Vapotherm (VAPO) 10-K 4 Mar 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Feb. 27, 2020	Jun. 30, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	Vapotherm Inc
Entity Central Index Key	0001253176
Entity Tax Identification Number	46-2259298
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 302,970,651
Entity File Number	001-38740
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Small Business	true
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	100 Domain Drive
Entity Address, City or Town	Exeter
Entity Address, State or Province	NH
Entity Address, Postal Zip Code	03833
City Area Code	603
Local Phone Number	658-0011
Entity Common Stock, Shares Outstanding		20,875,826
Title of 12(b) Security	Common Stock, $0.001 per value per share
Trading Symbol	VAPO
Security Exchange Name	NYSE
Documents Incorporated by Reference	Portions of the Registrant’s Definitive Proxy Statement relating to the Annual Meeting of Shareholders, scheduled to occur on June 23, 2020, are incorporated by reference into Part III of this Report.

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 71,655,000	$ 58,223,000
Accounts receivable, net	8,243,000	7,107,000
Inventories	9,137,000	13,710,000
Prepaid expenses and other current assets	4,066,000	2,683,000
Total current assets	93,101,000	81,723,000
Property and equipment, net	15,086,000	13,416,000
Restricted cash	1,852,000	1,799,000
Goodwill	588,000	0
Intangible assets, net	353,000	0
Deferred income tax assets	66,000
Other long-term assets	844,000	308,000
Total assets	111,890,000	97,246,000
Current liabilities
Accounts payable	2,753,000	3,148,000
Contract liabilities	137,000	79,000
Accrued expenses and other liabilities	9,809,000	7,653,000
Short-term line of credit	3,491,000	3,163,000
Total current liabilities	16,190,000	14,043,000
Long-term loans payable, net	41,787,000	31,317,000
Other long-term liabilities	174,000	325,000
Total liabilities	58,151,000	45,685,000
Commitments and contingencies (Note 11)
Stockholders' equity
Preferred stock ($.001 par value) 25,000,000 shares authorized; no shares issued and outstanding as of December 31, 2019 and 2018
Common stock ($.001 par value) 175,000,000 shares authorized as of December 31, 2019 and 2018; 20,851,531 and 16,782,837 shares issued and outstanding as of December 31, 2019 and 2018, respectively	21,000	17,000
Additional paid-in capital	319,115,000	265,926,000
Accumulated other comprehensive income	44,000
Accumulated deficit	(265,441,000)	(214,382,000)
Total stockholders' equity	53,739,000	51,561,000
Total liabilities and stockholders’ equity	$ 111,890,000	$ 97,246,000

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	175,000,000	175,000,000
Common stock, shares issued	20,851,531	16,782,837
Common stock, shares outstanding	20,851,531	16,782,837

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net revenue	$ 48,104,000	$ 42,377,000
Cost of revenue	26,793,000	25,605,000
Gross profit	21,311,000	16,772,000
Operating expenses
Research and development	13,376,000	8,771,000
Sales and marketing	37,689,000	33,927,000
General and administrative	18,410,000	11,186,000
Loss on disposal of property and equipment		121,000
Total operating expenses	69,475,000	54,005,000
Loss from operations	(48,164,000)	(37,233,000)
Other (expense) income
Foreign currency gain	44,000
Interest income	860,000	118,000
Gain on litigation settlement	1,151,000
Interest expense	(5,096,000)	(3,064,000)
Loss on extinguishment of debt		(2,842,000)
Gain on change in fair value of warrant liabilities		553,000
Net loss before income taxes	(51,205,000)	(42,468,000)
Benefit for income taxes	(146,000)	0
Net loss	(51,059,000)	(42,468,000)
Accretion of preferred stock to redemption value		(81,000)
Net loss attributable to common stockholders	(51,059,000)	(42,549,000)
Other comprehensive income, net of tax:
Foreign currency translation adjustments	44,000
Total other comprehensive income	44,000
Total comprehensive loss	$ (51,015,000)	$ (42,468,000)
Net loss per share attributable to common stockholders - basic and diluted	$ (2.74)	$ (14.65)
Weighted-average number of shares used in calculating net loss per share, basic and diluted	18,604,707	2,905,085

CONSOLIDATED STATEMENTS OF REDE

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Temporary equity, beginning balance at Dec. 31, 2017		$ 152,637
Temporary equity, beginning balance, shares at Dec. 31, 2017		10,515,351
Beginning balance at Dec. 31, 2017	$ (126,857)		$ 1	$ 45,056	$ (171,914)
Beginning balance, shares at Dec. 31, 2017			672,321
Temporary equity issuance of Series D redeemable convertible preferred stock, value		$ 9,919
Temporary equity issuance of Series D redeemable convertible preferred stock, shares		714,285
Accretion of Series D issuance costs	(81)			(81)
Temporary equity accretion of Series D issuance costs		$ 81
Conversion of redeemable convertible preferred stock	162,637		$ 11	162,626
Temporary equity conversion of redeemable convertible preferred stock, shares		(11,229,636)
Temporary equity conversion of redeemable convertible preferred stock		$ (162,637)
Conversion of redeemable convertible preferred stock, shares			11,229,636
Reclassification of warrants	(24)			(24)
Issuance of common stock, value	57,394		$ 5	57,389
Issuance of common stock, shares			4,600,000
Issuance of stock upon exercise of options	98			98
Issuance of stock upon exercise of options, shares			66,392
Issuance of restricted stock	360			360
Issuance of restricted stock, shares			214,488
Stock-based compensation expense	502			502
Net loss	(42,468)				(42,468)
Ending balance at Dec. 31, 2018	51,561		$ 17	265,926	(214,382)
Ending balance, shares at Dec. 31, 2018			16,782,837
Issuance of common stock, value	48,276		$ 4	48,272
Issuance of common stock, shares			3,570,750
Issuance of common stock warrants	293			293
Issuance of stock upon repayment of non-recourse loans	144			144
Issuance of stock upon repayment of non-recourse loans, shares			79,854
Issuance of stock upon exercise of warrants, shares			12,164
Issuance of stock upon exercise of options	$ 242			242
Issuance of stock upon exercise of options, shares	150,176		150,176
Issuance of restricted stock	$ 402			402
Issuance of restricted stock, shares			255,750
Stock-based compensation expense	3,836			3,836
Foreign currency translation adjustments	44					$ 44
Net loss	(51,059)				(51,059)
Ending balance at Dec. 31, 2019	$ 53,739		$ 21	$ 319,115	$ (265,441)	$ 44
Ending balance, shares at Dec. 31, 2019			20,851,531

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities
Net loss	$ (51,059)	$ (42,468)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	3,078	2,167
Stock-based compensation expense	3,836	502
Amortization of discount on debt	234	123
Loss on disposal of property and equipment	101	511
Provision for bad debts	104	273
Loss on extinguishment of debt		2,842
Gain on litigation settlement	(1,151)
Deferred income taxes	(147)
Change in fair value of warrants		(553)
Changes in operating assets and liabilities:
Accounts receivable	(833)	(425)
Inventories	5,063	(2,252)
Prepaid expenses and other assets	(1,218)	(443)
Accounts payable	98	896
Contract liabilities	58	15
Accrued expenses and other liabilities	2,174	(1,206)
Net cash used in operating activities	(39,662)	(40,018)
Cash flows from investing activities
Acquisition of business, net of cash acquired	(1,560)
Purchases of property and equipment	(4,747)	(5,180)
Net cash used in investing activities	(6,307)	(5,180)
Cash flows from financing activities
Proceeds from issuance of common stock in connection with public offering, net	48,669	59,892
Proceeds on loans	10,500	32,000
Proceeds from issuance of redeemable convertible preferred stock, net		9,919
Repayment of loans payable		(22,328)
Public offering costs	(393)	(2,498)
Debt issuance costs	(29)	(800)
Short-term line of credit	316	136
Proceeds from exercise of stock options and purchase of restricted stock	386	539
Net cash provided by financing activities	59,449	76,860
Effect of exchange rate changes on cash, cash equivalents and restricted cash	5
Net increase in cash, cash equivalents, and restricted cash	13,485	31,662
Cash, cash equivalents and restricted cash
Beginning of year	60,022	28,360
End of year	73,507	60,022
Supplemental disclosures of cash flow information
Interest paid during the period	4,793	3,028
Issuance of common stock upon vesting of restricted stock	402	360
Issuance of warrants in conjunction with debt draw down	293
Property and equipment purchases in accrued expenses	$ 135	21
Conversion of preferred stock to common stock		$ 162,637

