Vapotherm (VAPO) 10-Q 10 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 07, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	VAPO
Entity Registrant Name	Vapotherm Inc
Entity Central Index Key	0001253176
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		17,387,489

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 56,666	$ 58,223
Accounts receivable, net	6,658	7,107
Inventory	12,420	13,710
Prepaid expenses and other current assets	2,456	2,683
Total current assets	78,200	81,723
Property and equipment, net	13,901	13,416
Restricted cash	1,852	1,799
Goodwill	584
Intangible assets, net	455
Other long-term assets	350	308
Total assets	95,342	97,246
Current liabilities
Accounts payable	1,508	3,148
Contract liability	176	79
Accrued expenses and other liabilities	6,657	7,653
Short term line of credit	3,982	3,163
Total current liabilities	12,323	14,043
Long-term loans payable	41,574	31,317
Deferred tax liability	97
Other long-term liabilities	329	325
Total liabilities	54,323	45,685
Commitments and contingencies (Note 9)
Stockholders' equity
Preferred stock ($0.001 par value) 25,000,000 shares authorized as of March 31, 2019 and December 31, 2018, respectively; 0 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively
Common stock ($0.001 par value) 175,000,000 shares authorized as of March 31, 2019 and December 31, 2018, respectively; 16,899,685 and 16,782,837 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively	17	17
Additional paid-in capital	268,348	265,926
Accumulated deficit	(227,346)	(214,382)
Total stockholders' equity	41,019	51,561
Total liabilities and stockholders’ equity	$ 95,342	$ 97,246

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) - $ / shares	Mar. 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	16,899,685	16,782,837
Common stock, shares outstanding	16,899,685	16,782,837

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net revenue	$ 12,299	$ 10,739
Cost of goods sold	7,120	6,494
Gross profit	5,179	4,245
Operating expenses
Research and development	3,273	2,225
Sales and marketing	9,161	8,051
General and administrative	4,879	2,382
Loss on disposal of fixed assets		3
Total operating expenses	17,313	12,661
Loss from operations	(12,134)	(8,416)
Other (expense) income
Foreign currency loss	(9)	(3)
Interest income	203	1
Interest expense	(1,024)	(616)
Gain on change in fair value of warrant liabilities		128
Net loss	$ (12,964)	$ (8,906)
Net loss per share basic and diluted	$ (0.76)	$ (11.33)
Weighted-average number of shares used in calculating net loss per share, basic and diluted	16,949,027	786,184

CONSOLIDATED STATEMENTS OF REDE

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (unaudited) - USD ($)	Total	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance at Dec. 31, 2017	$ (126,857,000)		$ 1,000	$ 45,056,000	$ (171,914,000)
Beginning balance, shares at Dec. 31, 2017			672,321
Issuance of stock upon exercise of options	18,000			18,000
Issuance of stock upon exercise of options, shares			13,492
Issuance of restricted stock	83,000			83,000
Issuance of restricted stock, shares			50,385
Stock-based compensation expense	116,000			116,000
Net loss	(8,906,000)				(8,906,000)
Ending balance at Mar. 31, 2018	$ (135,546,000)		$ 1,000	45,273,000	(180,820,000)
Ending balance, shares at Mar. 31, 2018			736,198
Beginning balance at Dec. 31, 2017		10,515,351
Beginning balance at Dec. 31, 2017		$ 152,637,000
Ending balance at Mar. 31, 2018	10,515,351	10,515,351
Ending balance at Mar. 31, 2018		$ 152,637,000
Beginning balance at Dec. 31, 2018	$ 51,561,000		$ 17,000	265,926,000	(214,382,000)
Beginning balance, shares at Dec. 31, 2018			16,782,837
Issuance of common stock warrants	$ 293,000			293,000
Issuance of stock upon exercise of options, shares	268		268
Issuance of restricted stock	$ 226,000			226,000
Issuance of restricted stock, shares			116,580
Stock-based compensation expense	1,903,000			1,903,000
Net loss	(12,964,000)				(12,964,000)
Ending balance at Mar. 31, 2019	41,019,000		$ 17,000	$ 268,348,000	$ (227,346,000)
Ending balance, shares at Mar. 31, 2019			16,899,685
Beginning balance at Dec. 31, 2018	0
Ending balance at Mar. 31, 2019	$ 0

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (12,964)	$ (8,906)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	621	466
Stock-based compensation expense	1,903	116
Loss on disposal of fixed assets	23	150
Provision for bad debts	13	2
Amortization of discount on debt	44	14
Change in fair value of warrants		(128)
Changes in operating assets and liabilities:
Accounts receivable	847	189
Inventory	1,782	691
Prepaid expenses and other assets	197	75
Accounts payable	(1,658)	(597)
Contract liability	22	18
Accrued expenses and other liabilities	(661)	(2,570)
Net cash used in operating activities	(9,831)	(10,480)
Cash flows from investing activities
Acquisition of business, net of cash acquired	(1,560)
Purchases of property and equipment	(1,128)	(1,245)
Net cash used in investing activities	(2,688)	(1,245)
Cash flows from financing activities
Proceeds on loans	10,500
Debt issuance costs	(322)	(1)
Short term line of credit	837
Proceeds from exercise of stock options and purchase of restricted stock		393
Net cash provided by financing activities	11,015	392
Net decrease in cash, cash equivalents and restricted cash	(1,504)	(11,333)
Cash, cash equivalents and restricted cash
Beginning of period	60,022	28,360
End of period	58,518	17,027
Supplemental disclosures of cash flow information
Interest paid during the period	939	576
Issuance of warrants in conjunction with debt draw down	293
Property and equipment purchases in accrued expenses at period end	$ 42	$ 59

