Venus Concept (VERO) 10-Q 21 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	HAIR
Entity Registrant Name	Restoration Robotics, Inc.
Entity Central Index Key	1,409,269
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		28,930,095

Condensed Consolidated Balance

Condensed Consolidated Balance sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 5,769	$ 11,906
Accounts receivable	3,222	2,481
Inventory	2,677	2,742
Prepaid expenses and other current assets	858	810
Total current assets	12,526	17,939
Property and equipment, net	1,189	1,459
Other assets	2,323	100
TOTAL ASSETS	16,038	19,498
CURRENT LIABILITIES:
Accounts payable	2,934	1,740
Accrued and other liabilities	2,997	2,438
Deferred revenue	1,437	1,423
Current portion of long-term debt, net of discount of $340 and $551 as of September 30, 2017 and December 31, 2016	7,659	7,449
Convertible promissory notes	5,018
Total current liabilities	20,045	13,050
Other long-term liabilities	488	563
Preferred stock warrant liabilities	2,311	693
Long-term debt, net of discount of $70 and $299 as of September 30, 2017 and December 31, 2016	7,230	13,001
TOTAL LIABILITIES	30,074	27,307
Commitments and Contingencies (Note 6)
Convertible preferred stock, $0.0001 par value; 236,154,444 shares authorized as of September 30, 2017 and December 31, 2016; 22,671,601 and 21,142,295 shares issued and outstanding as of September 30, 2017 and December 31, 2016; aggregate liquidation preference of $153,166 as of September 30, 2017 and $142,231 as of December 31, 2016	145,944	135,735
STOCKHOLDERS’ DEFICIT:
Additional paid-in capital	3,452	3,087
Accumulated other comprehensive income (loss)	(8)	14
Accumulated deficit	(163,424)	(146,645)
TOTAL STOCKHOLDERS’ DEFICIT	(159,980)	(143,544)
TOTAL LIABILITIES, CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ DEFICIT	$ 16,038	$ 19,498

Condensed Consolidated Balance3

Condensed Consolidated Balance sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Current portion of long-term debt, discount	$ 340	$ 551
Long-term debt, discount	$ 70	$ 299
Convertible preferred stock at liquidation preference par value	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	236,154,444	236,154,444
Convertible preferred stock, shares issued	22,671,601	21,142,295
Convertible preferred stock, shares outstanding	22,671,601	21,142,295
Aggregate liquidation preference	$ 153,166	$ 142,231
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	350,490,000	350,490,000
Common stock, shares issued	1,624,464	1,615,495
Common stock, shares outstanding	1,624,464	1,615,495

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenue, net	$ 4,177	$ 3,676	$ 15,441	$ 10,422
Cost of revenue	2,474	2,404	9,053	7,267
Gross profit	1,703	1,272	6,388	3,155
Operating expenses:
Research and development	1,737	1,909	5,579	5,463
Sales and marketing	3,433	3,257	10,736	9,453
General and administrative	1,139	1,432	3,549	3,285
Total operating expenses	6,309	6,598	19,864	18,201
Loss from operations	(4,606)	(5,326)	(13,476)	(15,046)
Other income (expense), net:
Interest expense	(492)	(613)	(1,607)	(1,863)
Other income (expense), net	(1,473)	11	(1,646)	(4)
Total other expense, net	(1,965)	(602)	(3,253)	(1,867)
Net loss before provision for income taxes	(6,571)	(5,928)	(16,729)	(16,913)
Provision for income taxes	25		50
Net loss attributable to common stockholders	$ (6,596)	$ (5,928)	$ (16,779)	$ (16,913)
Net loss per share attributable to common stockholders, basic and diluted	$ (4.07)	$ (3.67)	$ (10.36)	$ (10.49)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	1,620,691	1,614,023	1,620,016	1,612,492

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (6,596)	$ (5,928)	$ (16,779)	$ (16,913)
Other comprehensive income (loss):
Cumulative translation adjustment	26	(37)	(22)	(34)
Comprehensive loss	$ (6,570)	$ (5,965)	$ (16,801)	$ (16,947)

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Convertible Preferred Stock
Beginning balance, value at Dec. 31, 2016	$ 135,735					$ 135,735
Beginning balance, shares at Dec. 31, 2016	21,142,295					21,142,295
Beginning balance, value at Dec. 31, 2016	$ (143,544)		$ 3,087	$ 14	$ (146,645)
Beginning balance, shares at Dec. 31, 2016		1,615,495
Issuance of common stock pursuant to stock option exercises of vested options	$ 16		16
Issuance of common stock pursuant to stock option exercises of vested options, shares	8,969	8,969
Issuance of preferred stock for cash, net of issuance costs, value	$ 10,209
Issuance of preferred stock for cash, net of issuance costs, shares	1,529,306
Stock-based compensation	$ 349		349
Other comprehensive loss	(22)			(22)
Net loss	(16,779)				(16,779)
Ending balance, value at Sep. 30, 2017	$ 145,944					$ 145,944
Ending balance, shares at Sep. 30, 2017	22,671,601					22,671,601
Ending balance, value at Sep. 30, 2017	$ (159,980)		$ 3,452	$ (8)	$ (163,424)
Ending balance, shares at Sep. 30, 2017		1,624,464

Condensed Consolidated Stateme7

Condensed Consolidated Statement of Convertible Preferred Stock and Stockholders' Deficit (Parenthetical) (Unaudited) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Statement Of Stockholders Equity [Abstract]
Issuance of preferred stock for cash, issuance costs	$ 726

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (16,779)	$ (16,913)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	452	498
Loss on disposal of property and equipment	34	19
Amortization of debt issuance costs	440	562
Stock-based compensation	349	359
Changes in fair value of preferred stock warrant liabilities	1,618
Changes in operating assets and liabilities:
Accounts receivable	(741)	86
Inventory	65	1,942
Prepaid expenses and other assets	(2,272)	256
Accounts payable	1,194	91
Accrued and other liabilities	1,264	(418)
Net cash used in operating activities	(14,376)	(13,518)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sale of property and equipment		2
Purchases of property and equipment	(215)	(328)
Net cash used in investing activities	(215)	(326)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from convertible notes, net	5,000
Proceeds from exercised stock options	16	39
Payment of deferred offering costs	(749)
Principal payments on long-term debt	(6,000)
Net cash provided by financing activities	8,476	9,977
NET DECREASE IN CASH AND CASH EQUIVALENTS	(6,115)	(3,867)
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(22)	(64)
CASH AND CASH EQUIVALENTS — Beginning of period	11,906	17,127
CASH AND CASH EQUIVALENTS — End of period	5,769	13,196
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for income taxes	4
Interest paid during the period	1,185	1,295
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION:
Deferred offering costs included in accounts payable and other accrued liabilities	1,474
Series C Preferred Stock
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of Series C convertible preferred stock, net	$ 10,209	$ 9,938