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	1. Description of Business Vapotherm, Inc. (the “Company”) was founded in 1993 and reincorporated under the laws of the State of Delaware in 2013. Since inception, the Company has focused on the development and commercialization of its proprietary Hi-VNI Technology products that are used to treat patients of all ages suffering from respiratory distress. The Company’s Hi-VNI Technology delivers non-invasive ventilatory support by providing heated, humidified and oxygenated air at a high velocity to patients through a comfortable small-bore nasal interface. The Company’s Precision Flow systems, which use Hi-VNI Technology, are clinically validated alternatives to, and address many limitations of, the current standard of care for the treatment of respiratory distress in a hospital setting. The Company offers four versions of its Precision Flow systems: Precision Flow Hi-VNI, Precision Flow Plus, Precision Flow Classic and Precision Flow Heliox. The Company generates revenue primarily from sales of disposable products utilized with its proprietary Precision Flow systems. The Company also generates revenue from the capital units themselves, and to a lesser extent, sales of its companion products, which include the Vapotherm Transfer Unit 2.0, the Q50 compressor and various adaptors. The Company offers different options to its hospital customers for acquiring Precision Flow capital units, ranging from the purchase of the Precision Flow capital units with payment in full at the time of purchase, to financed purchases of the Precision Flow capital units, to bundled discounts involving the placement of Precision Flow capital units for use by the customer at no upfront charge in connection with the customer’s ongoing purchase of disposable products. The Company sells Precision Flow systems to hospitals through a direct sales force in the United States and in the United Kingdom and through distributors in select other countries outside of the United States and United Kingdom In addition, the Company utilizes clinical educators who are typically experienced users of Hi-VNI Technology and who focus on medical education efforts to facilitate adoption and increase utilization. The Company is focused on physicians, respiratory therapists and nurses who work in acute hospital settings, including the emergency department and adult, pediatric and neonatal intensive care units (the “ICUs”). The Company’s relationship with these clinicians is particularly important, as it enables its products to follow patients through the care continuum. Since inception, the Company has financed its operations primarily through public offerings of its common stock, private placements of its convertible preferred stock, sales of its Precision Flow systems and amounts borrowed under its credit facilities. The Company has devoted the majority of its resources to research and development activities related to its Precision Flow systems, including regulatory initiatives and sales and marketing activities. The Company has invested heavily in its sales and marketing function by increasing the number of sales representatives and clinical educators to facilitate adoption and increase utilization of its Hi-VNI Technology products and expanded its digital marketing initiatives and medical education programs. The Company is subject to risks common to companies in the medical device industry, including, but not limited to, the successful development and commercialization of its Precision Flow products, fluctuations in operating results and financial risks, protection of proprietary knowledge and patent risks, dependence on key personnel and collaborative partners, competition, technological and manufacturing risks, customer acceptance and demand, compliance with the Food and Drug Administration and other governmental regulations, management of growth and effectiveness of marketing by the Company and by third parties. On November 16, 2018, the Company completed an initial public offering of 4,600,000 shares of common stock, which included the full exercise by the underwriters of their option to purchase 600,000 shares of common stock, at a price of $14.00 per share, which raised net proceeds of $57.4 million after deducting the underwriting discount of $4.5 million and offering expenses of $2.5 million. On February 28, 2019, the Company acquired its United Kingdom based distributor. See Note 3 “Business Combinations” to these consolidated financial statements for details of this transaction. In August 2019, the Company completed a public offering of 3,570,750 shares of common stock, which included the full exercise by the underwriters of their option to purchase 465,750 shares of common stock, at a price of $14.50 per share, which raised net proceeds of $48.3 million after deducting the underwriting discount of $3.1 million and offering expenses of $0.4 million.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Basis of Presentation The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Principles of Consolidation These consolidated financial statements include the financial statements of Solus Medical Ltd. (“Solus”), a wholly owned subsidiary of the Company based in the United Kingdom, which was acquired in the first quarter of 2019. All intercompany accounts and transactions have been eliminated upon consolidation. Segment Information Operating segments are defined as components of an enterprise for which separate discrete financial information is available and evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company globally manages the business within one reporting segment, Vapotherm, Inc. and two reporting units, Vapotherm and Solus. Segment information is consistent with how management reviews the business, makes investing and resource allocation decisions and assesses operating performance. The majority of the Company’s long-term assets are located in the United States. Long-term assets located outside the United States total $0.1 million at December 31, 2019. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires the Company to make judgments, assumptions, and estimates that affect the reported amounts of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and liabilities. The Company evaluates its estimates on an ongoing basis. The Company bases its estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Significant estimates relied upon in preparing these consolidated financial statements include calculation of stock-based compensation, valuation of warrants, fair values of acquired assets and liabilities, including goodwill and intangibles assets, realizability of inventories, allowance for bad debt, accrued expenses and the valuation allowances against deferred income tax assets. Actual results may differ from these estimates. Concentrations of Credit Risk As of December 31, 2019 and 2018, the Company’s financial instruments were comprised of cash and cash equivalents, restricted cash, accounts receivable, accounts payable and debt, the carrying amounts of which approximated fair value due to the short-term nature and market interest rates. All of the Company’s cash and cash equivalents are maintained at creditworthy financial institutions. At December 31, 2019 and 2018, deposits exceed the amount of any insurance provided. The Company extends credit to customers in the normal course of business but does not require collateral or any other security to support amounts due. Management performs ongoing credit evaluations of its customers. An allowance for potentially uncollectible accounts is provided based on history, economic conditions, and composition of the accounts receivable aging. In some cases, the Company makes allowances for specific customers based on these and other factors. Provisions for the allowance for doubtful accounts are recorded in general and administrative expenses in the accompanying consolidated statements of comprehensive loss. Supplier Risk The Company obtains some of the components and subassemblies included in its Precision Flow systems from single source suppliers and the partial or complete loss of one or more of these suppliers could cause significant production delays, an inability to meet customer demand and a substantial loss in revenue. Foreign Currency and Foreign Operations The functional currency of the Company is the currency of the primary economic environment in which the entity operates, which is the U.S. dollar. For our non-U.S. subsidiary that transacts in a functional currency other than the U.S. dollar, assets and liabilities are translated at current rates of exchange at the balance sheet date. Income and expense items are translated at the average foreign currency exchange rates for the period. Adjustments resulting from the translation of the financial statements of its foreign operations into U.S. dollars are excluded from the determination of net loss and are recorded in accumulated other comprehensive income, a separate component of stockholders’ equity. There were no assets or liabilities of foreign subsidiaries that were translated at period-end exchange rates as of December 31, 2018. See Note 3 “Business Combinations” to these consolidated financial statements for details of the Solus acquisition. The f unctional currency of Solus is its local currency, Pound Sterling (GBP). Realized foreign currency gains or losses arising from transactions denominated in foreign currencies are recorded in other (expense) income in the consolidated statements of comprehensive loss. Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid temporary investments purchased with original maturities of 90 days or less to be cash equivalents. The Company holds restricted cash related to certificates of deposits and collateral in relation to lease agreements. As of December 31, 2019, $0.3 million of our $73.5 million of cash, cash equivalents and restricted cash balance was located outside the U.S. The following table presents the components of total cash, cash equivalents, and restricted cash as set forth in the Company’s consolidated statements of cash flows: December 31, 2019 2018 Cash and cash equivalents $ 71,655 $ 58,223 Restricted cash 1,852 1,799 Total cash, cash equivalents, and restricted cash $ 73,507 $ 60,022 Inventories Inventories consist of finished goods and component parts and are valued at the lower of cost or net realizable value, determined by the first-in, first-out (“FIFO”) method. On a quarterly basis, the Company evaluates the carrying costs of both finished goods and component part items. To the extent that such costs exceed future demand estimates, exhibit historical turnover at rates less than current inventory levels, or exceed estimated selling prices less costs to sell, the Company reduces the carrying value of inventories to its net realizable value. The Company only capitalizes pre-launch inventories when purchased for commercial sale and it deems regulatory approval to be probable. Public Offering Costs The Company incurs public offering costs consisting of legal, accounting and other costs directly attributable to the Company’s public offerings and defers such costs until the closing of the offerings. Upon closing of offerings, such costs are netted against the proceeds received. As of December 31, 2019 and 2018, no amounts were deferred. Property and Equipment Property and equipment are recorded at cost. Depreciation is recognized over the estimated useful lives of the related assets on a straight-line basis. Amortization of leasehold improvements is computed on a straight-line basis over the shorter of the remaining lease term or the estimated useful lives of the improvements and is included in depreciation expense. Demonstration equipment represents internally manufactured capital equipment that is used on-site at trade shows and at customer locations to demonstrate the Precision Flow system. Depreciation expense on demonstration equipment is recorded in sales and marketing expense in the consolidated statements of comprehensive loss. Placement and evaluation systems represent capital equipment placed at customer locations under placement or evaluation agreements for which depreciation expense is included in cost of revenue in the accompanying consolidated statements of comprehensive loss. When impairment indicators are present, the Company evaluates the recoverability of its long-lived assets. If the assessment indicates an impairment, the affected assets are written down to fair value. There were no impairments during 2019 or 2018. Repairs and maintenance are expensed as incurred. Expenditures that increase the value or productive capacity of assets are capitalized. When property and equipment are retired, sold, or otherwise disposed of, the asset’s carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in operating expenses. The lives used in computing straight-line depreciation are as follows: Number of Years Equipment 3 - 7 Furniture 5 - 7 Manufacturing equipment 3 - 10 Software 3 Demonstration, placements and evaluation units 3 - 5 Leasehold improvements Lesser of life of lease or 10 years The Company’s policy is to periodically review the estimated useful life of all property and equipment. This review during fiscal year 2019 indicated that the estimated useful life of all property and equipment is consistent with fiscal year 2018, with the exception of certain manufacturing equipment placed in service in 2019, for which the maximum useful life increased from 7 years to 10 years. Property and equipment are evaluated for impairment whenever events or circumstances indicate an asset may be impaired. There were no impairments during 2019 or 2018. Intangible Assets Intangible assets related to customer agreements are amortized on a straight-line basis over their useful lives. Amortization is recorded within sales and marketing expenses in the consolidated statements of comprehensive loss. Intangible assets are evaluated for impairment whenever events or circumstances indicate an asset may be impaired. There were no impairments of intangible assets during 2019, and the Company had no intangible assets during 2018. Goodwill Goodwill represents the difference between the purchase price and the fair value of the identifiable tangible and intangible net assets when accounted for using the purchase method of accounting. Goodwill is not amortized but reviewed for impairment. Goodwill is reviewed annually, as of October 1, and whenever events or changes in circumstances indicate that the carrying value of the goodwill may not be recoverable. The Company compares the fair value of our reporting units to their carrying values. If the carrying value of the net assets assigned to a reporting unit exceeds the fair value of the reporting unit, the Company would record an impairment loss equal to the difference. There was no impairment of goodwill during 2019, and the Company had no goodwill during 2018. Leases & Deferred Rent Leases are classified at their inception as either operating or capital leases based on the economic substance of the agreement. Lease payments made under operating leases are recognized as an expense on a straight-line basis over the lease term. Any differences between the lease payments and the expense recognized on a straight-line basis is recorded as deferred rent. Deferred rent is recorded in accrued expenses and other liabilities in the consolidated balance sheets. Deferred rent totaled $0.2 million at both December 31, 2019 and 2018. Product Warranty The Company provides its customers with a standard one-year warranty on its capital equipment sales. Warranty costs are accrued based on actual historical trends and estimated at time of sale. The warranty liability is included within accrued expenses and other liabilities in the consolidated balance sheets. A roll-forward of the Company’s warranty liability is as follows: Balance at December 31, 2017 $ 317 Provisions for warranty obligations 355 Settlements (343 ) Balance at December 31, 2018 329 Provisions for warranty obligations 125 Settlements (229 ) Balance at December 31, 2019 $ 225 Deferred Financing Costs Direct financing costs are deferred and amortized as a component of interest expense, over the term of the related debt. The balance of unamortized costs is presented as a reduction of the related borrowing arrangement liability. Unamortized costs totaled $0.8 million and $0.7 million at December 31, 2019 and 2018, respectively. Revenue Recognition The Company’s revenue consists primarily of the sale of products, leases and services. Product revenue consists of capital equipment and single-use disposables that are shipped and billed to customers both domestically and internationally. The Company’s main capital equipment products are the Precision Flow Hi-VNI, Precision Flow Plus, Precision Flow Classic, Vapotherm Transfer Unit 2.0 and Q50 compressor. The Company’s main disposable products are single-use disposables and nasal interfaces, or cannulas, and adaptors. Lease revenue consists of capital equipment that the Company leases out to its customers. Service revenue consists of fees associated with routine service of capital units and the sale of extended service contracts and preventative maintenance plans, which are purchased by a small portion of the Company’s customer base. In addition, the Company sells small quantities of component parts in the United States, United Kingdom and to third-party international service centers who provide service on Precision Flow capital units outside of the United States. Freight revenue is based upon actual freight costs plus a percentage markup of such costs associated with the shipment of products domestically, and to a lesser extent, internationally, and is included in service revenue. Rebates and fees consist of contractually obligated administrative fees and percentage-of-sales rebates paid to Group Purchasing Organizations (“GPOs”), Integrated Delivery Networks (“IDNs”) and distributor partners and accounted for as a reduction of service revenue. Under Financial Accounting Standard Board (“FASB”) Accounting Standards Codifications (“ASC”) 606, Revenue from Contracts with Customers (“ASC 606”), revenue is recognized when a customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company 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 ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize 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 the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and assesses whether each promised good or service is distinct and determines those that are performance obligations. 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. Sales, value-added, and other taxes collected on behalf of third parties are excluded from revenue. The Company’s standard payment term is generally 30 days from date of sale. Contracts with customers may contain multiple performance obligations. For such arrangements, the transaction price is allocated to each performance obligation based on the estimated relative stand-alone selling prices of the promised products or services underlying each performance obligation. The Company determines stand-alone selling prices based on the price at which the performance obligation is sold separately. If the stand-alone selling price is not observable through past transactions, the Company estimates the stand-alone selling price taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. 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. Applying the practical expedient in paragraph 606-10-32-18, the Company does not assess whether a significant financing component exists if the period between when the Company performs its obligations under the contract and when the customer pays is one year or less. None of the Company’s contracts contained a significant financing component during the years ended December 31, 2019 or 2018. The Company’s contracts with its customers have a duration of less than one year. Therefore, the Company has elected to apply the practical expedient in paragraph ASC 340-40-25-4 and recognizes the incremental costs of obtaining contracts as an expense. These costs are included in sales and marketing expense in the accompanying consolidated statements of comprehensive loss. Lease Revenue The Company also enters into agreements to lease its capital equipment. For such sales, the Company accounts for revenue under ASC 840, Leases, and assesses and classifies these transactions as sales-type or operating leases based on whether the lease transfers ownership of the equipment to the lessee by the end of the lease term. This criterion is met in situations in which the lease agreement provides for the transfer of title at or shortly after the end of the lease term in exchange for the payment of a nominal fee, for example, the minimum required by statutory regulation to transfer title. Equipment included in arrangements including transfer of title are accounted for as sales-type leases and the Company recognizes the total value of the lease payments due over the lease term to revenue at the inception of the lease. The Company records the current value of future lease payments under prepaid expenses and other current assets in the accompanying consolidated balance sheets and these amounts totaled $0.9 million at both December 31, 2019 and 2018. Equipment included in arrangements that do not include the transfer of title, nor any of the capital lease criteria, are accounted for as operating leases and revenue is recognized on a straight-line basis as it becomes receivable monthly over the term of the lease. Shipping and Handling Costs Amounts billed to customers for shipping and handling are included in service revenue. Shipping and handling costs are included in costs of sales. The total costs of shipping and handling at both December 31, 2019 and 2018 amounted to $1.0 million. Sales and Value-Added Taxes When required by local jurisdictions, the Company bills its customers for sales tax and value-added tax calculated on each sales invoice and records a liability for the sales and value-added tax payable, which is included in accrued expenses and other liabilities in the consolidated balance sheets. Sales tax and value-added tax billed to a customer is not included in the Company’s revenue. Timing and Amount of Revenue Recognition The Company recognizes revenue on product sales and service of its capital equipment and product sales of disposables to its end users. In each instance, revenue is generally recognized when the customer obtains control of the Company’s product, which generally occurs at a point in time upon shipment based on the contractual shipping terms of a contract. Product and service 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 amount method to which the Company expects to be entitled. As such, revenue on sales are recorded net of prompt pay discounts and payments made to GPOs, IDNs and distributors. 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. 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. The Company believes that the estimates it has established are reasonable based upon current facts and circumstances. Applying different judgments to the same facts and circumstances could result in the estimated amounts to vary. Product Returns The Company provides its customers with the right to return products for a refund of the purchase price or for an account credit, if the return is made within a specified number of days from the original invoice date. The Company records a product return liability based upon an estimate of specific returns and a review of historical returns experienced. Adjustments are made to the product return liability as returns data and historical experience change. The provision for product return estimates is recorded as a reduction of revenue. The product return liability totaled less than $0.1 million at both December 31, 2019 and 2018 and is included in other current liabilities in the accompany consolidated balance sheets. Research and Development Costs Research and development costs are expensed when incurred and are related primarily to product design, prototype development and testing, the investigation of possible follow-on product enhancements and new product releases, and investigation of complementary technologies potentially available to enhance the Company’s offerings in the marketplace. Stock-Based Compensation The Company maintains an equity incentive plan to provide long-term incentives for employees, consultants, and members of the board of directors. The plan allows for the issuance of non-statutory and incentive stock options to employees and non-statutory stock options to consultants and non-employee directors. The Company recognizes stock-based compensation expense for awards of equity instruments to employees and non-employees based on the grant date fair value of those awards in accordance with ASC Topic 718, Stock Compensation (ASC 718). ASC 718 requires all equity-based compensation awards, including grants of restricted shares and stock options, to be recognized as expense in the statements of comprehensive loss based on their grant date fair values. The fair value of each option grant is estimated on the grant date using the Black-Scholes option pricing model. The fair value is then amortized on a straight-line basis over the requisite service period of the awards, which is generally the vesting period. For performance-based awards, the related compensation cost is amortized over the performance period on an accelerated attribution basis. Compensation cost associated with performance awards is based on fair value on the date of grant and the number of units expected to be earned after assessing the probability that certain performance criteria will be met and the associated targeted payout level that is forecasted will be achieved, net of expected forfeitures. Cumulative adjustments are recorded each quarter to reflect estimated outcomes of the performance-related conditions until the results are determined and settled. Use of a valuation model requires management to make certain assumptions with respect to selected model inputs, including the expected life (weighted average period of time that the options granted are expected to be outstanding), the volatility of the Company’s common stock and an assumed risk-free interest rate. Expected volatility is calculated based on historical volatility of a group of publicly traded companies that the Company considers a peer group. The expected life is estimated using the simplified method for “plain vanilla” options. The risk-free interest rate is based on U.S. Treasury rates with a remaining term that approximates the expected life assumed at the date of grant. No dividend yield is assumed as the Company does not pay, and does not expect to pay, dividends on its common stock. Company estimates forfeitures based on historical experience with pre-vested forfeitures. To the extent actual forfeitures differ from the estimate, the difference is recorded to compensation expense in the period of the forfeiture. Net Income (Loss) per Share The Company had followed the two-class method when computing net income (loss) per share as the Company had issued shares that met the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common shareholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net income (loss) per share attributable to common shareholders is computed by dividing the net income (loss) attributable to common shareholders by the weighted average number of common shares outstanding for the period. Diluted net income (loss) attributable to common shareholders is computed by adjusting net income (loss) attributable to common shareholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common shareholders is computed by dividing the diluted net income (loss) attributable to common shareholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares. For purpose of this calculation, outstanding options, unvested restricted common shares and convertible preferred shares are considered potential dilutive common shares. The Company’s convertible preferred shares contractually entitled the holders of such shares to participate in dividends but did not contractually require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reported a net loss attributable to common shareholders, such losses were not allocated to such participating securities. In periods in which the Company reported a net loss attributable to common shareholders, diluted net loss per share attributable to common shareholders was the same as basic net loss per share attributable to common shareholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss attributable to common shareholders for the years ended December 31, 2019 and 2018. On November 16, 2018, the Company completed an initial public offering. All preferred stock outstanding as of the initial public offering As a result, the Company no longer had any participating securities outstanding subsequent to November 16, 2018. Freestanding Preferred Stock Warrants Warrants to purchase the Company’s preferred stock were previously classified as a liability on the consolidated balance sheets. These warrants were subject to remeasurement at each balance sheet date and any change in fair value was recognized as a gain or loss on change in fair value of the warrant liabilities. Pursuant to the Company’s initial public offering in November 2018, all preferred stock warrants automatically converted into warrants to purchase common stock, were reclassified to stockholders’ equity, and were no longer required to be marked to market. Stock Split On November 2, 2018, the Company’s Board of Directors and stockholders approved a 14:1 reverse stock split. The effect of this event has been reflected in all of the share quantities and per share amounts throughout these financial statements. The shares of common stock retained a par value of $0.001. Income Tax The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the consolidated financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the consolidated financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. Recently Adopted Accounting Pronouncements Statement of Cash Flows (Topic 230): Restricted Cash In November 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”). ASU 2016-18 amends Accounting Standards Codification to add or clarify guidance on the classification and presentation of restricted cash in the statement of cash flows. The new standard requires cash and cash equivalents balances on the statement of cash flows to include restricted cash and cash equivalent balances. ASU 2016-18 requires the Company to provide appropriate disclosures about its accounting policies pertaining to restricted cash in accordance with U.S. GAAP. Additionally, changes in restricted cash and restricted cash equivalents that result from transfers between cash, cash equivalents, and restricted cash and restricted cash equivalents should not be presented as cash flow activities in the statement of cash flows. A company with a material balance of amounts generally described as restricted cash and restricted cash equivalents must disclose information about the nature of the restrictions. The new standard is effective for interim and annual periods beginning after December 15, 2018. The Company had not previously included restricted cash as a component of cash and cash equivalents as presented on its consolidated statements of cash flows. The Company adopted the new standard in the first quarter of fiscal 2019, under the retrospective adoption method, and the prior year restricted cash presentation has been reclassified to conform to current year presentation. Clarifying the Definition of a Business (Topic 805): In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business (Topic 805) Revenue from Contracts with Customers Compensation - Stock Compensation (Topic 718): In June 2018, the FASB issued ASU 2018-07, Stock-based Compensation: Improvements to Nonemployee Share-based Payment Accounting (“ASU 2018-07”). This guidance amends the existing accounting standards for share-based payments to nonemployees and aligns much of the guidance on measuring and classifying nonemployee awards with that of awards to employees. Under the new guidance, the measurement of nonemployee equity awards is fixed on the grant data. The Company adopted ASU 2018-07 on January 1, 2019 and the adoption ha

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Business Combinations	3. Business Combinations On February 28, 2019, the Company completed the acquisition of all outstanding equity securities of Solus, The Company has not yet finalized the purchase accounting for the Solus acquisition. The following table summarizes the preliminary purchase price allocation that includes the fair values of the separately identifiable assets acquired and liabilities assumed as of February 28, 2019: Cash $ 466 Accounts receivable 411 Inventory 492 Prepaids and other assets 3 Property and equipment 1 Goodwill 592 Intangible assets 455 Total assets acquired 2,420 Accounts payable and accrued expenses (241 ) Contract liabilities (75 ) Deferred taxes (78 ) Total liabilities assumed (394 ) Total purchase price $ 2,026 The excess of purchase consideration over the fair value of net tangible and identifiable intangible assets acquired was recorded as goodwill. The fair values assigned to tangible and identifiable intangible assets acquired and liabilities assumed are based on management’s estimates and assumptions. The fair values of assets acquired and liabilities assumed, including income taxes payable and deferred taxes, may be subject to change as additional information is received and certain tax returns are finalized. Accordingly, the provisional measurements of fair value of the income taxes payable and deferred taxes set forth above are subject to change. The Company expects to finalize the valuation as soon as practicable, but not later than one year from the acquisition date. In determining the purchase price allocation, the Company considered, among other factors, the opportunity provided by a supplier agreement with the National Health Service. The fair value of the intangible assets associated with this agreement were estimated using a discounted cash flow method with the application of the multi-period excess earnings method. Under this method, an intangible asset’s fair value is equal to the present value of the incremental after-tax cash flows attributable to only the subject intangible assets after deducting contributory asset charges. An income and expenses forecast was built based upon specific intangible asset revenue and expense estimates. The rate used to discount the estimated future net cash flows to their present values for each intangible asset was based upon a weighted average cost of capital calculation. The discount rate was determined after consideration of market rates of return on debt and equity capital, the weighted average return on invested capital and the risk associated with achieving forecasted sales related to the assets acquired from Solus. The total weighted average amortization period for the intangible assets is approximately 3.83 years. The intangible assets are being amortized on a straight-line basis, which is consistent with the pattern that the economic benefits of the intangible assets are expected to be utilized based upon estimated cash flows generated from such assets. Goodwill associated with the acquisition was primarily attributable to the market expansion opportunity in the United Kingdom. The goodwill attributable to the United Kingdom jurisdiction is not deductible for tax purposes. The Company has included the financial results of Solus in the consolidated financial statements from the date of acquisition. Net revenue and net loss related of Solus since the date of acquisition totaled $2.7 million and $0.6 million, respectively. The transaction costs associated with the acquisition were approximately $0.2 million and were recorded in general and administrative expense as incurred. Pro Forma Financial Information (Unaudited) The following unaudited pro forma information for the years ended December 31, 2019 and 2018, respectively, presents consolidated information as if the Solus acquisition occurred on January 1, 2018, which is the first day of the Company’s fiscal year 2018: Year Ended December 31, 2019 2018 Net revenue $ 48,341 $ 43,637 Net loss $ (51,003 ) $ (42,078 ) Net loss per share, basic $ (2.74 ) $ (14.48 )

