Vapotherm (VAPO) 10-Q 29 Jul 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 26, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
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		17,499,391
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity File Number	001-38740
Entity Tax Identification Number	462259298
Entity Address, Address Line One	100 Domain Drive
Entity Address, City or Town	Exeter
Entity Address, State or Province	N.H.
Entity Address, Postal Zip Code	03833
Local Phone Number	(603) 658-0011

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 46,055	$ 58,223
Accounts receivable, net	7,304	7,107
Inventory	11,219	13,710
Prepaid expenses and other current assets	2,256	2,683
Total current assets	66,834	81,723
Property and equipment, net	14,142	13,416
Restricted cash	1,852	1,799
Goodwill	584
Intangible assets, net	415
Other long-term assets	347	308
Total assets	84,174	97,246
Current liabilities
Accounts payable	1,570	3,148
Contract liability	138	79
Accrued expenses and other current liabilities	7,936	7,653
Short-term line of credit	3,162	3,163
Total current liabilities	12,806	14,043
Long-term loans payable	41,645	31,317
Deferred tax liability	97
Other long-term liabilities	277	325
Total liabilities	54,825	45,685
Commitments and contingencies (Note 9)
Stockholders' equity
Preferred stock ($0.001 par value) 25,000,000 shares authorized; 0 shares issued and outstanding as of June 30, 2019 and December 31, 2018
Common stock ($0.001 par value) 175,000,000 shares authorized as of June 30, 2019 and December 31, 2018, respectively; 17,166,368 and 16,782,837 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	17	17
Additional paid-in capital	269,556	265,926
Accumulated deficit	(240,226)	(214,382)
Accumulated other comprehensive income	2
Total stockholders' equity	29,349	51,561
Total liabilities and stockholders’ equity	$ 84,174	$ 97,246

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) - $ / shares	Jun. 30, 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	17,166,368	16,782,837
Common stock, shares outstanding	17,166,368	16,782,837

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net revenue	$ 11,986	$ 10,563	$ 24,285	$ 21,302
Cost of goods sold	6,527	6,468	13,647	12,962
Gross profit	5,459	4,095	10,638	8,340
Operating expenses
Research and development	3,167	2,083	6,440	4,308
Sales and marketing	9,432	8,523	18,593	16,574
General and administrative	4,532	2,603	9,411	4,985
Loss on disposal of fixed assets		39		42
Total operating expenses	17,131	13,248	34,444	25,909
Loss from operations	(11,672)	(9,153)	(23,806)	(17,569)
Other (expense) income
Foreign currency gain (loss)		1	(9)	(2)
Interest income	213	12	416	13
Interest expense	(1,421)	(498)	(2,445)	(1,114)
Loss on extinguishment of debt		(1,842)		(1,842)
Gain on change in fair value of warrant liabilities		254		382
Net loss	$ (12,880)	$ (11,226)	$ (25,844)	$ (20,132)
Net loss per share basic and diluted	$ (0.76)	$ (13.39)	$ (1.52)	$ (24.78)
Other comprehensive income, net of tax:
Foreign currency translation adjustments	$ 2		$ 2
Total other comprehensive income	2		2
Total comprehensive loss	$ (12,878)	$ (11,226)	$ (25,842)	$ (20,132)
Weighted-average number of shares used in calculating net loss per share, basic and diluted	17,055,628	838,428	17,019,002	812,451

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	Accumulated Other Comprehensive Income
Temporary equity, beginning balance at Dec. 31, 2017		$ 152,637,000
Temporary equity, beginning balance, shares at Dec. 31, 2017		10,515,351
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
Net loss	(20,132,000)				(20,132,000)
Issuance of stock upon exercise of options	50,000			50,000
Issuance of stock upon exercise of options, shares			31,098
Issuance of restricted stock	120,000			120,000
Issuance of restricted stock, shares			71,624
Stock-based compensation expense	234,000			234,000
Ending balance at Jun. 30, 2018	(146,585,000)		$ 1,000	45,460,000	(192,046,000)
Ending balance, shares at Jun. 30, 2018			775,043
Temporary equity, ending balance at Jun. 30, 2018		$ 152,637,000
Temporary equity, ending balance, shares at Jun. 30, 2018		10,515,351
Temporary equity, beginning balance at Mar. 31, 2018		$ 152,637,000
Temporary equity, beginning balance, shares at Mar. 31, 2018		10,515,351
Beginning balance at Mar. 31, 2018	(135,546,000)		$ 1,000	45,273,000	(180,820,000)
Beginning balance, shares at Mar. 31, 2018			736,198
Net loss	(11,226,000)				(11,226,000)
Issuance of stock upon exercise of options	32,000			32,000
Issuance of stock upon exercise of options, shares			17,606
Issuance of restricted stock	37,000			37,000
Issuance of restricted stock, shares			21,239
Stock-based compensation expense	118,000			118,000
Ending balance at Jun. 30, 2018	(146,585,000)		$ 1,000	45,460,000	(192,046,000)
Ending balance, shares at Jun. 30, 2018			775,043
Temporary equity, ending balance at Jun. 30, 2018		$ 152,637,000
Temporary equity, ending balance, shares at Jun. 30, 2018		10,515,351
Temporary equity, beginning balance at Dec. 31, 2018	0
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
Net loss	(25,844,000)				(25,844,000)
Foreign currency translation adjustments	2,000					$ 2,000
Issuance of common stock warrants	293,000			293,000
Issuance of stock upon repayment of non-recourse loans	144,000			144,000
Issuance of stock upon repayment of non-recourse loans, shares			79,854
Issuance of stock upon exercise of warrants, shares			12,164
Issuance of stock upon exercise of options	$ 193,000			193,000
Issuance of stock upon exercise of options, shares	122,765		122,765
Issuance of restricted stock	$ 385,000			385,000
Issuance of restricted stock, shares			168,748
Stock-based compensation expense	2,615,000			2,615,000
Ending balance at Jun. 30, 2019	29,349,000		$ 17,000	269,556,000	(240,226,000)	2,000
Ending balance, shares at Jun. 30, 2019			17,166,368
Temporary equity, ending balance at Jun. 30, 2019	0
Beginning balance at Mar. 31, 2019	41,019,000		$ 17,000	268,348,000	(227,346,000)
Beginning balance, shares at Mar. 31, 2019			16,899,685
Net loss	(12,880,000)				(12,880,000)
Foreign currency translation adjustments	2,000					2,000
Issuance of stock upon repayment of non-recourse loans	144,000			144,000
Issuance of stock upon repayment of non-recourse loans, shares			79,854
Issuance of stock upon exercise of warrants, shares			12,164
Issuance of stock upon exercise of options	193,000			193,000
Issuance of stock upon exercise of options, shares			122,497
Issuance of restricted stock	159,000			159,000
Issuance of restricted stock, shares			52,168
Stock-based compensation expense	712,000			712,000
Ending balance at Jun. 30, 2019	29,349,000		$ 17,000	$ 269,556,000	$ (240,226,000)	$ 2,000
Ending balance, shares at Jun. 30, 2019			17,166,368
Temporary equity, ending balance at Jun. 30, 2019	$ 0

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net loss	$ (25,844)	$ (20,132)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	1,407	991
Stock-based compensation expense	2,615	234
Loss on disposal of fixed assets	81	229
Provision for bad debts	64	10
Loss on extinguishment of debt		1,842
Amortization of discount on debt	108	40
Change in fair value of warrants		(382)
Changes in operating assets and liabilities, net of acquisition:
Accounts receivable	144	209
Inventory	2,988	805
Prepaid expenses and other assets	398	291
Accounts payable	(1,575)	1,342
Contract liability	(16)	7
Accrued expenses and other current liabilities	744	(2,571)
Net cash used in operating activities	(18,886)	(17,085)
Cash flows from investing activities
Acquisition of business, net of cash acquired	(1,560)
Purchases of property and equipment	(2,164)	(2,468)
Net cash used in investing activities	(3,724)	(2,468)
Cash flows from financing activities
Proceeds on loans	10,500	20,000
Repayment of loans payable		(21,328)
Debt issuance costs	(322)	(751)
Short-term line of credit	(7)	265
Proceeds from exercise of stock options and purchase of restricted stock	337	492
Net cash provided by (used in) financing activities	10,508	(1,322)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(13)
Net decrease in cash, cash equivalents and restricted cash	(12,115)	(20,875)
Cash, cash equivalents and restricted cash
Beginning of period	60,022	28,360
End of period	47,907	7,485
Supplemental disclosures of cash flow information
Interest paid during the period	2,290	1,173
Issuance of warrants in conjunction with debt draw down	293
Property and equipment purchases in accrued expenses	$ 115	$ 32