Nature of Operations

Nature of Operations	9 Months Ended
	Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations	1. Nature of Operations Restoration Robotics, Inc. is a medical technology company incorporated in the state of Delaware on November 22, 2002 and headquartered in San Jose, California. The Company develops an image-guided robotic system that enables follicular unit extraction (FUE) for use in the field of hair transplantation and markets the ARTAS® Robotic System in the United States and other countries. In these notes to the unaudited condensed consolidated financial statements, the “Company,” “Restoration Robotics,” “we,” “us,” and “our” refers to Restoration Robotics, Inc. and its subsidiaries on a consolidated basis. Initial Public Offering On October 11, 2017, the Company’s Registration Statement on Form S-1 (File No. 333-220303) relating to the initial public offering (IPO) of its common stock was declared effective by the Securities and Exchange Commission (SEC). Pursuant to such Registration Statement, the Company completed its initial public offering (the IPO) of 3,897,910 shares of its common stock (inclusive of 322,910 shares of common stock from the subsequent exercise of the over-allotment option granted to the underwriters) at a price of $7.00 per share for aggregate cash proceeds of approximately $22,674, after deducting underwriting discounts and commissions of approximately $1,910 and estimated offering expenses of approximately $2,701. Immediately prior to the closing of the IPO, all outstanding shares of convertible preferred stock converted into 22,671,601 shares of common stock and all the outstanding convertible preferred stock warrants converted into common stock warrants resulting in the reclassification of our preferred stock warrant liabilities to additional paid-in capital. In addition, the principal and accrued interest on the outstanding Convertible Notes converted into 718,184 shares of common stock. The IPO closed on October 16, 2017. Reverse Stock Split On September 15, 2017, the Company effected a 1-for-10 reverse stock split of its common stock. Upon the effectiveness of the reverse stock split, (i) every 10 shares of outstanding common stock were combined into one share of common stock, (ii) the number of shares of common stock for which each outstanding option to purchase common stock is exercisable was proportionately decreased on a 1-for-10 basis, (iii) the exercise price of each outstanding option to purchase common stock was proportionally decreased on a l-for-10 basis, and (iv) the conversion ratio for each share of outstanding preferred stock which is convertible into our common stock was proportionately reduced on a 1-for-10 basis. All of the outstanding common stock share numbers (including shares of common stock into which our outstanding convertible preferred stock shares are convertible), share prices, exercise prices and per share amounts have been adjusted in these consolidated statements, on a retroactive basis, to reflect this l-for-10 reverse stock split for all periods presented. The par value per share and the authorized number of shares of common stock and convertible preferred stock were not adjusted as a result of the reverse stock split.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Liquidity These condensed consolidated financial statements are prepared on a going concern basis that contemplates the realization of assets and extinguishment of liabilities in the normal course of business. The Company has incurred net operating losses and negative cash flows from operations since inception. As of September 30, 2017 and December 31, 2016, the Company has an accumulated deficit of $163,424 and $146,645 and, as of such dates, did not have sufficient capital to fund its planned operations. As a result of the Company’s recurring losses from operations and negative cash flows, the Company’s independent registered public accounting firm included an explanatory paragraph in its report on the Company’s consolidated financial statements as of, and for the year ended, December 31, 2016 that such factors raise substantial doubt about the Company’s ability to continue as a going concern. In order to continue its operations, the Company must achieve profitable operations and/or obtain additional financing. Until the Company generates revenue at a level to support its cost structure, the Company expects to continue to incur substantial operating losses and net cash outflows. The Company may never become profitable and even if it does attain profitable operations, it may not be able to sustain profitability or positive cash flows on a recurring basis. The Company will need to raise further capital in the future to service its debt or fund its operations until the time it can sustain positive cash flows. There can be no assurance that the Company will be successful in raising additional capital or that such capital, if available, will be on terms that are acceptable to the Company. If the Company is unable to raise sufficient additional capital, it may be compelled to reduce the scope of its operations and planned capital expenditures or sell certain assets, including intellectual property assets. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and, as such, the condensed consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or amounts and classification of liabilities that might be necessary should the Company be unable to continue in existence. Basis of Presentation The condensed consolidated balance sheet as of September 30, 2017, the condensed consolidated statements of operations and condensed consolidated statements of comprehensive loss for the three and nine months ended September 30, 2017 and 2016 and the condensed consolidated statements of cash flows for the nine months ended September 30, 2017 and 2016 and the condensed consolidated statement of convertible preferred stock and stockholders’ deficit for the nine months ended September 30, 2017 are unaudited. The unaudited condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair presentation of the Company’s condensed consolidated financial statements included in this report. The condensed consolidated financial data disclosed in these notes to the condensed consolidated financial statements related to the three and nine-month periods are also unaudited. The condensed consolidated results of operations for the three and nine months ended September 30, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017, or for any other future annual or interim period. The consolidated balance sheet as of December 31, 2016 included herein was derived from the audited consolidated financial statements as of that date. These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements included in the prospectus dated October 11, 2017, filed with the SEC pursuant to Rule 424 promulgated under the Securities Act of 1933, as amended. Principles of Consolidation The accompanying condensed c n s l i a e f i a c i a s t m n i c l u t u Restoration Robotics, Inc. A l i e rc m a n cc u n t r a s c i o a v b e l i m i a i o s l i a t i n Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. general accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to revenue recognition, the fair value of common stock, the fair value of preferred stock warrant liabilities, and the recoverability of the Company’s net deferred tax assets, and related valuation allowance. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates. Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Maker (CODM) in deciding how to allocate resources to an individual segment and in assessing performance. The Company's CODM is its Chief Executive Officer. The Company has determined it operates in a single operating segment and has one reportable segment, as the CODM reviews financial information presented on a consolidated basis for purposes of making operating decisions, allocating resources, and evaluating financial performance. Foreign Currency The functional currency of the Company’s non-U.S. subsidiaries is the local currency. Asset and liability balances denominated in non-U.S. dollar currencies are translated into U.S. dollars using period-end exchange rates, while revenue and expenses are based upon the exchange rate at the time of the transaction, if known, or at the average rate for the period. Differences are included in stockholders’ deficit as a component of accumulated other comprehensive loss. Financial assets and liabilities denominated in currencies other than the functional currency are recorded at the exchange rate at the time of the transaction and subsequent gains and losses related to changes in the foreign currency are included in other income (expense), net in the accompanying consolidated statements of operations. The net foreign transaction gain or losses were insignificant for all periods presented. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents consists primarily of funds invested in readily available checking and savings accounts and investments in money market funds and short-term time deposits. Restricted Cash As of September 30, 2017 and December 31, 2016, the Company was required to hold $100 in a separate money market account as collateral for credit cards. These amounts are recorded in other assets in the accompanying condensed consolidated balance sheets. Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, restricted cash and accounts receivable. Substantially all of the Company’s cash and cash equivalents and restricted cash are held with two financial institutions, and the account balances exceed the Federal Deposit Insurance Corporation (FDIC) insurance limit. Accounts are insured by the FDIC up to $250 per financial institution. The Company has not experienced any losses in such accounts with these financial institutions. Concentration of Customers For the three months ended September 30, 2017, two customers each accounted for 11% and 12% of the Company’s revenues. As of the nine months ended September 30, 2017 and three and nine months ended September 30, 2016, there were no customers accounting for more than 10% of the Company’s revenue. As of September 30, 2017, two customers each accounted for 11% and 15% of the Company’s accounts receivable. As of December 31, 2016, six customers accounted for 10%, 11%, 11%, 11%, 12%, and 13% of the Company’s accounts receivable. Accounts receivable do not bear interest and are typically not collateralized. The Company performs ongoing credit evaluations of its customers and maintains reserves for potential credit losses. Accounts receivable are deemed past due in accordance with the contractual terms of the agreement. Accounts are charged against the allowance for doubtful accounts once collection efforts are unsuccessful. Historically, such losses have been within management's expectations. The allowance for doubtful accounts is zero at September 30, 2017 and December 31, 2016. Inventory Inventory is stated at the lower of cost or market and cost is principally determined using the first-in, first-out method. Costs include material, labor and overhead. Inventory that is obsolete or in excess of forecasted usage is written down to its estimated net realizable value based on assumptions about future demand and market conditions. Inventory write-downs are charged to cost of goods sold and a new cost basis for the inventory is established. Concentration of Supplier The Company has a single source supplier manufacturing its system. If the supplier is not able to supply the requested orders, the Company would be unable to continue to derive revenues from the sale of systems until an alternative source is found, which could take a considerable length of time. Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which is between three and five years. Leasehold improvements are amortized over the lesser of the life of the lease or the useful life of the improvements. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the condensed consolidated balance sheet, and any resulting gain or loss is reflected in operations. Impairment of Long-Lived Assets Long-lived assets are reviewed annually for impairment or whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the carrying amount to the future net undiscounted cash flows that the assets are expected to generate. If the carrying amount of an asset group exceeds its estimated future cash flows, an impairment charge is recognized in the amount by which the carrying amount of the asset group exceeds the fair value of the asset group. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. There has been no impairment of long-lived assets for any of the periods presented. Deferred Offering Costs Deferred offering costs, consisting of legal, accounting and filing fees relating to an IPO, are capitalized. Upon the completion of the IPO (as discussed in Note 1), the deferred offering costs were offset against offering proceeds. As of September 30, 2017, $2,223 of deferred offering costs have been capitalized, which is included in other long-term assets in the condensed consolidated balance sheets. There were no deferred offering costs capitalized as of December 31, 2016. Preferred Stock Warrants Liabilities The Company accounts for freestanding warrants to purchase shares of convertible preferred stock that are contingently redeemable as liabilities in the condensed consolidated balance sheets at their estimated fair value because these warrants may obligate the Company to redeem them at some point in the future. At the end of each reporting period, changes in the estimated fair value of the warrants to purchase shares of convertible preferred stock are recorded as other income (expense), net in the consolidated statements of operations. Upon the completion of the IPO (as discussed in Note 1), the liability on the preferred stock warrants was reclassified to additional paid-in capital in stockholders’ deficit. Debt Issuance Costs Costs related to the issuance of debt are presented as a direct deduction to the carrying value of the debt and are amortized to interest expense using the effective interest rate method over the term of the related debt. Revenue Recognition The Company generates revenue from sales of robotic systems and related procedures, and related support and maintenance. The Company derives revenue primarily from two sources: (i) Product revenue, which includes robotic systems sales, installation, software, procedure key and disposable kits; and (ii) Support and maintenance revenue, which includes support, training, and service contracts. Revenue is recognized when all of the following criteria are met: (l) persuasive evidence of an arrangement exists; (2) the product or service has been delivered; (3) the sales price is fixed or determinable; and (4) collection is reasonably assured. The Company defines each of the four criteria above as follows: • Persuasive Evidence of Arrangement Exists. The Company uses purchase orders pursuant to the terms and conditions of a master agreement to support the evidence of an arrangement with distributors and uses purchase agreements as evidence of arrangement with direct customers. • Delivery has Occurred. Provided that all other revenue recognition criteria have been met, for direct sales the Company typically recognizes system revenue upon customer acceptance, or upon shipment for systems sold to distributors, as title and risk of loss are transferred at that time, and there are no further obligations and no rights of return. Procedure revenue is recognized upon shipment of disposable kits and delivery of the ARTAS key. Support and maintenance revenue is recognized over time as the services are delivered. • The Sales Price is Fixed or Determinable. The Company assesses whether the fee is fixed or determinable based on the payment terms associated with the transaction. If the terms are extended beyond the Company’s normal payment terms, the Company will recognize revenue as the payments become due. Payments from distributors are not contingent on the distributors’ receiving payment from the end-users. • Collection is Reasonably Assured. The Company assesses probability of collection on an individual basis based on a number of factors, including the credit-worthiness of the customer and past transaction history with the customer. The Company generally obtains a significant cash deposit from its customers prior to shipment. The Company records its revenues net of sales tax and shipping and handling costs. Incremental direct costs incurred related to the acquisition or origination of a customer contract are expensed as incurred. Multiple Element Arrangements The Company’s offering includes robotic systems containing software components that function together to provide the essential functionality of the product. Therefore, the Company’s hardware products (inclusive of the core software) are considered non-software deliverables and are not subject to industry-specific software revenue recognition guidance. The Company’s typical multiple element arrangement includes robotic systems (including the essential software), procedure key, installation (for direct sales to end-users), product training and service contracts. The Company considers each of these deliverables to be separate units of accounting based on whether the delivered items have stand-alone value. The Company has determined that each unit of accounting has stand-alone value because they are sold separately by the Company or, for hardware products, because the customers can resell them to others on a stand-alone basis. For the arrangements with multiple deliverables, the Company allocates the arrangement fee to each element based upon the relative selling price of such element. When applying the relative selling price method, the Company determines the selling price for each element using vendor-specific objective evidence (VSOE) of selling price, if it exists, or if not, third-party evidence (TPE) of selling price, if it exists. If neither VSOE nor TPE of selling price exist for an element, the Company uses its best estimated selling price (BESP) for that element. The revenue allocated to each element is then recognized when the basic revenue recognition criteria are met for that element. The Company is not able to establish a selling price of its deliverables using VSOE or to determine TPE for its products and services. TPE is determined based on competitor prices for similar deliverables when sold separately. Generally, the Company’s go-to-market strategy differs from that of its peers and its offerings contain a significant level of differentiation such that the comparable pricing of products with similar functionality cannot be obtained. When the Company is unable to establish the selling price of its deliverables using VSOE or TPE, the Company uses BESP in its allocation of arrangement consideration. The objective of BESP is to determine the price at which the Company would transact a sale if the product or service were sold on a stand-alone basis. The Company determines BESP for a product or service by considering multiple factors including, but not limited to, industry and market conditions, competitive landscape, standard pricing practices and internal cost models. Additionally, the Company considers historical transactions, including transactions whereby the deliverable was sold on a stand-alone basis. Deferred revenue primarily relates to support and maintenance and pertains to billings or payments received in advance where all of the revenue recognition criteria have not been met. The current portion of deferred revenue represents the amounts that are expected to be recognized as revenue within one year of the condensed consolidated balance sheet date. Cost of Revenue Cost of revenue consists of product and fulfillment costs. Product costs include the cost of systems and disposable kits manufacture, related labor and personnel costs and allocated shared costs. Fulfillment costs consist of costs incurred in the shipping and handling of inventory including the shipping costs to the Company's customers, labor and related personnel costs related to receiving, inspecting, warehousing, and preparing systems and reusable kits for shipment. Cost of revenue for customer service is expensed as incurred and primarily consists of personnel costs such as salaries, bonuses and benefits and stock‑based compensation for employees associated with service contracts, travel costs and allocated shared costs (including rent and information technology). Research and Development Research and development costs are charged to operations as incurred. Warranty The Company provides a one-year warranty on the ARTAS System and accrues for the estimated future costs of repair or replacement upon customer acceptance or shipment. The warranty expense is accrued as a liability and recorded to cost of goods sold and is based upon historical information for the cost to repair or replace the system. Sales Taxes Revenue is recorded net of taxes collected from customers that are remitted to governmental authorities with the collected taxes recorded as current liabilities in accrued and other liabilities in the accompanying condensed consolidated balance sheets until remitted to the relevant government authority. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the tax and financial reporting bases of the Company’s assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in future years in which those temporary differences are expected to be recovered or settled. Deferred tax assets are reduced through the establishment of a valuation allowance, if, based upon available evidence, it is determined that it is more likely than not that the deferred tax assets will not be realized. All deferred tax assets and liabilities are classified as non-current in the condensed consolidated financial statements. Uncertain Tax Positions The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained on examination based on the technical merit of the position. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates it is more likely than not that the position will be sustained on examination, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount, which is more than 50% likely of being realized upon ultimate settlement. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments. The Company recognizes interest charges and penalties related to unrecognized tax benefits as a component of the tax provision. Stock-Based Compensation U.S. GAAP requires the measurement and recognition of compensation expense for all share-based payment awards, including stock options, using a fair-value based method. The Company estimates the fair value of share-based payment awards on the date of grant using a Black-Scholes-Merton option-pricing model. Stock-based compensation is recognized on a straight-line basis over the requisite service period based on awards ultimately expected to vest. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Stock-based awards granted to non-employees are accounted for at fair value. The associated expense is recognized by the Company over the period the services are performed by non-employees. The fair value of stock-based awards granted to non-employees was nominal for the three and nine months ended September 30, 2017 and 2016. Net Loss Per Share Attributable to Common Stockholders The Company follows the two‑class method when computing net loss per common share as we issue shares that meet the definition of participating securities. The two‑class method determines net income (loss) per common share for each class of common stock and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two‑class method requires income available to common stockholders for the period to be allocated between common stock and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Our convertible preferred stock contractually entitles the holders of such shares to participate in dividends, but does not contractually require the holders of such shares to participate in our losses. For periods in which the Company has reported net losses, diluted net loss per common share attributable to common stockholders is the same as basic net loss per common share attributable to common stockholders, because potentially dilutive common shares are not assumed to have been issued if their effect is anti‑dilutive. Defined Contribution Plan In 2006, the Company adopted a defined contribution retirement savings plan under Section 401(k) of the Internal Revenue Code (IRC). This plan covers employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. Company contributions to the plan may be made at the discretion of the Board of Directors. There were no contributions by the Company during the three and nine months ended September 30, 2017 and 2016. JOBS Act Accounting Election The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recently Issued Accounting Standards In May 2014, the FASB issued ASU No. 2014‑09, Revenue from Contracts with Customers In March 2016, the FASB issued ASU No. 2016‑09, Compensation – Stock Compensation In August 2016, the FASB issued ASU No. 2016‑15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In February 2016, the FASB issued ASU No. 2016‑02, Leases (Topic 842) In July 2015, the FASB issued ASU No. 2015-11, Inventory, Simplifying the Measurement of Inventory