Description of Business

Description of Business	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
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 its Precision Flow systems, which include capital units and single-use disposables, 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 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. In addition, the Company utilizes clinical educators who are 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 an initial public offering 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 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 18 “Business Combinations” to these consolidated financial statements for details of this transaction.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of 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. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with our audited consolidated financial statements and the accompanying notes included in our Annual Report on Form 10-K for the year ended December 31, 2018 (the “2018 Form 10-K”). Our accounting policies are described in the “ Notes to Consolidated Financial Statements ” in our 2018 Form 10-K and updated, as necessary, in this report. The year-end consolidated balance sheet data presented for comparative purposes was derived from our audited financial statements but does not include all disclosures required by 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. Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America 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, fair values of acquired assets and liabilities, including goodwill and intangibles assets, warrant liabilities, realizability of inventories, allowance for bad debt and accrued expenses. Actual results may differ from these estimates. Unaudited Interim Financial Information The accompanying consolidated balance sheet as of March 31, 2019, the consolidated statements of operations, redeemable convertible preferred stock and stockholders’ equity (deficit) and of cash flows for the three months ended March 31, 2019 and 2018 are unaudited. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2019 and the results of its operations and its cash flows for the three months ended March 31, 2019 and 2018. The financial data and other information disclosed in these notes related to the three months ended March 31, 2019 and 2018 are also unaudited. The results of operations for the three months ended March 31, 2019, are not necessarily indicative of the operating results for the full year or for any other subsequent interim period. Recently Adopted Accounting Pronouncements Statement of Cash Flows (Topic 230): Restricted Cash In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”). ASU 2016-18 amends ASC 230 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 accounting principles generally accepted in the United States. 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 statement of cash flows. The Company adopted the new standard in the first quarter of fiscal 2019, under the retrospective adoption method, and prior year restricted cash 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) 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. The Company will adopt the new standard during interim and annual periods beginning after December 15, 2019. 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. 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. The Company has not yet determined the effects, if any, that the adoptions of ASU 2016-02 and ASU 2018-11 may 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. The new standard is effective for interim and annual periods beginning after December 15, 2019. 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. Foreign Currency 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 our 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. As of March 31, 2019, the Solus entity was included in our consolidated results due to the acquisition in February 2019. See Note 18 “Business Combinations” to these consolidated financial statements for details of this transaction. The f unctional currency for this entity 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 operations. Unrealized foreign currency gains or losses arising from transactions denominated in foreign currencies are recorded in other comprehensive income. 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. At March 31, 2019 and December 31, 2018, the Company had restricted cash related to certificates of deposits and collateral in relation to lease agreements. At March 31, 2019 and December 31, 2018, the Company did not hold any cash equivalents. 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 operations. Goodwill Goodwill represents the excess of purchase consideration over the fair value of net tangible and identifiable intangible assets acquired in a transaction 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 its reporting units to their carrying values. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, the Company would record an impairment loss equal to the difference. As described in Note 17 “Segment Reporting”, the Company operates in one operating segment and has two reporting units, Vapotherm and Solus. 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: Three Months Ended March 31, 2019 US International Total Net revenue by: Product Revenue Capital $ 1,510 $ 505 $ 2,015 Disposable 7,547 1,472 9,019 Subtotal Product Revenue 9,057 1,977 11,034 Lease Revenue 663 - 663 Service and Other Revenue 329 273 602 Total Revenue $ 10,049 $ 2,250 $ 12,299 Three Months Ended March 31, 2018 US International Total Net revenue by: Product Revenue Capital $ 1,572 $ 711 $ 2,283 Disposable 6,343 1,226 7,569 Subtotal Product Revenue 7,915 1,937 9,852 Lease Revenue 185 - 185 Service and Other Revenue 522 180 702 Total Revenue $ 8,622 $ 2,117 $ 10,739 Service and other revenue includes sales of non-Vapotherm products sold by Solus. Net revenue by U.S. and International is based on the customer location to which the product is shipped. No individual foreign country represents more than 10% of the Company’s total revenue. Product Returns 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 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 of less than $0.1 million is included in other current liabilities. 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. Business Combinations The Company uses its best estimates and assumptions to assign fair value to the tangible and intangible assets acquired and liabilities assumed at the acquisition date. The Company’s estimates are inherently uncertain and subject to refinement. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the fair value of these tangible and intangible assets acquired and liabilities assumed, with the corresponding offset to goodwill. In addition, uncertain tax positions and tax-related valuation allowances are initially recorded in connection with a business combination as of the acquisition date. The Company continues to collect information and re-evaluates these estimates and assumptions quarterly and records any adjustments to the Company’s preliminary estimates to goodwill provided that the Company is within the measurement period. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments will be recorded in the Company’s consolidated statement of operations. 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. The following table presents the components of total cash, cash equivalents, and restricted cash as set forth in our consolidated statements of cash flows: March 31, December 31, March 31, December 31, 2019 2018 2018 2017 Cash and cash equivalents $ 56,666 $ 58,223 $ 15,175 $ 26,508 Restricted cash 1,852 1,799 1,852 1,852 Total cash, cash equivalents, and restricted cash $ 58,518 $ 60,022 $ 17,027 $ 28,360

Accounts Receivable

Accounts Receivable	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Accounts Receivable	3. Accounts Receivable Accounts receivable owed to the Company by its customers and distributors consist of the following: March 31, 2019 December 31, 2018 United States $ 4,738 $ 4,948 International 2,203 2,493 Total accounts receivable 6,941 7,441 Less: Allowance for doubtful accounts (283 ) (334 ) Accounts receivable, net of allowance for doubtful accounts $ 6,658 $ 7,107 At March 31, 2019, the largest concentrations of accounts receivable, as a percentage of total accounts receivable, were with two distributors each representing 3% and one distributor representing 2% of total accounts receivable, respectively. At December 31, 2018, the largest concentrations of accounts receivable, as a percentage of total accounts receivable, were with one distributor representing 7% and two distributors representing 4% of total accounts receivable, respectively. No customers accounted for more than 10% of revenue or accounts receivable as of March 31, 2019 and December 31, 2018.

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2019
Investments All Other Investments [Abstract]
Financial Instruments	4. Financial Instruments As of March 31, 2019 and December 31, 2018, the Company’s financial instruments were comprised of cash, accounts receivables, accounts payable and debt, the carrying amounts of which approximated fair value due to the short-term nature and market interest rates. The Company’s warrant activity for the three months ended March 31, 2019 and March 31, 2018 are summarized as follows. Series A Redeemable Series B Redeemable Series C Redeemable Convertible Preferred Convertible Preferred Convertible Preferred Total Warrants Number of Shares Estimated Fair Value Weighted Average Exercise Price Number of Shares Estimated Fair Value Weighted Average Exercise Price Number of Shares Estimated Fair Value Weighted Average Exercise Price Number of Shares Estimated Fair Value Outstanding at December 31, 2017 158,202 $ 415 $ 14.00 12,857 $ 72 $ 14.00 4,285 $ 42 $ 14.00 175,344 $ 529 Gain on change in fair value - (127 ) - - (1 ) - - - - - (128 ) Outstanding at March 31, 2018 158,202 $ 288 $ 14.00 12,857 $ 71 $ 14.00 4,285 $ 42 $ 14.00 175,344 $ 401 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 Outstanding at March 31, 2019 250,085 $ 14.61 The Company did not grant any warrants in the three months ended March 31, 2018. During the three months ended March 31, 2019, in connection with an amendment to the Credit Agreement and Guaranty as further described in Note 8 “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, 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 less than $0.3 million, and is recorded as a discount against the principal owed on the related debt, to be amortized over the contractual term of the debt instrument.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Inventories	5. Inventories Inventories as of March 31, 2019 and December 31, 2018 consist of the following: March 31, 2019 December 31, 2018 Component parts $ 5,464 $ 5,601 Finished goods 6,956 8,109 Total inventory $ 12,420 $ 13,710

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2019
Property Plant And Equipment [Abstract]
Property and Equipment	6. Property and Equipment Property and equipment are carried at cost, less accumulated depreciation and amortization. A summary of the components of property and equipment, placed in service as of March 31, 2019 and December 31, 2018, is as follows: March 31, 2019 December 31, 2018 Equipment $ 939 $ 924 Furniture 962 957 Manufacturing equipment 4,175 4,166 Software 656 655 Demonstration, placements and evaluation units 8,013 7,135 Leasehold improvements 2,025 2,025 Construction in process 4,822 4,663 Total property and equipment 21,592 20,525 Less: Accumulated depreciation and amortization (7,691 ) (7,109 ) Total property and equipment, net $ 13,901 $ 13,416 Depreciation and amortization of property and equipment was $0.6 million and $0.5 million during the three months ended March 31, 2019 and March 31, 2018, respectively.

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	3 Months Ended
	Mar. 31, 2019
Payables And Accruals [Abstract]
Accrued Expenses and Other Liabilities	7. Accrued Expenses and Other Liabilities Accrued expenses and other liabilities as of March 31, 2019 and December 31, 2018 consist of the following: March 31, 2019 December 31, 2018 Accrued inventory $ 860 $ 1,070 Accrued commissions 747 1,464 Accrued bonuses 670 1,692 Accrued professional fees 644 253 Accrued payroll liability 435 86 Accrued vacation liability 431 427 Product warranty reserve 329 329 Accrued taxes 271 305 Refundable purchase price of unvested stock 265 346 Accrued employee reimbursement 177 178 Accrued rent and restoration costs 170 174 Accrued freight 85 52 Clinical studies 75 67 Accrued capital equipment 42 21 Other 1,456 1,189 Total accrued expenses and other liabilities $ 6,657 $ 7,653

Debt

Debt	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	8. 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 March 31, 2019 the interest rate was 7.3%. The outstanding balance under the Amended Revolver Agreement was $4.0 million at March 31, 2019 and there was no remaining availability based on eligible receivables. At December 31, 2018 the interest rate was 7.3%. 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 the $5.0 million tranches in January 2017 and March 2017, respectively. The Company pledged all assets as collateral with a double negative pledge on intellectual property. 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. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, 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 may draw the final $12.5 million of availability at any time through March 31, 2019 and eliminated the minimum 2018 revenue requirement of $43.2 million that was required to draw down the final tranche. 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 Perceptive warrants to purchase 3,769 shares of our Series D preferred stock. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, 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, exercisable at the option of the holder, in whole or in part, and expire in March 2029. 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. At March 31, 2019, the interest rate was 11.56%. The outstanding balance was $42.5 million at March 31, 2019 and there was no remaining availability. At December 31, 2018, the interest rate was 11.44%. The outstanding balance was $32.0 million at December 31, 2018 and the remaining availability was $10.5 million. 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 March 31, 2019, the Company was in compliance with these covenants. The annual principal maturities of the Amended Credit Agreement and Guaranty as of March 31, 2019 are as follows: 2019 $ - 2020 - 2021 - 2022 - 2023 42,539 Less: Discount on loans payable (965 ) Long-term loans payable $ 41,574