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 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 typically experienced users of Hi-VNI Technology and who focus on medical education efforts to facilitate adoption and increase utilization. The Company is focused on physicians, respiratory therapists and nurses who work in acute hospital settings, including the emergency department and adult, pediatric and neonatal intensive care units (the “ICUs”). The Company’s relationship with these clinicians is particularly important, as it enables its products to follow patients through the care continuum. Since inception, the Company has financed its operations primarily through 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	6 Months Ended
	Jun. 30, 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 (“U.S. GAAP”). 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 U.S. GAAP requires the Company to make judgments, assumptions, and estimates that affect the reported amounts of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and liabilities. The Company evaluates its estimates on an ongoing basis. The Company bases its estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Significant estimates relied upon in preparing these consolidated financial statements include calculation of stock-based compensation, fair values of acquired assets and liabilities, including goodwill and intangibles assets, 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 June 30, 2019, the consolidated statements of comprehensive loss, redeemable convertible preferred stock and stockholders’ equity (deficit) and of cash flows for the three and six months ended June 30, 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 June 30, 2019 and the results of its operations and its cash flows for the three and six months ended June 30, 2019 and 2018. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2019 and 2018 are also unaudited. The results of operations for the three and six months ended June 30, 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 Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”). ASU 2016-18 amends Accounting Standards Codification (“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 U.S. GAAP. Additionally, changes in restricted cash and restricted cash equivalents that result from transfers between cash, cash equivalents, and restricted cash and restricted cash equivalents should not be presented as cash flow activities in the statement of cash flows. A company with a material balance of amounts generally described as restricted cash and restricted cash equivalents must disclose information about the nature of the restrictions. The new standard is effective for interim and annual periods beginning after December 15, 2018. The Company had not previously included restricted cash as a component of cash and cash equivalents as presented on its consolidated 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 presentation has been reclassified to conform to current year presentation. Clarifying the Definition of a Business (Topic 805): In January 2017, the FASB issued ASU No. 2017-01 Clarifying the Definition of a Business (Topic 805) Recently Issued Accounting Pronouncements Leases (Topic 842): In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 establishes a comprehensive new lease accounting model. The new standard clarifies the definitions of a lease, requires a dual approach to lease classification similar to current lease classifications, and causes lessees to recognize leases on the balance sheet as a lease liability with a corresponding right-of-use asset for leases with a lease term of more than twelve months. In July 2019, the FASB issued a proposed ASU that would defer the effective date for ASU 2016-02. The Company intends to adopt the new standard during interim and annual periods beginning after December 15, 2020, in accordance with this proposed delay. 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. See Note 18 “Business Combinations” to these consolidated financial statements for details of the Solus acquisition. 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 comprehensive loss. Unrealized foreign currency gains or losses arising from transactions denominated in foreign currencies are recorded in accumulated other comprehensive income. Intangible Assets Intangible assets related to customer agreements are amortized on a straight-line basis, over their useful lives. Amortization is recorded within sales and marketing expenses in the consolidated statements of comprehensive loss. 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 June 30, Six Months Ended June 30, 2019 2019 US International Total US International Total Net revenue by: Product Revenue Capital $ 1,599 $ 1,046 $ 2,645 $ 3,109 $ 1,551 $ 4,660 Disposable 6,514 2,016 8,530 14,061 3,488 17,549 Subtotal Product Revenue 8,113 3,062 11,175 17,170 5,039 22,209 Lease Revenue 284 - 284 947 - 947 Service and Other Revenue 281 246 527 610 519 1,129 Total Revenue $ 8,678 $ 3,308 $ 11,986 $ 18,727 $ 5,558 $ 24,285 Three Months Ended June 30, Six Months Ended June 30, 2018 2018 US International Total US International Total Net revenue by: Product Revenue Capital $ 1,936 $ 1,270 $ 3,206 $ 3,508 $ 1,981 $ 5,489 Disposable 5,200 1,415 6,615 11,543 2,641 14,184 Subtotal Product Revenue 7,136 2,685 9,821 15,051 4,622 19,673 Lease Revenue 479 - 479 664 - 664 Service and Other Revenue 204 59 263 726 239 965 Total Revenue $ 7,819 $ 2,744 $ 10,563 $ 16,441 $ 4,861 $ 21,302 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 statements of comprehensive loss. Property and Equipment Property and equipment are recorded at cost. Depreciation is recognized over the estimated useful lives of the related assets using the straight-line method for consolidated financial statement purposes. The Company uses other depreciation methods (generally, accelerated depreciation methods) for tax purposes, where appropriate. Amortization of leasehold improvements is computed using the straight-line method over the shorter of the remaining lease term or the estimated useful lives of the improvements and is included in depreciation expense. When impairment indicators are present, the Company evaluates the recoverability of its long-lived assets. If the assessment indicates an impairment, the affected assets are written down to fair value. Repairs and maintenance are expensed as incurred. Expenditures that increase the value or productive capacity of assets are capitalized. When property and equipment are retired, sold, or otherwise disposed of, the asset’s carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in operating expenses. The lives used in computing straight-line depreciation for financial reporting purposes are as follows: Number of Years Property and equipment placed in service Equipment 3 - 7 Furniture 5 - 7 Manufacturing equipment 3 - 10 Software 3 Demonstration, placements and evaluation units 3 - 5 Leasehold improvements Lesser of life of lease or 10 years The Company’s policy is to periodically review the estimated useful life of all fixed assets. This review during fiscal year 2019 indicated that the estimated useful life of all fixed assets is consistent with fiscal year 2018, with the exception of manufacturing equipment. The maximum useful life increased from 7 years to 10 years. Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid temporary investments purchased with original maturities of 90 days or less to be cash equivalents. The Company holds restricted cash related to certificates of deposits and collateral in relation to lease agreements. As of June 30, 2019, $0.4 million of our $47.9 million of cash, cash equivalents and restricted cash balance was located outside the U.S. The following table presents the components of total cash, cash equivalents, and restricted cash as set forth in the Company’s consolidated statements of cash flows: June 30, 2019 December 31, 2018 June 30, 2018 December 31, 2017 Cash and cash equivalents $ 46,055 $ 58,223 $ 5,630 $ 26,508 Restricted cash 1,852 1,799 1,855 1,852 Total cash, cash equivalents, and restricted cash $ 47,907 $ 60,022 $ 7,485 $ 28,360

Accounts Receivable

Accounts Receivable	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Accounts Receivable	3. Accounts Receivable Accounts receivable owed to the Company by its customers and distributors consist of the following: June 30, 2019 December 31, 2018 United States $ 4,703 $ 4,948 International 2,881 2,493 Total accounts receivable 7,584 7,441 Less: Allowance for doubtful accounts (280 ) (334 ) Accounts receivable, net of allowance for doubtful accounts $ 7,304 $ 7,107 At June 30, 2019, the largest concentrations of accounts receivable, as a percentage of total accounts receivable, were with one distributor representing 9% and one distributor representing 3% 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 June 30, 2019 or December 31, 2018.

Financial Instruments

Financial Instruments	6 Months Ended
	Jun. 30, 2019
Investments All Other Investments [Abstract]
Financial Instruments	4. Financial Instruments As of June 30, 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. During the three months ended June 30, 2018, in connection with an amendment to the Credit Agreement and Guaranty as further described in Note 8 “Debt”, the Company granted warrants to purchase 37,693 shares Series D redeemable convertible preferred stock which were converted into shares of common stock at the time of the initial public offering. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, exercisable at the option of the holder, in whole or in part, and expire in April 2028. The estimated fair value at the time of issuance was less than $0.1 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. The Company did not grant any warrants in the three months ended June 30, 2019. During the three months ended June 30, 2019, 68,009 warrants were exercised of which 55,845 were forfeited and 12,164 were converted into shares of common stock as part of a cashless exercise. During the six months ended June 30, 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. The Company’s warrant activity for the three and six months ended June 30, 2019 and 2018 are summarized as follows. Series A Redeemable Series B Redeemable Series C Redeemable Series D Redeemable Convertible Preferred 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 Weighted Average Exercise Price Number of Shares Estimated Fair Value Outstanding at March 31, 2018 158,202 $ 288 $ 14.00 12,857 $ 71 $ 14.00 4,285 $ 42 $ 14.00 - $ - $ - $ 175,344 $ 401 Warrants granted - - - - - - - - - 37,693 59 15.92 37,693 59 Gain on change in fair value - (155 ) - - (61 ) - - (38 ) - - - - - (254 ) Outstanding at June 30, 2018 158,202 $ 133 $ 14.00 12,857 $ 10 $ 14.00 4,285 $ 4 $ 14.00 37,693 $ 59 $ 15.92 $ 213,037 $ 206 Common Stock Warrants Number of Shares Weighted Average Exercise Price Outstanding at March 31, 2019 250,085 $ 14.61 Warrants granted - - Warrants exercised (68,009 ) (14.00 ) Outstanding at June 30, 2019 182,076 $ 14.84 Series A Redeemable Series B Redeemable Series C Redeemable Series D Redeemable Convertible Preferred 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 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 Warrants granted - - - - - - - - - 37,693 59 15.92 37,693 59 Gain on change in fair value - (282 ) - - (62 ) - - (38 ) - - - - - (382 ) Outstanding at June 30, 2018 158,202 $ 133 $ 14.00 12,857 $ 10 $ 14.00 4,285 $ 4 $ 14.00 37,693 $ 59 $ 15.92 213,037 $ 206 Common Stock Warrants Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2018 230,295 $ 14.50 Warrants granted 19,790 15.92 Warrants exercised (68,009 ) (14.00 ) Outstanding at June 30, 2019 182,076 $ 14.84