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements In accordance with ASC 820, Fair Value Measurements and Disclosures, the Company generally defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The Company uses a three-tier fair value hierarchy, which classifies the inputs used in measuring fair values. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements), and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below: • Level 1 – inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 – inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. If the asset or liability has a specified (contractual) term, a Level 2 input must be observable for substantially the full term of the asset or liability. • Level 3 – inputs are unobservable inputs for the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date. As of December 31, 2019 and 2018, the Company had only one item, cash equivalents, measured at fair value on a recurring basis. The Company’s cash equivalents primarily consist of money market deposits which total approximately $70.8 million and $57.6 million at December 31, 2019 and 2018, respectively, and are valued based on Level 1 of the fair value hierarchy. As described in Note 14 “Warrants”, during 2019, the Company granted warrants to purchase 19,790 shares of common stock in connection with an amendment to its financing arrangement described in Note 10 “Debt”. These equity-classified warrants were valued using the Black-Scholes pricing model, which falls within Level 3 of the fair value hierarchy. The assumptions used in the Black-Scholes pricing model were as follows at the date of grant: Expected dividend yield 0.0 % Risk free interest rate 2.4 % Expected stock price volatility 60.9 % Expected term (years) 10.0

Accounts Receivable

Accounts Receivable	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Accounts Receivable	5. Accounts Receivable Accounts receivable consists of the following: December 31, 2019 2018 United States $ 5,574 $ 4,948 International 2,908 2,493 Total accounts receivable 8,482 7,441 Less: Allowance for doubtful accounts (239 ) (334 ) Accounts receivable, net of allowance for doubtful accounts $ 8,243 $ 7,107 No individual customers accounted for 10% or more of revenue or accounts receivable as of or for the years ended December 31, 2019 or 2018.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories	6. Inventories Inventories consist of the following: December 31, 2019 2018 Component parts $ 4,948 $ 5,601 Finished goods 4,189 8,109 $ 9,137 $ 13,710

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Property and Equipment	7. Property and Equipment Property and equipment are carried at cost less accumulated depreciation and amortization. A summary of the components of property and equipment is as follows: December 31, 2019 2018 Equipment $ 1,050 $ 924 Furniture 989 957 Manufacturing equipment 9,394 4,166 Software 718 655 Demonstration, placements and evaluation units 10,215 7,135 Leasehold improvements 2,085 2,025 Construction in process 612 4,663 Total property and equipment 25,063 20,525 Less: Accumulated depreciation and amortization (9,977 ) (7,109 ) Total property and equipment, net $ 15,086 $ 13,416 Depreciation of property and equipment was $3.0 million and $2.1 million during the years ended December 31, 2019 and 2018, respectively. Depreciation expense included in cost of revenue was $1.9 million and $1.2 million during the years ended December 31, 2019 and 2018, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	8. Goodwill and Intangible Assets The changes in the carrying amount of goodwill and intangible assets during 2019 are as follows: Goodwill Intangible Assets Balance at December 31, 2018 Acquired during the period $ 592 $ 455 Amortization - (95 ) Foreign currency exchange rate changes (4 ) (7 ) Balance at December 31, 2019 $ 588 $ 353 The following table presents a summary of acquired intangible assets: As of December 31, 2019 Period of amortization Gross Carrying Amount Accumulated Amortization Customer agreements 3.83 $ 448 $ (95 ) Total identifiable intangible assets $ 448 $ (95 ) The Company recognized $0.1 million of amortization expense within sales and marketing expenses related to the intangible assets during the year ended December 31, 2019. The Company did not recognize any amortization expense related to the intangible assets during the year ended December 31, 2018 as the assets were acquired as part of the acquisition of Solus in February 2019. The estimated amortization expense for intangible assets for future years is as follows: 2020 $ 118 2021 118 2022 117 Total $ 353

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	12 Months Ended
	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued Expenses and Other Liabilities	9. Accrued Expenses and Other Liabilities Accrued expenses and other liabilities consist of the following: December 31, 2019 2018 Accrued bonuses $ 3,071 $ 1,692 Accrued commissions 1,100 1,464 Accrued professional fees 1,092 305 Accrued taxes 983 305 Accrued inventory 620 1,070 Accrued vacation liability 490 427 Accrued employee-related costs 381 86 Deferred revenue 344 251 Product warranty reserve 225 329 Refundable purchase price of unvested stock 212 346 Accrued rent and restoration costs 208 174 Accrued capital equipment 135 21 Accrued employee reimbursement 102 178 Other 846 1,005 Total accrued expenses and other liabilities $ 9,809 $ 7,653

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	10. Debt Revolving Credit Line On November 16, 2016, the Company entered a Business Financing Agreement (the “Revolver Agreement”) with Western Alliance Bank, an Arizona Corporation, which replaced its then existing revolving line of credit. The Revolver Agreement made available $7.0 million of revolving credit upon the closing date. Availability under the Revolver Agreement is calculated based upon 80% of the eligible receivables (net of pre-paid deposits, pre-billed invoices, other offsets, and contras related to each specific account debtor). The original maturity date was September 30, 2018. The Company refinanced the Revolver Agreement in April 2018, increasing the credit line to $7.5 million and extending the maturity date to September 30, 2020. The principal is due upon maturity. On March 22, 2019, the Company entered into an amendment to the (as amended, the “Amended Revolver Agreement”), which increased the allowable permitted indebtedness under the Amended Revolver Agreement in connection with the Company’s credit card program from $0.3 million to $0.5 million. At December 31, 2019, the interest rate was 6.50%. The outstanding balance under the Amended Revolver Agreement was $3.5 million at December 31, 2019 and there was $0.8 million remaining availability based on eligible receivables. The outstanding balance under the Revolver Agreement Term Loans On November 16, 2016, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Solar Capital Ltd. (“Solar”). Pursuant to the Loan Agreement, a total of $20.0 million was available in three tranches. The first tranche was drawn down in the amount of $10.0 million upon closing which paid off the Company’s then existing term loan balance of $6.0 million in full. The Company achieved the minimum revenue threshold required to draw down the second tranche of $5.0 million of term debt financing and obtained a signed term sheet for an equity financing in excess of $10.0 million, which allowed the Company to draw down the third and final tranche of $5.0 million term debt financing. The Company drew down $5.0 million tranches in each of January 2017 and March 2017. On April 6, 2018, the Company entered into a Credit Agreement and Guaranty (the “Credit Agreement and Guaranty”) with Perceptive Credit Holdings II, LP (“Perceptive”). Pursuant to the Credit Agreement and Guaranty, a total of $42.5 million was available in three tranches. The first tranche was drawn down in the amount of $20.0 million on the closing date, April 6, 2018, which paid off the Loan Agreement in full. On July 20, 2018, pursuant to the Credit Agreement and Guaranty, the Company drew down the second tranche of $10.0 million. In connection with this draw down, the Company granted Perceptive warrants to purchase 18,846 shares of Series D preferred stock which were converted into warrants to purchase shares of common stock at the time of the initial public offering. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, are exercisable at the option of the holder, in whole or in part, and expire in July 2028. On September 27, 2018, the Company entered into the first amendment to the Credit Agreement and Guaranty (the “Amendment”, together with the Credit Agreement and Guaranty, the “Amended Credit Agreement and Guaranty”) with Perceptive. Pursuant to the Amended Credit Agreement and Guaranty, the Company was permitted to draw the final $12.5 million of availability at any time through March 31, 2019 and the minimum 2018 revenue requirement of $43.2 million that was required to draw down the final tranche was eliminated. Concurrently with the closing of the Amendment, the Company drew down $2.0 million of the remaining $12.5 million available. In connection with this draw down, the Company granted to Perceptive warrants to purchase 3,769 shares of its Series D preferred stock which were converted into warrants to purchase shares of common stock at the time of the initial public offering. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, are exercisable at the option of the holder, in whole or in part, and expire in September 2028. As of December 31, 2018, the Company had drawn $32.0 million of the $42.5 million available under the Credit Agreement and Guaranty, and on March 22, 2019, the Company drew the remaining $10.5 million. In connection with this draw down, the Company granted Perceptive warrants to purchase 19,790 shares of common stock. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, are exercisable at the option of the holder, in whole or in part, and expire in March 2029. The estimated fair value at the time of issuance was approximately $0.3 million, is recorded as a discount against the principal owed on the related debt, and is being amortized over the contractual term of the debt instrument. On March 22, 2019, the Company entered into a second amendment to the Amended Credit Agreement and Guaranty increasing the allowable permitted indebtedness in connection with the Company’s credit card program from $0.3 million to $0.5 million. Pursuant to the Amended Credit Agreement and Guaranty, the outstanding principal amount accrues interest at an annual rate equal to 9.06% plus the greater of (a) one-month LIBOR and (b) 1.75% per year. At December 31, 2019, the interest rate was 10.81%. The outstanding balance, including accretion of the additional final payment due upon maturity and described below, was $42.6 million at December 31, 2019 and there was no remaining availability. The Amended Credit Agreement and Guaranty is secured by substantially all of the Company’s personal property, including intellectual property. On the maturity date, in addition to the payment of principal and accrued interest, the Company will be required to make a payment of 0.5% of the total amount borrowed under the Amended Credit Agreement and Guaranty unless the Company has already made such a payment in connection with an acceleration or prepayment of borrowings under the agreement. In the event the Company prepays all or part of this term loan facility prior to the maturity date, the Company will be subject to additional prepayment fees which decrease as the time to maturity decreases. The Amended Credit Agreement and Guaranty requires the Company to comply with a minimum liquidity covenant at all times and a minimum revenue covenant measured at the end of each fiscal quarter. As of December 31, 2019, the Company was in compliance with all covenants. The annual principal maturities of the Company’s term loan as of December 31, 2019 are as follows: 2020 - 2021 - 2022 - 2023 $ 42,571 Less: Discount on loans payable (784 ) Long-term loans payable $ 41,787

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	11. Commitments and Contingencies In May 2016, the Company entered a lease agreement for 5,529 square feet of office space and 25,670 of storage space at 100 Domain Drive, Exeter New Hampshire. In September 2016, the Company entered into a new lease with its landlord for the space originally leased in May 2016 as well as an additional 16,550 of manufacturing space (including final assembly and inspection) and an additional 3,130 square feet of warehousing and storage space. In September 2017, the Company entered a first lease amendment with its landlord to add two additional expansion premises and extend the term of the lease. The first expansion premises consisted of an additional 16,823 rentable square feet of office space and 3,279 square feet of research and development space, for a total of 20,102 rentable square feet. The second expansion premises consisted of an additional 8,971 square feet of office space. In June 2018, the Company entered a second lease amendment with its landlord to add an additional 3,016 rentable square feet of general-purpose space. In July 2018, the Company entered a third lease amendment with its landlord to add an additional 1,172 rentable square feet of research and development space. In total the Company occupies 84,140 square feet of space at this facility. As amended, the lease will expire on January 28, 2025. The Company has the option to renew the lease for two additional five year terms by providing written notice twelve months prior to end of the initial or first lease extension term. In October 2019, the Company entered into an assignation and variation agreement for a lease of 453 square meters of office and warehouse space at 2 Dryden Loan, Bilston Glen Industrial Estate, Loanhead in the United Kingdom. The lease terminates on February 15, 2022. The following table summarizes the future minimum combined lease payments: Total Due Years Ended December 31, 2020 $ 1,621 2021 1,645 2022 1,630 2023 1,652 2024 1,679 Thereafter 140 Total $ 8,367 Rent expense for the years ended December 31, 2019 and 2018 was $2.0 million and $1.9 million, respectively. Legal Matters From time to time, the Company may become involved in various legal proceedings, including those that may arise in the ordinary course of business. The Company recently settled a litigation with Engineered Medical Systems, Inc., or EMS, a former supplier of a component of our Precision Flow systems. EMS filed a complaint against the Company in Indiana state court on June 12, 2018 alleging breach of contract and other causes of action and seeking damages of at least $0.8 million and all other forms of just and appropriate relief. This matter was subsequently removed to the United States District Court for the Southern District of Indiana. The Company filed a complaint against EMS in Superior Court in Rockingham County, New Hampshire on June 15, 2018 alleging breach of contract, violation of the New Hampshire Consumer Protection Act, and other causes of action and seeking damages of at least $2.1 million and all other forms of just and appropriate relief. Each party filed a motion to dismiss against the other party’s complaint. EMS’ motion to dismiss in Superior Court in Rockingham County, New Hampshire was denied. Following this decision, EMS withdrew its complaint in Indiana. The parties reached a settlement agreement on December 16, 2019 whereby EMS agreed to pay the Company $0.65 million in a series of monthly payments through December 2021, and the both the Company and EMS agreed to release each from any other outstanding claims, which included $0.5 million of accounts payable the Company had previously recorded. The Rockingham Superior Court approved the parties’ stipulation of dismissal with prejudice on January 2, 2020. As a result, the Company recorded a gain of $1.2 million in the consolidated statement of comprehensive loss during the fourth quarter of 2019. The Company believes there are no other litigation pending that could have, individually, or in the aggregate, a material adverse effect on the results of our operations or financial condition.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2019
Temporary Equity Disclosure [Abstract]
Redeemable Convertible Preferred Stock	12. Redeemable Convertible Preferred Stock Prior to the completion of the Company’s initial public offering in November 2018, the Company was authorized to issue Series A, Series B, Series C, and Series D preferred stock. On September 27, 2018, the Company entered into an equity financing agreement for Series D-1 preferred stock with its existing institutional investors whereby it offered to sell in the aggregate 714,285 shares of Series D-1 preferred stock for the purchase price of $15.92 per share in exchange for aggregate proceeds of $10.0 million. Pursuant to the initial public offering in November 2018, all outstanding redeemable convertible preferred stock converted to common stock on a one-to-one basis. In connection with certain of its redeemable convertible preferred stock issuances the Company had issued warrants for shares of its redeemable convertible preferred stock. Such warrants were recorded as liabilities as a result of non-standard anti-dilution rights and were carried at their estimated fair value using the Black-Scholes valuation model. Pursuant to the initial public offering in November 2018, these warrants converted to common stock warrants and were reclassified to stockholders’ equity.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity	13. Stockholders’ Equity Preferred Stock As of December 31, 2019 and 2018, the Company has authorized 25,000,000 shares of preferred stock, at a par value of $0.001. As of December 31, 2019 and 2018, there are no shares of preferred stock outstanding. Common Stock As of December 31, 2019 and 2018, the Company has authorized 175,000,000 shares of common stock. The Company has 20,851,531

Warrants

Warrants	12 Months Ended
	Dec. 31, 2019
Warrants And Rights Note Disclosure [Abstract]
Warrants	14. Warrants The table below sets forth the Company’s warrant activity for the year ended December 31, 2019: Common Stock Warrants Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2018 230,295 $ 14.50 Warrants granted 19,790 15.92 Warrants exercised (68,009 ) (14.00 ) Outstanding at December 31, 2019 182,076 $ 14.84 The Company has the following warrants outstanding at December 31, 2019: Dates of Expiration Exercise Price Number of Warrants Periods ranging from September 27, 2020 to July 28, 2025 $ 14.00 101,979 Periods ranging from April 6, 2028 through March 22, 2029 $ 15.92 80,097 Total Common Stock Warrants 182,076 On March 22, 2019, in connection with an amendment to the Credit Agreement and Guaranty as further described in Note 10 “Debt”, the Company granted warrants to purchase 19,790 shares of common stock. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, are exercisable at the option of the holder, in whole or in part, and expire in March 2029. The estimated fair value at the time of issuance was approximately $0.3 million, is recorded as a discount against the principal owed on the related debt, and is being amortized over the contractual term of the debt instrument. During 2019, warrants to purchase 68,009 shares of common stock were net exercised, which resulted in the issuance of 12,164 shares of common stock.

