Entellus Medical (ENTL) 10-Q 4 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 02, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	ENTL
Entity Registrant Name	ENTELLUS MEDICAL INC
Entity Central Index Key	1,374,128
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		18,864,035

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	[1]
CURRENT ASSETS
Cash and cash equivalents	$ 15,236	$ 28,548
Short-term investments	23,967	38,210
Accrued interest income	80	247
Accounts receivable, net of allowance for doubtful accounts of $150 and $135, respectively	11,744	10,440
Inventories	5,893	3,889
Prepaid expenses and other current assets	1,420	1,691
Total current assets	58,340	83,025
Property and equipment, net	6,490	4,126
Intangible assets, net	6,239
Goodwill	4,327
Other non-current assets	316	34
Total assets	75,712	87,185
CURRENT LIABILITIES
Accounts payable	4,040	2,208
Accrued expenses	10,368	6,995
Current portion of long-term debt	6,553
Total current liabilities	20,961	9,203
LONG-TERM LIABILITIES
Long-term debt, less current portion, net of debt issuance cost of $ 131 and $ 176, respectively	13,316	19,824
Other non-current liabilities	913	562
Total liabilities	35,190	29,589
COMMITMENTS AND CONTINGENCIES (See Note M)
STOCKHOLDERS' EQUITY (see Note I)
Preferred stock, $0.001 par value per share: Authorized shares: 10,000 at September 30, 2016 and December 31, 2015 Issued and outstanding shares: none
Common stock, $0.001 par value per share: Authorized shares: 200,000 at September 30, 2016 and December 31, 2015; Issued and outstanding shares: 18,863 and 18,794 at September 30, 2016 and December 31, 2015, respectively	19	19
Additional paid-in capital	184,111	179,673
Accumulated other comprehensive loss	(138)	(38)
Accumulated deficit	(143,470)	(122,058)
Total stockholders' equity	40,522	57,596
Total liabilities and stockholders' equity	$ 75,712	$ 87,185
[1]	Amounts derived from audited financial statements of Entellus Medical, Inc. included in its Annual Report on Form 10-K for the year ended December 31, 2015.

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Accounts receivable, net of allowance for doubtful accounts	$ 150	$ 135
Long-term debt, less current portion, debt issuance cost	$ 131	$ 176
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares Issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	18,863,000	18,794,000
Common stock, shares outstanding	18,863,000	18,794,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Revenue	$ 17,880	$ 14,804	$ 53,512	$ 43,497
Cost of goods sold	4,648	3,431	13,107	9,728
Gross profit	13,232	11,373	40,405	33,769
Operating expenses
Selling and marketing	15,364	12,308	41,857	32,010
Research and development	2,047	1,392	5,832	4,000
General and administrative	4,807	3,230	12,594	9,120
Total operating expenses	22,218	16,930	60,283	45,130
Loss from operations	(8,986)	(5,557)	(19,878)	(11,361)
Other income (expense)
Interest income	75	47	228	118
Interest expense	(562)	(561)	(1,686)	(2,042)
Other non-operating expense	(12)		(42)	(2)
Loss before income taxes expense	(9,485)	(6,071)	(21,378)	(13,287)
Income tax expense	34		34
Net loss	(9,519)	(6,071)	(21,412)	(13,287)
Other comprehensive income (loss)
Unrealized (loss)/gain on short term investments, net of tax	(39)	23	26	21
Foreign currency translation loss, net of tax	(28)	(8)	(123)	(9)
Comprehensive loss	$ (9,586)	$ (6,056)	$ (21,509)	$ (13,275)
Net loss per share, basic and diluted	$ (0.50)	$ (0.32)	$ (1.14)	$ (0.80)
Weighted average common shares used to compute net loss per share, basic and diluted	18,855	18,738	18,827	16,688