Inventories

Inventories	6 Months Ended
	Jun. 30, 2019
Inventory Disclosure [Abstract]
Inventories	5. Inventories Inventories as of June 30, 2019 and December 31, 2018 consist of the following: June 30, 2019 December 31, 2018 Component parts $ 6,183 $ 5,601 Finished goods 5,036 8,109 Total inventory $ 11,219 $ 13,710

Property and Equipment

Property and Equipment	6 Months Ended
	Jun. 30, 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 June 30, 2019 and December 31, 2018, is as follows: June 30, 2019 December 31, 2018 Equipment $ 985 $ 924 Furniture 977 957 Manufacturing equipment 8,312 4,166 Software 713 655 Demonstration, placements and evaluation units 8,471 7,135 Leasehold improvements 2,078 2,025 Construction in process 1,033 4,663 Total property and equipment 22,569 20,525 Less: Accumulated depreciation and amortization (8,427 ) (7,109 ) Total property and equipment, net $ 14,142 $ 13,416 Depreciation and amortization of property and equipment was $0.7 million and $1.4 million during the three and six months ended June 30, 2019, respectively. Depreciation and amortization of property and equipment was $0.5 million and $1.0 million during the three and six months ended June 30, 2018, respectively.

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	6 Months Ended
	Jun. 30, 2019
Payables And Accruals [Abstract]
Accrued Expenses and Other Liabilities	7. Accrued Expenses and Other Liabilities Accrued expenses and other liabilities as of June 30, 2019 and December 31, 2018 consist of the following: June 30, 2019 December 31, 2018 Accrued payroll and employee related liabilities $ 1,336 $ 170 Accrued bonuses 1,245 1,692 Accrued commissions 916 1,464 Accrued inventory 852 1,070 Accrued professional fees 644 253 Accrued vacation liability 522 427 Product warranty reserve 329 329 Accrued taxes 260 305 Refundable purchase price of unvested stock 236 346 Accrued rent and restoration costs 192 174 Accrued employee reimbursement 126 178 Accrued capital equipment 115 21 Accrued board of director retainers 106 52 Clinical studies 86 67 Accrued freight 74 52 Other 897 1,053 Total accrued expenses and other liabilities $ 7,936 $ 7,653

Debt

Debt	6 Months Ended
	Jun. 30, 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 June 30, 2019 the interest rate was 7.3%. The outstanding balance under the Amended Revolver Agreement was $3.2 million at June 30, 2019 and there was $0.3 million 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 which were converted into shares of common stock at the time of the initial public offering. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, exercisable at the option of the holder, in whole or in part, and expire in July 2028. On September 27, 2018, the Company entered into the first amendment to the Credit Agreement and Guaranty (the “Amendment”, together with the Credit Agreement and Guaranty, the “Amended Credit Agreement and Guaranty”) with Perceptive. Pursuant to the Amended Credit Agreement and Guaranty, the Company was permitted to draw the final $12.5 million of availability at any time through March 31, 2019 and the minimum 2018 revenue requirement of $43.2 million that was required to draw down the final tranche was eliminated. Concurrently with the closing of the Amendment, the Company drew down $2.0 million of the remaining $12.5 million available. In connection with this draw down, the Company granted to Perceptive warrants to purchase 3,769 shares of its Series D preferred stock which were converted into shares of common stock at the time of the initial public offering. The warrants have an exercise price of $15.92 per share, were fully vested upon issuance, 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 June 30, 2019, the interest rate was 11.56%. The outstanding balance was $42.5 million at June 30, 2019 and there was no remaining availability. At December 31, 2018, the interest rate was 11.44%. 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 June 30, 2019, the Company was in compliance with these covenants. The annual principal maturities of the Amended Credit Agreement and Guaranty as of June 30, 2019 are as follows: 2019 $ - 2020 - 2021 - 2022 - 2023 42,550 Less: Discount on loans payable (905 ) Long-term loans payable $ 41,645

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 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 June 30, 2019 Remainder of 2019 $ 778 2020 1,577 2021 1,601 2022 1,626 2023 1,652 Thereafter 1,820 Total $ 9,054 Rent expense for the three and six months ended June 30, 2019 was $0.5 million and $1.0 million, respectively. Rent expense for the three and six months ended June 30, 2018 was $0.4 million and $0.9 million, respectively. Legal Matters From time to time the Company may become involved in various legal proceedings, including those that may arise in the ordinary course of business. The Company 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 its operations or financial condition.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Federal income tax (benefit) at statutory rate 21.0 % 34.0 % 21.0 % 34.0 % (Increase) decrease income tax benefit resulting from: Permanent differences (0.3 )% (0.3 )% (0.3 )% (0.3 )% Change in valuation allowance (21.0 )% (34.0 )% (21.0 )% (34.0 )% Other 0.3 % 0.3 % 0.3 % 0.3 % Income tax expense (benefit) 0.0 % 0.0 % 0.0 % 0.0 % Significant components of the Company’s net deferred tax asset are as follows: June 30, 2019 December 31, 2018 Deferred Tax Assets Net operating loss carryforwards $ 46,711 $ 42,444 Tax credit carryforwards 3,537 3,012 Deduction of research and development costs 5,139 4,239 Accounts receivable collection allowance 56 70 Inventory valuation reserves 311 154 Accrued bonus and vacation 475 579 Accrued warranty 86 86 Allowance for sales returns 18 18 Stock option expense attributed to non-ISO stock 1,043 358 Accrued other expenses 1,355 818 Other temporary differences (272 ) (70 ) Total gross deferred tax assets 58,459 51,708 Less: Valuation allowance (58,459 ) (51,708 ) Deferred tax asset after valuation allowance $ - $ - The Company’s major tax jurisdictions are the United States, New Hampshire and the United Kingdom. As of June 30, 2019, the Company had federal and state net operating loss carryforwards of $200.7 million and $90.7 million, respectively, which begin to expire in 2020. As of June 30, 2019, the Company had federal research and development tax credits carryforwards of $3.3 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 $58.5 million and $51.7 million has been established at June 30, 2019 and December 31, 2018, respectively. The valuation allowance increased $6.8 million during the six months ended June 30, 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 March 1, 2019 to June 30,2019, Solus had a book loss of $0.2 million, resulting from sales of $1.0 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	6 Months Ended
	Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Plans and Stock-Based Compensation	11. Stock Plans and Stock-Based Compensation As of June 30, 2019 and December 31, 2018, 937,400 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 fair value on the date 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 fair value on the date of grant and the number of units expected to be earned after assessing the probability that certain performance criteria will be met and the associated targeted payout level that is forecasted will be achieved, net of 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Fair value of common stock $ 19.28 $ 3.78 $ 17.18 $ 3.78 Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 % Risk free interest rate 2.5 % 2.8 % 2.5 % 2.5 % Expected stock price volatility 58.8 % 58.9 % 70.0 % 59.0 % Expected term (years) 9.0 6.1 7.1 6.0 Stock Options Stock option activity for the six months ended 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 776,196 17.18 Options exercised (122,765 ) 1.58 Options canceled (42,988 ) 3.12 Outstanding at June 30, 2019 1,397,432 $ 10.69 8.76 $ 17,203 Exercisable at June 30, 2019 361,419 $ 1.94 7.19 $ 7,611 Vested and unvested expected to vest at June 30, 2019 1,397,432 $ 10.69 8.76 $ 17,203 The weighted average grant date fair value of options granted during the three months ended June 30, 2019 and 2018 was $12.73 and $1.68 per share, respectively. The weighted average grant date fair value of options granted during the six months ended June 30, 2019 and 2018 was $11.97 and $1.68 per share, respectively. The aggregate intrinsic value of options exercised during the three months ended June 30, 2019 and 2018 was $2.0 million and less than $0.1 million, respectively. The aggregate intrinsic value of options exercised during the six months ended June 30, 2019 and 2018 was $2.1 million and less than $0.1 million, respectively. The aggregate intrinsic value was calculated based on a positive difference between the closing stock price on June 30, 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 of June 30, 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 June 30, 2019 and 2018 was $0.3 million and less than $0.1 million, respectively. The compensation expense associated with stock options recognized during the six months ended June 30, 2019 and 2018 was $0.7 million and $0.1 million, respectively. Stock-based compensation is recorded in the consolidated statements of comprehensive loss Restricted Stock A summary of restricted stock activity for the six months ended June 30, 2019 is as follows: Weighted Average Grant Date Shares Fair Value Unvested at December 31, 2018 399,485 $ 1.68 Granted/purchased 74,483 17.44 Vested (168,748 ) 4.58 Canceled - - Unvested at June 30, 2019 305,220 $ 3.95 The weighted average grant date fair value of restricted stock granted during the six months ended June 30, 2019 and 2018 was $17.44 and $0.94 per share, respectively. The compensation expense associated with restricted stock recognized during the three months ended June 30, 2019 and 2018 was $0.4 million and less than $0.1 million, respectively. The compensation expense associated with restricted stock recognized during the six months ended June 30, 2019 and 2018 was $1.9 million and $0.1 million, respectively. Stock-based compensation is recorded in the consolidated statements of comprehensive loss