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies The Company’s principal office is located at 100 Domain Drive, Exeter, New Hampshire 03833, where it leases approximately 84,140 square feet of office, manufacturing, research & development and warehouse space. The Company leases this space under an agreement that terminates on January 29, 2026. The following table summarizes the future minimum combined lease payments for the years ended December 31, 2019 through 2023 and thereafter: Total Due As of March 31, 2019 Remainder of 2019 $ 1,166 2020 1,577 2021 1,601 2022 1,626 2023 1,652 Thereafter 1,820 Total $ 9,442 Rent expense for each of the three months ended March 31, 2019 and March 31, 2018 was $0.5 million. 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 is currently engaged in a litigation with Engineered Medical Systems, Inc. (“EMS”) a former supplier of a component of our Precision Flow systems. EMS filed a complaint against us in Indiana state court on June 12, 2018 alleging breach of contract and other causes of action and seeking damages of at least $800,000 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 and discovery is now underway in the New Hampshire matter. Following this decision, EMS withdrew its complaint in Indiana. The Company does not believe this matter will have a material adverse impact on the consolidated financial statements. 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.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes There is no provision for income taxes because the Company has historically incurred operating losses and maintains a full valuation allowance against its net deferred tax assets. The reported amount of income tax expense for the years differs from the amount that would result from applying domestic federal statutory tax rates to pretax losses primarily because of changes in valuation allowance. A reconciliation of income tax expense (benefit) is computed as the statutory federal income tax rate to income taxes as reflected in the financial statement as follows: Three Months Ended March 31, 2019 2018 Federal income tax (benefit) at statutory rate 21.0 % 34.0 % (Increase) decrease income tax benefit resulting from: Permanent differences 0.4 % 0.0 % Change in valuation allowance (21.0 )% (34.0 )% Other (0.4 )% 0.0 % Income tax expense (benefit) 0.0 % 0.0 % Significant components of the Company’s net deferred tax asset at March 31, 2019 and December 31, 2018 are as follows: March 31, December 31, 2019 2018 Deferred Tax Assets Net operating loss carryforwards $ 45,793 $ 42,444 Tax credit carryforwards 3,325 3,012 Deduction of research and development costs 4,676 4,239 Accounts receivable collection allowance 56 70 Inventory valuation reserves 306 154 Accrued bonus and vacation 278 579 Accrued warranty 86 86 Allowance for sales returns 18 18 Stock option expense attributed to non-ISO stock 567 358 Accrued other expenses 1,025 818 Other temporary differences (178 ) (70 ) Total gross deferred tax assets 55,952 51,708 Less: Valuation allowance (55,952 ) (51,708 ) Deferred tax asset after valuation allowance $ - $ - The Company’s major tax jurisdictions are the United States and New Hampshire. As of March 31, 2019, the Company had federal and state net operating loss carryforwards of $192.2 million and $86.3 million, respectively, which begin to expire in 2020. As of March 31, 2019, the Company had federal research and development tax credits carryforwards of $3.1 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, 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 full valuation allowance of $56.0 million and $51.7 million has been established at March 31, 2019 and December 31, 2018, respectively. The valuation allowance increased $4.3 million during the three months ended March 31, 2019, due primarily to net operating losses generated. Utilization of the net operating loss and research and development credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986 due to ownership change limitations that have occurred previously or that could occur in the future. On February 28, 2019, the Company acquired the shares of Solus For the period from February 29, 2019 to March 31,2019, Solus had a book loss of less than $0.1 million, resulting from sales of $0.2 million. Due to the short period of ownership, and related book loss, the tax provision for Solus is immaterial.

Stock Plans and Stock-Based Com

Stock Plans and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Plans and Stock-Based Compensation	11. Stock Plans and Stock-Based Compensation As of March 31, 2019 and December 31, 2018, 945,675 and 972,628 shares of common stock remain available for issuance under the 2018 Stock Incentive Plan (the “2018 SI Plan”), respectively. 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. On January 23, 2019, the Company established a French Qualifying Subplan that sits underneath the 2018 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 2018 SI Plan. The fair value of each option grant is estimated 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, related compensation cost is amortized over the performance period on an accelerated attribution basis. Compensation expense associated with performance awards are based upon the stock price 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 estimated forfeitures. Cumulative adjustments are recorded each quarter to reflect estimated outcome of the performance-related conditions until the date results are determined and settled. The weighted average assumptions used in the Black-Scholes options pricing model are as follows: Three Months Ended March 31, 2019 2018 Estimated fair value of common stock $ 19.65 $ 1.68 Expected dividend yield 0.0 % 0.0 % Risk free interest rate 2.5 % 2.4 % Expected stock price volatility 75.5 % 59.1 % Expected term (years) 6.1 6.0 Stock Options Stock option activity for the three months ended March 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 752,346 17.11 Options exercised (268 ) 1.64 Options canceled (23,396 ) 2.73 Outstanding at March 31, 2019 1,515,671 $ 9.71 8.59 $ 15,071 Exercisable at March 31, 2019 449,659 $ 1.83 6.46 $ 8,014 Vested and unvested expected to vest at March 31, 2019 1,515,671 $ 9.71 8.59 $ 15,071 The weighted average grant date fair value of options granted during the three months ended March 31, 2019 and 2018 was $11.59 and $0.95 per share, respectively. The aggregate intrinsic value of options exercised during the three months ended March 31, 2019 and 2018 was less than $0.1 million. The aggregate intrinsic value was calculated based on a positive difference between the closing stock price on March 31, 2019 and the exercise price per share of the underlying options. The aggregate intrinsic value was calculated based on a positive difference between the estimated fair value of the Company’s common stock as March 31, 2018 of $0.95 per share, and the exercise price per share of the underlying options. The compensation expense associated with stock options recognized during the three months ended March 31, 2019 and 2018 was $1.5 million and less than $0.1 million, respectively. Stock-based compensation is recorded in the consolidated statements of operations. As of March 31, 2019, the Company had unrecognized stock-based compensation expense related to its unvested stock options awards of $7.9 million, which is expected to be recognized over the remaining weighted average vesting period of 2.4 years. Restricted Stock A summary of restricted stock activity for the three months ended March 31, 2019 is as follows: Weighted Average Grant Date Shares Fair Value Unvested at December 31, 2018 399,485 $ 1.68 Granted/purchased 70,466 2.09 Vested (116,580 ) 1.67 Canceled - - Unvested at March 31, 2019 353,371 $ 1.68 The weighted average grant date fair value of restricted stock granted during the three months ended March 31, 2019 and 2018 was $15.65 and $0.94 per share, respectively. The compensation expense associated with restricted stock recognized during the three months ended March 31, 2019 and 2018 was $0.4 million and less than $0.1 million, respectively. Stock-based compensation is recorded in the consolidated statements of operations. As of March 31, 2019, the Company had unrecognized stock-based compensation expense related to its unvested restricted stock of $1.2 million, which is expected to be recognized over the remaining weighted average vesting period of 3.1 years.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Share	12. Earnings Per Share Net Loss per Share Basic and diluted net loss per share attributable to common shareholders was calculated as follows: Three Months Ended March 31, 2019 2018 Numerator: Net loss $ (12,964 ) $ (8,906 ) Net loss attributable to common stockholders $ (12,964 ) $ (8,906 ) Denominator: Weighted average common shares outstanding—basic and diluted 16,949,027 786,184 Net loss per share attributable to common stockholders— basic and diluted $ (0.76 ) $ (11.33 ) 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: Three Months Ended March 31, 2019 2018 Options to purchase common stock 1,515,671 745,078 Warrants to purchase redeemable convertible preferred stock (as converted to common stock) 250,085 175,345 Unvested restricted stock 353,371 388,888 Redeemable convertible preferred stock (as converted to common stock) - 10,515,351 2,119,127 11,824,662