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Net Loss per Share	3. NET LOSS PER SHARE Net Loss Per Share Attributable to Common Stockholders Basic net loss per share is calculated by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. For purposes of this calculation, convertible preferred stock, preferred stock warrants and stock options are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following outstanding shares of common stock equivalents were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive: As of September 30, 2017 2016 Options to purchase common stock 1,912,644 2,178,280 Convertible preferred stock 22,671,601 20,528,306 Warrants for preferred stock 385,126 385,126 Total potential dilutive shares 24,969,371 23,091,712 In future periods, if the Company were to generate net income, it would allocate participating securities a proportional share of the net income, determined by dividing total weighted-average participating securities by the sum of the total weighted-average common shares and participating securities (the two-class method). The Company’s Series A convertible preferred stock, Series B convertible preferred stock, Series C convertible preferred stock and the Series AA convertible preferred stock participate in any dividends declared by the Company and are therefore considered to be participating securities. Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. To date, the Company has only incurred net losses and has not allocated any losses to participating securities because the preferred stockholders have no contractual obligation to share in the losses of the Company. The Company computes diluted loss per common share after giving consideration to the dilutive effect of stock options, warrants and non-vested stock that are outstanding during the period, except where such non-participating securities would be anti-dilutive.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. FAIR Cash and cash The Company’s lease obligation, term loan and Convertible Notes have fair values that approximate their carrying value. U.S. Observable Level - Quoted prices are available in active markets for identical assets or liabilities as of the report date. A quoted price for an identical asset or liability in an active market provides the most reliable fair value measurement because it is directly observable to the market. Level - Pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the report date. The nature of these securities include investments for which quoted prices are available but traded less frequently and investments that are fair valued using other securities, the parameters of which can be directly observed. Level - Securities that have little to no pricing observability as of the report date. These securities are measured using management’s best estimate of fair value, where the inputs into the determination of fair value are not observable and require significant management judgment or estimation. A financial The following Fair Value Measurements as of September 30, 2017 Quoted Prices in Active Markets using Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets Cash Equivalents: Money market accounts $ 5,769 $ — $ — $ 5,769 Restricted cash 100 — — 100 Total assets $ 5,869 $ — $ — $ 5,869 Liabilities Preferred stock warrant liabilities $ — $ — $ 2,311 $ 2,311 Fair Value Measurements as of December 31, 2016 Quoted Prices in Active Markets using Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets Cash Equivalents: Money market accounts $ 11,906 $ — $ — $ 11,906 Restricted cash 100 — — 100 Total assets $ 12,006 $ — $ — $ 12,006 Liabilities Preferred stock warrant liabilities $ — $ — $ 693 $ 693 The following Fair value measurements of warrants using significant unobservable inputs (Level 3) Balance as of December 31, 2016 $ 693 Change in fair value of preferred stock warrants 1,618 Balance as of September 30, 2017 $ 2,311

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2017
Balance Sheet Components [Abstract]
Balance Sheet Components	5. BALANCE Inventory Inventory September 30, December 31, 2017 2016 Finished goods $ 2,677 $ 2,580 Raw materials — 162 Total inventory $ 2,677 $ 2,742 Prepaid Prepaid September 30, December 31, 2017 2016 Insurance $ 50 $ 153 Lease deposit 100 149 Marketing tradeshows 255 140 Rent 51 — Other * 402 368 Total prepaid expenses and other current assets $ 858 $ 810 * Other consists of items that are individually less than 5% of total prepaid expenses and other current assets. Property Property September 30, December 31, 2017 2016 Computer hardware and software $ 706 $ 647 Equipment 2,873 2,818 Leasehold improvements 869 1,094 Furniture and fixtures 270 82 Total property and equipment 4,718 4,641 Less: Accumulated depreciation and amortization (3,529 ) (3,182 ) Total property and equipment, net $ 1,189 $ 1,459 Depreciation and amortization expense was $139 and $452 for three and nine months ended September 31, 2017 and $148 and $498 for three and nine months ended September 30, 2016. Accrued and Other Liabilities Accrued September 30, December 31, 2017 2016 Payroll and related expense $ 1,439 $ 1,647 Warranty 105 114 Customer deposits 23 98 Sales taxes 25 129 Accrued professional fees 816 38 Other* 589 412 Total accrued and other liabilities $ 2,997 $ 2,438

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. COMMITMENTS Operating The Company has various The Company recognizes Aggregate future minimum lease payments required under the Company’s operating leases as of September 30, 2017 are as follows: Years Ending December 31, 2017 (remainder) $ 124 2018 503 2019 518 2020 534 2021 550 Thereafter 188 Total future minimum lease payments $ 2,417 Total rent expense was $103 and $310 for three and nine months ended September 30, 2017 and $82 and $260 for three and nine months ended September 30, 2016. Licensing In July 2006, the Company entered into a license agreement with Rassman Licensing, LLC (Rassman) for non-exclusive, royalty bearing, non-transferable, perpetual, world-wide rights for use on approved fields relating to robotically controlled hair removal and implantation procedures. In consideration for this license, the Company paid Rassman a one-time payment of $1,000. The agreement terminates on May 9, 2020. In February 2012, the Company amended its license agreement with Rassman. In exchange for a one-time $400 payment to Rassman, the Company now has a fully paid royalty-free license to a patent subject to this license agreement. Royalties for the three and nine months ended September 30, 2017 and 2016 were $0. In July 2006, the Company entered into a license agreement with HSC Development, LLC for exclusive non-transferable, royalty-free worldwide rights for use in approved fields relating to a computer-controlled system in which a device is carried on a mechanized arm for extraction or implantation of a follicular unit without manual manipulation. In consideration for this license, the Company paid HSC Development, LLC a one-time payment of $25 and issued 2,500 shares of the Company’s common stock valued. The agreement terminates on July 27, 2024.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Long-Term Debt	7. LONG-TERM Loan and Security Agreement In May 2015, the Company entered into a loan and security agreement with Oxford Finance, LLC, or Oxford, (the Agreement). Under the terms of the loan and security agreement, the Company borrowed $20,000 with an interest rate at prime plus 8.5% per annum, which is collateralized by all personal property of the Company, excluding intellectual property, and issued 10-year warrants to purchase 110,486 shares of Series C Preferred Stock at $7.15 per share. The estimated fair value of the warrants at issuance was recorded as a discount on the loan and amortized into interest expense over the expected life of the loan. In connection with the loan agreement, the Company recorded $246 of credit facility fees and $153 of debt issuance cost as of January 31, 2015. The credit facility fees and debt issuance costs are a discount on the debt and are being amortized to interest expense over the term of the loan using the effective-interest method. The loan will mature in July 2019, at which time the Company must repay the outstanding principal balance which includes a final payment of $1,300. The outstanding balance on the loan was $15,300 and accrued interest totaled $99 as of September 30, 2017. The interest rate was 12.8% at September 30, 2017. Borrowings under the Agreement are collateralized by all the assets of the Company, excluding intellectual property. The Agreement includes customary restrictive covenants that impose operating and financial restrictions on the Company, including restrictions on our ability to take actions that could be in the Company’s best interests. These restrictive covenants include operating covenants restricting, among other things, the Company’s ability to incur additional indebtedness, effect certain acquisitions or make other fundamental changes. The Company was in compliance with all of the covenants as of September 30, 2017 and December 31, 2016. The scheduled principal payments on the outstanding borrowings as of September 30, 2017 are as follows: For the year ended December 31, 2017 (remainder) $ 2,000 2018 8,000 2019 5,299 Total 15,299 Less debt discount (410 ) Less current portion (7,659 ) Non-current portion $ 7,230 During the nine months ended September 30, 2017, the Company made principal repayments of $6,000. Convertible Notes On September 6, 2017, the Company issued $5,000 in subordinated convertible notes (Convertible Notes) that accrued interest at 5.0% per annum, in a private placement transaction with certain of the Company’s existing stockholders and their affiliated entities, including investors affiliated with certain of the Company’s directors. As of September 30, 2017, the outstanding principal balance on the Convertible Notes was $5,000 and the accrued but unpaid interest was $18. Pursuant to the terms of the Convertible Notes, the aggregate outstanding principal and unpaid but accrued interest automatically converted into 718,184 shares of the Company’s common stock, upon the consummation of the IPO (as discussed in Note 1).

Convertible Preferred Stock

Convertible Preferred Stock	9 Months Ended
	Sep. 30, 2017
Temporary Equity Disclosure [Abstract]
Convertible Preferred Stock	8. CONVERTIBLE The convertible preferred stock consists of the following: September 30, 2017 Shares Shares Net Carrying Liquidation Convertible Preferred Stock: Authorized Outstanding Value Preference Series A 25,092,906 2,509,232 $ 11,140 $ 11,292 Series B 38,461,538 3,846,132 24,926 25,000 Series C 170,100,000 16,066,237 107,902 114,874 Series AA 2,500,000 250,000 1,976 2,000 Total convertible preferred stock 236,154,444 22,671,601 $ 145,944 $ 153,166 December 31, 2016 Shares Shares Net Carrying Liquidation Convertible Preferred Stock: Authorized Outstanding Value Preference Series A 25,092,906 2,509,232 $ 11,140 $ 11,292 Series B 38,461,538 3,846,132 24,926 25,000 Series C 170,100,000 14,536,931 97,693 103,939 Series AA 2,500,000 250,000 1,976 2,000 Total convertible preferred stock 236,154,444 21,142,295 $ 135,735 $ 142,231 On issuance, the Company’s convertible preferred stock is recorded at fair value or the amount of allocated proceeds, net of issuance costs. The Company classifies the convertible preferred stock outside of stockholders’ deficit because, in the event of certain liquidation events that are not solely within the control of the Company (including merger, acquisition, or sale of all or substantially all of the assets), the shares would become redeemable at the option of the holders. The Company did not adjust the carrying values of the convertible preferred stock to the deemed liquidation values of such shares since a liquidation event was not probable at any of the reporting dates. Subsequent adjustments to increase or decrease the carrying values to the ultimate liquidation values will be made only if and when it becomes probable that such a liquidation event will occur. Immediately prior to the closing of the IPO (as discussed in Note 1), all shares of our outstanding convertible preferred stock automatically converted into 22,671,601