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: Net loss $ (12,880 ) $ (11,226 ) $ (25,844 ) $ (20,132 ) Net loss attributable to common stockholders $ (12,880 ) $ (11,226 ) $ (25,844 ) $ (20,132 ) Denominator: Weighted average common shares outstanding— basic and diluted 17,055,628 838,428 17,019,002 812,451 Net loss per share attributable to common stockholders— basic and diluted $ (0.76 ) $ (13.39 ) $ (1.52 ) $ (24.78 ) 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Options to purchase common stock 1,397,432 773,868 1,397,432 773,868 Warrants to purchase redeemable convertible preferred stock (as converted to common stock) 182,076 213,038 182,076 213,038 Unvested restricted stock 305,220 622,455 305,220 622,455 Redeemable convertible preferred stock (as converted to common stock) - 10,515,351 - 10,515,351 1,884,728 12,124,712 1,884,728 12,124,712

Employee Benefit Plan

Employee Benefit Plan	6 Months Ended
	Jun. 30, 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 and $0.1 million for the three and six months ended June 30, 2019, respectively. The Company contributed less than $0.1 million for each of the three and six months ended June 30, 2018, respectively.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 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 stockholders that are vendors of the Company. The total amount billed from these vendors during the three months ended June 30, 2019 and 2018 was less than $0.1 million and $0.5 million, respectively. The total amount billed from these vendors during the six months ended June 30, 2019 and 2018 was less than $0.1 million and $1.2 million, respectively. The accounts payable balance for these vendors was $0.5 million as of June 30, 2019 and December 31, 2018, respectively. In addition, the Company sells its products to a hospital customer who is an affiliate of a current stockholder. The total amount billed to this customer during the three months ended June 30, 2019 and 2018 was $0.3 million and $0.4 million, respectively. The total amount billed to this customer during the six months ended June 30, 2019 and 2018 was $0.7 million and $1.2 million, respectively. The accounts receivable balance for this customer was $0.1 million as of June 30, 2019 and December 31, 2018, respectively. All transactions are at arms’ length and occur at published list prices.

Warrants

Warrants	6 Months Ended
	Jun. 30, 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 June 30, 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	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Stockholders' Equity	16. Stockholders’ Equity Preferred Stock As of June 30, 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 June 30, 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 June 30, 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 June 30, 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	6 Months Ended
	Jun. 30, 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 and two reporting units, Vapotherm and Solus. Segment information is consistent with how management reviews the business, makes investing and resource allocation decisions and assesses operating performance. All assets are in the United States, United Kingdom or at contracted suppliers.

Business Combinations

Business Combinations	6 Months Ended
	Jun. 30, 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. 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 United Kingdom. The goodwill attributable to the United Kingdom jurisdiction is not deductible for tax purposes. The Company has included the financial results of Solus in the consolidated financial statements from the date of acquisition. 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 three and six months ended June 30, 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: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Net revenue $ 11,986 $ 11,511 $ 24,522 $ 23,017 Net loss $ (12,880 ) $ (11,440 ) $ (26,134 ) $ (20,578 ) Net loss per share, basic $ (0.76 ) $ (13.64 ) $ (1.54 ) $ (25.33 )

Intangibles

Intangibles	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Intangibles	19. Intangibles The following table presents a summary of acquired intangible assets: As of June 30, 2019 Period of amortization Gross Carrying Amount Accumulated Amortization Customer agreements 3.83 years $ 455 $ (40 ) Total identifiable intangible assets $ 455 $ (40 ) The Company recognized less than $0.1 million of amortization expense within sales and marketing expenses related to the intangible assets during the six months ended June 30, 2019. The Company did not recognize any amortization expense related to the intangible assets during the three and six months ended June 30, 2018, respectively, as the assets were acquired in acquisition of Solus in February 2019. The estimated amortization expense for intangible assets for each of the five succeeding fiscal years is as follows: In thousands Estimated Amortization Expense Remainder of 2019 $ 60 2020 119 2021 118 2022 118 2023 - Total $ 415

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). 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 U.S. GAAP requires the Company to make judgments, assumptions, and estimates that affect the reported amounts of assets, liabilities, revenue and expenses, and the related disclosure of contingent assets and liabilities. The Company evaluates its estimates on an ongoing basis. The Company bases its estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Significant estimates relied upon in preparing these consolidated financial statements include calculation of stock-based compensation, fair values of acquired assets and liabilities, including goodwill and intangibles assets, 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 June 30, 2019, the consolidated statements of comprehensive loss, redeemable convertible preferred stock and stockholders’ equity (deficit) and of cash flows for the three and six months ended June 30, 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 June 30, 2019 and the results of its operations and its cash flows for the three and six months ended June 30, 2019 and 2018. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2019 and 2018 are also unaudited. The results of operations for the three and six months ended June 30, 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 Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”). ASU 2016-18 amends Accounting Standards Codification (“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 U.S. GAAP. Additionally, changes in restricted cash and restricted cash equivalents that result from transfers between cash, cash equivalents, and restricted cash and restricted cash equivalents should not be presented as cash flow activities in the statement of cash flows. A company with a material balance of amounts generally described as restricted cash and restricted cash equivalents must disclose information about the nature of the restrictions. The new standard is effective for interim and annual periods beginning after December 15, 2018. The Company had not previously included restricted cash as a component of cash and cash equivalents as presented on its consolidated 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 presentation has been reclassified to conform to current year presentation. Clarifying the Definition of a Business (Topic 805): In January 2017, the FASB issued ASU No. 2017-01 Clarifying the Definition of a Business (Topic 805) Recently Issued Accounting Pronouncements Leases (Topic 842): In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 establishes a comprehensive new lease accounting model. The new standard clarifies the definitions of a lease, requires a dual approach to lease classification similar to current lease classifications, and causes lessees to recognize leases on the balance sheet as a lease liability with a corresponding right-of-use asset for leases with a lease term of more than twelve months. In July 2019, the FASB issued a proposed ASU that would defer the effective date for ASU 2016-02. The Company intends to adopt the new standard during interim and annual periods beginning after December 15, 2020, in accordance with this proposed delay. 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. See Note 18 “Business Combinations” to these consolidated financial statements for details of the Solus acquisition. 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 comprehensive loss. Unrealized foreign currency gains or losses arising from transactions denominated in foreign currencies are recorded in accumulated other comprehensive income.
Intangible Assets	Intangible Assets Intangible assets related to customer agreements are amortized on a straight-line basis, over their useful lives. Amortization is recorded within sales and marketing expenses in the consolidated statements of comprehensive loss.
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 June 30, Six Months Ended June 30, 2019 2019 US International Total US International Total Net revenue by: Product Revenue Capital $ 1,599 $ 1,046 $ 2,645 $ 3,109 $ 1,551 $ 4,660 Disposable 6,514 2,016 8,530 14,061 3,488 17,549 Subtotal Product Revenue 8,113 3,062 11,175 17,170 5,039 22,209 Lease Revenue 284 - 284 947 - 947 Service and Other Revenue 281 246 527 610 519 1,129 Total Revenue $ 8,678 $ 3,308 $ 11,986 $ 18,727 $ 5,558 $ 24,285 Three Months Ended June 30, Six Months Ended June 30, 2018 2018 US International Total US International Total Net revenue by: Product Revenue Capital $ 1,936 $ 1,270 $ 3,206 $ 3,508 $ 1,981 $ 5,489 Disposable 5,200 1,415 6,615 11,543 2,641 14,184 Subtotal Product Revenue 7,136 2,685 9,821 15,051 4,622 19,673 Lease Revenue 479 - 479 664 - 664 Service and Other Revenue 204 59 263 726 239 965 Total Revenue $ 7,819 $ 2,744 $ 10,563 $ 16,441 $ 4,861 $ 21,302 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 statements of comprehensive loss.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost. Depreciation is recognized over the estimated useful lives of the related assets using the straight-line method for consolidated financial statement purposes. The Company uses other depreciation methods (generally, accelerated depreciation methods) for tax purposes, where appropriate. Amortization of leasehold improvements is computed using the straight-line method over the shorter of the remaining lease term or the estimated useful lives of the improvements and is included in depreciation expense. When impairment indicators are present, the Company evaluates the recoverability of its long-lived assets. If the assessment indicates an impairment, the affected assets are written down to fair value. Repairs and maintenance are expensed as incurred. Expenditures that increase the value or productive capacity of assets are capitalized. When property and equipment are retired, sold, or otherwise disposed of, the asset’s carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in operating expenses. The lives used in computing straight-line depreciation for financial reporting purposes are as follows: Number of Years Property and equipment placed in service Equipment 3 - 7 Furniture 5 - 7 Manufacturing equipment 3 - 10 Software 3 Demonstration, placements and evaluation units 3 - 5 Leasehold improvements Lesser of life of lease or 10 years The Company’s policy is to periodically review the estimated useful life of all fixed assets. This review during fiscal year 2019 indicated that the estimated useful life of all fixed assets is consistent with fiscal year 2018, with the exception of manufacturing equipment. The maximum useful life increased from 7 years to 10 years.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid temporary investments purchased with original maturities of 90 days or less to be cash equivalents. The Company holds restricted cash related to certificates of deposits and collateral in relation to lease agreements. As of June 30, 2019, $0.4 million of our $47.9 million of cash, cash equivalents and restricted cash balance was located outside the U.S. The following table presents the components of total cash, cash equivalents, and restricted cash as set forth in the Company’s consolidated statements of cash flows: June 30, 2019 December 31, 2018 June 30, 2018 December 31, 2017 Cash and cash equivalents $ 46,055 $ 58,223 $ 5,630 $ 26,508 Restricted cash 1,852 1,799 1,855 1,852 Total cash, cash equivalents, and restricted cash $ 47,907 $ 60,022 $ 7,485 $ 28,360