Employee Benefit Plan

Employee Benefit Plan	3 Months Ended
	Mar. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	13. 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 25% of his or her compensation to the 401(k) Plan each year, subject to certain Internal Revenue Service limitations. On April 1, 2017, the Company began an employer 401(k) match. The match was effective for any funds contributed after April 1, 2017 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 for employees with annual earnings greater than $50,000. The Company contributed less than $0.1 million for the three months ended March 31, 2019 and March 31, 2018, respectively.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	14. Related Party Transactions As described in Note 15 “Redeemable Convertible Preferred Stock 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. The Company has two investors that are vendors of the Company. The total amount billed from these vendors during the three months ended March 31, 2019 and 2018 was less than $0.1 million and $0.7 million, respectively. The accounts payable balance for these vendors was $0.5 million as of March 31, 2019 and December 31, 2018, respectively. In addition, the Company sells its products to a hospital customer who is an affiliate of a current investor. The total amount billed to this customer during the three months ended March 31, 2019 and 2018 was $0.4 million, respectively. The accounts receivable balance for this customer was $0.1 million as of March 31, 2019 and December 31, 2018, respectively. All transactions are at arms’ length and occur at published list prices.

Warrants

Warrants	3 Months Ended
	Mar. 31, 2019
Warrants And Rights Note Disclosure [Abstract]
Warrants	15. Warrants In connection with certain of its redeemable convertible preferred stock issuances, the Company issued warrants for shares of its redeemable convertible preferred stock in fiscal year 2018 and earlier. See Note 4 “Financial Instruments” of the 2018 Form 10-K There was no outstanding redeemable convertible preferred stock as of March 31, 2019 or December 31, 2018. See Note “4 Financial Instruments” in this Quarterly Report on Form 10-Q for a rollforward of the Company’s common stock warrants.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity	16. Stockholders’ Equity Preferred Stock As of March 31, 2019 and December 31, 2018, the Company has authorized 25,000,000 shares of preferred stock, respectively, at a par value of $0.001. As of March 31, 2019 and December 31, 2018, there were no shares of preferred stock outstanding. Prior to the completion of the Company’s initial public offering in November 2018, the Company was authorized to issue common stock and Series A, Series B, Series C, and Series D preferred stock. A summary of the terms of the various types of redeemable convertible preferred stock at March 31, 2018, is as follows: Series A B C D Total Shares authorized 2,560,863 1,727,143 3,575,714 2,848,417 10,712,137 Shares issued 2,402,649 1,714,286 3,571,429 2,826,987 10,515,351 Conversion rate 1.0 1.0 1.0 1.0 Liquidation preference per share $ 14.000 $ 14.000 $ 14.000 $ 15.918 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. Common Stock As of March 31, 2019 and December 31, 2018, the Company has authorized 175,000,000 shares of common stock, respectively, at a par value of $0.001. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the Board of Directors, subject to the prior rights of holders of all classes of stock outstanding.

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Reporting	17. Segment Reporting 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. Segment information is consistent with how management reviews the business, makes investing and resource allocation decisions and assesses operating performance. All assets are in the United States, United Kingdom or at contracted suppliers.

Business Combinations

Business Combinations	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Business Combinations	18. Business Combinations On February 28, 2019, the Company completed the acquisition of the outstanding equity securities of Solus Medical Ltd. (“Solus”) The Company has not yet finalized the purchase accounting for the Solus acquisition during the first quarter of 2019. 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 11 Property and equipment 1 Goodwill 584 Intangible assets 455 Total assets acquired 2,420 Accounts payable and accrued expenses (222 ) Deferred revenue (75 ) Deferred taxes (97 ) 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 supplier agreements 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 U.K. 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. 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 The following unaudited pro forma information for the first quarter of fiscal year 2019 and 2018, respectively presents consolidated information as if the Solus acquisition occurred on January 1, 2018, which is the first day of our fiscal year 2018: March 31, 2019 2018 Net revenue $ 12,536 $ 11,506 Net loss $ (13,252 ) $ (9,138 ) Net loss per share, basic $ (0.78 ) $ (11.62 )

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	19. Subsequent Events As disclosed in the Company’s 2018 Form 10-K and in other filings with the SEC, in 2018 Stamford Devices Limited filed an opposition against its European patent – EP2806926. The title of the invention is Systems for Providing Respiratory Therapy. The patent is part of the accessory technologies in our patent portfolio. It provides an improved system for delivering breathing gas and aerosolized medications. The claims opposed were not embodied in any of the Company’s current commercialized products. A hearing on the matter with no payments exchanged in either direction was scheduled for May 9, 2019, however, the Company and Stamford Devices Limited reached an agreement on the matter and as a result Stamford Devices Limited withdrew their opposition on April 29, 2019 and the Opposition Division of the European Patent Office canceled the hearing on May 7, 2019, noting the matter would be continued with a written decision.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 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. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with our audited consolidated financial statements and the accompanying notes included in our Annual Report on Form 10-K for the year ended December 31, 2018 (the “2018 Form 10-K”). Our accounting policies are described in the “ Notes to Consolidated Financial Statements ” in our 2018 Form 10-K and updated, as necessary, in this report. The year-end consolidated balance sheet data presented for comparative purposes was derived from our audited financial statements but does not include all disclosures required by 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.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America 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, fair values of acquired assets and liabilities, including goodwill and intangibles assets, warrant liabilities, realizability of inventories, allowance for bad debt and accrued expenses. Actual results may differ from these estimates.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying consolidated balance sheet as of March 31, 2019, the consolidated statements of operations, redeemable convertible preferred stock and stockholders’ equity (deficit) and of cash flows for the three months ended March 31, 2019 and 2018 are unaudited. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2019 and the results of its operations and its cash flows for the three months ended March 31, 2019 and 2018. The financial data and other information disclosed in these notes related to the three months ended March 31, 2019 and 2018 are also unaudited. The results of operations for the three months ended March 31, 2019, are not necessarily indicative of the operating results for the full year or for any other subsequent interim period.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements Statement of Cash Flows (Topic 230): Restricted Cash In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”). ASU 2016-18 amends ASC 230 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 accounting principles generally accepted in the United States. 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 statement of cash flows. The Company adopted the new standard in the first quarter of fiscal 2019, under the retrospective adoption method, and prior year restricted cash 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) 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. The Company will adopt the new standard during interim and annual periods beginning after December 15, 2019. 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. 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. The Company has not yet determined the effects, if any, that the adoptions of ASU 2016-02 and ASU 2018-11 may 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. The new standard is effective for interim and annual periods beginning after December 15, 2019. 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.
Foreign Currency	Foreign Currency 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 our 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. As of March 31, 2019, the Solus entity was included in our consolidated results due to the acquisition in February 2019. See Note 18 “Business Combinations” to these consolidated financial statements for details of this transaction. The f unctional currency for this entity 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 operations. Unrealized foreign currency gains or losses arising from transactions denominated in foreign currencies are recorded in other comprehensive income.
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. At March 31, 2019 and December 31, 2018, the Company had restricted cash related to certificates of deposits and collateral in relation to lease agreements. At March 31, 2019 and December 31, 2018, the Company did not hold any cash equivalents. 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. The following table presents the components of total cash, cash equivalents, and restricted cash as set forth in our consolidated statements of cash flows: March 31, December 31, March 31, December 31, 2019 2018 2018 2017 Cash and cash equivalents $ 56,666 $ 58,223 $ 15,175 $ 26,508 Restricted cash 1,852 1,799 1,852 1,852 Total cash, cash equivalents, and restricted cash $ 58,518 $ 60,022 $ 17,027 $ 28,360
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 operations.
Goodwill	Goodwill Goodwill represents the excess of purchase consideration over the fair value of net tangible and identifiable intangible assets acquired in a transaction 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 its reporting units to their carrying values. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, the Company would record an impairment loss equal to the difference. As described in Note 17 “Segment Reporting”, the Company operates in one operating segment and has two reporting units, Vapotherm and Solus.
Disaggregated Revenue	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: Three Months Ended March 31, 2019 US International Total Net revenue by: Product Revenue Capital $ 1,510 $ 505 $ 2,015 Disposable 7,547 1,472 9,019 Subtotal Product Revenue 9,057 1,977 11,034 Lease Revenue 663 - 663 Service and Other Revenue 329 273 602 Total Revenue $ 10,049 $ 2,250 $ 12,299 Three Months Ended March 31, 2018 US International Total Net revenue by: Product Revenue Capital $ 1,572 $ 711 $ 2,283 Disposable 6,343 1,226 7,569 Subtotal Product Revenue 7,915 1,937 9,852 Lease Revenue 185 - 185 Service and Other Revenue 522 180 702 Total Revenue $ 8,622 $ 2,117 $ 10,739 Service and other revenue includes sales of non-Vapotherm products sold by Solus. Net revenue by U.S. and International is based on the customer location to which the product is shipped. No individual foreign country represents more than 10% of the Company’s total revenue.
Product Returns	Product Returns 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 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 of less than $0.1 million is included in other current liabilities.
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.
Business Combinations	Business Combinations The Company uses its best estimates and assumptions to assign fair value to the tangible and intangible assets acquired and liabilities assumed at the acquisition date. The Company’s estimates are inherently uncertain and subject to refinement. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the fair value of these tangible and intangible assets acquired and liabilities assumed, with the corresponding offset to goodwill. In addition, uncertain tax positions and tax-related valuation allowances are initially recorded in connection with a business combination as of the acquisition date. The Company continues to collect information and re-evaluates these estimates and assumptions quarterly and records any adjustments to the Company’s preliminary estimates to goodwill provided that the Company is within the measurement period. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments will be recorded in the Company’s consolidated statement of operations.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [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: Three Months Ended March 31, 2019 US International Total Net revenue by: Product Revenue Capital $ 1,510 $ 505 $ 2,015 Disposable 7,547 1,472 9,019 Subtotal Product Revenue 9,057 1,977 11,034 Lease Revenue 663 - 663 Service and Other Revenue 329 273 602 Total Revenue $ 10,049 $ 2,250 $ 12,299 Three Months Ended March 31, 2018 US International Total Net revenue by: Product Revenue Capital $ 1,572 $ 711 $ 2,283 Disposable 6,343 1,226 7,569 Subtotal Product Revenue 7,915 1,937 9,852 Lease Revenue 185 - 185 Service and Other Revenue 522 180 702 Total Revenue $ 8,622 $ 2,117 $ 10,739
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 our consolidated statements of cash flows: March 31, December 31, March 31, December 31, 2019 2018 2018 2017 Cash and cash equivalents $ 56,666 $ 58,223 $ 15,175 $ 26,508 Restricted cash 1,852 1,799 1,852 1,852 Total cash, cash equivalents, and restricted cash $ 58,518 $ 60,022 $ 17,027 $ 28,360