Preferred Stock Warrant Liabili

Preferred Stock Warrant Liabilities	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Preferred Stock Warrant Liabilities	9. PREFERRED STOCK WARRANT LIABILITIES The Company classifies its convertible preferred stock warrants as liabilities on the accompanying condensed consolidated balance sheets. As of September 30, 2017 and December 31, 2016, the preferred stock warrant liabilities were $2,311 and $693. The key terms of the preferred stock warrants are summarized in the following table: Warrants Outstanding Warrants Warrants Outstanding Outstanding September 30, December 31, Exercise 2017 2016 Price Expiration Series C preferred stock warrants 274,640 274,640 $ 7.15 Various dates in 2023-2024 Series C preferred stock warrants 110,486 110,486 7.15 May 19, 2025 Total preferred stock warrants 385,126 385,126 The exercise price is not fixed and may be adjusted to the price per share paid by investors in a qualified financing in the event the price per share is less than the $7.15 per share. During the nine months ended September 30, 2017 and 2016, no warrants were exercised. Prior to its IPO, at each reporting date, the Company remeasures the convertible preferred stock warrants to fair value using a probability weighed expected return method (PWERM) that uses an option pricing method (OPM), together with a Monte Carlo simulation to incorporate the anti-dilution provisions on the convertible preferred stock, to allocate the estimated value of the Company. The OPM treats classes of stock as call options on a company's enterprise value which takes into consideration differences in the right of various securities including rights to dividends, liquidation preferences, and conversion rights. The OPM prices the call option using the Black-Scholes model. The PWERM relies on a forward-looking analysis to predict the possible future value of a company by weighing discrete future outcomes. The fair value of preferred stock warrants was determined using the following assumptions: Nine Year Ended September 30, December 31, 2017 2016 Expected term (years) 1.25 2.00 Risk-free interest rate 1.35 % 1.20 % Expected volatility 72.2 % 70.9 % The assumptions used in calculating the estimated fair market value at each reporting period represent the Company’s best estimate, however inherent uncertainties are involved. As a result, if factors or assumptions change the warrant liability, the estimated fair value could be materially different. The estimated expected volatility was derived from historical volatilities of several unrelated publicly listed peer companies over a period approximately equal to the remaining term of the warrants. When making the selections of the Company’s industry peer companies to be used in the volatility calculation, the Company considered the size and operational and economic similarities to the Company’s principle business operations. The estimated expected term represents either the lesser of (i) the remaining contractual term of the warrants or (ii) the remaining term under probable scenarios used to determine the fair value of the underlying stock. The risk-free interest rate was based on the U.S. Treasury yield for a term consistent with the estimated expected term. The significant unobservable inputs used in the fair value measurement of the convertible preferred stock warrant liability are the fair value of the underlying stock at the valuation date, the expected volatility, and the estimated term of the warrants. Generally, increases (decreases) in the fair value of the underlying stock, expected volatility and expected term would result in a directionally similar impact to the fair value measurement. The warrants are immediately exercisable in whole or in part over the term of the warrants. Certain of the Company’s outstanding preferred stock warrants will expire twelve months after the IPO if not exercised prior to such date, while the remaining warrants expire according to the original term. On the completion of the IPO (as discussed in Note 1), the liability on the preferred stock warrants was reclassified to additional paid-in capital in stockholders’ deficit and the preferred stock warrants automatically converted into common stock warrants and, as such, no further remeasurements to fair value will occur.

Common Stock Reserved For Issua

Common Stock Reserved For Issuance	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Common Stock Reserved For Issuance	10. COMMON STOCK RESERVED The Company is September 30, December 31, 2017 2016 Conversion of outstanding Series A convertible preferred stock 2,509,232 2,509,232 Conversion of outstanding Series B convertible preferred stock 3,846,132 3,846,132 Conversion of outstanding Series C convertible preferred stock 16,066,237 14,536,931 Conversion of outstanding Series AA convertible preferred stock 250,000 250,000 Outstanding preferred stock warrants 385,126 385,126 Outstanding and issued stock options 1,912,644 1,831,757 Shares reserved for future option grants 301,131 392,306 Total common stock reserved for issuance 25,270,502 23,751,484

Stock Option Plan

Stock Option Plan	9 Months Ended
	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Option Plan	11. STOCK OPTION PLAN 2005 and 2015 Plan In 2005, the Company established its 2005 Stock Option Plan (the 2005 Plan), which provides for the granting of stock options to employees, directors, and consultants of the Company. Options granted under the Plan may be either incentive stock options (ISOs) or non-statutory stock options (NSOs), as determined by the Administrator at the time of grant. The term and vesting period of each option shall be stated in the option agreements. However, the term shall be no more than ten years from the date of the grant and the vesting period shall be generally four years. In the case of an ISO granted to an optionee who, at the time the option is granted, owns stock representing more than ten percent (10%) of the voting power of all classes of stock of the Company, the term of the option shall be five years from the date of grant or such shorter term as may be provided in the option agreement. In 2015, the Company established its 2015 Equity Incentive Plan (the 2015 Plan), which superseded and replaced the 2005 Plan. A total of 2,221,655 shares have been reserved for issuance under the 2005 Plan and 2015 Plan. 2017 Plan In September 2017, the Company adopted the 2017 Equity Incentive Plan (the 2017 Plan). The Company’s 2017 Plan provides for the grant of incentive stock options (ISOs), nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, and other forms of equity compensation to employees, directors and consultants. In addition, the Company’s 2017 Plan provides for the grant of performance cash awards to employees, directors and consultants. The 2017 Plan became effective upon the closing date of the IPO. As discussed in Note 15, the 2017 Plan became effective on October 11, 2017. As a result, no further grants will be made under the Company’s 2005 Plan and the 2015 Plan; however, any outstanding stock awards granted under those Plans will remain outstanding, subject to the terms of the Company’s 2005 Plan and 2015 Plan and the applicable stock award agreements, until such outstanding stock awards that are stock options are exercised or until they terminate or expire by their terms, or until such stock awards are fully settled, terminated or forfeited. On the effective date of the 2017 Plan, the Company reserved 1,913,831 shares of common stock for issuance under the 2017 Plan, plus the remaining reserved and unissued shares under the 2015 plan. The number of shares reserved for issuance under the 2017 Equity Plan will increase automatically on the first day of each fiscal year beginning in 2018 and ending in 2027, equal to the lesser of (i) 4% of the shares of stock outstanding on the last day of the immediately preceding fiscal year or (ii) number of shares of stock as determined by the Company’s board of directors. The Company recognized Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Cost of revenue $ 3 $ 3 $ 8 $ 10 Research and development 25 25 76 78 Sales and marketing 18 18 53 68 General and administrative 72 124 212 203 Total stock-based compensation $ 118 $ 170 $ 349 $ 359 Determination The estimated Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Expected term (years) — 5.98-6.05 4.95-7.50 5.94-6.11 Risk-free interest rate — 1.30-1.31% 1.77-2.13% 1.30-1.48% Expected volatility — 52.71-52.98% 51.62-53.58% 52.71-53.37% Dividend yield 0% 0% 0% 0% The fair value of each stock option grant was determined by the Company using the methods and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment and estimation by management. Expected —The expected term represents the period that stock-based awards are expected to be outstanding. The expected term for option grants is determined using the simplified method. The simplified method deems the term to be the average of the time-to-vesting and the contractual life of the stock-based awards. The expected term for options issued to non-employees is the contractual term. Expected y —Since the Company does not have a trading history for its common stock, the expected volatility was derived from the historical stock volatilities of comparable peer public companies within its industry that are considered to be comparable to the Company’s business over a period equivalent to the expected term of the stock-based awards. Risk-Free —The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the date of grant for zero-coupon U.S. Treasury notes with maturities approximately equal to the stock-based awards’ expected term. Expected Dividend Rate —The expected dividend is zero as the Company has not paid nor does it anticipate paying any dividends on its common stock in the foreseeable future. Forfeiture —The forfeiture rate is estimated based on an analysis of actual forfeitures. Management will continue to evaluate the adequacy of the forfeiture rate based on actual forfeiture experience, analysis of employee turnover behavior and other factors. The impact from any forfeiture rate adjustment would be recognized in full in the period of adjustment and if the actual number of future forfeitures differs from management’s estimates, the Company might be required to record adjustments to stock-based compensation in future periods. Fair Value of Common k —Because the Company as of September 30, 2017 was a private company, there was no public market for the Company’s common stock as of September 30, 2017 and December 31, 2016, the Company’s board of directors determined the fair value of the common stock by considering a number of objective and subjective factors, including having valuations of its common stock performed by an unrelated valuation specialist, valuations of comparable peer public companies, sales of the Company’s convertible preferred stock to unrelated third parties, operating and financial performance, the lack of liquidity of the Company’s capital stock, and general and industry-specific economic outlook. After the closing of the Company’s IPO, the fair value of the Company’s common stock will be used to estimate the fair value of the stock-based awards at grant date. Weighted- Weighted- Average Average Remaining Aggregate Number of Exercise Price Contractual Intrinsic Shares per Share Term Value Outstanding — December 31, 2016 1,831,757 1.80 8.7 $ 14 Options granted 133,870 1.72 Options exercised (8,969 ) 1.83 Options cancelled (44,014 ) 1.82 Outstanding — September 30, 2017 1,912,644 $ 1.76 8.1 $ 10,029 Vested and expected to vest — September 30, 2017 1,610,419 $ 1.77 8.0 $ 8,421 Exercisable — September 30, 2017 872,687 $ 1.81 7.5 $ 5,803 The following table summarizes stock option activity under the Company’s stock option plan: The weighted-average grant date fair value of options granted was $0 and $1.02 per share for three and nine months ended September 30, 2017, and $0.86 per share for three and nine months ended September 30, 2016. The total intrinsic value of options exercised were $0 for three and nine months ended September 30, 2017 and 2016. Unamortized stock-based compensation was $654 as of September 30, 2017, which is expected to be recognized over a weighted-average period of approximately 2.52 years.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	12. INCOME TAXES The Company did not record a provision for federal income taxes for the three and nine months ended September 30, 2017 because it expects to generate a loss for the year ended December 31, 2017. The income tax expense of $25 and $50 for the three and nine months ended September 30, 2017 represents foreign taxes. The Company’s deferred tax assets continue to be offset by a valuation allowance.

Geographic Information

Geographic Information	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Geographic Information	13. GEOGRAPHIC INFORMATION The following Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 United States $ 1,429 $ 1,330 $ 6,242 $ 4,086 Europe and Middle East 1,205 998 4,333 2,173 Asia Pacific 874 974 3,192 2,709 Rest of World 669 374 1,674 1,454 Total revenue $ 4,177 $ 3,676 $ 15,441 $ 10,422 As of September 30, 2017 and December 31, 2016, all long-term assets were located within the United States.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	14. RELATED During the year ended December 31, 2016, the Company has engaged in a commercial transaction with a then-member of the Company’s board of directors. The aggregate revenue for this transaction was $240 for the year ended December 31, 2016. There were no accounts receivable due from this then-member of the board of directors as of December 31, 2016. In January 2017, that member of the Company’s board of directors resigned.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	15. SUBSEQUENT EVENTS Initial Public Offering As discussed in Note 1, in connection with the Company’s IPO that closed on October 16, 2017, the following events occurred: • the Company issued 3,897,910 shares of its common stock (inclusive of 322,910 shares of common stock from the subsequent exercise by the underwriters of the over-allotment option, which occurred on October 26, 2017) at a price of $7.00 per share for aggregate cash proceeds of $22,674, net of underwriting discounts and commissions and offering costs. • all outstanding shares of convertible preferred stock converted into 22,671,601 shares of common stock; • all the outstanding preferred stock warrants converted into common stock warrants resulting in the reclassification of our preferred stock warrant liabilities to additional paid-in capital; and • the outstanding principal and accrued but unpaid interest on the Convertible Notes converted into 718,184 shares of common stock. Following completion of the Company’s IPO and in connection with the preparation of this Quarterly Report on Form 10-Q, management reassessed its current operating plans and capital resources. As a result of this reassessment, the Company believes that, as of the filing date of the Quarterly Report, its existing cash and cash equivalents (inclusive of the net proceeds from its IPO and the issuance of the Convertible Notes) and cash expected to be generated from the sale of its products, will be sufficient to fund its planned operations for the next 12 months. However, the Company will need additional capital to fund its future operations and intends to obtain such capital through the sale of additional share of capital stock or related securities. 2017 Plan As discussed in Note 11, the Company adopted its 2017 Equity Incentive Plan (the 2017 Plan) in September 2017, which became effective on the closing date of the IPO. The 2017 Plan became effective on October 11, 2017. The Company’s 2017 Plan provides for the grant of incentive stock options (“ISOs”), nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, and other forms of equity compensation to employees, directors and consultants. In addition, the Company’s 2017 Plan provides for the grant of performance cash awards to employees, directors and consultants. On the effective date of the 2017 Plan, the Company reserved 1,913,831 shares of common stock for issuance under the 2017 Plan, plus the remaining reserved and unissued shares under the 2015 plan. The number of shares reserved for issuance under the 2017 Equity Plan will increase automatically on the first day of each fiscal year beginning in 2018 and ending in 2027, equal to the lesser of (i) 4% of the shares of stock outstanding on the last day of the immediately preceding fiscal year or (ii) number of shares of stock as determined by the Company’s board of directors. No further grants will be made under the Company’s 2005 Plan and the 2015 Plan.