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 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 June 30, Six Months Ended June 30, 2019 2019 US International Total US International Total Net revenue by: Product Revenue Capital $ 1,599 $ 1,046 $ 2,645 $ 3,109 $ 1,551 $ 4,660 Disposable 6,514 2,016 8,530 14,061 3,488 17,549 Subtotal Product Revenue 8,113 3,062 11,175 17,170 5,039 22,209 Lease Revenue 284 - 284 947 - 947 Service and Other Revenue 281 246 527 610 519 1,129 Total Revenue $ 8,678 $ 3,308 $ 11,986 $ 18,727 $ 5,558 $ 24,285 Three Months Ended June 30, Six Months Ended June 30, 2018 2018 US International Total US International Total Net revenue by: Product Revenue Capital $ 1,936 $ 1,270 $ 3,206 $ 3,508 $ 1,981 $ 5,489 Disposable 5,200 1,415 6,615 11,543 2,641 14,184 Subtotal Product Revenue 7,136 2,685 9,821 15,051 4,622 19,673 Lease Revenue 479 - 479 664 - 664 Service and Other Revenue 204 59 263 726 239 965 Total Revenue $ 7,819 $ 2,744 $ 10,563 $ 16,441 $ 4,861 $ 21,302
Lives Used in Computing Straight-Line Depreciation	The lives used in computing straight-line depreciation for financial reporting purposes are as follows: Number of Years Property and equipment placed in service Equipment 3 - 7 Furniture 5 - 7 Manufacturing equipment 3 - 10 Software 3 Demonstration, placements and evaluation units 3 - 5 Leasehold improvements Lesser of life of lease or 10 years
Components of Cash, Cash Equivalents and Restricted Cash	The following table presents the components of total cash, cash equivalents, and restricted cash as set forth in the Company’s consolidated statements of cash flows: June 30, 2019 December 31, 2018 June 30, 2018 December 31, 2017 Cash and cash equivalents $ 46,055 $ 58,223 $ 5,630 $ 26,508 Restricted cash 1,852 1,799 1,855 1,852 Total cash, cash equivalents, and restricted cash $ 47,907 $ 60,022 $ 7,485 $ 28,360

Accounts Receivable (Tables)

Accounts Receivable (Tables)	6 Months Ended
	Jun. 30, 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: June 30, 2019 December 31, 2018 United States $ 4,703 $ 4,948 International 2,881 2,493 Total accounts receivable 7,584 7,441 Less: Allowance for doubtful accounts (280 ) (334 ) Accounts receivable, net of allowance for doubtful accounts $ 7,304 $ 7,107

Financial Instruments (Tables)

Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2019
Warrants And Rights Note Disclosure [Abstract]
Summary of Warrant Activity	The Company’s warrant activity for the three and six months ended June 30, 2019 and 2018 are summarized as follows. Series A Redeemable Series B Redeemable Series C Redeemable Series D Redeemable Convertible Preferred 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 Weighted Average Exercise Price Number of Shares Estimated Fair Value Outstanding at March 31, 2018 158,202 $ 288 $ 14.00 12,857 $ 71 $ 14.00 4,285 $ 42 $ 14.00 - $ - $ - $ 175,344 $ 401 Warrants granted - - - - - - - - - 37,693 59 15.92 37,693 59 Gain on change in fair value - (155 ) - - (61 ) - - (38 ) - - - - - (254 ) Outstanding at June 30, 2018 158,202 $ 133 $ 14.00 12,857 $ 10 $ 14.00 4,285 $ 4 $ 14.00 37,693 $ 59 $ 15.92 $ 213,037 $ 206 Common Stock Warrants Number of Shares Weighted Average Exercise Price Outstanding at March 31, 2019 250,085 $ 14.61 Warrants granted - - Warrants exercised (68,009 ) (14.00 ) Outstanding at June 30, 2019 182,076 $ 14.84 Series A Redeemable Series B Redeemable Series C Redeemable Series D Redeemable Convertible Preferred 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 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 Warrants granted - - - - - - - - - 37,693 59 15.92 37,693 59 Gain on change in fair value - (282 ) - - (62 ) - - (38 ) - - - - - (382 ) Outstanding at June 30, 2018 158,202 $ 133 $ 14.00 12,857 $ 10 $ 14.00 4,285 $ 4 $ 14.00 37,693 $ 59 $ 15.92 213,037 $ 206 Common Stock Warrants Number of Shares Weighted Average Exercise Price Outstanding at December 31, 2018 230,295 $ 14.50 Warrants granted 19,790 15.92 Warrants exercised (68,009 ) (14.00 ) Outstanding at June 30, 2019 182,076 $ 14.84

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2019
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories as of June 30, 2019 and December 31, 2018 consist of the following: June 30, 2019 December 31, 2018 Component parts $ 6,183 $ 5,601 Finished goods 5,036 8,109 Total inventory $ 11,219 $ 13,710

Property and Equipment (Tables)

Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2019 and December 31, 2018, is as follows: June 30, 2019 December 31, 2018 Equipment $ 985 $ 924 Furniture 977 957 Manufacturing equipment 8,312 4,166 Software 713 655 Demonstration, placements and evaluation units 8,471 7,135 Leasehold improvements 2,078 2,025 Construction in process 1,033 4,663 Total property and equipment 22,569 20,525 Less: Accumulated depreciation and amortization (8,427 ) (7,109 ) Total property and equipment, net $ 14,142 $ 13,416

Accrued Expenses and Other Li_2

Accrued Expenses and Other Liabilities (Tables)	6 Months Ended
	Jun. 30, 2019
Payables And Accruals [Abstract]
Schedule of Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities as of June 30, 2019 and December 31, 2018 consist of the following: June 30, 2019 December 31, 2018 Accrued payroll and employee related liabilities $ 1,336 $ 170 Accrued bonuses 1,245 1,692 Accrued commissions 916 1,464 Accrued inventory 852 1,070 Accrued professional fees 644 253 Accrued vacation liability 522 427 Product warranty reserve 329 329 Accrued taxes 260 305 Refundable purchase price of unvested stock 236 346 Accrued rent and restoration costs 192 174 Accrued employee reimbursement 126 178 Accrued capital equipment 115 21 Accrued board of director retainers 106 52 Clinical studies 86 67 Accrued freight 74 52 Other 897 1,053 Total accrued expenses and other liabilities $ 7,936 $ 7,653

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2019 are as follows: 2019 $ - 2020 - 2021 - 2022 - 2023 42,550 Less: Discount on loans payable (905 ) Long-term loans payable $ 41,645

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2019 Remainder of 2019 $ 778 2020 1,577 2021 1,601 2022 1,626 2023 1,652 Thereafter 1,820 Total $ 9,054