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015
Cash flows from operating activities:
Net loss	$ (21,412)		$ (13,287)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,312		686
Amortization of debt issuance costs	45		45
Amortization of premium on investments	113		297
Accretion of final payment fee on long-term debt	230		230
Loss on disposal of property and equipment	7
Deferred tax expense	34
Deferred rent	108		4
Stock-based compensation	4,060		1,776
Changes in fair value of convertible preferred stock warrants			357
Changes in operating assets and liabilities, net of acquired assets:
Accrued interest income	167		(192)
Accounts receivables, net	(1,377)		(1,432)
Inventories	(2,004)		(838)
Prepaid expenses and other current assets	490		(616)
Other non-current assets	(283)		1,684
Accounts payable	1,834		1,005
Accrued expenses	3,393		2,380
Net cash used in operating activities	(13,283)		(7,901)
Cash flows from investing activities:
Purchase of property and equipment, net of acquired assets	(3,469)		(2,611)
XeroGel acquisition	(11,000)
Purchase of investments	(32,182)		(111,051)
Proceeds from maturities of short-term investments	46,339		45,551
Net cash used in investing activities	(312)		(68,111)
Cash flows from financing activities:
Proceeds from stock options exercised	101		282
Proceeds from common stock issuance from employee stock purchase plan	271
Proceeds from initial public offering, net of issuance costs			80,953
Repurchase of common stock			(1)
Net cash provided by financing activities	372		81,234
Effect of exchange rate changes on cash and cash equivalents	(89)		(1)
Net (decrease) increase in cash and cash equivalents	(13,312)		5,221
Cash and cash equivalents - beginning of period	28,548	[1]	3,484
Cash and cash equivalents - end of period	15,236		8,705
Supplemental cash flow information:
Cash paid for interest	$ 1,410		$ 1,394
[1]	Amounts derived from audited financial statements of Entellus Medical, Inc. included in its Annual Report on Form 10-K for the year ended December 31, 2015.