Accounts Receivable (Tables)

Accounts Receivable (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Summary of Accounts Receivable Owned to Company by Customers and Distributors	Accounts receivable owed to the Company by its customers and distributors consist of the following: March 31, 2019 December 31, 2018 United States $ 4,738 $ 4,948 International 2,203 2,493 Total accounts receivable 6,941 7,441 Less: Allowance for doubtful accounts (283 ) (334 ) Accounts receivable, net of allowance for doubtful accounts $ 6,658 $ 7,107

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2019
Warrants And Rights Note Disclosure [Abstract]
Summary of Warrant Activity	The Company’s warrant activity for the three months ended March 31, 2019 and March 31, 2018 are summarized as follows. Series A Redeemable Series B Redeemable Series C Redeemable Convertible Preferred Convertible Preferred Convertible Preferred Total Warrants Number of Shares Estimated Fair Value Weighted Average Exercise Price Number of Shares Estimated Fair Value Weighted Average Exercise Price Number of Shares Estimated Fair Value Weighted Average Exercise Price Number of Shares Estimated Fair Value Outstanding at December 31, 2017 158,202 $ 415 $ 14.00 12,857 $ 72 $ 14.00 4,285 $ 42 $ 14.00 175,344 $ 529 Gain on change in fair value - (127 ) - - (1 ) - - - - - (128 ) Outstanding at March 31, 2018 158,202 $ 288 $ 14.00 12,857 $ 71 $ 14.00 4,285 $ 42 $ 14.00 175,344 $ 401 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 Outstanding at March 31, 2019 250,085 $ 14.61

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories as of March 31, 2019 and December 31, 2018 consist of the following: March 31, 2019 December 31, 2018 Component parts $ 5,464 $ 5,601 Finished goods 6,956 8,109 Total inventory $ 12,420 $ 13,710

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2019
Property Plant And Equipment [Abstract]
Summary of Components of Property and Equipment, Placed in Service	Property and equipment are carried at cost, less accumulated depreciation and amortization. A summary of the components of property and equipment, placed in service as of March 31, 2019 and December 31, 2018, is as follows: March 31, 2019 December 31, 2018 Equipment $ 939 $ 924 Furniture 962 957 Manufacturing equipment 4,175 4,166 Software 656 655 Demonstration, placements and evaluation units 8,013 7,135 Leasehold improvements 2,025 2,025 Construction in process 4,822 4,663 Total property and equipment 21,592 20,525 Less: Accumulated depreciation and amortization (7,691 ) (7,109 ) Total property and equipment, net $ 13,901 $ 13,416

Accrued Expenses and Other Li_2

Accrued Expenses and Other Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
Payables And Accruals [Abstract]
Schedule of Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities as of March 31, 2019 and December 31, 2018 consist of the following: March 31, 2019 December 31, 2018 Accrued inventory $ 860 $ 1,070 Accrued commissions 747 1,464 Accrued bonuses 670 1,692 Accrued professional fees 644 253 Accrued payroll liability 435 86 Accrued vacation liability 431 427 Product warranty reserve 329 329 Accrued taxes 271 305 Refundable purchase price of unvested stock 265 346 Accrued employee reimbursement 177 178 Accrued rent and restoration costs 170 174 Accrued freight 85 52 Clinical studies 75 67 Accrued capital equipment 42 21 Other 1,456 1,189 Total accrued expenses and other liabilities $ 6,657 $ 7,653

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of Annual Principal Maturities of Amended Credit Agreement and Guaranty	The annual principal maturities of the Amended Credit Agreement and Guaranty as of March 31, 2019 are as follows: 2019 $ - 2020 - 2021 - 2022 - 2023 42,539 Less: Discount on loans payable (965 ) Long-term loans payable $ 41,574

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Summary of Future Minimum Combined Lease Payments	The following table summarizes the future minimum combined lease payments for the years ended December 31, 2019 through 2023 and thereafter: Total Due As of March 31, 2019 Remainder of 2019 $ 1,166 2020 1,577 2021 1,601 2022 1,626 2023 1,652 Thereafter 1,820 Total $ 9,442

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Income Tax Expense (Benefit)	A reconciliation of income tax expense (benefit) is computed as the statutory federal income tax rate to income taxes as reflected in the financial statement as follows: Three Months Ended March 31, 2019 2018 Federal income tax (benefit) at statutory rate 21.0 % 34.0 % (Increase) decrease income tax benefit resulting from: Permanent differences 0.4 % 0.0 % Change in valuation allowance (21.0 )% (34.0 )% Other (0.4 )% 0.0 % Income tax expense (benefit) 0.0 % 0.0 %
Significant Components of Net Deferred Tax Asset	Significant components of the Company’s net deferred tax asset at March 31, 2019 and December 31, 2018 are as follows: March 31, December 31, 2019 2018 Deferred Tax Assets Net operating loss carryforwards $ 45,793 $ 42,444 Tax credit carryforwards 3,325 3,012 Deduction of research and development costs 4,676 4,239 Accounts receivable collection allowance 56 70 Inventory valuation reserves 306 154 Accrued bonus and vacation 278 579 Accrued warranty 86 86 Allowance for sales returns 18 18 Stock option expense attributed to non-ISO stock 567 358 Accrued other expenses 1,025 818 Other temporary differences (178 ) (70 ) Total gross deferred tax assets 55,952 51,708 Less: Valuation allowance (55,952 ) (51,708 ) Deferred tax asset after valuation allowance $ - $ -