Disaggregated Revenue

Disaggregated Revenue	12 Months Ended
	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
Disaggregated Revenue	15. Disaggregated Revenue The following table shows the Company’s net revenue disaggregated into categories the Company considers meaningful to depict how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors: For the Year Ended December 31, 2019 US International Total Net revenue by: Product Revenue Capital $ 6,144 $ 3,180 $ 9,324 Disposable 27,753 7,302 35,055 Subtotal Product Revenue 33,897 10,482 44,379 Lease Revenue 1,721 - 1,721 Service Revenue 965 1,039 2,004 Total Revenue $ 36,583 $ 11,521 $ 48,104 For the Year Ended December 31, 2018 US International Total Net revenue by: Product Revenue Capital $ 7,293 $ 3,487 $ 10,780 Disposable 23,024 5,429 28,453 Subtotal Product Revenue 30,317 8,916 39,233 Lease Revenue 1,334 - 1,334 Service Revenue 1,359 451 1,810 Total Revenue $ 33,010 $ 9,367 $ 42,377 Net revenue by U.S. and International is based on the customer location to which the product is shipped. No

Stock Plans and Stock-Based Com

Stock Plans and Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Plans and Stock-Based Compensation	16. Stock Plans and Stock-Based Compensation The Company’s 2005 Stock Incentive Plan (the “2005 SI Plan”) allowed for the granting of restricted stock and incentive and non-statutory stock options to purchase shares of common stock. On July 22, 2015, the Company established the Company’s 2015 Stock Incentive Plan (the “2015 SI Plan”) which allowed for the granting of restricted stock and incentive and non-statutory stock options to purchase shares of common stock. The 2015 SI Plan reserved 1,413,749 shares plus any shares available for grant under the Company’s 2005 SI Plan for issuance under the plan. On July 18, 2018, the Company established a French Qualifying Subplan that sits underneath the 2015 SI Plan which allows for the granting of stock options to purchase shares of common stock for employees and officers who are residents of France. The options under the French Qualifying Subplan reside under the umbrella of the 2015 SI Plan. On October 17, 2018, the Company established the Company’s 2018 Stock Incentive Plan (the “2018 SI Plan”) which allows for the granting of restricted stock and incentive and non-statutory stock options to purchase shares of common stock. The 2018 SI Plan reserved 998,900 shares plus any shares available for grant under the Company’s 2015 SI Plan for issuance under the plan. As of December 31, 2018, the Company has reserved 3,279,682 shares of its common stock for issuance collectively under the 2000 LTI Plan, 2005 SI Plan, 2015 SI Plan and the 2018 SI Plan to eligible employees, officers, directors, advisors, and consultants. On January 23, 2019, the Company established a French Qualifying Subplan which allows for the granting of stock options to purchase shares of common stock for employees and officers who are residents of France. The options under the French Qualifying Subplan reside under the umbrella of the 2018 Stock Incentive Plan. As of December 31, 2018 and 2019, no shares of common stock remain available for issuance under the 2000 LTI Plan, the 2005 SI Plan or the 2015 SI Plan. As of December 31, 2019, 834,423 shares of common stock remain available for issuance under the 2018 SI Plan. Under the terms of the 2018 SI Plan, the exercise price of the options is determined by the Board of Directors at the time of grant. Options granted under the plans vest ratably over a period of one to four years from the date of grant and are exercisable over a period of not more than ten years from the date of grant. Stock Options Stock option activity for the year ended December 31, 2019 is as follows: Weighted Number of Weighted Average Underlying Average Remaining Aggregate Common Exercise Contractual Intrinsic Shares Price Term Value Outstanding at December 31, 2018 786,989 $ 2.41 7.87 $ 13,801 Options granted 969,646 16.61 Options exercised (150,176 ) 1.62 Options canceled (576,311 ) 15.10 Outstanding at December 31, 2019 1,030,148 $ 8.91 8.18 $ 5,544 Exercisable at December 31, 2019 407,120 $ 2.37 6.90 $ 4,025 Vested and unvested expected to vest at December 31, 2019 1,030,148 $ 8.91 8.18 $ 5,544 The weighted average grant date fair value of options granted during the years ended December 31, 2019 and 2018 was $9.20 and $3.26 per share, respectively. The aggregate intrinsic value of options exercised during the year ended December 31, 2019 was $2.3 million. As of December 31, 2019, the Company had unrecognized stock-based compensation expense related to its unvested stock options awards of $2.9 million, which is expected to be recognized over the remaining weighted average vesting period of 2.7 years. Certain members of the Company’s management elected to receive their option grants in the form of restricted stock, which contains vesting provisions. Upon election of restricted stock, the Company records a liability for the unvested portion of the grant. As the restricted stock vests, the Company reclassifies the liability into additional paid-in capital. During the first quarter of 2019, the Company modified certain previously granted performance awards where the performance condition had not been met. The modification resulted in the granting of 68,526 shares of restricted stock for which 25% was immediately vested with the remaining portion vesting over 36 months. During 2016, the Company permitted the exercise of 79,865 stock options via nonrecourse notes. There were no exercises of stock options via nonrecourse notes in fiscal year 2018 or 2019. The nonrecourse notes were fully paid during 2019 and the related shares were issued. The weighted average assumptions used in the Black-Scholes options pricing model are as follows: Year Ended December 31, 2019 2018 Expected dividend yield 0.0 % 0.0 % Risk free interest rate 1.9 % 2.6 % Expected stock price volatility 64.5 % 54.4 % Expected term (years) 6.2 6.1 The Company assumed an average forfeiture rates of 6.73% and 8.32% for the year ended December 31, 2019 and 2018, respectively, based on historical experience with pre-vested forfeitures. A summary of restricted stock activity for the year ended December 31, 2019 is as follows: Weighted Average Grant Date Shares Fair Value Unvested at December 31, 2018 399,485 $ 1.68 Granted/purchased 86,170 15.52 Vested (255,742 ) 4.46 Canceled - - Unvested at December 31, 2019 229,913 $ 3.76 Stock-based compensation expense was allocated based on the employees’ and non-employees’ functions as follows: Year Ended December 31, 2019 2018 Cost of revenue $ 187 $ 27 Research and development 405 119 Sales and marketing 782 146 General and administrative 2,462 210 Total $ 3,836 $ 502

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	17. Income Taxes Net loss before income taxes is as follows: Year Ended December 31, 2019 2018 United States $ (50,343 ) $ (42,468 ) United Kingdom (862 ) - $ (51,205 ) $ (42,468 ) The Company recorded a tax benefit of approximately $0.1 million, related to foreign net deferred income tax assets deemed more likely than not to be realized in the United Kingdom. There were no current foreign income taxes due to foreign net losses during the year ended December 31, 2019. Because the Company has historically incurred operating losses and maintains a full valuation allowance against its United States net deferred tax assets, no tax benefit or provision was recorded on its United States results in either the year ended December 31, 2019 or 2018. The reported amount of income tax benefit for both 2019 and 2018 differs from the amount that would result from applying domestic federal statutory tax rates to pretax losses primarily because of changes in the valuation allowance. There was no provision or benefit for income taxes recorded during the year ended December 31, 2018. A reconciliation of income tax expense is computed as the statutory federal income tax rate to income taxes as reflected in the financial statement as follows: Year Ended December 31, 2019 2018 Federal income tax benefit at statutory rate (21.0 %) (21.0 %) Permanent differences (6.7 %) 2.6 % Change in valuation allowance 26.9 % 21.0 % Other 0.5 % (2.6 %) Income tax expense (0.3 %) 0.0 % Significant components of the Company’s net deferred tax assets are as follows: December 31, 2019 2018 Deferred Tax Assets Net operating loss carryforwards $ 51,303 $ 42,444 Deduction of research and development costs 5,985 4,239 Tax credit carryforwards 4,109 3,012 Accrued expenses 1,976 1,184 Stock option expense attributed to non-ISO stock 1,098 358 Accrued bonus and vacation 703 579 Inventory valuation reserves 280 154 Deferred revenue 230 - Accounts receivable allowance 63 70 Accrued warranty 61 86 Allowance for sales returns - 18 Other temporary differences 492 - Gross deferred tax assets 66,300 52,144 Less: Valuation allowance (65,515 ) (51,708 ) Deferred tax assets after valuation allowance 785 436 Deferred Tax Liabilities Depreciation (593 ) (366 ) Intangible assets (68 ) - Other temporary differences (58 ) (70 ) Gross deferred tax liabilities (719 ) (436 ) Net Deferred Tax Assets $ 66 $ - The Company’s major tax jurisdictions are the United States, New Hampshire and the United Kingdom. As of December 31, 2019, the Company had federal and state net operating loss carryforwards of $218.9 million and $89.7 million, respectively, which begin to expire in 2020. Federal net operating loss carryforwards generated during or after the year ended December 31, 2018 will carryforward indefinitely. As of December 31, 2019, the Company had federal research and development tax credits carryforwards of $3.9 million which begin to expire in 2021. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets generated from our UK subsidiary, which are comprised principally of net operating loss carryforwards. Under the applicable accounting standards management has concluded that the Company will realize the benefit of the subsidiary’s deferred tax asset. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its domestic deferred tax assets, which are comprised principally of net operating loss carryforwards and research and development credits. Under the applicable accounting standards, management has considered the Company’s history of losses and concluded that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets. Accordingly, a valuation allowance of $65.5 million and $51.7 million has been established at December 31, 2019 and 2018, respectively. The valuation allowance increased $13.8 million during the year ended December 31, 2019, due primarily to net operating losses generated. Years prior to 2016 are generally closed due to statute of limitations for purposes of taxing jurisdictions assessing additional tax; however, the tax attributes, including net operating losses and research credits, from such years can still be reviewed and reduced upon audit. Years beginning in 2016 remain open to examination for both federal and state purposes. The Company accounts for uncertain tax positions pursuant to ASC 740, Income Taxes, which prescribes a recognition threshold and measurement process for financial statement recognition of uncertain tax positions taken or expected to be taken in a tax return. If the tax position meets this threshold, the benefit to be recognized is measured as the tax benefit having the highest likelihood of being realized upon ultimate settlement with the taxing authority. The Company recognizes interest accrued related to unrecognized tax benefits and penalties in the provision for income taxes. Management is not aware of any uncertain tax positions. As of December 31, 2019, and 2018, the Company determined that there were no liabilities associated with uncertain tax positions and no related interest and penalties. The Company’s policy is to recognize interest and penalties related to income tax matters as a component of income taxes, when and if incurred. Utilization of the net operating loss and tax credit carryforwards may be subject to a substantial annual limitation under Section 382 and 383 of the Internal Revenue Code of 1986 due to ownership change limitations that have occurred previously or that could occur in the future. These ownership changes may limit the amount of net operating loss and tax credit carryforwards that can be utilized to offset future taxable income and tax, respectively. The Company has not currently completed an evaluation of ownership changes through December 31, 2019 or 2018 to assess whether utilization of the Company’s net operating loss and tax credit carryforwards would be subject to an annual limitation under Section 382 and 383. To the extent an ownership change is determined to have occurred under IRC 382 and 383, the net operating loss and credit carryforwards may be subject to limitation. On December 22, 2017, the Tax Cuts and Jobs Act (the “TCJA”) was signed into United States law. The TCJA includes a number of changes to existing tax law, including, among other things, a permanent reduction in the federal corporate income tax rate from 34% to 21%, effective as of January 1, 2018, as well as limitation of the deduction for net operating losses to 80% of annual taxable income and elimination of net operating loss carrybacks, in each case, for losses arising in taxable years beginning after December 31, 2017 (though any such net operating losses may be carried forward indefinitely). The tax rate change resulted in (i) a reduction in the gross amount of the Company’s deferred tax assets recorded as of December 31, 2017, without an impact on the net amount of its deferred tax assets, which are recorded with a full valuation allowance, and (ii) no income tax expense or benefit being recognized as of the enactment date of the TCJA. The staff of the SEC issued Staff Accounting Bulletin No. 118 to address the application of accounting principles generally accepted in the United States in situations when a registrant does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the TCJA. In connection with the analysis of the impact of the TCJA, the Company remeasured its deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21% for federal tax purposes. The remeasurement of the Company’s deferred tax assets and liabilities was offset by a change in the valuation allowance. The Company finalized the accounting in 2018 which did not result in any adjustments.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	18. Net Loss Per Share The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Year Ended December 31, 2019 2018 Options to purchase common stock 1,030,148 786,989 Warrants to purchase common stock 182,076 230,295 Unvested restricted stock 229,913 399,485 1,442,137 1,416,769

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	19. Related Party Transactions As described in Note 12, “Redeemable Convertible Preferred Stock”, the Company issued Series A, B, C and D preferred stock to private investors. Certain executive officers of the Company are owners/investors in certain venture funds who purchased Series A, B, C and D preferred stock. The total amount of preferred stock purchased by related party organizations as of November 16, 2018 was $33.2 million. In connection with the Company’s public offering in November 2018, all outstanding redeemable convertible preferred stock converted to common stock on a one-to-one basis. The Company has two investors that are vendors of the Company. The total amount billed from these vendors during the year was less than $0.1 million and $1.2 million in 2019 and 2018, respectively. The accounts payable balance for these vendors was $0.5 million as of December 31, 2018, and there was no outstanding balances for these vendors at December 31, 2019. In addition, the Company sells its products to a hospital customer who is an affiliate of a current stockholder. The total amount billed to this customer during the year was $1.4 million and $2.2 million in 2019 and 2018, respectively. The accounts receivable balance for this customer was $0.2 million and $0.1 million as of December 31, 2019 and 2018, respectively. All transactions are at arms’ length and occur at published list prices.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	20. Employee Benefit Plan The Company has a 401(k) retirement plan (the “401(k) Plan”) for the benefit of eligible employees, as defined. Each participant may elect to contribute up to 100% of his or her compensation to the 401(k) Plan each year, subject to certain Internal Revenue Service limitations. The Company matches employee contributions at a rate of 50% of the first 4% of employee contributions. The employer match is capped at $1,000 per year for employees with annual earnings less than $50,000 and $500 per year for employees with annual earnings greater than $50,000. The Company contributed $0.1 million in both the years ended December 31, 2019 and 2018.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial data (Unaudited)	21. Selected Quarterly Financial Data (Unaudited) The following table sets forth our unaudited quarterly operating results for each of the Company’s quarters in the years ended December 31, 2019 and 2018. In the opinion of management, the quarterly financial information reflects all necessary adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of this data. 2019 Quarters 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Year Revenue $ 12,299 $ 11,986 $ 10,809 $ 13,010 $ 48,104 Cost of revenue 7,120 6,527 5,999 7,147 26,793 Gross profit 5,179 5,459 4,810 5,863 21,311 Operating expenses: Research and development 3,273 3,167 3,280 3,656 13,376 Sales and marketing 9,161 9,432 9,193 9,903 37,689 General and administrative 4,879 4,532 3,978 5,021 18,410 Total operating expenses 17,313 17,131 16,451 18,580 69,475 Loss from operations (12,134 ) (11,672 ) (11,641 ) (12,717 ) (48,164 ) Other expenses, net (830 ) (1,208 ) (1,124 ) 121 (3,041 ) Net loss before income taxes (12,964 ) (12,880 ) (12,765 ) (12,596 ) (51,205 ) Benefit for income taxes - - - (146 ) (146 ) Net loss $ (12,964 ) $ (12,880 ) $ (12,765 ) $ (12,450 ) $ (51,059 ) 2018 Quarters 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Year Revenue $ 10,739 $ 10,563 $ 9,389 $ 11,686 $ 42,377 Cost of revenue 6,494 6,469 5,774 6,868 25,605 Gross profit 4,245 4,094 3,615 4,818 16,772 Operating expenses: Research and development 2,225 2,081 1,768 2,697 8,771 Sales and marketing 8,051 8,525 7,755 9,596 33,927 General and administrative 2,382 2,603 2,804 3,397 11,186 Loss on disposal of fixed assets 3 39 17 62 121 Total operating expenses 12,661 13,248 12,344 15,752 54,005 Loss from operations (8,416 ) (9,154 ) (8,729 ) (10,934 ) (37,233 ) Other expense, net (489 ) (2,073 ) (730 ) (1,943 ) (5,235 ) Net loss $ (8,905 ) $ (11,227 ) $ (9,459 ) $ (12,877 ) $ (42,468 )