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Federal income tax (benefit) at statutory rate 21.0 % 34.0 % 21.0 % 34.0 % (Increase) decrease income tax benefit resulting from: Permanent differences (0.3 )% (0.3 )% (0.3 )% (0.3 )% Change in valuation allowance (21.0 )% (34.0 )% (21.0 )% (34.0 )% Other 0.3 % 0.3 % 0.3 % 0.3 % Income tax expense (benefit) 0.0 % 0.0 % 0.0 % 0.0 %
Significant Components of Net Deferred Tax Asset	Significant components of the Company’s net deferred tax asset are as follows: June 30, 2019 December 31, 2018 Deferred Tax Assets Net operating loss carryforwards $ 46,711 $ 42,444 Tax credit carryforwards 3,537 3,012 Deduction of research and development costs 5,139 4,239 Accounts receivable collection allowance 56 70 Inventory valuation reserves 311 154 Accrued bonus and vacation 475 579 Accrued warranty 86 86 Allowance for sales returns 18 18 Stock option expense attributed to non-ISO stock 1,043 358 Accrued other expenses 1,355 818 Other temporary differences (272 ) (70 ) Total gross deferred tax assets 58,459 51,708 Less: Valuation allowance (58,459 ) (51,708 ) Deferred tax asset after valuation allowance $ - $ -

Stock Plans and Stock-Based C_2

Stock Plans and Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Fair value of common stock $ 19.28 $ 3.78 $ 17.18 $ 3.78 Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 % Risk free interest rate 2.5 % 2.8 % 2.5 % 2.5 % Expected stock price volatility 58.8 % 58.9 % 70.0 % 59.0 % Expected term (years) 9.0 6.1 7.1 6.0
Summary of Stock Option Activity	Stock option activity for the six months ended 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 776,196 17.18 Options exercised (122,765 ) 1.58 Options canceled (42,988 ) 3.12 Outstanding at June 30, 2019 1,397,432 $ 10.69 8.76 $ 17,203 Exercisable at June 30, 2019 361,419 $ 1.94 7.19 $ 7,611 Vested and unvested expected to vest at June 30, 2019 1,397,432 $ 10.69 8.76 $ 17,203
Summary of Restricted Stock Activity	Restricted Stock A summary of restricted stock activity for the six months ended June 30, 2019 is as follows: Weighted Average Grant Date Shares Fair Value Unvested at December 31, 2018 399,485 $ 1.68 Granted/purchased 74,483 17.44 Vested (168,748 ) 4.58 Canceled - - Unvested at June 30, 2019 305,220 $ 3.95

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: Net loss $ (12,880 ) $ (11,226 ) $ (25,844 ) $ (20,132 ) Net loss attributable to common stockholders $ (12,880 ) $ (11,226 ) $ (25,844 ) $ (20,132 ) Denominator: Weighted average common shares outstanding— basic and diluted 17,055,628 838,428 17,019,002 812,451 Net loss per share attributable to common stockholders— basic and diluted $ (0.76 ) $ (13.39 ) $ (1.52 ) $ (24.78 )
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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Options to purchase common stock 1,397,432 773,868 1,397,432 773,868 Warrants to purchase redeemable convertible preferred stock (as converted to common stock) 182,076 213,038 182,076 213,038 Unvested restricted stock 305,220 622,455 305,220 622,455 Redeemable convertible preferred stock (as converted to common stock) - 10,515,351 - 10,515,351 1,884,728 12,124,712 1,884,728 12,124,712

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 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)	6 Months Ended
	Jun. 30, 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 three and six months ended June 30, 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: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Net revenue $ 11,986 $ 11,511 $ 24,522 $ 23,017 Net loss $ (12,880 ) $ (11,440 ) $ (26,134 ) $ (20,578 ) Net loss per share, basic $ (0.76 ) $ (13.64 ) $ (1.54 ) $ (25.33 )

Intangibles (Tables)

Intangibles (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Acquired Intangible Assets	The following table presents a summary of acquired intangible assets: As of June 30, 2019 Period of amortization Gross Carrying Amount Accumulated Amortization Customer agreements 3.83 years $ 455 $ (40 ) Total identifiable intangible assets $ 455 $ (40 )
Schedule of Estimated Amortization Expense for Intangible Assets	The estimated amortization expense for intangible assets for each of the five succeeding fiscal years is as follows: In thousands Estimated Amortization Expense Remainder of 2019 $ 60 2020 119 2021 118 2022 118 2023 - Total $ 415

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	Jun. 30, 2019USD ($)Segment$ / shares	Dec. 31, 2018USD ($)$ / shares	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
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
Cash, cash equivalents and restricted cash balance		$ 47,907,000	$ 60,022,000	$ 7,485,000	$ 28,360,000
Outside U.S.
Summary Of Significant Accounting Policies [Line Items]
Cash, cash equivalents and restricted cash balance		400,000
Maximum
Summary Of Significant Accounting Policies [Line Items]
Product return liability		$ 100,000
Maximum | Manufacturing Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of fixed assets		10 years	7 years
Minimum | Manufacturing Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of fixed assets		3 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Net Revenue Disaggregated into Categories (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 11,986	$ 10,563	$ 24,285	$ 21,302
US
Disaggregation Of Revenue [Line Items]
Total Revenue	8,678	7,819	18,727	16,441
International
Disaggregation Of Revenue [Line Items]
Total Revenue	3,308	2,744	5,558	4,861
Product Revenue, Capital
Disaggregation Of Revenue [Line Items]
Total Revenue	2,645	3,206	4,660	5,489
Product Revenue, Capital | US
Disaggregation Of Revenue [Line Items]
Total Revenue	1,599	1,936	3,109	3,508
Product Revenue, Capital | International
Disaggregation Of Revenue [Line Items]
Total Revenue	1,046	1,270	1,551	1,981
Product Revenue, Disposable
Disaggregation Of Revenue [Line Items]
Total Revenue	8,530	6,615	17,549	14,184
Product Revenue, Disposable | US
Disaggregation Of Revenue [Line Items]
Total Revenue	6,514	5,200	14,061	11,543
Product Revenue, Disposable | International
Disaggregation Of Revenue [Line Items]
Total Revenue	2,016	1,415	3,488	2,641
Subtotal Product Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	11,175	9,821	22,209	19,673
Subtotal Product Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	8,113	7,136	17,170	15,051
Subtotal Product Revenue | International
Disaggregation Of Revenue [Line Items]
Total Revenue	3,062	2,685	5,039	4,622
Lease Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	284	479	947	664
Lease Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	284	479	947	664
Service and Other Revenue
Disaggregation Of Revenue [Line Items]
Total Revenue	527	263	1,129	965
Service and Other Revenue | US
Disaggregation Of Revenue [Line Items]
Total Revenue	281	204	610	726
Service and Other Revenue | International
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 246	$ 59	$ 519	$ 239

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Lives Used in Computing Straight-Line Depreciation (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	3 years
Equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	7 years
Furniture | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	5 years
Furniture | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	7 years
Manufacturing Equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	3 years
Manufacturing Equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	10 years	7 years
Software | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	3 years
Demonstration, Placements and Evaluation Units | Minimum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	3 years
Demonstration, Placements and Evaluation Units | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Term	Lesser of life of lease or 10 years
Leasehold Improvements | Maximum
Property Plant And Equipment [Line Items]
Property and equipment placed in service, Number of years	10 years

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Components of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 46,055	$ 58,223	$ 5,630	$ 26,508
Restricted cash	1,852	1,799	1,855	1,852
Total cash, cash equivalents, and restricted cash	$ 47,907	$ 60,022	$ 7,485	$ 28,360

Accounts Receivable - Summary o

Accounts Receivable - Summary of Accounts Receivable Owned to Company by Customers and Distributors (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	$ 7,584	$ 7,441
Less: Allowance for doubtful accounts	(280)	(334)
Accounts receivable, net of allowance for doubtful accounts	7,304	7,107
US
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	4,703	4,948
International
Accounts Notes And Loans Receivable [Line Items]
Total accounts receivable	$ 2,881	$ 2,493

Accounts Receivable - Additiona

Accounts Receivable - Additional Information (Details) - Accounts Receivable - Customer Concentration Risk	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Distributor One
Accounts Notes And Loans Receivable [Line Items]
Percentage of accounts receivable	9.00%	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		4.00%

Financial Instruments - Additio

Financial Instruments - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019
Amendment To Credit Agreement And Guaranty
Class Of Warrant Or Right [Line Items]
Granted warrants to purchase shares	19,790		19,790
Warrants exercise price	$ 15.92		$ 15.92
Series D Redeemable Convertible Preferred Stock | Maximum
Class Of Warrant Or Right [Line Items]
Estimated fair value of warrants at the time of issuance		$ 0.1
Series D Redeemable Convertible Preferred Stock | Amendment To Credit Agreement And Guaranty
Class Of Warrant Or Right [Line Items]
Granted warrants to purchase shares		37,693
Warrants exercise price		$ 15.92
Warrants expiration, month and year		2028-04
Common Stock Warrants
Class Of Warrant Or Right [Line Items]
Number of warrants granted	0		19,790
Warrants exercised	68,009		68,009
Warrants forfeited	55,845
Number of warrants converted into shares of common stock	12,164
Common Stock Warrants | Maximum
Class Of Warrant Or Right [Line Items]
Estimated fair value of warrants at the time of issuance			$ 0.3
Common Stock Warrants | Amendment To Credit Agreement And Guaranty
Class Of Warrant Or Right [Line Items]
Granted warrants to purchase shares	19,790		19,790
Warrants exercise price	$ 15.92		$ 15.92
Warrants expiration, month and year			2029-03