Stock Plans and Stock-Based C_2

Stock Plans and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
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: Three Months Ended March 31, 2019 2018 Estimated fair value of common stock $ 19.65 $ 1.68 Expected dividend yield 0.0 % 0.0 % Risk free interest rate 2.5 % 2.4 % Expected stock price volatility 75.5 % 59.1 % Expected term (years) 6.1 6.0
Summary of Stock Option Activity	Stock option activity for the three months ended March 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 752,346 17.11 Options exercised (268 ) 1.64 Options canceled (23,396 ) 2.73 Outstanding at March 31, 2019 1,515,671 $ 9.71 8.59 $ 15,071 Exercisable at March 31, 2019 449,659 $ 1.83 6.46 $ 8,014 Vested and unvested expected to vest at March 31, 2019 1,515,671 $ 9.71 8.59 $ 15,071
Summary of Restricted Stock Activity	Restricted Stock A summary of restricted stock activity for the three months ended March 31, 2019 is as follows: Weighted Average Grant Date Shares Fair Value Unvested at December 31, 2018 399,485 $ 1.68 Granted/purchased 70,466 2.09 Vested (116,580 ) 1.67 Canceled - - Unvested at March 31, 2019 353,371 $ 1.68

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Summary of Basic and diluted Net Loss Per Share Attributable to Common Shareholders	Basic and diluted net loss per share attributable to common shareholders was calculated as follows: Three Months Ended March 31, 2019 2018 Numerator: Net loss $ (12,964 ) $ (8,906 ) Net loss attributable to common stockholders $ (12,964 ) $ (8,906 ) Denominator: Weighted average common shares outstanding—basic and diluted 16,949,027 786,184 Net loss per share attributable to common stockholders— basic and diluted $ (0.76 ) $ (11.33 )
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: Three Months Ended March 31, 2019 2018 Options to purchase common stock 1,515,671 745,078 Warrants to purchase redeemable convertible preferred stock (as converted to common stock) 250,085 175,345 Unvested restricted stock 353,371 388,888 Redeemable convertible preferred stock (as converted to common stock) - 10,515,351 2,119,127 11,824,662

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Summary of Terms of Various Types of Redeemable Convertible Preferred Stock	A summary of the terms of the various types of redeemable convertible preferred stock at March 31, 2018, is as follows: Series A B C D Total Shares authorized 2,560,863 1,727,143 3,575,714 2,848,417 10,712,137 Shares issued 2,402,649 1,714,286 3,571,429 2,826,987 10,515,351 Conversion rate 1.0 1.0 1.0 1.0 Liquidation preference per share $ 14.000 $ 14.000 $ 14.000 $ 15.918

Business Combinations (Tables)

Business Combinations (Tables)	3 Months Ended
	Mar. 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 11 Property and equipment 1 Goodwill 584 Intangible assets 455 Total assets acquired 2,420 Accounts payable and accrued expenses (222 ) Deferred revenue (75 ) Deferred taxes (97 ) Total liabilities assumed (394 ) Total purchase price $ 2,026
Summary of Business Acquisition Pro Forma Information	The following unaudited pro forma information for the first quarter of fiscal year 2019 and 2018, respectively presents consolidated information as if the Solus acquisition occurred on January 1, 2018, which is the first day of our fiscal year 2018: March 31, 2019 2018 Net revenue $ 12,536 $ 11,506 Net loss $ (13,252 ) $ (9,138 ) Net loss per share, basic $ (0.78 ) $ (11.62 )

Description of Business - Addit

Description of Business - Additional Information (Details) - Initial Public Offering - Common Stock $ / shares in Units, $ in Millions	Nov. 16, 2018USD ($)$ / sharesshares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued | shares	4,600,000
Public offering price of common stock | $ / shares	$ 14
Proceeds from initial offering net of underwriting discounts and offering costs	$ 57.4
Underwriting discount	4.5
Offering expenses	$ 2.5

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	Nov. 02, 2018$ / shares	Mar. 31, 2019USD ($)Segment$ / shares	Dec. 31, 2018USD ($)$ / shares
Summary Of Significant Accounting Policies [Line Items]
Cash equivalents | $		$ 0	$ 0
Number of operating segment | Segment		1
Number of reporting units | Segment		2
Standard product warranty period		1 year
Reverse stock split	14
Common stock, par value | $ / shares	$ 0.001	$ 0.001	$ 0.001
Maximum
Summary Of Significant Accounting Policies [Line Items]
Product return liability | $		$ 100,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Net Revenue Disaggregated into Categories (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 12,299	$ 10,739
US
Disaggregation Of Revenue [Line Items]
Total Revenue	10,049	8,622
International
Disaggregation Of Revenue [Line Items]
Total Revenue	2,250	2,117
Product Revenue, Capital
Disaggregation Of Revenue [Line Items]
Total Revenue	2,015	2,283
Product Revenue, Capital | US
Disaggregation Of Revenue [Line Items]
Total Revenue	1,510	1,572
Product Revenue, Capital | International
Disaggregation Of Revenue [Line Items]
Total Revenue	505	711
Product Revenue, Disposable
Disaggregation Of Revenue [Line Items]
Total Revenue	9,019	7,569
Product Revenue, Disposable | US
Disaggregation Of Revenue [Line Items]
Total Revenue	7,547	6,343
Product Revenue, Disposable | International
Disaggregation Of Revenue [Line Items]
Total Revenue	1,472	1,226
Subtotal Product Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	11,034	9,852
Subtotal Product Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	9,057	7,915
Subtotal Product Revenue | International
Disaggregation Of Revenue [Line Items]
Total Revenue	1,977	1,937
Lease Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	663	185
Lease Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	663	185
Service and Other Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	602	702
Service and Other Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	329	522
Service and Other Revenue | International
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 273	$ 180

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Components of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 56,666	$ 58,223	$ 15,175	$ 26,508
Restricted cash	1,852	1,799	1,852	1,852
Total cash, cash equivalents, and restricted cash	$ 58,518	$ 60,022	$ 17,027	$ 28,360

Accounts Receivable - Summary o

Accounts Receivable - Summary of Accounts Receivable Owned to Company by Customers and Distributors (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	$ 6,941	$ 7,441
Less: Allowance for doubtful accounts	(283)	(334)
Accounts receivable, net of allowance for doubtful accounts	6,658	7,107
US
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	4,738	4,948
International
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	$ 2,203	$ 2,493

Accounts Receivable - Additiona

Accounts Receivable - Additional Information (Details) - Accounts Receivable - Customer Concentration Risk	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Distributor One
Accounts Notes And Loans Receivable [Line Items]
Percentage of accounts receivable	3.00%	7.00%
Distributor Two
Accounts Notes And Loans Receivable [Line Items]
Percentage of accounts receivable	3.00%	4.00%
Distributor Three
Accounts Notes And Loans Receivable [Line Items]
Percentage of accounts receivable	2.00%	4.00%