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Liquidity	Liquidity These condensed consolidated financial statements are prepared on a going concern basis that contemplates the realization of assets and extinguishment of liabilities in the normal course of business. The Company has incurred net operating losses and negative cash flows from operations since inception. As of September 30, 2017 and December 31, 2016, the Company has an accumulated deficit of $163,424 and $146,645 and, as of such dates, did not have sufficient capital to fund its planned operations. As a result of the Company’s recurring losses from operations and negative cash flows, the Company’s independent registered public accounting firm included an explanatory paragraph in its report on the Company’s consolidated financial statements as of, and for the year ended, December 31, 2016 that such factors raise substantial doubt about the Company’s ability to continue as a going concern. In order to continue its operations, the Company must achieve profitable operations and/or obtain additional financing. Until the Company generates revenue at a level to support its cost structure, the Company expects to continue to incur substantial operating losses and net cash outflows. The Company may never become profitable and even if it does attain profitable operations, it may not be able to sustain profitability or positive cash flows on a recurring basis. The Company will need to raise further capital in the future to service its debt or fund its operations until the time it can sustain positive cash flows. There can be no assurance that the Company will be successful in raising additional capital or that such capital, if available, will be on terms that are acceptable to the Company. If the Company is unable to raise sufficient additional capital, it may be compelled to reduce the scope of its operations and planned capital expenditures or sell certain assets, including intellectual property assets. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and, as such, the condensed consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or amounts and classification of liabilities that might be necessary should the Company be unable to continue in existence.
Basis of Presentation	Basis of Presentation The condensed consolidated balance sheet as of September 30, 2017, the condensed consolidated statements of operations and condensed consolidated statements of comprehensive loss for the three and nine months ended September 30, 2017 and 2016 and the condensed consolidated statements of cash flows for the nine months ended September 30, 2017 and 2016 and the condensed consolidated statement of convertible preferred stock and stockholders’ deficit for the nine months ended September 30, 2017 are unaudited. The unaudited condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair presentation of the Company’s condensed consolidated financial statements included in this report. The condensed consolidated financial data disclosed in these notes to the condensed consolidated financial statements related to the three and nine-month periods are also unaudited. The condensed consolidated results of operations for the three and nine months ended September 30, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017, or for any other future annual or interim period. The consolidated balance sheet as of December 31, 2016 included herein was derived from the audited consolidated financial statements as of that date. These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements included in the prospectus dated October 11, 2017, filed with the SEC pursuant to Rule 424 promulgated under the Securities Act of 1933, as amended.
Principles of Consolidation	Principles of Consolidation The accompanying condensed c n s l i a e f i a c i a s t m n i c l u t u Restoration Robotics, Inc. A l i e rc m a n cc u n t r a s c i o a v b e l i m i a i o s l i a t i n
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. general accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to revenue recognition, the fair value of common stock, the fair value of preferred stock warrant liabilities, and the recoverability of the Company’s net deferred tax assets, and related valuation allowance. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates.
Segments	Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Maker (CODM) in deciding how to allocate resources to an individual segment and in assessing performance. The Company's CODM is its Chief Executive Officer. The Company has determined it operates in a single operating segment and has one reportable segment, as the CODM reviews financial information presented on a consolidated basis for purposes of making operating decisions, allocating resources, and evaluating financial performance.
Foreign Currency	Foreign Currency The functional currency of the Company’s non-U.S. subsidiaries is the local currency. Asset and liability balances denominated in non-U.S. dollar currencies are translated into U.S. dollars using period-end exchange rates, while revenue and expenses are based upon the exchange rate at the time of the transaction, if known, or at the average rate for the period. Differences are included in stockholders’ deficit as a component of accumulated other comprehensive loss. Financial assets and liabilities denominated in currencies other than the functional currency are recorded at the exchange rate at the time of the transaction and subsequent gains and losses related to changes in the foreign currency are included in other income (expense), net in the accompanying consolidated statements of operations. The net foreign transaction gain or losses were insignificant for all periods presented.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents consists primarily of funds invested in readily available checking and savings accounts and investments in money market funds and short-term time deposits.
Restricted Cash	Restricted Cash As of September 30, 2017 and December 31, 2016, the Company was required to hold $100 in a separate money market account as collateral for credit cards. These amounts are recorded in other assets in the accompanying condensed consolidated balance sheets.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, restricted cash and accounts receivable. Substantially all of the Company’s cash and cash equivalents and restricted cash are held with two financial institutions, and the account balances exceed the Federal Deposit Insurance Corporation (FDIC) insurance limit. Accounts are insured by the FDIC up to $250 per financial institution. The Company has not experienced any losses in such accounts with these financial institutions.
Concentration of Customers	Concentration of Customers For the three months ended September 30, 2017, two customers each accounted for 11% and 12% of the Company’s revenues. As of the nine months ended September 30, 2017 and three and nine months ended September 30, 2016, there were no customers accounting for more than 10% of the Company’s revenue. As of September 30, 2017, two customers each accounted for 11% and 15% of the Company’s accounts receivable. As of December 31, 2016, six customers accounted for 10%, 11%, 11%, 11%, 12%, and 13% of the Company’s accounts receivable. Accounts receivable do not bear interest and are typically not collateralized. The Company performs ongoing credit evaluations of its customers and maintains reserves for potential credit losses. Accounts receivable are deemed past due in accordance with the contractual terms of the agreement. Accounts are charged against the allowance for doubtful accounts once collection efforts are unsuccessful. Historically, such losses have been within management's expectations. The allowance for doubtful accounts is zero at September 30, 2017 and December 31, 2016.
Inventory	Inventory Inventory is stated at the lower of cost or market and cost is principally determined using the first-in, first-out method. Costs include material, labor and overhead. Inventory that is obsolete or in excess of forecasted usage is written down to its estimated net realizable value based on assumptions about future demand and market conditions. Inventory write-downs are charged to cost of goods sold and a new cost basis for the inventory is established.
Concentration of Supplier	Concentration of Supplier The Company has a single source supplier manufacturing its system. If the supplier is not able to supply the requested orders, the Company would be unable to continue to derive revenues from the sale of systems until an alternative source is found, which could take a considerable length of time.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which is between three and five years. Leasehold improvements are amortized over the lesser of the life of the lease or the useful life of the improvements. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the condensed consolidated balance sheet, and any resulting gain or loss is reflected in operations.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets are reviewed annually for impairment or whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the carrying amount to the future net undiscounted cash flows that the assets are expected to generate. If the carrying amount of an asset group exceeds its estimated future cash flows, an impairment charge is recognized in the amount by which the carrying amount of the asset group exceeds the fair value of the asset group. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. There has been no impairment of long-lived assets for any of the periods presented.
Deferred Offering Costs	Deferred Offering Costs Deferred offering costs, consisting of legal, accounting and filing fees relating to an IPO, are capitalized. Upon the completion of the IPO (as discussed in Note 1), the deferred offering costs were offset against offering proceeds. As of September 30, 2017, $2,223 of deferred offering costs have been capitalized, which is included in other long-term assets in the condensed consolidated balance sheets. There were no deferred offering costs capitalized as of December 31, 2016.
Preferred Stock Warrants Liabilities	Preferred Stock Warrants Liabilities The Company accounts for freestanding warrants to purchase shares of convertible preferred stock that are contingently redeemable as liabilities in the condensed consolidated balance sheets at their estimated fair value because these warrants may obligate the Company to redeem them at some point in the future. At the end of each reporting period, changes in the estimated fair value of the warrants to purchase shares of convertible preferred stock are recorded as other income (expense), net in the consolidated statements of operations. Upon the completion of the IPO (as discussed in Note 1), the liability on the preferred stock warrants was reclassified to additional paid-in capital in stockholders’ deficit.
Debt Issuance Costs	Debt Issuance Costs Costs related to the issuance of debt are presented as a direct deduction to the carrying value of the debt and are amortized to interest expense using the effective interest rate method over the term of the related debt.
Revenue Recognition	Revenue Recognition The Company generates revenue from sales of robotic systems and related procedures, and related support and maintenance. The Company derives revenue primarily from two sources: (i) Product revenue, which includes robotic systems sales, installation, software, procedure key and disposable kits; and (ii) Support and maintenance revenue, which includes support, training, and service contracts. Revenue is recognized when all of the following criteria are met: (l) persuasive evidence of an arrangement exists; (2) the product or service has been delivered; (3) the sales price is fixed or determinable; and (4) collection is reasonably assured. The Company defines each of the four criteria above as follows: • Persuasive Evidence of Arrangement Exists. The Company uses purchase orders pursuant to the terms and conditions of a master agreement to support the evidence of an arrangement with distributors and uses purchase agreements as evidence of arrangement with direct customers. • Delivery has Occurred. Provided that all other revenue recognition criteria have been met, for direct sales the Company typically recognizes system revenue upon customer acceptance, or upon shipment for systems sold to distributors, as title and risk of loss are transferred at that time, and there are no further obligations and no rights of return. Procedure revenue is recognized upon shipment of disposable kits and delivery of the ARTAS key. Support and maintenance revenue is recognized over time as the services are delivered. • The Sales Price is Fixed or Determinable. The Company assesses whether the fee is fixed or determinable based on the payment terms associated with the transaction. If the terms are extended beyond the Company’s normal payment terms, the Company will recognize revenue as the payments become due. Payments from distributors are not contingent on the distributors’ receiving payment from the end-users. • Collection is Reasonably Assured. The Company assesses probability of collection on an individual basis based on a number of factors, including the credit-worthiness of the customer and past transaction history with the customer. The Company generally obtains a significant cash deposit from its customers prior to shipment. The Company records its revenues net of sales tax and shipping and handling costs. Incremental direct costs incurred related to the acquisition or origination of a customer contract are expensed as incurred. Multiple Element Arrangements The Company’s offering includes robotic systems containing software components that function together to provide the essential functionality of the product. Therefore, the Company’s hardware products (inclusive of the core software) are considered non-software deliverables and are not subject to industry-specific software revenue recognition guidance. The Company’s typical multiple element arrangement includes robotic systems (including the essential software), procedure key, installation (for direct sales to end-users), product training and service contracts. The Company considers each of these deliverables to be separate units of accounting based on whether the delivered items have stand-alone value. The Company has determined that each unit of accounting has stand-alone value because they are sold separately by the Company or, for hardware products, because the customers can resell them to others on a stand-alone basis. For the arrangements with multiple deliverables, the Company allocates the arrangement fee to each element based upon the relative selling price of such element. When applying the relative selling price method, the Company determines the selling price for each element using vendor-specific objective evidence (VSOE) of selling price, if it exists, or if not, third-party evidence (TPE) of selling price, if it exists. If neither VSOE nor TPE of selling price exist for an element, the Company uses its best estimated selling price (BESP) for that element. The revenue allocated to each element is then recognized when the basic revenue recognition criteria are met for that element. The Company is not able to establish a selling price of its deliverables using VSOE or to determine TPE for its products and services. TPE is determined based on competitor prices for similar deliverables when sold separately. Generally, the Company’s go-to-market strategy differs from that of its peers and its offerings contain a significant level of differentiation such that the comparable pricing of products with similar functionality cannot be obtained. When the Company is unable to establish the selling price of its deliverables using VSOE or TPE, the Company uses BESP in its allocation of arrangement consideration. The objective of BESP is to determine the price at which the Company would transact a sale if the product or service were sold on a stand-alone basis. The Company determines BESP for a product or service by considering multiple factors including, but not limited to, industry and market conditions, competitive landscape, standard pricing practices and internal cost models. Additionally, the Company considers historical transactions, including transactions whereby the deliverable was sold on a stand-alone basis. Deferred revenue primarily relates to support and maintenance and pertains to billings or payments received in advance where all of the revenue recognition criteria have not been met. The current portion of deferred revenue represents the amounts that are expected to be recognized as revenue within one year of the condensed consolidated balance sheet date.
Cost of Revenue	Cost of Revenue Cost of revenue consists of product and fulfillment costs. Product costs include the cost of systems and disposable kits manufacture, related labor and personnel costs and allocated shared costs. Fulfillment costs consist of costs incurred in the shipping and handling of inventory including the shipping costs to the Company's customers, labor and related personnel costs related to receiving, inspecting, warehousing, and preparing systems and reusable kits for shipment. Cost of revenue for customer service is expensed as incurred and primarily consists of personnel costs such as salaries, bonuses and benefits and stock‑based compensation for employees associated with service contracts, travel costs and allocated shared costs (including rent and information technology).
Research and Development	Research and Development Research and development costs are charged to operations as incurred.
Warranty	Warranty The Company provides a one-year warranty on the ARTAS System and accrues for the estimated future costs of repair or replacement upon customer acceptance or shipment. The warranty expense is accrued as a liability and recorded to cost of goods sold and is based upon historical information for the cost to repair or replace the system.
Sales Taxes	Sales Taxes Revenue is recorded net of taxes collected from customers that are remitted to governmental authorities with the collected taxes recorded as current liabilities in accrued and other liabilities in the accompanying condensed consolidated balance sheets until remitted to the relevant government authority.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the tax and financial reporting bases of the Company’s assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in future years in which those temporary differences are expected to be recovered or settled. Deferred tax assets are reduced through the establishment of a valuation allowance, if, based upon available evidence, it is determined that it is more likely than not that the deferred tax assets will not be realized. All deferred tax assets and liabilities are classified as non-current in the condensed consolidated financial statements. Uncertain Tax Positions The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained on examination based on the technical merit of the position. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates it is more likely than not that the position will be sustained on examination, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount, which is more than 50% likely of being realized upon ultimate settlement. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments. The Company recognizes interest charges and penalties related to unrecognized tax benefits as a component of the tax provision.
Stock-Based Compensation	Stock-Based Compensation U.S. GAAP requires the measurement and recognition of compensation expense for all share-based payment awards, including stock options, using a fair-value based method. The Company estimates the fair value of share-based payment awards on the date of grant using a Black-Scholes-Merton option-pricing model. Stock-based compensation is recognized on a straight-line basis over the requisite service period based on awards ultimately expected to vest. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Stock-based awards granted to non-employees are accounted for at fair value. The associated expense is recognized by the Company over the period the services are performed by non-employees. The fair value of stock-based awards granted to non-employees was nominal for the three and nine months ended September 30, 2017 and 2016.
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common Stockholders The Company follows the two‑class method when computing net loss per common share as we issue shares that meet the definition of participating securities. The two‑class method determines net income (loss) per common share for each class of common stock and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two‑class method requires income available to common stockholders for the period to be allocated between common stock and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Our convertible preferred stock contractually entitles the holders of such shares to participate in dividends, but does not contractually require the holders of such shares to participate in our losses. For periods in which the Company has reported net losses, diluted net loss per common share attributable to common stockholders is the same as basic net loss per common share attributable to common stockholders, because potentially dilutive common shares are not assumed to have been issued if their effect is anti‑dilutive.
Defined Contribution Plan	Defined Contribution Plan In 2006, the Company adopted a defined contribution retirement savings plan under Section 401(k) of the Internal Revenue Code (IRC). This plan covers employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. Company contributions to the plan may be made at the discretion of the Board of Directors. There were no contributions by the Company during the three and nine months ended September 30, 2017 and 2016.
Jobs Act Accounting Election	JOBS Act Accounting Election The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it is (i) no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In May 2014, the FASB issued ASU No. 2014‑09, Revenue from Contracts with Customers In March 2016, the FASB issued ASU No. 2016‑09, Compensation – Stock Compensation In August 2016, the FASB issued ASU No. 2016‑15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In February 2016, the FASB issued ASU No. 2016‑02, Leases (Topic 842) In July 2015, the FASB issued ASU No. 2015-11, Inventory, Simplifying the Measurement of Inventory

