%
Financing Arrangement [Member] | Term Loans [Member] | Year 2 of Loan Issuance [Member]
Debt prepayment fee (percent)	1.50%				1.50%
Financing Arrangement [Member] | Term Loans [Member] | Year 3 of Loan Issuance [Member]
Debt prepayment fee (percent)					1.00%
Financing Arrangement [Member] | Term Loans [Member] | Minimum [Member]
Interest rate							8.83%
Subsequent Event [Member] | Financing Arrangement [Member] | Additonal Term Loan [Member]
Principle amount outstanding	$ 2,750
Basis spread on variable interest rate	7.25%
Description of variable interest rate base	ICE Benchmark LIBOR
Debt final payment fee (percent)	6.00%
Issuance of warrants	$ 300,000
Subsequent Event [Member] | Financing Arrangement [Member] | Additonal Term Loan [Member] | Minimum [Member]
Interest rate	8.83%
Exercise price	$ 1.3796
Subsequent Event [Member] | Securities Purchase Agreement [Member] | Private Placement [Member]
Number of stock issued (in shares)			10,872,716
Number of stock issued (in dollars per share)			$ 1.3796
Gross proceeds from sale of common stock				$ 19,800
Net proceeds from sale of common stock				$ 19,500
Common stock lock-in period				6 months
Subsequent Event [Member] | Securities Purchase Agreement [Member] | Second Closing Private Placement [Member]
Number of stock issued (in shares)		3,512,124