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”).
Principles of Consolidation	Principles of Consolidation These consolidated financial statements include the financial statements of Solus Medical Ltd. (“Solus”), a wholly owned subsidiary of the Company based in the United Kingdom, which was acquired in the first quarter of 2019. All intercompany accounts and transactions have been eliminated upon consolidation.
Segment Information	Segment Information Operating segments are defined as components of an enterprise for which separate discrete financial information is available and evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company globally manages the business within one reporting segment, Vapotherm, Inc. and two reporting units, Vapotherm and Solus. Segment information is consistent with how management reviews the business, makes investing and resource allocation decisions and assesses operating performance. The majority of the Company’s long-term assets are located in the United States. Long-term assets located outside the United States total $0.1 million at December 31, 2019.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires the Company to make judgments, assumptions, and estimates that affect the reported amounts of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and liabilities. The Company evaluates its estimates on an ongoing basis. The Company bases its estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Significant estimates relied upon in preparing these consolidated financial statements include calculation of stock-based compensation, valuation of warrants, fair values of acquired assets and liabilities, including goodwill and intangibles assets, realizability of inventories, allowance for bad debt, accrued expenses and the valuation allowances against deferred income tax assets. Actual results may differ from these estimates.
Concentrations of Credit Risk	Concentrations of Credit Risk As of December 31, 2019 and 2018, the Company’s financial instruments were comprised of cash and cash equivalents, restricted cash, accounts receivable, accounts payable and debt, the carrying amounts of which approximated fair value due to the short-term nature and market interest rates. All of the Company’s cash and cash equivalents are maintained at creditworthy financial institutions. At December 31, 2019 and 2018, deposits exceed the amount of any insurance provided. The Company extends credit to customers in the normal course of business but does not require collateral or any other security to support amounts due. Management performs ongoing credit evaluations of its customers. An allowance for potentially uncollectible accounts is provided based on history, economic conditions, and composition of the accounts receivable aging. In some cases, the Company makes allowances for specific customers based on these and other factors. Provisions for the allowance for doubtful accounts are recorded in general and administrative expenses in the accompanying consolidated statements of comprehensive loss.
Supplier Risk	Supplier Risk The Company obtains some of the components and subassemblies included in its Precision Flow systems from single source suppliers and the partial or complete loss of one or more of these suppliers could cause significant production delays, an inability to meet customer demand and a substantial loss in revenue.
Foreign Currency and Foreign Operations	Foreign Currency and Foreign Operations The functional currency of the Company is the currency of the primary economic environment in which the entity operates, which is the U.S. dollar. For our non-U.S. subsidiary that transacts in a functional currency other than the U.S. dollar, assets and liabilities are translated at current rates of exchange at the balance sheet date. Income and expense items are translated at the average foreign currency exchange rates for the period. Adjustments resulting from the translation of the financial statements of its foreign operations into U.S. dollars are excluded from the determination of net loss and are recorded in accumulated other comprehensive income, a separate component of stockholders’ equity. There were no assets or liabilities of foreign subsidiaries that were translated at period-end exchange rates as of December 31, 2018. See Note 3 “Business Combinations” to these consolidated financial statements for details of the Solus acquisition. The f unctional currency of Solus is its local currency, Pound Sterling (GBP). Realized foreign currency gains or losses arising from transactions denominated in foreign currencies are recorded in other (expense) income in the consolidated statements of comprehensive loss.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid temporary investments purchased with original maturities of 90 days or less to be cash equivalents. The Company holds restricted cash related to certificates of deposits and collateral in relation to lease agreements. As of December 31, 2019, $0.3 million of our $73.5 million of cash, cash equivalents and restricted cash balance was located outside the U.S. The following table presents the components of total cash, cash equivalents, and restricted cash as set forth in the Company’s consolidated statements of cash flows: December 31, 2019 2018 Cash and cash equivalents $ 71,655 $ 58,223 Restricted cash 1,852 1,799 Total cash, cash equivalents, and restricted cash $ 73,507 $ 60,022
Inventories	Inventories Inventories consist of finished goods and component parts and are valued at the lower of cost or net realizable value, determined by the first-in, first-out (“FIFO”) method. On a quarterly basis, the Company evaluates the carrying costs of both finished goods and component part items. To the extent that such costs exceed future demand estimates, exhibit historical turnover at rates less than current inventory levels, or exceed estimated selling prices less costs to sell, the Company reduces the carrying value of inventories to its net realizable value. The Company only capitalizes pre-launch inventories when purchased for commercial sale and it deems regulatory approval to be probable.
Public Offering Costs	Public Offering Costs The Company incurs public offering costs consisting of legal, accounting and other costs directly attributable to the Company’s public offerings and defers such costs until the closing of the offerings. Upon closing of offerings, such costs are netted against the proceeds received. As of December 31, 2019 and 2018, no amounts were deferred.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost. Depreciation is recognized over the estimated useful lives of the related assets on a straight-line basis. Amortization of leasehold improvements is computed on a straight-line basis over the shorter of the remaining lease term or the estimated useful lives of the improvements and is included in depreciation expense. Demonstration equipment represents internally manufactured capital equipment that is used on-site at trade shows and at customer locations to demonstrate the Precision Flow system. Depreciation expense on demonstration equipment is recorded in sales and marketing expense in the consolidated statements of comprehensive loss. Placement and evaluation systems represent capital equipment placed at customer locations under placement or evaluation agreements for which depreciation expense is included in cost of revenue in the accompanying consolidated statements of comprehensive loss. When impairment indicators are present, the Company evaluates the recoverability of its long-lived assets. If the assessment indicates an impairment, the affected assets are written down to fair value. There were no impairments during 2019 or 2018. Repairs and maintenance are expensed as incurred. Expenditures that increase the value or productive capacity of assets are capitalized. When property and equipment are retired, sold, or otherwise disposed of, the asset’s carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in operating expenses. The lives used in computing straight-line depreciation are as follows: Number of Years Equipment 3 - 7 Furniture 5 - 7 Manufacturing equipment 3 - 10 Software 3 Demonstration, placements and evaluation units 3 - 5 Leasehold improvements Lesser of life of lease or 10 years The Company’s policy is to periodically review the estimated useful life of all property and equipment. This review during fiscal year 2019 indicated that the estimated useful life of all property and equipment is consistent with fiscal year 2018, with the exception of certain manufacturing equipment placed in service in 2019, for which the maximum useful life increased from 7 years to 10 years. Property and equipment are evaluated for impairment whenever events or circumstances indicate an asset may be impaired. There were no impairments during 2019 or 2018.
Intangible Assets	Intangible Assets Intangible assets related to customer agreements are amortized on a straight-line basis over their useful lives. Amortization is recorded within sales and marketing expenses in the consolidated statements of comprehensive loss. Intangible assets are evaluated for impairment whenever events or circumstances indicate an asset may be impaired. There were no impairments of intangible assets during 2019, and the Company had no intangible assets during 2018.
Goodwill	Goodwill Goodwill represents the difference between the purchase price and the fair value of the identifiable tangible and intangible net assets when accounted for using the purchase method of accounting. Goodwill is not amortized but reviewed for impairment. Goodwill is reviewed annually, as of October 1, and whenever events or changes in circumstances indicate that the carrying value of the goodwill may not be recoverable. The Company compares the fair value of our reporting units to their carrying values. If the carrying value of the net assets assigned to a reporting unit exceeds the fair value of the reporting unit, the Company would record an impairment loss equal to the difference. There was no impairment of goodwill during 2019, and the Company had no goodwill during 2018.
Leases and Deferred Rent	Leases & Deferred Rent Leases are classified at their inception as either operating or capital leases based on the economic substance of the agreement. Lease payments made under operating leases are recognized as an expense on a straight-line basis over the lease term. Any differences between the lease payments and the expense recognized on a straight-line basis is recorded as deferred rent. Deferred rent is recorded in accrued expenses and other liabilities in the consolidated balance sheets. Deferred rent totaled $0.2 million at both December 31, 2019 and 2018.
Product Warranty	Product Warranty The Company provides its customers with a standard one-year warranty on its capital equipment sales. Warranty costs are accrued based on actual historical trends and estimated at time of sale. The warranty liability is included within accrued expenses and other liabilities in the consolidated balance sheets. A roll-forward of the Company’s warranty liability is as follows: Balance at December 31, 2017 $ 317 Provisions for warranty obligations 355 Settlements (343 ) Balance at December 31, 2018 329 Provisions for warranty obligations 125 Settlements (229 ) Balance at December 31, 2019 $ 225
Deferred Financing Costs	Deferred Financing Costs Direct financing costs are deferred and amortized as a component of interest expense, over the term of the related debt. The balance of unamortized costs is presented as a reduction of the related borrowing arrangement liability. Unamortized costs totaled $0.8 million and $0.7 million at December 31, 2019 and 2018, respectively.
Revenue Recognition	Revenue Recognition The Company’s revenue consists primarily of the sale of products, leases and services. Product revenue consists of capital equipment and single-use disposables that are shipped and billed to customers both domestically and internationally. The Company’s main capital equipment products are the Precision Flow Hi-VNI, Precision Flow Plus, Precision Flow Classic, Vapotherm Transfer Unit 2.0 and Q50 compressor. The Company’s main disposable products are single-use disposables and nasal interfaces, or cannulas, and adaptors. Lease revenue consists of capital equipment that the Company leases out to its customers. Service revenue consists of fees associated with routine service of capital units and the sale of extended service contracts and preventative maintenance plans, which are purchased by a small portion of the Company’s customer base. In addition, the Company sells small quantities of component parts in the United States, United Kingdom and to third-party international service centers who provide service on Precision Flow capital units outside of the United States. Freight revenue is based upon actual freight costs plus a percentage markup of such costs associated with the shipment of products domestically, and to a lesser extent, internationally, and is included in service revenue. Rebates and fees consist of contractually obligated administrative fees and percentage-of-sales rebates paid to Group Purchasing Organizations (“GPOs”), Integrated Delivery Networks (“IDNs”) and distributor partners and accounted for as a reduction of service revenue. Under Financial Accounting Standard Board (“FASB”) Accounting Standards Codifications (“ASC”) 606, Revenue from Contracts with Customers (“ASC 606”), revenue is recognized when a customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company 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 ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize 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 the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and assesses whether each promised good or service is distinct and determines those that are performance obligations. 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. Sales, value-added, and other taxes collected on behalf of third parties are excluded from revenue. The Company’s standard payment term is generally 30 days from date of sale. Contracts with customers may contain multiple performance obligations. For such arrangements, the transaction price is allocated to each performance obligation based on the estimated relative stand-alone selling prices of the promised products or services underlying each performance obligation. The Company determines stand-alone selling prices based on the price at which the performance obligation is sold separately. If the stand-alone selling price is not observable through past transactions, the Company estimates the stand-alone selling price taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. 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. Applying the practical expedient in paragraph 606-10-32-18, the Company does not assess whether a significant financing component exists if the period between when the Company performs its obligations under the contract and when the customer pays is one year or less. None of the Company’s contracts contained a significant financing component during the years ended December 31, 2019 or 2018. The Company’s contracts with its customers have a duration of less than one year. Therefore, the Company has elected to apply the practical expedient in paragraph ASC 340-40-25-4 and recognizes the incremental costs of obtaining contracts as an expense. These costs are included in sales and marketing expense in the accompanying consolidated statements of comprehensive loss.
Lease Revenue	Lease Revenue The Company also enters into agreements to lease its capital equipment. For such sales, the Company accounts for revenue under ASC 840, Leases, and assesses and classifies these transactions as sales-type or operating leases based on whether the lease transfers ownership of the equipment to the lessee by the end of the lease term. This criterion is met in situations in which the lease agreement provides for the transfer of title at or shortly after the end of the lease term in exchange for the payment of a nominal fee, for example, the minimum required by statutory regulation to transfer title. Equipment included in arrangements including transfer of title are accounted for as sales-type leases and the Company recognizes the total value of the lease payments due over the lease term to revenue at the inception of the lease. The Company records the current value of future lease payments under prepaid expenses and other current assets in the accompanying consolidated balance sheets and these amounts totaled $0.9 million at both December 31, 2019 and 2018. Equipment included in arrangements that do not include the transfer of title, nor any of the capital lease criteria, are accounted for as operating leases and revenue is recognized on a straight-line basis as it becomes receivable monthly over the term of the lease.
Shipping and Handling Costs	Shipping and Handling Costs Amounts billed to customers for shipping and handling are included in service revenue. Shipping and handling costs are included in costs of sales. The total costs of shipping and handling at both December 31, 2019 and 2018 amounted to $1.0 million.
Sales and Value Added Taxes	Sales and Value-Added Taxes When required by local jurisdictions, the Company bills its customers for sales tax and value-added tax calculated on each sales invoice and records a liability for the sales and value-added tax payable, which is included in accrued expenses and other liabilities in the consolidated balance sheets. Sales tax and value-added tax billed to a customer is not included in the Company’s revenue.
Timing and Amount of Revenue Recognition	Timing and Amount of Revenue Recognition The Company recognizes revenue on product sales and service of its capital equipment and product sales of disposables to its end users. In each instance, revenue is generally recognized when the customer obtains control of the Company’s product, which generally occurs at a point in time upon shipment based on the contractual shipping terms of a contract. Product and service 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 amount method to which the Company expects to be entitled. As such, revenue on sales are recorded net of prompt pay discounts and payments made to GPOs, IDNs and distributors. 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. 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. The Company believes that the estimates it has established are reasonable based upon current facts and circumstances. Applying different judgments to the same facts and circumstances could result in the estimated amounts to vary.
Product Returns	Product Returns The Company provides its customers with the right to return products for a refund of the purchase price or for an account credit, if the return is made within a specified number of days from the original invoice date. The Company records a product return liability based upon an estimate of specific returns and a review of historical returns experienced. Adjustments are made to the product return liability as returns data and historical experience change. The provision for product return estimates is recorded as a reduction of revenue. The product return liability totaled less than $0.1 million at both December 31, 2019 and 2018 and is included in other current liabilities in the accompany consolidated balance sheets.
Research and Development Costs	Research and Development Costs Research and development costs are expensed when incurred and are related primarily to product design, prototype development and testing, the investigation of possible follow-on product enhancements and new product releases, and investigation of complementary technologies potentially available to enhance the Company’s offerings in the marketplace.
Stock-Based Compensation	Stock-Based Compensation The Company maintains an equity incentive plan to provide long-term incentives for employees, consultants, and members of the board of directors. The plan allows for the issuance of non-statutory and incentive stock options to employees and non-statutory stock options to consultants and non-employee directors. The Company recognizes stock-based compensation expense for awards of equity instruments to employees and non-employees based on the grant date fair value of those awards in accordance with ASC Topic 718, Stock Compensation (ASC 718). ASC 718 requires all equity-based compensation awards, including grants of restricted shares and stock options, to be recognized as expense in the statements of comprehensive loss based on their grant date fair values. The fair value of each option grant is estimated on the grant date using the Black-Scholes option pricing model. The fair value is then amortized on a straight-line basis over the requisite service period of the awards, which is generally the vesting period. For performance-based awards, the related compensation cost is amortized over the performance period on an accelerated attribution basis. Compensation cost associated with performance awards is based on fair value on the date of grant and the number of units expected to be earned after assessing the probability that certain performance criteria will be met and the associated targeted payout level that is forecasted will be achieved, net of expected forfeitures. Cumulative adjustments are recorded each quarter to reflect estimated outcomes of the performance-related conditions until the results are determined and settled. Use of a valuation model requires management to make certain assumptions with respect to selected model inputs, including the expected life (weighted average period of time that the options granted are expected to be outstanding), the volatility of the Company’s common stock and an assumed risk-free interest rate. Expected volatility is calculated based on historical volatility of a group of publicly traded companies that the Company considers a peer group. The expected life is estimated using the simplified method for “plain vanilla” options. The risk-free interest rate is based on U.S. Treasury rates with a remaining term that approximates the expected life assumed at the date of grant. No dividend yield is assumed as the Company does not pay, and does not expect to pay, dividends on its common stock. Company estimates forfeitures based on historical experience with pre-vested forfeitures. To the extent actual forfeitures differ from the estimate, the difference is recorded to compensation expense in the period of the forfeiture.
Net Income (Loss) per Share	Net Income (Loss) per Share The Company had followed the two-class method when computing net income (loss) per share as the Company had issued shares that met the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common shareholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net income (loss) per share attributable to common shareholders is computed by dividing the net income (loss) attributable to common shareholders by the weighted average number of common shares outstanding for the period. Diluted net income (loss) attributable to common shareholders is computed by adjusting net income (loss) attributable to common shareholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common shareholders is computed by dividing the diluted net income (loss) attributable to common shareholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares. For purpose of this calculation, outstanding options, unvested restricted common shares and convertible preferred shares are considered potential dilutive common shares. The Company’s convertible preferred shares contractually entitled the holders of such shares to participate in dividends but did not contractually require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reported a net loss attributable to common shareholders, such losses were not allocated to such participating securities. In periods in which the Company reported a net loss attributable to common shareholders, diluted net loss per share attributable to common shareholders was the same as basic net loss per share attributable to common shareholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss attributable to common shareholders for the years ended December 31, 2019 and 2018. On November 16, 2018, the Company completed an initial public offering. All preferred stock outstanding as of the initial public offering As a result, the Company no longer had any participating securities outstanding subsequent to November 16, 2018.
Freestanding Preferred Stock Warrants	Freestanding Preferred Stock Warrants Warrants to purchase the Company’s preferred stock were previously classified as a liability on the consolidated balance sheets. These warrants were subject to remeasurement at each balance sheet date and any change in fair value was recognized as a gain or loss on change in fair value of the warrant liabilities. Pursuant to the Company’s initial public offering in November 2018, all preferred stock warrants automatically converted into warrants to purchase common stock, were reclassified to stockholders’ equity, and were no longer required to be marked to market.
Stock Split	Stock Split On November 2, 2018, the Company’s Board of Directors and stockholders approved a 14:1 reverse stock split. The effect of this event has been reflected in all of the share quantities and per share amounts throughout these financial statements. The shares of common stock retained a par value of $0.001.
Income Tax	Income Tax The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the consolidated financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the consolidated financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Statement of Cash Flows (Topic 230): Restricted Cash In November 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”). ASU 2016-18 amends Accounting Standards Codification to add or clarify guidance on the classification and presentation of restricted cash in the statement of cash flows. The new standard requires cash and cash equivalents balances on the statement of cash flows to include restricted cash and cash equivalent balances. ASU 2016-18 requires the Company to provide appropriate disclosures about its accounting policies pertaining to restricted cash in accordance with U.S. GAAP. Additionally, changes in restricted cash and restricted cash equivalents that result from transfers between cash, cash equivalents, and restricted cash and restricted cash equivalents should not be presented as cash flow activities in the statement of cash flows. A company with a material balance of amounts generally described as restricted cash and restricted cash equivalents must disclose information about the nature of the restrictions. The new standard is effective for interim and annual periods beginning after December 15, 2018. The Company had not previously included restricted cash as a component of cash and cash equivalents as presented on its consolidated statements of cash flows. The Company adopted the new standard in the first quarter of fiscal 2019, under the retrospective adoption method, and the prior year restricted cash presentation has been reclassified to conform to current year presentation. Clarifying the Definition of a Business (Topic 805): In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business (Topic 805) Revenue from Contracts with Customers Compensation - Stock Compensation (Topic 718): In June 2018, the FASB issued ASU 2018-07, Stock-based Compensation: Improvements to Nonemployee Share-based Payment Accounting (“ASU 2018-07”). This guidance amends the existing accounting standards for share-based payments to nonemployees and aligns much of the guidance on measuring and classifying nonemployee awards with that of awards to employees. Under the new guidance, the measurement of nonemployee equity awards is fixed on the grant data. The Company adopted ASU 2018-07 on January 1, 2019 and the adoption had no impact to our consolidated financial statements as there were no share-based awards to non-employees outstanding at that time. Recently Issued Accounting Pronouncements Leases (Topic 842): In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 establishes a comprehensive new lease accounting model. The new standard clarifies the definitions of a lease, requires a dual approach to lease classification similar to current lease classifications, and causes lessees to recognize leases on the balance sheet as a lease liability with a corresponding right-of-use asset for leases with a lease term of more than twelve months. In July 2018, the FASB issued ASU No. 2018-11 Leases (Topic 842) (“ASU 2018-11”) which provided another transition method in addition to the existing transition method by allowing entities to initially apply the new leases standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. In November 2019, the FASB issued ASU 2019-10, Financial Instruments-Credit Losses (Topic 326), Derivative and Hedging (Topic 815) and Leases (Topic 842), which defers the effective date for ASU 2016-02 to annual periods beginning after December 15, 2020 and interim periods beginning after December 15, 2021. The new standard originally required a modified retrospective transition for capital or operating leases existing at or entered into after the beginning of the earliest comparative period presented in the financial statements, but it does not require transition accounting for leases that expire prior to the date of the initial application. The Company has not yet determined the effects that the adoptions of ASU 2016-02 and ASU 2018-11 will have on its financial position, results of operations, cash flows, or disclosures. Credit Losses (Topic 326): In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). This standard requires that credit losses be reported using an expected losses model rather than the incurred losses model that is currently used and establishes additional disclosures related to credit risks. In November 2019, the FASB issued ASU 2019-10, Financial Instruments-Credit Losses (Topic 326), Derivative and Hedging (Topic 815) and Leases (Topic 842), which defers the effective date for ASU 2016-13 to interim and annual periods beginning after December 15, 2022. The Company has not yet determined the effects, if any, that the adoption of ASU 2016-13 may have on its financial position, results of operations, cash flows, or disclosures.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Components of Cash, Cash Equivalents and Restricted Cash	The following table presents the components of total cash, cash equivalents, and restricted cash as set forth in the Company’s consolidated statements of cash flows: December 31, 2019 2018 Cash and cash equivalents $ 71,655 $ 58,223 Restricted cash 1,852 1,799 Total cash, cash equivalents, and restricted cash $ 73,507 $ 60,022
Lives Used in Computing Straight-Line Depreciation	The lives used in computing straight-line depreciation are as follows: Number of Years Equipment 3 - 7 Furniture 5 - 7 Manufacturing equipment 3 - 10 Software 3 Demonstration, placements and evaluation units 3 - 5 Leasehold improvements Lesser of life of lease or 10 years
Summary of Roll-Forward Warranty Liability	A roll-forward of the Company’s warranty liability is as follows: Balance at December 31, 2017 $ 317 Provisions for warranty obligations 355 Settlements (343 ) Balance at December 31, 2018 329 Provisions for warranty obligations 125 Settlements (229 ) Balance at December 31, 2019 $ 225