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Outstanding Shares of Common Stock Equivalents Excluded from Calculation of Diluted Net Loss per Share Attributable to Common Stockholders	The following outstanding shares of common stock equivalents were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive: As of September 30, 2017 2016 Options to purchase common stock 1,912,644 2,178,280 Convertible preferred stock 22,671,601 20,528,306 Warrants for preferred stock 385,126 385,126 Total potential dilutive shares 24,969,371 23,091,712

Fair Value Measurements - (Tabl

Fair Value Measurements - (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Schedule for Levels of Fair Value Measurements of Cash Equivalents, Investments and Preferred Stock Warrants Liabilities	The following Fair Value Measurements as of September 30, 2017 Quoted Prices in Active Markets using Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets Cash Equivalents: Money market accounts $ 5,769 $ — $ — $ 5,769 Restricted cash 100 — — 100 Total assets $ 5,869 $ — $ — $ 5,869 Liabilities Preferred stock warrant liabilities $ — $ — $ 2,311 $ 2,311 Fair Value Measurements as of December 31, 2016 Quoted Prices in Active Markets using Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets Cash Equivalents: Money market accounts $ 11,906 $ — $ — $ 11,906 Restricted cash 100 — — 100 Total assets $ 12,006 $ — $ — $ 12,006 Liabilities Preferred stock warrant liabilities $ — $ — $ 693 $ 693
Schedule of Preferred Stock Warrant Liabilities Activity Subject to Level 3 Inputs Measured on Recurring Basis	The following Fair value measurements of warrants using significant unobservable inputs (Level 3) Balance as of December 31, 2016 $ 693 Change in fair value of preferred stock warrants 1,618 Balance as of September 30, 2017 $ 2,311

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2017
Balance Sheet Components [Abstract]
Schedule of Inventory	Inventory September 30, December 31, 2017 2016 Finished goods $ 2,677 $ 2,580 Raw materials — 162 Total inventory $ 2,677 $ 2,742
Schedule of Prepaid Expenses and Other Current Assets	Prepaid September 30, December 31, 2017 2016 Insurance $ 50 $ 153 Lease deposit 100 149 Marketing tradeshows 255 140 Rent 51 — Other * 402 368 Total prepaid expenses and other current assets $ 858 $ 810 * Other consists of items that are individually less than 5% of total prepaid expenses and other current assets.
Schedule of Property and Equipment, Net	Property September 30, December 31, 2017 2016 Computer hardware and software $ 706 $ 647 Equipment 2,873 2,818 Leasehold improvements 869 1,094 Furniture and fixtures 270 82 Total property and equipment 4,718 4,641 Less: Accumulated depreciation and amortization (3,529 ) (3,182 ) Total property and equipment, net $ 1,189 $ 1,459
Schedule of Accrued and Other Liabilities	Accrued September 30, December 31, 2017 2016 Payroll and related expense $ 1,439 $ 1,647 Warranty 105 114 Customer deposits 23 98 Sales taxes 25 129 Accrued professional fees 816 38 Other* 589 412 Total accrued and other liabilities $ 2,997 $ 2,438 * Other consists of items that are individually less than 5% of total accrued and other liabilities.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2017
Commitments And Contingencies Disclosure [Abstract]
Summary of Aggregate Future Minimum Lease Payments under Operating Leases	Aggregate future minimum lease payments required under the Company’s operating leases as of September 30, 2017 are as follows: Years Ending December 31, 2017 (remainder) $ 124 2018 503 2019 518 2020 534 2021 550 Thereafter 188 Total future minimum lease payments $ 2,417

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule Principal Payments on Outstanding Borrowings	The scheduled principal payments on the outstanding borrowings as of September 30, 2017 are as follows: For the year ended December 31, 2017 (remainder) $ 2,000 2018 8,000 2019 5,299 Total 15,299 Less debt discount (410 ) Less current portion (7,659 ) Non-current portion $ 7,230

Convertible Preferred Stock (Ta

Convertible Preferred Stock (Tables)	9 Months Ended
	Sep. 30, 2017
Temporary Equity Disclosure [Abstract]
Schedule of Convertible Preferred Stock	The convertible preferred stock consists of the following: September 30, 2017 Shares Shares Net Carrying Liquidation Convertible Preferred Stock: Authorized Outstanding Value Preference Series A 25,092,906 2,509,232 $ 11,140 $ 11,292 Series B 38,461,538 3,846,132 24,926 25,000 Series C 170,100,000 16,066,237 107,902 114,874 Series AA 2,500,000 250,000 1,976 2,000 Total convertible preferred stock 236,154,444 22,671,601 $ 145,944 $ 153,166 December 31, 2016 Shares Shares Net Carrying Liquidation Convertible Preferred Stock: Authorized Outstanding Value Preference Series A 25,092,906 2,509,232 $ 11,140 $ 11,292 Series B 38,461,538 3,846,132 24,926 25,000 Series C 170,100,000 14,536,931 97,693 103,939 Series AA 2,500,000 250,000 1,976 2,000 Total convertible preferred stock 236,154,444 21,142,295 $ 135,735 $ 142,231

Preferred Stock Warrant Liabi31

Preferred Stock Warrant Liabilities (Tables)	9 Months Ended
	Sep. 30, 2017
Summary of Preferred Stock Warrants	The key terms of the preferred stock warrants are summarized in the following table: Warrants Outstanding Warrants Warrants Outstanding Outstanding September 30, December 31, Exercise 2017 2016 Price Expiration Series C preferred stock warrants 274,640 274,640 $ 7.15 Various dates in 2023-2024 Series C preferred stock warrants 110,486 110,486 7.15 May 19, 2025 Total preferred stock warrants 385,126 385,126
Assumptions of Fair Value Preferred Stock Warrants	The estimated Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Expected term (years) — 5.98-6.05 4.95-7.50 5.94-6.11 Risk-free interest rate — 1.30-1.31% 1.77-2.13% 1.30-1.48% Expected volatility — 52.71-52.98% 51.62-53.58% 52.71-53.37% Dividend yield 0% 0% 0% 0%
Preferred Stock Warrants
Assumptions of Fair Value Preferred Stock Warrants	The fair value of preferred stock warrants was determined using the following assumptions: Nine Year Ended September 30, December 31, 2017 2016 Expected term (years) 1.25 2.00 Risk-free interest rate 1.35 % 1.20 % Expected volatility 72.2 % 70.9 %