Financial Instruments - Summary

Financial Instruments - Summary of Warrant Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Class Of Warrant Or Right [Line Items]
Gain on change in fair value		$ 128
Common Stock Warrants
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance	230,295
Number of shares, warrants granted	19,790
Number of shares, ending balance	250,085
Common Stock Warrants | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise Price, beginning balance	$ 14.50
Weighted average exercise price, warrants granted	15.92
Weighted average exercise Price, ending balance	$ 14.61
Warrants
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance		175,344
Number of shares, ending balance		175,344
Estimated fair value, beginning balance		$ 529
Gain on change in fair value		(128)
Estimated fair value, ending balance		$ 401
Warrants | Series A Redeemable Convertible Preferred
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance		158,202
Number of shares, ending balance		158,202
Estimated fair value, beginning balance		$ 415
Gain on change in fair value		(127)
Estimated fair value, ending balance		$ 288
Warrants | Series A Redeemable Convertible Preferred | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise Price, beginning balance		$ 14
Weighted average exercise Price, ending balance		$ 14
Warrants | Series B Redeemable Convertible Preferred member
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance		12,857
Number of shares, ending balance		12,857
Estimated fair value, beginning balance		$ 72
Gain on change in fair value		(1)
Estimated fair value, ending balance		$ 71
Warrants | Series B Redeemable Convertible Preferred member | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise Price, beginning balance		$ 14
Weighted average exercise Price, ending balance		$ 14
Warrants | Series C Redeemable Convertible Preferred member
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance		4,285
Number of shares, ending balance		4,285
Estimated fair value, beginning balance		$ 42
Estimated fair value, ending balance		$ 42
Warrants | Series C Redeemable Convertible Preferred member | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise Price, beginning balance		$ 14
Weighted average exercise Price, ending balance		$ 14

Financial Instruments - Additio

Financial Instruments - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Class Of Warrant Or Right [Line Items]
Granted warrants to purchase shares		0
Estimated fair value of warrants	$ 0.3
Amendment To Credit Agreement And Guaranty
Class Of Warrant Or Right [Line Items]
Granted warrants to purchase shares	19,790
Warrants exercise price	$ 15.92
Warrants expiration, month and year	2029-03

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Component parts	$ 5,464	$ 5,601
Finished goods	6,956	8,109
Total inventory	$ 12,420	$ 13,710

Property and Equipment - Summar

Property and Equipment - Summary of Components of Property and Equipment, Placed in Service (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total property and equipment	$ 21,592	$ 20,525
Less: Accumulated depreciation and amortization	(7,691)	(7,109)
Total property and equipment, net	13,901	13,416
Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	939	924
Furniture
Property Plant And Equipment [Line Items]
Total property and equipment	962	957
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	4,175	4,166
Software
Property Plant And Equipment [Line Items]
Total property and equipment	656	655
Demonstration, Placements and Evaluation Units
Property Plant And Equipment [Line Items]
Total property and equipment	8,013	7,135
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	2,025	2,025
Construction in Progress
Property Plant And Equipment [Line Items]
Total property and equipment	$ 4,822	$ 4,663

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation and amortization	$ 621	$ 466

Accrued Expenses and Other Li_3

Accrued Expenses and Other Liabilities - Schedule of Accrued expenses and other liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued inventory	$ 860	$ 1,070
Accrued commissions	747	1,464
Accrued bonuses	670	1,692
Accrued professional fees	644	253
Accrued payroll liability	435	86
Accrued vacation liability	431	427
Product warranty reserve	329	329
Accrued taxes	271	305
Refundable purchase price of unvested stock	265	346
Accrued employee reimbursement	177	178
Accrued rent and restoration costs	170	174
Accrued freight	85	52
Clinical studies	75	67
Accrued capital equipment	42	21
Other	1,456	1,189
Total accrued expenses and other liabilities	$ 6,657	$ 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

Nov. 16, 2016USD ($)Tranche

Apr. 30, 2018USD ($)

Mar. 31, 2017USD ($)

Jan. 31, 2017USD ($)

Mar. 31, 2019USD ($)

Mar. 21, 2019USD ($)

Mar. 31, 2018shares

Debt Instrument [Line Items]

Proceeds from term loan

$ 10,500,000

Granted warrants to purchase shares | shares

0

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

Line of credit, interest rate

7.30%

Outstanding balance under line of credit

$ 3,200,000

Line of credit, remaining availability under agreement

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

7.30%

Outstanding balance under line of credit

$ 4,000,000

Line of credit, remaining availability under agreement

0

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

32,000,000

$ 42,500,000

$ 42,500,000

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

Warrants exercise price | $ / shares

$ 15.92

Warrants expiration, month and year

2029-03

Term loan, interest rate

11.44%

11.56%

Term loan, remaining availability under agreement

$ 10,500,000

$ 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 March 31, 2019, the Company was in compliance with these covenants.

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 Amended Credit Agreement and Guaranty (Details) - Loans Payable $ in Thousands	Mar. 31, 2019USD ($)
Debt Instrument [Line Items]
2019	$ 0
2020	0
2021	0
2022	0
2023	42,539
Less: Discount on loans payable	(965)
Long-term loans payable	$ 41,574

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Jun. 15, 2018USD ($)	Jun. 12, 2018USD ($)	Mar. 31, 2019USD ($)ft²	Mar. 31, 2018USD ($)
Loss Contingencies [Line Items]
Area of office leases | ft²			84,140
Lease terminates date			Jan. 29, 2026
Rent expense			$ 500,000	$ 500,000
Minimum
Loss Contingencies [Line Items]
Breach of contract and other causes of action and seeking damages	$ 2,100,000	$ 800,000

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Future Minimum Combined Lease Payments (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
Remainder of 2019	$ 1,166
2020	1,577
2021	1,601
2022	1,626
2023	1,652
Thereafter	1,820
Total	$ 9,442

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Income Tax Contingency [Line Items]
Provision for income taxes		$ 0
Valuation allowance	$ 55,952,000	55,952,000		$ 51,708,000
Increase in valuation allowance		4,300,000
Book loss		(12,964,000)	$ (8,906,000)
Sales		12,299,000	$ 10,739,000
Solus
Income Tax Contingency [Line Items]
Sales	200,000
Solus | Maximum
Income Tax Contingency [Line Items]
Book loss	100,000
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	192,200,000	$ 192,200,000
Net operating loss carryforwards, expiration beginning year		2020
Federal | Research and Development
Income Tax Contingency [Line Items]
Tax credit carryforward	3,100,000	$ 3,100,000
Tax credit carryforward, expiration beginning year		2021
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 86,300,000	$ 86,300,000
Net operating loss carryforwards, expiration beginning year		2020

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Income Tax Expense (Benefit) (Details)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Federal income tax (benefit) at statutory rate	21.00%	34.00%
(Increase) decrease income tax benefit resulting from:
Permanent differences	0.40%	0.00%
Change in valuation allowance	(21.00%)	(34.00%)
Other	(0.40%)	0.00%
Income tax expense (benefit)	0.00%	0.00%

Income Taxes - Significant Comp

Income Taxes - Significant Components of Net Deferred Tax Asset (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Deferred Tax Assets
Net operating loss carryforwards	$ 45,793	$ 42,444
Tax credit carryforwards	3,325	3,012
Deduction of research and development costs	4,676	4,239
Accounts receivable collection allowance	56	70
Inventory valuation reserves	306	154
Accrued bonus and vacation	278	579
Accrued warranty	86	86
Allowance for sales returns	18	18
Stock option expense attributed to non-ISO stock	567	358
Accrued other expenses	1,025	818
Other temporary differences	(178)	(70)
Total gross deferred tax assets	55,952	51,708
Less: Valuation allowance	(55,952)	(51,708)
Deferred tax asset after valuation allowance	$ 0	$ 0

Stock Plans and Stock-Based C_3

Stock Plans and Stock-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Average forfeiture rates	4.74%	5.07%
Weighted average grant date fair value of options granted	$ 11.59	$ 0.95
Aggregate intrinsic value of options exercised	$ 100,000	$ 100,000
Estimated fair value of common stock		$ 0.95
Unrecognized stock-based compensation expense	$ 7,900,000
Unrecognized stock-based compensation expense recognized, remaining weighted average vesting period	2 years 4 months 24 days
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense recognized	$ 1,500,000
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	3 years 1 month 6 days
Compensation expense recognized	$ 400,000
Unrecognized stock-based compensation expense	$ 1,200,000
Weighted average grant date fair value, granted	$ 15.65	$ 0.94
Maximum | Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense recognized		$ 100,000
Maximum | Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense recognized		$ 100,000
2018 SI Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock remain available for issuance	945,675		972,628
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