Financial Instruments - Summary

Financial Instruments - Summary of Warrant Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Class Of Warrant Or Right [Line Items]
Gain on change in fair value		$ 254		$ 382
Series D Redeemable Convertible Preferred | Maximum
Class Of Warrant Or Right [Line Items]
Estimated fair value, warrants granted		$ 100
Common Stock Warrants
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance	250,085		230,295
Number of shares, warrants granted	0		19,790
Number of shares, warrants exercised	(68,009)		(68,009)
Number of shares, ending balance	182,076		182,076
Common Stock Warrants | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise Price, beginning balance	$ 14.61		$ 14.50
Weighted average exercise price, warrants granted			15.92
Weighted average exercise price, warrants exercised	(14)		(14)
Weighted average exercise Price, ending balance	$ 14.84		$ 14.84
Common Stock Warrants | Maximum
Class Of Warrant Or Right [Line Items]
Estimated fair value, warrants granted			$ 300
Warrants
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance		175,344		175,344
Number of shares, warrants granted		37,693		37,693
Number of shares, ending balance		213,037		213,037
Estimated fair value, beginning balance		$ 401		$ 529
Estimated fair value, warrants granted		59		59
Gain on change in fair value		(254)		(382)
Estimated fair value, ending balance		$ 206		$ 206
Warrants | Series A Redeemable Convertible Preferred
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance		158,202		158,202
Number of shares, ending balance		158,202		158,202
Estimated fair value, beginning balance		$ 288		$ 415
Gain on change in fair value		(155)		(282)
Estimated fair value, ending balance		$ 133		$ 133
Warrants | Series A Redeemable Convertible Preferred | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise Price, beginning balance		$ 14		$ 14
Weighted average exercise Price, ending balance		$ 14		$ 14
Warrants | Series B Redeemable Convertible Preferred
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance		12,857		12,857
Number of shares, ending balance		12,857		12,857
Estimated fair value, beginning balance		$ 71		$ 72
Gain on change in fair value		(61)		(62)
Estimated fair value, ending balance		$ 10		$ 10
Warrants | Series B Redeemable Convertible Preferred | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise Price, beginning balance		$ 14		$ 14
Weighted average exercise Price, ending balance		$ 14		$ 14
Warrants | Series C Redeemable Convertible Preferred
Class Of Warrant Or Right [Line Items]
Number of shares, beginning balance		4,285		4,285
Number of shares, ending balance		4,285		4,285
Estimated fair value, beginning balance		$ 42		$ 42
Gain on change in fair value		(38)		(38)
Estimated fair value, ending balance		$ 4		$ 4
Warrants | Series C Redeemable Convertible Preferred | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise Price, beginning balance		$ 14		$ 14
Weighted average exercise Price, ending balance		$ 14		$ 14
Warrants | Series D Redeemable Convertible Preferred
Class Of Warrant Or Right [Line Items]
Number of shares, warrants granted		37,693		37,693
Number of shares, ending balance		37,693		37,693
Estimated fair value, warrants granted		$ 59		$ 59
Estimated fair value, ending balance		$ 59		$ 59
Warrants | Series D Redeemable Convertible Preferred | Weighted Average
Class Of Warrant Or Right [Line Items]
Weighted average exercise price, warrants granted		$ 15.92		$ 15.92
Weighted average exercise Price, ending balance		$ 15.92		$ 15.92

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Component parts	$ 6,183	$ 5,601
Finished goods	5,036	8,109
Total inventory	$ 11,219	$ 13,710

Property and Equipment - Summar

Property and Equipment - Summary of Components of Property and Equipment, Placed in Service (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total property and equipment	$ 22,569	$ 20,525
Less: Accumulated depreciation and amortization	(8,427)	(7,109)
Total property and equipment, net	14,142	13,416
Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	985	924
Furniture
Property Plant And Equipment [Line Items]
Total property and equipment	977	957
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	8,312	4,166
Software
Property Plant And Equipment [Line Items]
Total property and equipment	713	655
Demonstration, Placements and Evaluation Units
Property Plant And Equipment [Line Items]
Total property and equipment	8,471	7,135
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	2,078	2,025
Construction in Progress
Property Plant And Equipment [Line Items]
Total property and equipment	$ 1,033	$ 4,663

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Property Plant And Equipment [Abstract]
Depreciation and amortization	$ 700	$ 500	$ 1,407	$ 991

Accrued Expenses and Other Li_3

Accrued Expenses and Other Liabilities - Schedule of Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued payroll and employee related liabilities	$ 1,336	$ 170
Accrued bonuses	1,245	1,692
Accrued commissions	916	1,464
Accrued inventory	852	1,070
Accrued professional fees	644	253
Accrued vacation liability	522	427
Product warranty reserve	329	329
Accrued taxes	260	305
Refundable purchase price of unvested stock	236	346
Accrued rent and restoration costs	192	174
Accrued employee reimbursement	126	178
Accrued capital equipment	115	21
Accrued board of director retainers	106	52
Clinical studies	86	67
Accrued freight	74	52
Other	897	1,053
Total accrued expenses and other liabilities	$ 7,936	$ 7,653

Debt - Additional Information (

Debt - Additional Information (Details)

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

Dec. 31, 2018USD ($)

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

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

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

Nov. 16, 2016USD ($)Tranche

Apr. 30, 2018USD ($)

Mar. 31, 2017USD ($)

Jan. 31, 2017USD ($)

Jun. 30, 2019USD ($)

Jun. 30, 2018USD ($)

Mar. 21, 2019USD ($)

Debt Instrument [Line Items]

Proceeds from term loan

$ 10,500,000

$ 20,000,000

Repayment of term loan balance

$ 21,328,000

Western Alliance Bank | Revolving Credit Line | Revolver Agreement

Debt Instrument [Line Items]

Line of credit made available under agreement

$ 7,000,000

$ 7,500,000

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

80.00%

Line of credit, maturity date

Sep. 30, 2018

Sep. 30, 2020

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

$ 3,200,000

Line of credit, remaining availability under agreement

300,000

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

Debt Instrument [Line Items]

Line of credit made available under agreement

$ 500,000

Solar Capital Ltd. | Term Loan

Debt Instrument [Line Items]

Repayment of term loan balance

$ 6,000,000

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

Debt Instrument [Line Items]

Term loan, face amount

$ 20,000,000

Number of tranches available under agreement | Tranche

3

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

$ 10,000,000

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

Debt Instrument [Line Items]

Proceeds from term loan

$ 10,000,000

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

Debt Instrument [Line Items]

Proceeds from term loan

$ 5,000,000

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

Debt Instrument [Line Items]

Proceeds from term loan

$ 5,000,000

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

Debt Instrument [Line Items]

Term loan, face amount

$ 42,500,000

$ 42,500,000

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

37,693

Warrants exercise price | $ / shares

$ 15.92

$ 15.92

Warrants expiration, month and year

2029-03

2028-04

Term loan, interest rate

11.44%

11.56%

Term loan, remaining availability under agreement

$ 0

Line of credit, covenant compliance description

The Amended Credit Agreement and Guaranty requires the Company to comply with a minimum liquidity covenant at all times and a minimum revenue covenant measured at the end of each fiscal quarter. As of June 30, 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	Jun. 30, 2019USD ($)
Debt Instrument [Line Items]
2019	$ 0
2020	0
2021	0
2022	0
2023	42,550
Less: Discount on loans payable	(905)
Long-term loans payable	$ 41,645

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Jun. 15, 2018USD ($)	Jun. 12, 2018USD ($)	Jun. 30, 2019USD ($)ft²	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)ft²	Jun. 30, 2018USD ($)
Loss Contingencies [Line Items]
Area of office leases | ft²			84,140		84,140
Lease terminates date					Jan. 29, 2026
Rent expense			$ 500,000	$ 400,000	$ 1,000,000	$ 900,000
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	Jun. 30, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
Remainder of 2019	$ 778
2020	1,577
2021	1,601
2022	1,626
2023	1,652
Thereafter	1,820
Total	$ 9,054