Common Stock Reserved For Iss32

Common Stock Reserved For Issuance (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Schedule of Effect the Conversion of All Outstanding Shares of Convertible Preferred Stock Under the Incentive Plans	The Company is September 30, December 31, 2017 2016 Conversion of outstanding Series A convertible preferred stock 2,509,232 2,509,232 Conversion of outstanding Series B convertible preferred stock 3,846,132 3,846,132 Conversion of outstanding Series C convertible preferred stock 16,066,237 14,536,931 Conversion of outstanding Series AA convertible preferred stock 250,000 250,000 Outstanding preferred stock warrants 385,126 385,126 Outstanding and issued stock options 1,912,644 1,831,757 Shares reserved for future option grants 301,131 392,306 Total common stock reserved for issuance 25,270,502 23,751,484

Stock Option Plan (Tables)

Stock Option Plan (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Recognized Stock-based Compensation Expense for Employees and Non-employees	The Company recognized Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Cost of revenue $ 3 $ 3 $ 8 $ 10 Research and development 25 25 76 78 Sales and marketing 18 18 53 68 General and administrative 72 124 212 203 Total stock-based compensation $ 118 $ 170 $ 349 $ 359
Assumptions of Fair Value Preferred Stock Warrants	The estimated Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Expected term (years) — 5.98-6.05 4.95-7.50 5.94-6.11 Risk-free interest rate — 1.30-1.31% 1.77-2.13% 1.30-1.48% Expected volatility — 52.71-52.98% 51.62-53.58% 52.71-53.37% Dividend yield 0% 0% 0% 0%
Summary of Stock Option Activity	Weighted- Weighted- Average Average Remaining Aggregate Number of Exercise Price Contractual Intrinsic Shares per Share Term Value Outstanding — December 31, 2016 1,831,757 1.80 8.7 $ 14 Options granted 133,870 1.72 Options exercised (8,969 ) 1.83 Options cancelled (44,014 ) 1.82 Outstanding — September 30, 2017 1,912,644 $ 1.76 8.1 $ 10,029 Vested and expected to vest — September 30, 2017 1,610,419 $ 1.77 8.0 $ 8,421 Exercisable — September 30, 2017 872,687 $ 1.81 7.5 $ 5,803

Geographic Information (Tables)

Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Schedule of Revenue by Geographic Area	The following Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 United States $ 1,429 $ 1,330 $ 6,242 $ 4,086 Europe and Middle East 1,205 998 4,333 2,173 Asia Pacific 874 974 3,192 2,709 Rest of World 669 374 1,674 1,454 Total revenue $ 4,177 $ 3,676 $ 15,441 $ 10,422

Nature of Operations - Addition

Nature of Operations - Additional Information (Details) $ / shares in Units, $ in Thousands	Oct. 26, 2017shares	Oct. 16, 2017USD ($)$ / sharesshares	Sep. 15, 2017
Nature of Operations [Line Items]
Reverse stock split of common stock, description			1-for-10 reverse stock split
Reverse stock split of common stock, ratio			0.1
Subsequent Event | IPO
Nature of Operations [Line Items]
Number of common stock shares issued		3,897,910
Shares issued price per share | $ / shares		$ 7
Aggregate proceeds from initial public offering | $		$ 22,674
Underwriting discounts and commissions | $		1,910
Estimated offering expenses | $		$ 2,701
Outstanding shares of convertible preferred stock converted into common stock		22,671,601
Subsequent Event | IPO | Subordinated Convertible Notes
Nature of Operations [Line Items]
Outstanding convertible notes converted into common stock		718,184
Subsequent Event | Over-Allotment Option
Nature of Operations [Line Items]
Number of common stock shares issued	322,910	322,910

Summary of Significant Accoun36

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)InstitutionCustomer	Sep. 30, 2016USD ($)Customer	Sep. 30, 2017USD ($)SegmentInstitutionCustomer	Sep. 30, 2016USD ($)Customer	Dec. 31, 2016USD ($)Customer
Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit	$ (163,424,000)		$ (163,424,000)		$ (146,645,000)
Number of operating segments | Segment			1
Number of reportable segments | Segment			1
Impairment of long-lived assets			$ 0
Deferred revenue expected recognized period			1 year
Warrant period on ARTAS system accrues estimated future costs of repair			1 year
Effective tax benefit realized upon ultimate settlement			50.00%
Board of Directors
Summary Of Significant Accounting Policies [Line Items]
Defined contribution plan employer contribution amount	$ 0	$ 0	$ 0	$ 0
Maximum | Property and Equipment
Summary Of Significant Accounting Policies [Line Items]
Depreciation and amortization, estimated useful lives of assets			5 years
Minimum | Property and Equipment
Summary Of Significant Accounting Policies [Line Items]
Depreciation and amortization, estimated useful lives of assets			3 years
Credit Concentration Risk
Summary Of Significant Accounting Policies [Line Items]
Number of financial institution | Institution	2		2
Credit Concentration Risk | Maximum
Summary Of Significant Accounting Policies [Line Items]
FDIC insured amount	$ 250,000		$ 250,000
Customer Concentration Risk | Revenue
Summary Of Significant Accounting Policies [Line Items]
Number of major customers | Customer	2	0	0	0
Customer Concentration Risk | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Number of major customers | Customer			2		6
Allowance for doubtful accounts	$ 0		$ 0		$ 0
Customer Concentration Risk | Customer One | Revenue
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	11.00%
Customer Concentration Risk | Customer One | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage			11.00%		10.00%
Customer Concentration Risk | Customer Two | Revenue
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	12.00%
Customer Concentration Risk | Customer Two | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage			15.00%		11.00%
Customer Concentration Risk | Customer Three | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage					11.00%
Customer Concentration Risk | Customer Four | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage					11.00%
Customer Concentration Risk | Customer Five | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage					12.00%
Customer Concentration Risk | Customer Six | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage					13.00%
Other Long-term Assets
Summary Of Significant Accounting Policies [Line Items]
Deferred offering costs capitalized	$ 2,223,000		$ 2,223,000		$ 0
Collateral for Credit Cards | Other Assets
Summary Of Significant Accounting Policies [Line Items]
Restricted cash	$ 100,000		$ 100,000		$ 100,000

Net Loss Per Share - Outstandin

Net Loss Per Share - Outstanding Shares of Common Stock Equivalents Excluded from Calculation of Diluted Net Loss per Share Attributable to Common Stockholders (Details) - shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	24,969,371	23,091,712
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	1,912,644	2,178,280
Warrants for Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	385,126	385,126
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	22,671,601	20,528,306

Fair Value Measurements - Sched

Fair Value Measurements - Schedule for Levels of Fair Value Measurements of Cash Equivalents, Investments and Preferred Stock Warrants Liabilities - (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total assets	$ 5,869	$ 12,006
Preferred Stock Warrant Liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities	2,311	693
Quoted Prices in Active Markets using Identical Assets (Level 1)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total assets	5,869	12,006
Significant Unobservable Inputs (Level 3) | Preferred Stock Warrant Liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities	2,311	693
Money Market Accounts
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash Equivalents	5,769	11,906
Money Market Accounts | Quoted Prices in Active Markets using Identical Assets (Level 1)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash Equivalents	5,769	11,906
Restricted Cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash Equivalents	100	100
Restricted Cash | Quoted Prices in Active Markets using Identical Assets (Level 1)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash Equivalents	$ 100	$ 100

Fair Value Measurements - Sch39

Fair Value Measurements - Schedule of Preferred Stock Warrant Liabilities Activity Subject to Level 3 Inputs Measured on Recurring Basis - (Detail) - Preferred Stock Warrant Liabilities - Fair Value Measurements of Warrants using Significant Unobservable Inputs (Level 3) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 693
Change in fair value of preferred stock warrants	1,618
Ending balance	$ 2,311

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Finished goods	$ 2,677	$ 2,580
Raw materials		162
Total inventory	$ 2,677	$ 2,742

Balance Sheet Components - Sc41

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Insurance		$ 50	$ 153
Lease deposit		100	149
Marketing tradeshows		255	140
Rent		51
Other	[1]	402	368
Total prepaid expenses and other current assets		$ 858	$ 810
[1]	Other consists of items that are individually less than 5% of total prepaid expenses and other current assets.

Balance Sheet Components - Sc42

Balance Sheet Components - Schedule of Prepaid Expenses and Other Current Assets (Parenthetical) (Details)	Sep. 30, 2017	Dec. 31, 2016
Maximum
Prepaid Expenses And Other Current Assets [Line Items]
Percentage on other prepaid expense of prepaid expense and other current assets	5.00%	5.00%

Balance Sheet Components - Sc43

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Computer hardware and software	$ 706	$ 647
Equipment	2,873	2,818
Leasehold improvements	869	1,094
Furniture and fixtures	270	82
Total property and equipment	4,718	4,641
Less: Accumulated depreciation and amortization	(3,529)	(3,182)
Total property and equipment, net	$ 1,189	$ 1,459

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Property Plant And Equipment [Abstract]
Depreciation and amortization	$ 139	$ 148	$ 452	$ 498

Balance Sheet Components - Sc45

Balance Sheet Components - Schedule of Accrued and Other Liabilities (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Payroll and related expense		$ 1,439	$ 1,647
Warranty		105	114
Customer deposits		23	98
Sales taxes		25	129
Accrued professional fees		816	38
Other	[1]	589	412
Total accrued and other liabilities		$ 2,997	$ 2,438
[1]	Other consists of items that are individually less than 5% of total accrued and other liabilities.

Balance Sheet Components - Sc46

Balance Sheet Components - Schedule of Accrued and Other Liabilities (Parenthetical) (Details)	Sep. 30, 2017	Dec. 31, 2016
Maximum
Accrued Expenses And Other Liabilities [Line Items]
Percentage on other accrued liabilities of accrued and other liabilities	5.00%	5.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Feb. 29, 2012USD ($)	Jul. 31, 2006USD ($)shares	Sep. 30, 2017USD ($)ft²	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)ft²	Sep. 30, 2016USD ($)
Commitment And Contingencies [Line Items]
Rent expense			$ 103	$ 82	$ 310	$ 260
Rassman Licensing, LLC
Commitment And Contingencies [Line Items]
License agreement termination date		May 9, 2020
Rassman Licensing, LLC | License Agreement
Commitment And Contingencies [Line Items]
One time payment of royalty related to license	$ 400	$ 1,000
Royalty expense			$ 0	$ 0	$ 0	$ 0
HSC Development, LLC
Commitment And Contingencies [Line Items]
License agreement termination date		Jul. 27, 2024
HSC Development, LLC | License Agreement
Commitment And Contingencies [Line Items]
One time payment of royalty related to license		$ 25
Number of common stock shares issued | shares		2,500
San Jose, California
Commitment And Contingencies [Line Items]
Operating lease office space area | ft²			23,000		23,000
Operating lease expiration date					2022-04

Commitments and Contingencies48

Commitments and Contingencies - Summary of Aggregate Future Minimum Lease Payments under Operating Leases (Detail) $ in Thousands	Sep. 30, 2017USD ($)
Commitments And Contingencies Disclosure [Abstract]
2017 (remainder)	$ 124
2,018	503
2,019	518
2,020	534
2,021	550
Thereafter	188
Total future minimum lease payments	$ 2,417