Stock Plans and Stock-Based C_4

Stock Plans and Stock-Based Compensation - Schedule of Weighted Average Assumptions Used in Black-Scholes Options Pricing Model (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Estimated fair value of common stock	$ 19.65	$ 1.68
Expected dividend yield	0.00%	0.00%
Risk free interest rate	2.50%	2.40%
Expected stock price volatility	75.50%	59.10%
Expected term (years)	6 years 1 month 6 days	6 years

Stock Plans and Stock-Based C_5

Stock Plans and Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 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	752,346
Number of Underlying Common Shares, Options exercised	(268)
Number of Underlying Common Shares, Options canceled	(23,396)
Number of Underlying Common Shares, Outstanding, Ending balance	1,515,671	786,989
Number of Underlying Common Shares, Exercisable	449,659
Number of Underlying Common Shares, Vested and unvested expected to vest	1,515,671
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 2.41
Weighted Average Exercise Price, Options granted	17.11
Weighted Average Exercise Price, Options exercised	1.64
Weighted Average Exercise Price, Options canceled	2.73
Weighted Average Exercise Price, Outstanding, Ending balance	9.71	$ 2.41
Weighted Average Exercise Price, Exercisable	1.83
Weighted Average Exercise Price, Vested and unvested expected to vest	$ 9.71
Weighted Average Remaining Contractual Term	8 years 7 months 2 days	7 years 10 months 13 days
Weighted Average Remaining Contractual Term, Exercisable	6 years 5 months 15 days
Weighted Average Remaining Contractual Term, Vested and unvested expected to vest	8 years 7 months 2 days
Aggregate Intrinsic Value, Outstanding	$ 15,071	$ 13,801
Aggregate Intrinsic Value, Exercisable	8,014
Aggregate Intrinsic Value, Vested and unvested expected to vest	$ 15,071

Stock Plans and Stock-Based C_6

Stock Plans and Stock-Based Compensation - Summary of Restricted Stock Activity (Details) - Restricted Stock	3 Months Ended
	Mar. 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	70,466
Shares, Vested | shares	(116,580)
Shares, Canceled | shares	0
Shares, Unvested Ending balance | shares	353,371
Weighted Average Grant Date Fair Value, Unvested, Beginning balance | $ / shares	$ 1.68
Weighted Average Grant Date Fair Value, Granted/purchased | $ / shares	2.09
Weighted Average Grant Date Fair Value, Vested | $ / shares	1.67
Weighted Average Grant Date Fair Value, Canceled | $ / shares	0
Weighted Average Grant Date Fair Value, Unvested Ending balance | $ / shares	$ 1.68

Earnings Per Share - Summary of

Earnings Per Share - Summary of Basic and diluted Net Loss Per Share Attributable to Common Shareholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net loss	$ (12,964)	$ (8,906)
Net loss attributable to common stockholders	$ (12,964)	$ (8,906)
Denominator:
Weighted-average number of shares used in calculating net loss per share, basic and diluted	16,949,027	786,184
Net loss per share attributable to common stockholders— basic and diluted	$ (0.76)	$ (11.33)

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,119,127	11,824,662
Redeemable Convertible Preferred Stock (as Converted to Common Stock)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		10,515,351
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	1,515,671	745,078
Warrants to Purchase Redeemable Convertible Preferred Stock (as Converted to Common Stock)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	250,085	175,345
Unvested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	353,371	388,888

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Details) - USD ($)	Apr. 01, 2017	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined contribution, plan name		401(k) retirement plan
Maximum annual contributions per employee	4.00%	25.00%
Employer matching contribution percentage	50.00%
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
Defined contribution plan		$ 100,000	$ 100,000
Minimum
Defined Benefit Plan Disclosure [Line Items]
Employees annual earnings	$ 50,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 30, 2018	Mar. 31, 2019USD ($)Investor	Dec. 31, 2018USD ($)	Mar. 31, 2018USD ($)
Related Party Transaction [Line Items]
Number of investor | Investor		2
Accounts payable to vendors		$ 0.5	$ 0.5
Total amount due from customer		0.4		$ 0.4
Accounts receivable from customer		0.1	0.1
Maximum
Related Party Transaction [Line Items]
Total amount billed from related parties		$ 0.1		$ 0.7
Redeemable Convertible Preferred Stock
Related Party Transaction [Line Items]
Preferred stock purchased by related party			$ 33.2
Temporary equity to permanent equity conversion basis		one-to-one basis
Temporary to permanent equity conversion ratio	100.00%

Warrants - Additional Informati

Warrants - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Class Of Warrant Or Right [Line Items]
Outstanding redeemable convertible preferred stock	$ 0		$ 0
Long term debt draw down	10,500,000
Granted warrants to purchase shares		0
Gain on change in fair value of preferred stock warrants		$ 100,000
Amended Credit Agreement and Guaranty
Class Of Warrant Or Right [Line Items]
Long term debt draw down	$ 10,500,000
Granted warrants to purchase shares	19,790
Warrants exercise price	$ 15.92
Warrants expire date	2029-03

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details)	1 Months Ended	3 Months Ended
	Nov. 30, 2018	Mar. 31, 2019Vote$ / sharesshares	Dec. 31, 2018$ / sharesshares	Nov. 02, 2018$ / shares
Stockholders Equity [Line Items]
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, 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
Redeemable Convertible Preferred Stock
Stockholders Equity [Line Items]
Temporary equity to permanent equity conversion basis		one-to-one basis
Temporary to permanent equity conversion ratio	100.00%

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Terms of Various Types of Redeemable Convertible Preferred Stock (Details)	Nov. 02, 2018	Mar. 31, 2018$ / sharesshares
Temporary Equity [Line Items]
Shares authorized		10,712,137
Shares issued		10,515,351
Conversion rate	14
Series A Redeemable Convertible Preferred
Temporary Equity [Line Items]
Shares authorized		2,560,863
Shares issued		2,402,649
Conversion rate		1
Liquidation preference per share | $ / shares		$ 14
Series B Redeemable Convertible Preferred member
Temporary Equity [Line Items]
Shares authorized		1,727,143
Shares issued		1,714,286
Conversion rate		1
Liquidation preference per share | $ / shares		$ 14
Series C Redeemable Convertible Preferred member
Temporary Equity [Line Items]
Shares authorized		3,575,714
Shares issued		3,571,429
Conversion rate		1
Liquidation preference per share | $ / shares		$ 14
Series D Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Shares authorized		2,848,417
Shares issued		2,826,987
Conversion rate		1
Liquidation preference per share | $ / shares		$ 15.918

Segment Reporting - Additional

Segment Reporting - Additional Information (Details)	3 Months Ended
	Mar. 31, 2019Segment
Segment Reporting [Abstract]
Number of reporting segment	1

Business Combinations - Additio

Business Combinations - Additional Information (Details) - USD ($) $ in Thousands	Feb. 28, 2019	Mar. 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
Loss on settlement of preexisting relationship	400
Business combination estimate of contingent payments as compensation to be recognized	$ 2,400
Business combination, contingent payments as compensation, payment period	2 years
Weighted average amortization period for intangible assets		3 years 9 months 29 days
Solus | General and Administrative Expense
Business Acquisition [Line Items]
Transaction costs associated with acquisition		$ 200

Business Combinations - Summary

Business Combinations - Summary of Preliminary Purchase Price Allocation (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Feb. 28, 2019
Business Acquisition [Line Items]
Goodwill	$ 584
Solus
Business Acquisition [Line Items]
Cash		$ 466
Accounts receivable		411
Inventory		492
Prepaids and other assets		11
Property and equipment		1
Goodwill		584
Intangible assets		455
Total assets acquired		2,420
Accounts payable and accrued expenses		(222)
Deferred revenue		(75)
Deferred taxes		(97)
Total liabilities assumed		(394)
Total purchase price		$ 2,026

Business Combinations - Summa_2

Business Combinations - Summary of Business Acquisition Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Business Combinations [Abstract]
Net revenue	$ 12,536	$ 11,506
Net loss	$ (13,252)	$ (9,138)
Net loss per share, basic	$ (0.78)	$ (11.62)