Business Combinations (Tables)

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Summary of Preliminary Purchase Price Allocation	The following table summarizes the preliminary purchase price allocation that includes the fair values of the separately identifiable assets acquired and liabilities assumed as of February 28, 2019: Cash $ 466 Accounts receivable 411 Inventory 492 Prepaids and other assets 3 Property and equipment 1 Goodwill 592 Intangible assets 455 Total assets acquired 2,420 Accounts payable and accrued expenses (241 ) Contract liabilities (75 ) Deferred taxes (78 ) Total liabilities assumed (394 ) Total purchase price $ 2,026
Summary of Business Acquisition Pro Forma Information	The following unaudited pro forma information for the years ended December 31, 2019 and 2018, respectively, presents consolidated information as if the Solus acquisition occurred on January 1, 2018, which is the first day of the Company’s fiscal year 2018: Year Ended December 31, 2019 2018 Net revenue $ 48,341 $ 43,637 Net loss $ (51,003 ) $ (42,078 ) Net loss per share, basic $ (2.74 ) $ (14.48 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Warrants
Schedule of Assumptions Used in Black-Scholes Options Pricing Model at the Date of Grant	The assumptions used in the Black-Scholes pricing model were as follows at the date of grant: Expected dividend yield 0.0 % Risk free interest rate 2.4 % Expected stock price volatility 60.9 % Expected term (years) 10.0

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Summary of Accounts Receivable	Accounts receivable consists of the following: December 31, 2019 2018 United States $ 5,574 $ 4,948 International 2,908 2,493 Total accounts receivable 8,482 7,441 Less: Allowance for doubtful accounts (239 ) (334 ) Accounts receivable, net of allowance for doubtful accounts $ 8,243 $ 7,107

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consist of the following: December 31, 2019 2018 Component parts $ 4,948 $ 5,601 Finished goods 4,189 8,109 $ 9,137 $ 13,710

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Summary of Components of Property and Equipment	Property and equipment are carried at cost less accumulated depreciation and amortization. A summary of the components of property and equipment is as follows: December 31, 2019 2018 Equipment $ 1,050 $ 924 Furniture 989 957 Manufacturing equipment 9,394 4,166 Software 718 655 Demonstration, placements and evaluation units 10,215 7,135 Leasehold improvements 2,085 2,025 Construction in process 612 4,663 Total property and equipment 25,063 20,525 Less: Accumulated depreciation and amortization (9,977 ) (7,109 ) Total property and equipment, net $ 15,086 $ 13,416

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill and Intangible Assets	The changes in the carrying amount of goodwill and intangible assets during 2019 are as follows: Goodwill Intangible Assets Balance at December 31, 2018 Acquired during the period $ 592 $ 455 Amortization - (95 ) Foreign currency exchange rate changes (4 ) (7 ) Balance at December 31, 2019 $ 588 $ 353
Summary of Acquired Intangible Assets	The following table presents a summary of acquired intangible assets: As of December 31, 2019 Period of amortization Gross Carrying Amount Accumulated Amortization Customer agreements 3.83 $ 448 $ (95 ) Total identifiable intangible assets $ 448 $ (95 )
Schedule of Estimated Amortization Expense for Intangible Assets	The estimated amortization expense for intangible assets for future years is as follows: 2020 $ 118 2021 118 2022 117 Total $ 353

Accrued Expenses and Other Li_2

Accrued Expenses and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2019
Payables And Accruals [Abstract]
Schedule of Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities consist of the following: December 31, 2019 2018 Accrued bonuses $ 3,071 $ 1,692 Accrued commissions 1,100 1,464 Accrued professional fees 1,092 305 Accrued taxes 983 305 Accrued inventory 620 1,070 Accrued vacation liability 490 427 Accrued employee-related costs 381 86 Deferred revenue 344 251 Product warranty reserve 225 329 Refundable purchase price of unvested stock 212 346 Accrued rent and restoration costs 208 174 Accrued capital equipment 135 21 Accrued employee reimbursement 102 178 Other 846 1,005 Total accrued expenses and other liabilities $ 9,809 $ 7,653

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Annual Principal Maturities of Term Loan	The annual principal maturities of the Company’s term loan as of December 31, 2019 are as follows: 2020 - 2021 - 2022 - 2023 $ 42,571 Less: Discount on loans payable (784 ) Long-term loans payable $ 41,787

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Summary of Future Minimum Combined Lease Payments	The following table summarizes the future minimum combined lease payments: Total Due Years Ended December 31, 2020 $ 1,621 2021 1,645 2022 1,630 2023 1,652 2024 1,679 Thereafter 140 Total $ 8,367

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2019
Warrants And Rights Note Disclosure [Abstract]
Summary of Warrants Activity	The table below sets forth the Company’s warrant activity for the year ended December 31, 2019: Common Stock Warrants Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2018 230,295 $ 14.50 Warrants granted 19,790 15.92 Warrants exercised (68,009 ) (14.00 ) Outstanding at December 31, 2019 182,076 $ 14.84
Schedule of Warrants Outstanding	The Company has the following warrants outstanding at December 31, 2019: Dates of Expiration Exercise Price Number of Warrants Periods ranging from September 27, 2020 to July 28, 2025 $ 14.00 101,979 Periods ranging from April 6, 2028 through March 22, 2029 $ 15.92 80,097 Total Common Stock Warrants 182,076

Disaggregated Revenue (Tables)

Disaggregated Revenue (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
Net Revenue Disaggregated into Categories	The following table shows the Company’s net revenue disaggregated into categories the Company considers meaningful to depict how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors: For the Year Ended December 31, 2019 US International Total Net revenue by: Product Revenue Capital $ 6,144 $ 3,180 $ 9,324 Disposable 27,753 7,302 35,055 Subtotal Product Revenue 33,897 10,482 44,379 Lease Revenue 1,721 - 1,721 Service Revenue 965 1,039 2,004 Total Revenue $ 36,583 $ 11,521 $ 48,104 For the Year Ended December 31, 2018 US International Total Net revenue by: Product Revenue Capital $ 7,293 $ 3,487 $ 10,780 Disposable 23,024 5,429 28,453 Subtotal Product Revenue 30,317 8,916 39,233 Lease Revenue 1,334 - 1,334 Service Revenue 1,359 451 1,810 Total Revenue $ 33,010 $ 9,367 $ 42,377

Stock Plans and Stock-Based C_2

Stock Plans and Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity	Stock option activity for the year ended December 31, 2019 is as follows: Weighted Number of Weighted Average Underlying Average Remaining Aggregate Common Exercise Contractual Intrinsic Shares Price Term Value Outstanding at December 31, 2018 786,989 $ 2.41 7.87 $ 13,801 Options granted 969,646 16.61 Options exercised (150,176 ) 1.62 Options canceled (576,311 ) 15.10 Outstanding at December 31, 2019 1,030,148 $ 8.91 8.18 $ 5,544 Exercisable at December 31, 2019 407,120 $ 2.37 6.90 $ 4,025 Vested and unvested expected to vest at December 31, 2019 1,030,148 $ 8.91 8.18 $ 5,544
Schedule of Weighted Average Assumptions Used in Black-Scholes Options Pricing Model	The weighted average assumptions used in the Black-Scholes options pricing model are as follows: Year Ended December 31, 2019 2018 Expected dividend yield 0.0 % 0.0 % Risk free interest rate 1.9 % 2.6 % Expected stock price volatility 64.5 % 54.4 % Expected term (years) 6.2 6.1
Summary of Restricted Stock Activity	A summary of restricted stock activity for the year ended December 31, 2019 is as follows: Weighted Average Grant Date Shares Fair Value Unvested at December 31, 2018 399,485 $ 1.68 Granted/purchased 86,170 15.52 Vested (255,742 ) 4.46 Canceled - - Unvested at December 31, 2019 229,913 $ 3.76
Summary of Allocated Stock Based Compensation Expense	Stock-based compensation expense was allocated based on the employees’ and non-employees’ functions as follows: Year Ended December 31, 2019 2018 Cost of revenue $ 187 $ 27 Research and development 405 119 Sales and marketing 782 146 General and administrative 2,462 210 Total $ 3,836 $ 502

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Net Loss Before Income Taxes	Net loss before income taxes is as follows: Year Ended December 31, 2019 2018 United States $ (50,343 ) $ (42,468 ) United Kingdom (862 ) - $ (51,205 ) $ (42,468 )
Schedule of Reconciliation of Income Tax Expense	A reconciliation of income tax expense is computed as the statutory federal income tax rate to income taxes as reflected in the financial statement as follows: Year Ended December 31, 2019 2018 Federal income tax benefit at statutory rate (21.0 %) (21.0 %) Permanent differences (6.7 %) 2.6 % Change in valuation allowance 26.9 % 21.0 % Other 0.5 % (2.6 %) Income tax expense (0.3 %) 0.0 %
Significant Components of Net Deferred Tax Assets	Significant components of the Company’s net deferred tax assets are as follows: December 31, 2019 2018 Deferred Tax Assets Net operating loss carryforwards $ 51,303 $ 42,444 Deduction of research and development costs 5,985 4,239 Tax credit carryforwards 4,109 3,012 Accrued expenses 1,976 1,184 Stock option expense attributed to non-ISO stock 1,098 358 Accrued bonus and vacation 703 579 Inventory valuation reserves 280 154 Deferred revenue 230 - Accounts receivable allowance 63 70 Accrued warranty 61 86 Allowance for sales returns - 18 Other temporary differences 492 - Gross deferred tax assets 66,300 52,144 Less: Valuation allowance (65,515 ) (51,708 ) Deferred tax assets after valuation allowance 785 436 Deferred Tax Liabilities Depreciation (593 ) (366 ) Intangible assets (68 ) - Other temporary differences (58 ) (70 ) Gross deferred tax liabilities (719 ) (436 ) Net Deferred Tax Assets $ 66 $ -

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Computation of Diluted Net Loss Per Share Attributable to Common Stockholders	The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Year Ended December 31, 2019 2018 Options to purchase common stock 1,030,148 786,989 Warrants to purchase common stock 182,076 230,295 Unvested restricted stock 229,913 399,485 1,442,137 1,416,769

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule Of Selected Quarterly Financial Data	The following table sets forth our unaudited quarterly operating results for each of the Company’s quarters in the years ended December 31, 2019 and 2018. In the opinion of management, the quarterly financial information reflects all necessary adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of this data. 2019 Quarters 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Year Revenue $ 12,299 $ 11,986 $ 10,809 $ 13,010 $ 48,104 Cost of revenue 7,120 6,527 5,999 7,147 26,793 Gross profit 5,179 5,459 4,810 5,863 21,311 Operating expenses: Research and development 3,273 3,167 3,280 3,656 13,376 Sales and marketing 9,161 9,432 9,193 9,903 37,689 General and administrative 4,879 4,532 3,978 5,021 18,410 Total operating expenses 17,313 17,131 16,451 18,580 69,475 Loss from operations (12,134 ) (11,672 ) (11,641 ) (12,717 ) (48,164 ) Other expenses, net (830 ) (1,208 ) (1,124 ) 121 (3,041 ) Net loss before income taxes (12,964 ) (12,880 ) (12,765 ) (12,596 ) (51,205 ) Benefit for income taxes - - - (146 ) (146 ) Net loss $ (12,964 ) $ (12,880 ) $ (12,765 ) $ (12,450 ) $ (51,059 ) 2018 Quarters 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Year Revenue $ 10,739 $ 10,563 $ 9,389 $ 11,686 $ 42,377 Cost of revenue 6,494 6,469 5,774 6,868 25,605 Gross profit 4,245 4,094 3,615 4,818 16,772 Operating expenses: Research and development 2,225 2,081 1,768 2,697 8,771 Sales and marketing 8,051 8,525 7,755 9,596 33,927 General and administrative 2,382 2,603 2,804 3,397 11,186 Loss on disposal of fixed assets 3 39 17 62 121 Total operating expenses 12,661 13,248 12,344 15,752 54,005 Loss from operations (8,416 ) (9,154 ) (8,729 ) (10,934 ) (37,233 ) Other expense, net (489 ) (2,073 ) (730 ) (1,943 ) (5,235 ) Net loss $ (8,905 ) $ (11,227 ) $ (9,459 ) $ (12,877 ) $ (42,468 )