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 16, 2017	May 31, 2015	Sep. 30, 2017	Sep. 06, 2017	Jan. 31, 2015
Debt Instrument [Line Items]
Net deferred debt costs			$ 410
Repayments of long-term debt			6,000
IPO | Subsequent Event
Debt Instrument [Line Items]
Shares issued price per share	$ 7
Loan and Security Agreement | Oxford Finance, LLC
Debt Instrument [Line Items]
Debt instrument, borrowed amount		$ 20,000
Credit facility fees					$ 246
Net deferred debt costs					$ 153
Debt Instrument, maturity month and year		2019-07
Debt instrument, final payment amount upon maturity		$ 1,300
Debt instrument, outstanding balance			15,300
Debt instrument, accrued interest			$ 99
Debt instrument, interest rate			12.80%
Loan and Security Agreement | Oxford Finance, LLC | Series C Convertible Preferred Stock
Debt Instrument [Line Items]
Debt conversion, warrants issued		110,486
Shares issued price per share		$ 7.15
Loan and Security Agreement | Oxford Finance, LLC | Warrants for Preferred Stock
Debt Instrument [Line Items]
Debt instrument, term		10 years
Loan and Security Agreement | Oxford Finance, LLC | Prime Rate
Debt Instrument [Line Items]
Debt instrument, stated Interest rate		8.50%
Subordinated Convertible Notes | Private Placement
Debt Instrument [Line Items]
Debt instrument, borrowed amount				$ 5,000
Debt instrument, stated Interest rate				5.00%
Debt instrument, outstanding balance			$ 5,000
Debt instrument, accrued interest			$ 18
Subordinated Convertible Notes | IPO | Subsequent Event
Debt Instrument [Line Items]
Outstanding convertible notes converted into common stock	718,184

Long-Term Debt - Schedule Princ

Long-Term Debt - Schedule Principal Payments on Outstanding Borrowings (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
2017 (remainder)	$ 2,000
2,018	8,000
2,019	5,299
Total	15,299
Less debt discount	(410)
Less current portion	(7,659)	$ (7,449)
Non-current portion	$ 7,230	$ 13,001

Convertible Preferred Stock - S

Convertible Preferred Stock - Schedule of Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Temporary Equity [Line Items]
Shares Authorized	236,154,444	236,154,444
Shares Outstanding	22,671,601	21,142,295
Net Carrying Value	$ 145,944	$ 135,735
Aggregate liquidation preference	$ 153,166	$ 142,231
Series A Convertible Preferred Stock
Temporary Equity [Line Items]
Shares Authorized	25,092,906	25,092,906
Shares Outstanding	2,509,232	2,509,232
Net Carrying Value	$ 11,140	$ 11,140
Aggregate liquidation preference	$ 11,292	$ 11,292
Series B Convertible Preferred Stock
Temporary Equity [Line Items]
Shares Authorized	38,461,538	38,461,538
Shares Outstanding	3,846,132	3,846,132
Net Carrying Value	$ 24,926	$ 24,926
Aggregate liquidation preference	$ 25,000	$ 25,000
Series C Convertible Preferred Stock
Temporary Equity [Line Items]
Shares Authorized	170,100,000	170,100,000
Shares Outstanding	16,066,237	14,536,931
Net Carrying Value	$ 107,902	$ 97,693
Aggregate liquidation preference	$ 114,874	$ 103,939
Series A A Convertible Preferred Stock
Temporary Equity [Line Items]
Shares Authorized	2,500,000	2,500,000
Shares Outstanding	250,000	250,000
Net Carrying Value	$ 1,976	$ 1,976
Aggregate liquidation preference	$ 2,000	$ 2,000

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Details)	Oct. 16, 2017shares
Subsequent Event | IPO
Temporary Equity [Line Items]
Outstanding shares of convertible preferred stock converted into common stock	22,671,601

Preferred Stock Warrant Liabi53

Preferred Stock Warrant Liabilities - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Class Of Warrant Or Right [Line Items]
Warrants exercised	0		0
IPO
Class Of Warrant Or Right [Line Items]
Warrants expiration period	12 months
Maximum
Class Of Warrant Or Right [Line Items]
Exercise price per share	$ 7.15
Preferred Stock
Class Of Warrant Or Right [Line Items]
Warrants liability	$ 2,311	$ 693

Preferred Stock Warrant Liabi54

Preferred Stock Warrant Liabilities - Summary of Preferred Stock Warrants (Details) - $ / shares	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Class Of Warrant Or Right [Line Items]
Warrants outstanding	385,126	385,126
Series C Preferred Stock Warrants One
Class Of Warrant Or Right [Line Items]
Warrants outstanding	274,640	274,640
Warrants outstanding exercise price	$ 7.15
Warrants outstanding expiration date description	Various dates in 2023-2024
Series C Preferred Stock Warrants Two
Class Of Warrant Or Right [Line Items]
Warrants outstanding	110,486	110,486
Warrants outstanding exercise price	$ 7.15
Warrants outstanding expiration date	May 19, 2025

Preferred Stock Warrant Liabi55

Preferred Stock Warrant Liabilities - Assumptions of Fair Value Preferred Stock Warrants (Details) - Preferred Stock Warrants	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Class Of Warrant Or Right [Line Items]
Expected term (years)	1 year 3 months	2 years
Risk-free interest rate	1.35%	1.20%
Expected volatility	72.20%	70.90%

Common Stock Reserved For Iss56

Common Stock Reserved For Issuance - Schedule of Effect the Conversion of All Outstanding Shares of Convertible Preferred Stock Under the Incentive Plans (Details) - shares	Sep. 30, 2017	Dec. 31, 2016
Class Of Stock [Line Items]
Outstanding preferred stock warrants	385,126	385,126
Outstanding and issued stock options	1,912,644	1,831,757
Shares reserved for future option grants	301,131	392,306
Total common stock reserved for issuance	25,270,502	23,751,484
Series A Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of outstanding preferred stock	2,509,232	2,509,232
Series B Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of outstanding preferred stock	3,846,132	3,846,132
Series C Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of outstanding preferred stock	16,066,237	14,536,931
Series A A Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of outstanding preferred stock	250,000	250,000

Stock Option Plan - Additional

Stock Option Plan - Additional Information (Details) - USD ($)	Oct. 11, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance		25,270,502		25,270,502		23,751,484
Shares reserved for future option grants		301,131		301,131		392,306
Expected dividend				$ 0
Weighted-average grant date fair value of options granted		$ 0	$ 0.86	$ 1.02	$ 0.86
Total intrinsic value of options exercised		$ 0	$ 0	$ 0	$ 0
Unamortized stock-based compensation		$ 654,000		$ 654,000
Unamortized stock-based compensation, weighted-average period				2 years 6 months 8 days
2005 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period				4 years
Minimum percentage of voting rights of all classes of stock				10.00%
Term of incentive stock options granted				5 years
2005 Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period				10 years
2005 Plan and 2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance							2,221,655
2005 Plan and 2015 Plan | Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for future option grants	0
2017 Plan | Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance	1,913,831
Effective date of plan	Oct. 11, 2017
Annual increase in shares reserved for issuance beginning year	2,018
Annual increase in shares reserved for issuance ending year	2,027
Percentage threshold of increase in shares reserved for issuance	4.00%

Stock Option Plan - Summary of

Stock Option Plan - Summary of Recognized Stock-based Compensation Expense for Employees and Non-employees (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation			$ 349	$ 359
Employees and Non-employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 118	$ 170	349	359
Cost of Revenue | Employees and Non-employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	3	3	8	10
Research and Development | Employees and Non-employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	25	25	76	78
Sales and Marketing | Employees and Non-employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	18	18	53	68
General and Administrative | Employees and Non-employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 72	$ 124	$ 212	$ 203

Stock Option Plan - Estimated G

Stock Option Plan - Estimated Grant-Date Fair Value of Stock-Based Awards Calculated Using Black-Scholes-Merton Option Pricing Model (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum		1.30%	1.77%	1.30%
Risk-free interest rate, maximum		1.31%	2.13%	1.48%
Expected volatility, minimum		52.71%	51.62%	52.71%
Expected volatility, maximum		52.98%	53.58%	53.37%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)		5 years 11 months 23 days	4 years 11 months 12 days	5 years 11 months 8 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)		6 years 18 days	7 years 6 months	6 years 1 month 9 days

Stock Option Plan - Summary o60

Stock Option Plan - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward
Number of Shares, Outstanding, Beginning Balance	1,831,757
Number of Shares, Options granted	133,870
Number of Shares, Options exercised	(8,969)
Number of Shares, Options cancelled	(44,014)
Number of Shares, Outstanding, Ending Balance	1,912,644	1,831,757
Number of Shares, Vested and expected to vest	1,610,419
Number of Shares, Exercisable	872,687
Weighted-Average Exercise Price Per Share, Outstanding, Beginning Balance	$ 1.80
Weighted-Average Exercise Price Per Share, Options granted	1.72
Weighted-Average Exercise Price Per Share, Options exercised	1.83
Weighted-Average Exercise Price Per Share, Options cancelled	1.82
Weighted-Average Exercise Price Per Share, Outstanding, Ending Balance	1.76	$ 1.80
Weighted-Average Exercise Price Per Share, Vested and expected to vest	1.77
Weighted-Average Exercise Price Per Share, Exercisable	$ 1.81
Weighted-Average Remaining Contractual Term, Outstanding	8 years 1 month 7 days	8 years 8 months 12 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	8 years
Weighted-Average Remaining Contractual Term, Exercisable	7 years 6 months
Aggregate Intrinsic Value, Outstanding	$ 10,029	$ 14
Aggregate Intrinsic Value, Vested and expected to vest	8,421
Aggregate Intrinsic Value, Exercisable	$ 5,803

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Income Taxes [Line Items]
Provision for income taxes	$ 25,000	$ 50,000
Federal
Income Taxes [Line Items]
Provision for income taxes	0	0
Foreign
Income Taxes [Line Items]
Provision for income taxes	$ 25,000	$ 50,000

Geographic Information - Schedu

Geographic Information - Schedule of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 4,177	$ 3,676	$ 15,441	$ 10,422
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	1,429	1,330	6,242	4,086
Europe and Middle East
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	1,205	998	4,333	2,173
Asia Pacific
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	874	974	3,192	2,709
Rest of World
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenue	$ 669	$ 374	$ 1,674	$ 1,454

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - Member of Board of Directors - Commercial Transaction	12 Months Ended
	Dec. 31, 2016USD ($)
Related Party Transaction [Line Items]
Aggregate revenue	$ 240,000
Accounts receivable due from related party	$ 0

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 26, 2017	Oct. 16, 2017	Oct. 11, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Shares reserved for issuance				25,270,502	23,751,484
Shares reserved for future option grants				301,131	392,306
2005 Plan and 2015 Plan
Subsequent Event [Line Items]
Shares reserved for issuance						2,221,655
Subsequent Event | 2017 Plan
Subsequent Event [Line Items]
Shares reserved for issuance			1,913,831
Effective date of plan			Oct. 11, 2017
Percentage threshold of increase in shares reserved for issuance			4.00%
Annual increase in shares reserved for issuance beginning year			2,018
Annual increase in shares reserved for issuance ending year			2,027
Subsequent Event | 2005 Plan and 2015 Plan
Subsequent Event [Line Items]
Shares reserved for future option grants			0
Subsequent Event | IPO
Subsequent Event [Line Items]
Number of common stock shares issued		3,897,910
Shares issued price per share		$ 7
Aggregate proceeds from initial public offering		$ 22,674
Outstanding shares of convertible preferred stock converted into common stock		22,671,601
Subsequent Event | IPO | Subordinated Convertible Notes
Subsequent Event [Line Items]
Outstanding convertible notes converted into common stock		718,184
Subsequent Event | Over-Allotment Option
Subsequent Event [Line Items]
Number of common stock shares issued	322,910	322,910