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		4 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Tax Contingency [Line Items]
Provision for income taxes				$ 0
Valuation allowance	$ 58,459,000		$ 58,459,000	58,459,000		$ 51,708,000
Increase in valuation allowance				6,800,000
Book loss	(12,880,000)	$ (11,226,000)		(25,844,000)	$ (20,132,000)
Sales	11,986,000	$ 10,563,000		24,285,000	$ 21,302,000
Solus
Income Tax Contingency [Line Items]
Book loss			200,000
Sales			1,000,000
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	200,700,000		200,700,000	$ 200,700,000
Net operating loss carryforwards, expiration beginning year				2020
Federal | Research and Development
Income Tax Contingency [Line Items]
Tax credit carryforward	3,300,000		3,300,000	$ 3,300,000
Tax credit carryforward, expiration beginning year				2021
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 90,700,000		$ 90,700,000	$ 90,700,000
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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Federal income tax (benefit) at statutory rate	21.00%	34.00%	21.00%	34.00%
(Increase) decrease income tax benefit resulting from:
Permanent differences	(0.30%)	(0.30%)	(0.30%)	(0.30%)
Change in valuation allowance	(21.00%)	(34.00%)	(21.00%)	(34.00%)
Other	0.30%	0.30%	0.30%	0.30%
Income tax expense (benefit)	0.00%	0.00%	0.00%	0.00%

Income Taxes - Significant Comp

Income Taxes - Significant Components of Net Deferred Tax Asset (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Deferred Tax Assets
Net operating loss carryforwards	$ 46,711	$ 42,444
Tax credit carryforwards	3,537	3,012
Deduction of research and development costs	5,139	4,239
Accounts receivable collection allowance	56	70
Inventory valuation reserves	311	154
Accrued bonus and vacation	475	579
Accrued warranty	86	86
Allowance for sales returns	18	18
Stock option expense attributed to non-ISO stock	1,043	358
Accrued other expenses	1,355	818
Other temporary differences	(272)	(70)
Total gross deferred tax assets	58,459	51,708
Less: Valuation allowance	(58,459)	(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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Average forfeiture rates	4.78%	8.22%	4.76%	6.85%
Weighted average grant date fair value of options granted	$ 12.73	$ 1.68	$ 11.97	$ 1.68
Aggregate intrinsic value of options exercised	$ 2,000,000		$ 2,100,000
Estimated fair value of common stock		$ 0.95		$ 0.95
Unrecognized stock-based compensation expense	7,000,000		$ 7,000,000
Unrecognized stock-based compensation expense recognized, remaining weighted average vesting period			2 years 9 months 18 days
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense recognized	300,000		$ 700,000	$ 100,000
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			2 years 9 months 18 days
Compensation expense recognized	400,000		$ 1,900,000	$ 100,000
Unrecognized stock-based compensation expense	$ 600,000		$ 600,000
Weighted average grant date fair value, granted			$ 17.44	$ 0.94
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate intrinsic value of options exercised		$ 100,000		$ 100,000
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	937,400		937,400		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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Fair value of common stock	$ 19.28	$ 3.78	$ 17.18	$ 3.78
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Risk free interest rate	2.50%	2.80%	2.50%	2.50%
Expected stock price volatility	58.80%	58.90%	70.00%	59.00%
Expected term (years)	9 years	6 years 1 month 6 days	7 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) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Underlying Common Shares, Outstanding, Beginning balance | shares	786,989
Number of Underlying Common Shares, Options granted | shares	776,196
Number of Underlying Common Shares, Options exercised | shares	(122,765)
Number of Underlying Common Shares, Options canceled | shares	(42,988)
Number of Underlying Common Shares, Outstanding, Ending balance | shares	1,397,432	786,989
Number of Underlying Common Shares, Exercisable | shares	361,419
Number of Underlying Common Shares, Vested and unvested expected to vest | shares	1,397,432
Weighted Average Exercise Price, Outstanding, Beginning balance | $ / shares	$ 2.41
Weighted Average Exercise Price, Options granted | $ / shares	17.18
Weighted Average Exercise Price, Options exercised | $ / shares	1.58
Weighted Average Exercise Price, Options canceled | $ / shares	3.12
Weighted Average Exercise Price, Outstanding, Ending balance | $ / shares	10.69	$ 2.41
Weighted Average Exercise Price, Exercisable | $ / shares	1.94
Weighted Average Exercise Price, Vested and unvested expected to vest | $ / shares	$ 10.69
Weighted Average Remaining Contractual Term	8 years 9 months 3 days	7 years 10 months 13 days
Weighted Average Remaining Contractual Term, Exercisable	7 years 2 months 8 days
Weighted Average Remaining Contractual Term, Vested and unvested expected to vest	8 years 9 months 3 days
Aggregate Intrinsic Value, Outstanding | $	$ 17,203	$ 13,801
Aggregate Intrinsic Value, Exercisable | $	7,611
Aggregate Intrinsic Value, Vested and unvested expected to vest | $	$ 17,203

Stock Plans and Stock-Based C_6

Stock Plans and Stock-Based Compensation - Summary of Restricted Stock Activity (Details) - Restricted Stock	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Unvested, Beginning balance | shares	399,485
Shares, Granted/purchased | shares	74,483
Shares, Vested | shares	(168,748)
Shares, Canceled | shares	0
Shares, Unvested Ending balance | shares	305,220
Weighted Average Grant Date Fair Value, Unvested, Beginning balance | $ / shares	$ 1.68
Weighted Average Grant Date Fair Value, Granted/purchased | $ / shares	17.44
Weighted Average Grant Date Fair Value, Vested | $ / shares	4.58
Weighted Average Grant Date Fair Value, Canceled | $ / shares	0
Weighted Average Grant Date Fair Value, Unvested Ending balance | $ / shares	$ 3.95

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net loss	$ (12,880)	$ (11,226)	$ (25,844)	$ (20,132)
Net loss attributable to common stockholders	$ (12,880)	$ (11,226)	$ (25,844)	$ (20,132)
Denominator:
Weighted-average number of shares used in calculating net loss per share, basic and diluted	17,055,628	838,428	17,019,002	812,451
Net loss per share attributable to common stockholders— basic and diluted	$ (0.76)	$ (13.39)	$ (1.52)	$ (24.78)

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,884,728	12,124,712	1,884,728	12,124,712
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		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	1,397,432	773,868	1,397,432	773,868
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	182,076	213,038	182,076	213,038
Unvested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	305,220	622,455	305,220	622,455

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Details) - USD ($)	Apr. 01, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 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	$ 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)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 30, 2018	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)Stockholder	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Related Party Transaction [Line Items]
Number of stockholders that are vendors | Stockholder				2
Total amount billed from related parties			$ 500,000		$ 1,200,000
Accounts payable to vendors		$ 500,000		$ 500,000		$ 500,000
Revenue from related party		300,000	$ 400,000	700,000	$ 1,200,000
Accounts receivable from customer		100,000		100,000		100,000
Maximum
Related Party Transaction [Line Items]
Total amount billed from related parties		$ 100,000		$ 100,000
Redeemable Convertible Preferred Stock
Related Party Transaction [Line Items]
Preferred stock purchased by related party						$ 33,200,000
Temporary equity to permanent equity conversion basis				one-to-one basis
Temporary to permanent equity conversion ratio	100.00%

Warrants - Additional Informati

Warrants - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 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	$ 20,000,000
Gain on change in fair value of preferred stock warrants	$ 300,000		$ 400,000
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	6 Months Ended
	Nov. 30, 2018	Jun. 30, 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	Jun. 30, 2018$ / sharesshares
Temporary Equity [Line Items]
Shares authorized		10,712,137
Shares issued		10,515,351
Conversion rate	14
Series A Redeemable Convertible Preferred Stock
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 Stock
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 Stock
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)	6 Months Ended
	Jun. 30, 2019Segment
Segment Reporting [Abstract]
Number of reporting segment	1
Number of reporting units	2

Business Combinations - Additio

Business Combinations - Additional Information (Details) - USD ($) $ in Thousands	Feb. 28, 2019	Jun. 30, 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	Jun. 30, 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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Combinations [Abstract]
Net revenue	$ 11,986	$ 11,511	$ 24,522	$ 23,017
Net loss	$ (12,880)	$ (11,440)	$ (26,134)	$ (20,578)
Net loss per share, basic	$ (0.76)	$ (13.64)	$ (1.54)	$ (25.33)

Intangibles - Summary of Acquir

Intangibles - Summary of Acquired Intangible Assets (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 455
Accumulated Amortization	$ (40)
Customer Agreements
Acquired Finite Lived Intangible Assets [Line Items]
Period of amortization	3 years 9 months 29 days
Gross Carrying Amount	$ 455
Accumulated Amortization	$ (40)

Intangibles - Additioanal Infor

Intangibles - Additioanal Information (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 0		$ 0
Sales and Marketing Expenses | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Amortization expense of intangible assets		$ 100,000

Intangibles - Schedule of Estim

Intangibles - Schedule of Estimated Amortization Expense for Intangible Assets (Details) $ in Thousands	Jun. 30, 2019USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Remainder of 2019	$ 60
2020	119
2021	118
2022	118
Total	$ 415