Description of Business - Addit

Description of Business - Additional Information (Details) $ / shares in Units, $ in Millions	Nov. 16, 2018USD ($)$ / sharesshares	Aug. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2019Systemshares	Dec. 31, 2018shares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Entity founded year			1993
Entity reincorporated year			2013
Number of versions of precision flow systems | System			4
Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued | shares			3,570,750	4,600,000
Initial Public Offering | Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued | shares	4,600,000	3,570,750
Exercise of underwriters option to purchase shares | shares	600,000	465,750
Public offering price of common stock | $ / shares	$ 14	$ 14.50
Proceeds from initial offering net of underwriting discounts and offering costs | $	$ 57.4	$ 48.3
Underwriting discount | $	4.5	3.1
Offering expenses | $	$ 2.5	$ 0.4

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Details)	Nov. 02, 2018$ / shares	Dec. 31, 2019USD ($)Segment$ / shares	Dec. 31, 2018USD ($)$ / shares	Nov. 16, 2018shares	Dec. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reporting segment | Segment		1
Number of reporting units | Segment		2
Maturity period of highly liquid investments with original maturities		90 days
Cash, cash equivalents and restricted cash balance		$ 73,507,000	$ 60,022,000		$ 28,360,000
Impairment of long-lived assets		0	0
Impairments of intangible assets		0
Intangible assets, net		353,000	0
Impairment of goodwill		0
Goodwill		588,000	0
Deferred rent		$ 200,000	200,000
Standard product warranty period		1 year
Unamortized costs		$ 800,000	700,000
Standard payment term to customer		30 days
Revenue, performance obligation, description of payment terms		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. Applying the practical expedient in paragraph 606-10-32-18, the Company does not assess whether a significant financing component exists if the period between when the Company performs its obligations under the contract and when the customer pays is one year or less.
Revenue, remaining performance obligation, amount		$ 0	$ 0
Dividend yield assumed		0.00%	0.00%
Reverse stock split	14
Common stock, par value | $ / shares	$ 0.001	$ 0.001	$ 0.001
Deferred costs		$ 0	$ 0
Common Stock
Summary Of Significant Accounting Policies [Line Items]
Convertible preferred stock, shares issued upon conversion | shares				11,229,636
Shipping and Handling
Summary Of Significant Accounting Policies [Line Items]
Shipping and handling costs		1,000,000	1,000,000
Prepaid Expenses and Other Current Assets
Summary Of Significant Accounting Policies [Line Items]
Current value of future lease payments		900,000	900,000
Maximum
Summary Of Significant Accounting Policies [Line Items]
Product return liability		100,000	100,000
Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Impairment of long-lived assets		$ 0	$ 0
Leasehold Improvements | Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment		10 years
Manufacturing Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment		3 years
Manufacturing Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment		10 years	7 years
Outside U.S.
Summary Of Significant Accounting Policies [Line Items]
Long-term assets		$ 100,000
Cash, cash equivalents and restricted cash balance		$ 300,000

Significant Accounting Polici_5

Significant Accounting Policies - Components of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 71,655	$ 58,223
Restricted cash	1,852	1,799
Total cash, cash equivalents, and restricted cash	$ 73,507	$ 60,022	$ 28,360

Significant Accounting Polici_6

Significant Accounting Policies - Lives Used in Computing Straight-Line Depreciation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	3 years
Equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	7 years
Furniture | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	5 years
Furniture | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	7 years
Manufacturing Equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	3 years
Manufacturing Equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	10 years	7 years
Software | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	3 years
Demonstration, Placements and Evaluation Units | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	3 years
Demonstration, Placements and Evaluation Units | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Term	Lesser of life of lease or 10 years
Leasehold Improvements | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	10 years

Significant Accounting Polici_7

Significant Accounting Policies - Summary of Roll-Forward Warranty Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Balance, beginning of period	$ 329	$ 317
Provisions for warranty obligations	125	355
Settlements	(229)	(343)
Balance, end of period	$ 225	$ 329

Business Combinations - Additio

Business Combinations - Additional Information (Details) - USD ($) $ in Thousands	Feb. 28, 2019	Mar. 04, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Purchase price, net of cash acquired			$ 1,560
Solus
Business Acquisition [Line Items]
Acquisition date			Feb. 28, 2019
Purchase price, net of cash acquired	$ 2,000
Initial cash payment	1,600
Settlement of receivable from preexisting relationship	$ 400
Contingent consideration as compensation expense			$ 1,000
Weighted average amortization period for intangible assets			3 years 9 months 29 days
Revenues			$ 2,700
Net loss			600
Solus | General and administrative
Business Acquisition [Line Items]
Transaction costs associated with acquisition			$ 200
Solus | Subsequent Event
Business Acquisition [Line Items]
Additional contingent consideration as compensation to be recognized		$ 1,200

Business Combinations - Summary

Business Combinations - Summary of Preliminary Purchase Price Allocation (Details) - USD ($)	Dec. 31, 2019	Feb. 28, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill	$ 588,000		$ 0
Solus
Business Acquisition [Line Items]
Cash		$ 466,000
Accounts receivable		411,000
Inventory		492,000
Prepaids and other assets		3,000
Property and equipment		1,000
Goodwill		592,000
Intangible assets		455,000
Total assets acquired		2,420,000
Accounts payable and accrued expenses		(241,000)
Contract liabilities		(75,000)
Deferred taxes		(78,000)
Total liabilities assumed		(394,000)
Total purchase price		$ 2,026,000

Business Combinations - Summa_2

Business Combinations - Summary of Business Acquisition Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
Net revenue	$ 48,341	$ 43,637
Net loss	$ (51,003)	$ (42,078)
Net loss per share, basic	$ (2.74)	$ (14.48)

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2019	Mar. 22, 2019	Dec. 31, 2018
Amendment To Financing Arrangement | Common Stock Warrants
Class Of Warrant Or Right [Line Items]
Granted warrants to purchase shares		19,790
Level 1 | Money Market Deposits
Class Of Warrant Or Right [Line Items]
Cash equivalents	$ 70.8		$ 57.6

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assumptions Used in Black-Scholes Options Pricing Model at the Date of Grant (Details)	Dec. 31, 2019
Class Of Warrant Or Right [Line Items]
Expected term (years)	10 years
Expected Dividend Yield
Class Of Warrant Or Right [Line Items]
Key inputs used in valuation	0
Risk Free Interest Rate
Class Of Warrant Or Right [Line Items]
Key inputs used in valuation	0.024
Expected Stock Price Volatility
Class Of Warrant Or Right [Line Items]
Key inputs used in valuation	0.609

Accounts Receivable - Summary o

Accounts Receivable - Summary of Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	$ 8,482	$ 7,441
Less: Allowance for doubtful accounts	(239)	(334)
Accounts receivable, net of allowance for doubtful accounts	8,243	7,107
US
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	5,574	4,948
International
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	$ 2,908	$ 2,493

Accounts Receivable - Additiona

Accounts Receivable - Additional Information (Details) - Customer Concentration Risk - Customer	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue
Accounts Notes And Loans Receivable [Line Items]
Number of customer accounted more than 10%	0	0
Percentage of concentration risk	10.00%	10.00%
Accounts Receivable
Accounts Notes And Loans Receivable [Line Items]
Number of customer accounted more than 10%	0	0
Percentage of concentration risk	10.00%	10.00%

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Component parts	$ 4,948	$ 5,601
Finished goods	4,189	8,109
Total inventory	$ 9,137	$ 13,710

Property and Equipment - Summar

Property and Equipment - Summary of Components of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total property and equipment	$ 25,063	$ 20,525
Less: Accumulated depreciation and amortization	(9,977)	(7,109)
Total property and equipment, net	15,086	13,416
Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	1,050	924
Furniture
Property Plant And Equipment [Line Items]
Total property and equipment	989	957
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	9,394	4,166
Software
Property Plant And Equipment [Line Items]
Total property and equipment	718	655
Demonstration, Placements and Evaluation Units
Property Plant And Equipment [Line Items]
Total property and equipment	10,215	7,135
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	2,085	2,025
Construction in Process
Property Plant And Equipment [Line Items]
Total property and equipment	$ 612	$ 4,663

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation of property and equipment	$ 3	$ 2.1
Depreciation expense included in cost of revenue	$ 1.9	$ 1.2

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill and Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill
Balance at December 31, 2018	$ 0
Acquired during the period	592,000
Foreign currency exchange rate changes	(4,000)
Balance at December 31, 2019	588,000	$ 0
Intangible Assets
Acquired during the period	455,000
Amortization	(95,000)	$ 0
Foreign currency exchange rate changes	(7,000)
Balance at December 31, 2019	$ 353,000

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Summary of Acquired Intangible Assets (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 448
Accumulated Amortization	$ (95)
Customer Agreements
Acquired Finite Lived Intangible Assets [Line Items]
Period of amortization	3 years 9 months 29 days
Gross Carrying Amount	$ 448
Accumulated Amortization	$ (95)

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 95,000	$ 0
Sales and marketing
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 100,000

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Schedule of Estimated Amortization Expense for Intangible Assets (Details) $ in Thousands	Dec. 31, 2019USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2020	$ 118
2021	118
2022	117
Total	$ 353

Accrued Expenses and Other Li_3

Accrued Expenses and Other Liabilities - Schedule of Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued bonuses	$ 3,071	$ 1,692
Accrued commissions	1,100	1,464
Accrued professional fees	1,092	305
Accrued taxes	983	305
Accrued inventory	620	1,070
Accrued vacation liability	490	427
Accrued employee-related costs	381	86
Deferred revenue	344	251
Product warranty reserve	225	329
Refundable purchase price of unvested stock	212	346
Accrued rent and restoration costs	208	174
Accrued capital equipment	135	21
Accrued employee reimbursement	102	178
Other	846	1,005
Total accrued expenses and other liabilities	$ 9,809	$ 7,653

Debt - Additional Information (

Debt - Additional Information (Details)

Mar. 22, 2019USD ($)$ / sharesshares

Dec. 31, 2018USD ($)

Sep. 27, 2018USD ($)$ / sharesshares

Jul. 20, 2018USD ($)$ / sharesshares

Apr. 06, 2018USD ($)Tranche$ / sharesshares

Nov. 16, 2016USD ($)Tranche

Apr. 30, 2018USD ($)

Mar. 31, 2017USD ($)

Jan. 31, 2017USD ($)

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Mar. 21, 2019USD ($)

Debt Instrument [Line Items]

Proceeds from term loan

$ 10,500,000

$ 32,000,000

Repayment of term loan balance

22,328,000

Common Stock Warrants

Debt Instrument [Line Items]

Estimated fair value of warrants at the time of issuance

$ 300,000

Western Alliance Bank | Revolving Credit Line | Revolver Agreement

Debt Instrument [Line Items]

Line of credit made available under agreement

$ 7,000,000

$ 7,500,000

Percentage of eligible receivables used as base to calculate line of credit availability

80.00%

Line of credit, maturity date

Sep. 30, 2018

Sep. 30, 2020

Outstanding balance under line of credit

$ 3,200,000

3,200,000

Line of credit, remaining availability under agreement

1,000,000

$ 1,000,000

Western Alliance Bank | Revolving Credit Line | Revolver Agreement | Credit Card Program

Debt Instrument [Line Items]

Line of credit made available under agreement

$ 300,000

Western Alliance Bank | Revolving Credit Line | Amended Revolver Agreement

Debt Instrument [Line Items]

Line of credit, interest rate

6.50%

Outstanding balance under line of credit

$ 3,500,000

Line of credit, remaining availability under agreement

800,000

Western Alliance Bank | Revolving Credit Line | Amended Revolver Agreement | Credit Card Program

Debt Instrument [Line Items]

Line of credit made available under agreement

500,000

Solar Capital Ltd. | Term Loan

Debt Instrument [Line Items]

Repayment of term loan balance

$ 6,000,000

Solar Capital Ltd. | Loan and Security Agreement | Term Loan

Debt Instrument [Line Items]

Term loan, face amount

$ 20,000,000

Number of tranches available under agreement | Tranche

3

Minimum revenue threshold required to draw down second tranche and to obtain singed term sheet for equity financing

$ 10,000,000

Solar Capital Ltd. | Loan and Security Agreement | First Tranche | Term Loan

Debt Instrument [Line Items]

Proceeds from term loan

$ 10,000,000

Solar Capital Ltd. | Loan and Security Agreement | Second Tranche | Term Loan

Debt Instrument [Line Items]

Proceeds from term loan

$ 5,000,000

Solar Capital Ltd. | Loan and Security Agreement | Third and Final Tranche | Term Loan

Debt Instrument [Line Items]

Proceeds from term loan

$ 5,000,000

Perceptive Credit Holdings II, LP | Credit Agreement and Guaranty | Term Loan

Debt Instrument [Line Items]

Term loan, face amount

$ 42,500,000

$ 42,600,000

Number of tranches available under agreement | Tranche

3

Proceeds from term loan

$ 10,500,000

$ 32,000,000

Granted warrants to purchase shares | shares

19,790

37,693

Warrants exercise price | $ / shares

$ 15.92

$ 15.92

Warrants expiration, month and year

2029-03

2028-04

Term loan, interest rate

9.06%

10.81%

Debt instrument rate

1.75%

Debt instrument, description

one-month LIBOR

Term loan, remaining availability under agreement

$ 0

Line of credit, covenant compliance description

The Amended Credit Agreement and Guaranty requires the Company to comply with a minimum liquidity covenant at all times and a minimum revenue covenant measured at the end of each fiscal quarter. As of December 31, 2019, the Company was in compliance with all covenants.

Line of credit facility percentage of amount borrowed

0.50%

Perceptive Credit Holdings II, LP | Credit Agreement and Guaranty | Term Loan | Common Stock Warrants

Debt Instrument [Line Items]

Estimated fair value of warrants at the time of issuance

$ 300,000

Perceptive Credit Holdings II, LP | Credit Agreement and Guaranty | First Tranche | Term Loan

Debt Instrument [Line Items]

Proceeds from term loan

$ 20,000,000

Perceptive Credit Holdings II, LP | Credit Agreement and Guaranty | Second Tranche | Term Loan

Debt Instrument [Line Items]

Proceeds from term loan

$ 10,000,000

Granted warrants to purchase shares | shares

18,846

Warrants exercise price | $ / shares

$ 15.92

Warrants expiration, month and year

2028-07

Perceptive Credit Holdings II, LP | First Amendment to Credit Agreement and Guaranty | Term Loan

Debt Instrument [Line Items]

Term loan available to be drawn

$ 12,500,000

Minimum revenue requirement to draw final tranche

43,200,000

Perceptive Credit Holdings II, LP | First Amendment to Credit Agreement and Guaranty | Credit Card Program | Term Loan

Debt Instrument [Line Items]

Line of credit made available under agreement

$ 300,000

Perceptive Credit Holdings II, LP | First Amendment to Credit Agreement and Guaranty | Third and Final Tranche | Term Loan

Debt Instrument [Line Items]

Proceeds from term loan

$ 2,000,000

Granted warrants to purchase shares | shares

3,769

Warrants exercise price | $ / shares

$ 15.92

Warrants expiration, month and year

2028-09

Perceptive Credit Holdings II, LP | Second Amendment to Credit Agreement and Guaranty | Credit Card Program | Term Loan

Debt Instrument [Line Items]

Line of credit made available under agreement

$ 500,000

Debt - Schedule of Annual Princ

Debt - Schedule of Annual Principal Maturities of Term Loan (Details) - Loans Payable $ in Thousands	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
2020	$ 0
2021	0
2022	0
2023	42,571
Less: Discount on loans payable	(784)
Long-term loans payable	$ 41,787

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)

Dec. 16, 2019USD ($)

Jun. 15, 2018USD ($)

Jun. 12, 2018USD ($)

Dec. 31, 2019USD ($)ft²

Dec. 31, 2019USD ($)ft²Renewal

Dec. 31, 2018USD ($)

Oct. 31, 2019m²

Jul. 31, 2018ft²

Jun. 30, 2018ft²

Sep. 30, 2017ft²

Sep. 30, 2016ft²

May 31, 2016ft²

Loss Contingencies [Line Items]

Rent expense | $

$ 2,000,000

$ 1,900,000

Agreement to pay settlement | $

$ 650,000

Agreement settlement terms

The parties reached a settlement agreement on December 16, 2019 whereby EMS agreed to pay the Company $0.65 million in a series of monthly payments through December 2021, and the both the Company and EMS agreed to release each from any other outstanding claims, which included $0.5 million of accounts payable the Company had previously recorded. The Rockingham Superior Court approved the parties’ stipulation of dismissal with prejudice on January 2, 2020.

Gain on litigation settlement | $

$ 1,200,000

$ 1,151,000

Accounts Payable

Loss Contingencies [Line Items]

Outstanding claims for settlement | $

$ 500,000

Minimum

Loss Contingencies [Line Items]

Breach of contract and other causes of action and seeking damages | $

$ 2,100,000

$ 800,000

100 Domain Drive, Exeter New Hampshire

Loss Contingencies [Line Items]

Area of space under lease

25,670

Lease expiration

Jan. 28, 2025

Lease renewal term

5 years

Lease number of renewals | Renewal

2

100 Domain Drive, Exeter New Hampshire | Office Space

Loss Contingencies [Line Items]

Area of land

5,529

100 Domain Drive, Exeter New Hampshire | Manufacturing Space

Loss Contingencies [Line Items]

Area of space under lease

16,550

100 Domain Drive, Exeter New Hampshire | Warehousing and Storage Space

Loss Contingencies [Line Items]

Area of space under lease

3,130

100 Domain Drive, Exeter New Hampshire | First Lease Amendment

Loss Contingencies [Line Items]

Area of space under lease

20,102

100 Domain Drive, Exeter New Hampshire | First Lease Amendment | Office Space

Loss Contingencies [Line Items]

Area of space under lease

16,823

100 Domain Drive, Exeter New Hampshire | First Lease Amendment | Research And Development Space

Loss Contingencies [Line Items]

Area of space under lease

3,279

100 Domain Drive, Exeter New Hampshire | Second Lease Expansion | Office Space

Loss Contingencies [Line Items]

Area of space under lease

8,971

100 Domain Drive, Exeter New Hampshire | Second Lease Amendment

Loss Contingencies [Line Items]

Area of space under lease

3,016

100 Domain Drive, Exeter New Hampshire | Third Lease Amendment

Loss Contingencies [Line Items]

Area of space under lease

84,140

84,140

100 Domain Drive, Exeter New Hampshire | Third Lease Amendment | Research And Development Space

Loss Contingencies [Line Items]

Area of space under lease

1,172

2 Dryden Loan, Bilston Glen Industrial Estate, Loanhead in the United Kingdom

Loss Contingencies [Line Items]

Area of land | m²

453

Lease expiration

Feb. 15, 2022

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Future Minimum Combined Lease Payments (Details) $ in Thousands	Dec. 31, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
2020	$ 1,621
2021	1,645
2022	1,630
2023	1,652
2024	1,679
Thereafter	140
Total	$ 8,367

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 27, 2018	Dec. 31, 2019	Dec. 31, 2018
Temporary Equity [Line Items]
Proceeds from issuance of redeemable convertible preferred stock			$ 9,919
Series D-1 Preferred Stock
Temporary Equity [Line Items]
Preferred stock shares issued	714,285
Preferred stock shares issued, price per share	$ 15.92
Proceeds from issuance of redeemable convertible preferred stock	$ 10,000
Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Temporary equity to permanent equity conversion basis		one-to-one basis

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019Vote$ / sharesshares	Dec. 31, 2018$ / sharesshares	Nov. 02, 2018$ / shares
Equity [Abstract]
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, par value | $ / shares	$ 0.001	$ 0.001
Preferred stock, shares outstanding	0	0
Common stock, shares authorized	175,000,000	175,000,000
Common stock, shares issued	20,851,531	16,782,837
Common stock, shares outstanding	20,851,531	16,782,837
Common stock, par value | $ / shares	$ 0.001	$ 0.001	$ 0.001
Common stock voting rights	Each share of common stock is entitled to one vote.
Number of vote each share of common stock entitled | Vote	1

Warrants - Summary of Warrants

Warrants - Summary of Warrants Activity (Details) - Common Stock Warrants	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance | shares	230,295
Number of shares, warrants granted | shares	19,790
Number of shares, warrants exercised | shares	(68,009)
Number of shares, ending balance | shares	182,076
Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise price, beginning balance | $ / shares	$ 14.50
Weighted average exercise price, warrants granted | $ / shares	15.92
Weighted average exercise price, warrants exercised | $ / shares	(14)
Weighted average exercise price, ending balance | $ / shares	$ 14.84

Warrants - Schedule of Warrants

Warrants - Schedule of Warrants Outstanding (Details) - Common Stock Warrants - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Class Of Warrant Or Right [Line Items]
Number of Warrants	182,076	230,295
Periods Ranging from September 27, 2020 to July 28, 2025
Class Of Warrant Or Right [Line Items]
Warrants exercise price	$ 14
Number of Warrants	101,979
Periods Ranging from April 6, 2028 through March 22, 2029
Class Of Warrant Or Right [Line Items]
Warrants exercise price	$ 15.92
Number of Warrants	80,097

Warrants - Additional Informati

Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 22, 2019	Dec. 31, 2019
Common Stock Warrants
Class Of Warrant Or Right [Line Items]
Estimated fair value of warrants at the time of issuance	$ 0.3
Warrants to purchase of common stock shares, net exercised		68,009
Issuance of stock upon exercise of warrants, shares		12,164
Amended Credit Agreement and Guaranty
Class Of Warrant Or Right [Line Items]
Granted warrants to purchase shares	19,790
Warrants exercise price	$ 15.92
Warrants expire date	2029-03

Disaggregated Revenue - Net Rev

Disaggregated Revenue - Net Revenue Disaggregated into Categories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 48,104	$ 42,377
US
Disaggregation Of Revenue [Line Items]
Total Revenue	36,583	33,010
International
Disaggregation Of Revenue [Line Items]
Total Revenue	11,521	9,367
Product Revenue, Capital
Disaggregation Of Revenue [Line Items]
Total Revenue	9,324	10,780
Product Revenue, Capital | US
Disaggregation Of Revenue [Line Items]
Total Revenue	6,144	7,293
Product Revenue, Capital | International
Disaggregation Of Revenue [Line Items]
Total Revenue	3,180	3,487
Product Revenue, Disposable
Disaggregation Of Revenue [Line Items]
Total Revenue	35,055	28,453
Product Revenue, Disposable | US
Disaggregation Of Revenue [Line Items]
Total Revenue	27,753	23,024
Product Revenue, Disposable | International
Disaggregation Of Revenue [Line Items]
Total Revenue	7,302	5,429
Subtotal Product Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	44,379	39,233
Subtotal Product Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	33,897	30,317
Subtotal Product Revenue | International
Disaggregation Of Revenue [Line Items]
Total Revenue	10,482	8,916
Lease Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	1,721	1,334
Lease Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	1,721	1,334
Service Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	2,004	1,810
Service Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	965	1,359
Service Revenue | International
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 1,039	$ 451

Stock Plans and Stock-Based C_3

Stock Plans and Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016	Oct. 17, 2018	Jul. 22, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance			3,279,682
Weighted average grant date fair value of options granted		$ 9.20	$ 3.26
Aggregate intrinsic value of options exercised		$ 2.3
Unrecognized stock-based compensation expense		$ 2.9
Unrecognized stock-based compensation expense recognized, remaining weighted average vesting period		2 years 8 months 12 days
Issuance of stock upon exercise of options, shares		150,176
Average forfeiture rates		6.73%	8.32%
Nonrecourse Notes
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of stock upon exercise of options, shares		0	0	79,865
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	36 months
Number of shares granted	68,526
Award vesting percentage	25.00%
2015 SI Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock remain available for issuance		0	0			1,413,749
2018 SI Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock remain available for issuance		834,423			998,900
2018 SI Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		1 year
2018 SI Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
Options exercisable, period		10 years
2000 LTI Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock remain available for issuance		0	0
2005 SI Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock remain available for issuance		0	0

Stock Plans and Stock-Based C_4

Stock Plans and Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Underlying Common Shares, Outstanding, Beginning balance	786,989
Number of Underlying Common Shares, Options granted	969,646
Number of Underlying Common Shares, Options exercised	(150,176)
Number of Underlying Common Shares, Options canceled	(576,311)
Number of Underlying Common Shares, Outstanding, Ending balance	1,030,148	786,989
Number of Underlying Common Shares, Exercisable	407,120
Number of Underlying Common Shares, Vested and unvested expected to vest	1,030,148
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 2.41
Weighted Average Exercise Price, Options granted	16.61
Weighted Average Exercise Price, Options exercised	1.62
Weighted Average Exercise Price, Options canceled	15.10
Weighted Average Exercise Price, Outstanding, Ending balance	8.91	$ 2.41
Weighted Average Exercise Price, Exercisable	2.37
Weighted Average Exercise Price, Vested and unvested expected to vest	$ 8.91
Weighted Average Remaining Contractual Term	8 years 2 months 4 days	7 years 10 months 13 days
Weighted Average Remaining Contractual Term, Exercisable	6 years 10 months 24 days
Weighted Average Remaining Contractual Term, Vested and unvested expected to vest	8 years 2 months 4 days
Aggregate Intrinsic Value, Outstanding	$ 5,544	$ 13,801
Aggregate Intrinsic Value, Exercisable	4,025
Aggregate Intrinsic Value, Vested and unvested expected to vest	$ 5,544

Stock Plans and Stock-Based C_5

Stock Plans and Stock-Based Compensation - Schedule of Weighted Average Assumptions Used in Black-Scholes Options Pricing Model (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected dividend yield	0.00%	0.00%
Risk free interest rate	1.90%	2.60%
Expected stock price volatility	64.50%	54.40%
Expected term (years)	6 years 2 months 12 days	6 years 1 month 6 days

Stock Plans and Stock-Based C_6

Stock Plans and Stock-Based Compensation - Summary of Restricted Stock Activity (Details) - Restricted Stock	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Unvested, Beginning balance | shares	399,485
Shares, Granted/purchased | shares	86,170
Shares, Vested | shares	(255,742)
Shares, Canceled | shares	0
Shares, Unvested Ending balance | shares	229,913
Weighted Average Grant Date Fair Value, Unvested, Beginning balance | $ / shares	$ 1.68
Weighted Average Grant Date Fair Value, Granted/purchased | $ / shares	15.52
Weighted Average Grant Date Fair Value, Vested | $ / shares	4.46
Weighted Average Grant Date Fair Value, Canceled | $ / shares	0
Weighted Average Grant Date Fair Value, Unvested Ending balance | $ / shares	$ 3.76

Stock Plans and Stock-Based C_7

Stock Plans and Stock-Based Compensation - Summary of Allocated Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated stock based compensation expense	$ 3,836	$ 502
Cost of revenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated stock based compensation expense	187	27
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated stock based compensation expense	405	119
Sales and marketing
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated stock based compensation expense	782	146
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated stock based compensation expense	$ 2,462	$ 210

Income Taxes - Schedule of Net

Income Taxes - Schedule of Net Loss Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
United States					$ (50,343)	$ (42,468)
United Kingdom					(862)
Net loss before income taxes	$ (12,596)	$ (12,765)	$ (12,880)	$ (12,964)	$ (51,205)	$ (42,468)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Income tax benefit, related to foreign net deferred income tax assets		$ 100,000
Current foreign income tax		0
Income tax provision, United States		0	$ 0
Provision or (benefit) for income taxes	$ (146,000)	(146,000)	0
Valuation allowance	65,515,000	65,515,000	51,708,000
Increase in valuation allowance		$ 13,800,000
Income tax examination, description		Years beginning in 2016 remain open to examination for both federal and state purposes.
Liabilities associated with uncertain tax positions	0	$ 0	0
Uncertain tax positions, interest and penalties		$ 0	$ 0
Federal corporate income tax rate		21.00%	21.00%	34.00%
Limitation of deduction for net operating losses, percentage of annual taxable income		80.00%
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	218,900,000	$ 218,900,000
Net operating loss carryforwards, expiration beginning year		2020
Federal | Research and Development
Income Tax Contingency [Line Items]
Tax credit carryforward	3,900,000	$ 3,900,000
Tax credit carryforward, expiration beginning year		2021
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 89,700,000	$ 89,700,000
Net operating loss carryforwards, expiration beginning year		2020

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Income Tax Expense (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal income tax benefit at statutory rate	(21.00%)	(21.00%)	(34.00%)
Permanent differences	(6.70%)	2.60%
Change in valuation allowance	26.90%	21.00%
Other	0.50%	(2.60%)
Income tax expense	(0.30%)	(0.00%)

Income Taxes - Significant Comp

Income Taxes - Significant Components of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets
Net operating loss carryforwards	$ 51,303	$ 42,444
Deduction of research and development costs	5,985	4,239
Tax credit carryforwards	4,109	3,012
Accrued expenses	1,976	1,184
Stock option expense attributed to non-ISO stock	1,098	358
Accrued bonus and vacation	703	579
Inventory valuation reserves	280	154
Deferred revenue	230
Accounts receivable allowance	63	70
Accrued warranty	61	86
Allowance for sales returns		18
Other temporary differences	492
Gross deferred tax assets	66,300	52,144
Less: Valuation allowance	(65,515)	(51,708)
Deferred tax assets after valuation allowance	785	436
Deferred Tax Liabilities
Depreciation	(593)	(366)
Intangible assets	(68)
Other temporary differences	(58)	(70)
Gross deferred tax liabilities	(719)	$ (436)
Net Deferred Tax Assets	$ 66

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,442,137	1,416,769
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,030,148	786,989
Warrants to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	182,076	230,295
Unvested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	229,913	399,485

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details)	Nov. 16, 2018USD ($)	Nov. 30, 2018	Dec. 31, 2019USD ($)Investor	Dec. 31, 2018USD ($)
Related Party Transaction [Line Items]
Preferred stock purchased by related party			$ 48,276,000	$ 57,394,000
Number of investors that are vendors | Investor			2
Total amount billed from related parties				1,200,000
Accounts payable to vendors			$ 0	500,000
Revenue from related party			1,400,000	2,200,000
Accounts receivable from customer			200,000	$ 100,000
Maximum
Related Party Transaction [Line Items]
Total amount billed from related parties			$ 100,000
Redeemable Convertible Preferred Stock
Related Party Transaction [Line Items]
Preferred stock purchased by related party	$ 33,200,000
Temporary equity to permanent equity conversion basis			one-to-one basis
Temporary to permanent equity conversion ratio		100.00%

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined contribution, plan name	401(k) retirement plan
Maximum annual contributions per employee	100.00%
Employer matching contribution percentage	50.00%
Maximum employer contribution amount of employee compensation	4.00%
Defined contribution plan	$ 100,000	$ 100,000
For Employee with Annual Earnings Less Than $50,000
Defined Benefit Plan Disclosure [Line Items]
Annual contributions per employee	1,000
For Employee with Annual Earnings Greater Than $50,000
Defined Benefit Plan Disclosure [Line Items]
Annual contributions per employee	500
Maximum
Defined Benefit Plan Disclosure [Line Items]
Employees annual earnings	50,000
Minimum
Defined Benefit Plan Disclosure [Line Items]
Employees annual earnings	$ 50,000

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) - Schedule Of Quarterly Financial Data (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Net revenue	$ 13,010,000	$ 10,809,000	$ 11,986,000	$ 12,299,000	$ 11,686,000	$ 9,389,000	$ 10,563,000	$ 10,739,000	$ 48,104,000	$ 42,377,000
Cost of revenue	7,147,000	5,999,000	6,527,000	7,120,000	6,868,000	5,774,000	6,469,000	6,494,000	26,793,000	25,605,000
Gross profit	5,863,000	4,810,000	5,459,000	5,179,000	4,818,000	3,615,000	4,094,000	4,245,000	21,311,000	16,772,000
Operating expenses
Research and development	3,656,000	3,280,000	3,167,000	3,273,000	2,697,000	1,768,000	2,081,000	2,225,000	13,376,000	8,771,000
Sales and marketing	9,903,000	9,193,000	9,432,000	9,161,000	9,596,000	7,755,000	8,525,000	8,051,000	37,689,000	33,927,000
General and administrative	5,021,000	3,978,000	4,532,000	4,879,000	3,397,000	2,804,000	2,603,000	2,382,000	18,410,000	11,186,000
Loss on disposal of property and equipment					62,000	17,000	39,000	3,000		121,000
Total operating expenses	18,580,000	16,451,000	17,131,000	17,313,000	15,752,000	12,344,000	13,248,000	12,661,000	69,475,000	54,005,000
Loss from operations	(12,717,000)	(11,641,000)	(11,672,000)	(12,134,000)	(10,934,000)	(8,729,000)	(9,154,000)	(8,416,000)	(48,164,000)	(37,233,000)
Other expenses, net	121,000	(1,124,000)	(1,208,000)	(830,000)	(1,943,000)	(730,000)	(2,073,000)	(489,000)	(3,041,000)	(5,235,000)
Net loss before income taxes	(12,596,000)	(12,765,000)	(12,880,000)	(12,964,000)					(51,205,000)	(42,468,000)
Benefit for income taxes	(146,000)								(146,000)	0
Net loss	$ (12,450,000)	$ (12,765,000)	$ (12,880,000)	$ (12,964,000)	$ (12,877,000)	$ (9,459,000)	$ (11,227,000)	$ (8,905,000)	$ (51,059,000)	$ (42,468,000)