Organization

Organization	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Organization	NOTE A. ORGANIZATION Nature of Business Entellus Medical, Inc. (the “Company”) was incorporated in Minnesota in April 2006 and was reincorporated in Delaware in August 2006. The Company is focused on delivering superior patient and physician experiences through products designed for the minimally invasive treatment of chronic and recurrent sinusitis in both adult and pediatric patients. The Company’s platform of products provides effective and easy-to-use solutions to simplify everything from diagnosis and patient selection, to complex case revisions and post-operative care. The Company’s three core product lines, XprESS™ Multi-Sinus Dilation Systems, MiniFESS™ Surgical Instruments, and FocESS™ Imaging & Navigation, are designed to enable ear, nose and throat (“ENT”) physicians to conveniently and comfortably perform a broad range of procedures in the ENT physician office and simplify operating room based treatment. The Company currently sells product through its direct sales force in the United States and United Kingdom and in a limited number of additional countries through international distributors. The Company operates in one reporting segment.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE B. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Preparation The financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”). The interim financial data as of September 30, 2016 is unaudited and is not necessarily indicative of the results for a full year. In the opinion of the Company’s management, the interim data includes only normal and recurring adjustments necessary for a fair statement of the Company’s financial results for the three and nine months ended September 30, 2016 and 2015. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to SEC rules and regulations relating to interim financial statements. The accompanying condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 that has been filed with the SEC. Initial Public Offering In February 2015, the Company completed its initial public offering (“IPO”) by issuing 5.3 million shares of common stock, at an offering price of $17.00 per share, for net proceeds of approximately $81.0 million, after deducting underwriting discounts, commissions and offering expenses payable by the Company. In connection with the IPO, the Company’s outstanding shares of convertible preferred stock were automatically converted into an aggregate of 11.4 million shares of common stock, and the Company’s outstanding warrants to purchase shares of convertible preferred stock were automatically converted into warrants to purchase up to an aggregate of less than 0.1 million shares of common stock, resulting in the reclassification of the related redeemable convertible preferred stock warrant liability of $0.6 million to additional paid-in-capital. 1-for-4 Reverse Stock Split In connection with the IPO, the Company’s board of directors and stockholders approved a reverse stock split of the Company’s common stock on a 1-for-4 basis. The reverse stock split became effective on January 12, 2015. The par value of the common stock was not adjusted as a result of the reverse stock split. Adjustments corresponding to the reverse stock split were made to the ratio at which the convertible preferred stock converted into common stock immediately prior to the closing of the IPO. Accordingly, all share and per share amounts for all periods presented in these financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect the reverse stock split and adjustment of the preferred stock’s conversion ratios. Business Combination On June 29, 2016, the Company acquired and entered into an exclusive license for the XeroGel™ assets with CogENT Therapeutics, LLC for $11.0 million in cash (the “XeroGel acquisition”). T (in thousands) Purchase Price Allocation Technologies $ 6,000 Trade names 350 Tangible assets 323 Total identifiable assets 6,673 Goodwill $ 4,327 The Company incurred transaction costs in connection with the acquisition of approximately $0.3 million for the nine months ended September 30, 2016, which are included in general and administrative expenses. The estimated fair value of the net assets acquired is preliminary and subject to change. While the Company uses its best estimates and assumptions as a part of the purchase price allocation process to accurately value assets acquired at the acquisition date, its estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, the Company may record adjustments to the assets acquired, with the corresponding offset to goodwill. Under the terms of the XeroGel acquisition agreements, the Company became the manufacturer of XeroGel and will continue to market and sell XeroGel to hospitals, offices and ambulatory surgery centers. Prior to the transaction, the Company was the exclusive distributor of XeroGel in the United States. The distribution agreement between the two parties was terminated in connection with the transaction. As a result of the XeroGel acquisition, the Company began recognizing all XeroGel revenue on a gross basis effective June 29, 2016. The Company has concluded that the XeroGel acquisition was not material for purposes of including pro forma information in this report and therefore has not provided any such information herein. Goodwill and Intangible Assets Goodwill represents the excess of the purchase price over the fair value of net assets acquired in a business combination. Intangible assets are recorded at their estimated fair value at the date of acquisition. In the year following the period in which identified intangible assets become fully amortized, the fully amortized balances are removed from the gross asset and accumulated amortization amounts. Goodwill is not amortized, but is instead subject to impairment testing. Intangible assets with finite lives are amortized using a straight-line method over their respective useful lives. Goodwill Impairment Policy The Company chose November 1 as the date to assess its On an annual basis, or more frequently upon the occurrence of certain events, the Company will test for goodwill impairment using a three-step process. T The second step is to identify a potential impairment by comparing the calculated fair value of a reporting unit with its carrying amount. The fair value of a reporting unit is determined based on a discounted cash flow analysis and further analyzed using other methods of valuation. A discounted cash flow analysis requires the Company to make various assumptions, including assumptions about future cash flows, growth rates and discount rates. The assumptions about future cash flows and growth rates are based on the Company’s long-term projections. In addition, an assumed terminal value is used to project future cash flows beyond base years. Assumptions used in the Company’s impairment testing will be consistent with the Company’s internal forecasts and operating plans. The Company’s discount rate will be based on its debt and equity balances, adjusted for current market conditions and investor expectations of return on its equity. If the fair value of a reporting unit exceeds its carrying amount, there will be no impairment. If the calculated fair value is less than the carrying value, the third step of the goodwill impairment test compares the implied fair value of the reporting unit’s goodwill with its carrying amount. To the extent the carrying amount of the reporting unit’s goodwill exceeds its implied fair value, a write-down of the reporting unit’s goodwill would be necessary. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reported period. Actual results could differ from those estimates. Significant Accounting Policies There have been no changes in the Company’s significant accounting policies for the nine months ended September 30, 2016, as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2015, other than the new policies described above which have become significant accounting policies for the Company as a result of the XeroGel acquisition. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers. This standard will eliminate the transaction and industry specific revenue recognition guidance under current U.S. GAAP and replace it with a principles based approach for determining revenue recognition. The new guidance is effective for annual and interim periods beginning after December 15, 2017. The Company is in the process of evaluating the impact of this standard on its consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance, which changes the presentation of debt issuance costs in financial statements. Under ASU 2015-03, an entity presents such costs in the balance sheet as a direct deduction from the related debt liability rather than as an asset. Amortization of the costs is reported as interest expense. ASU 2015-03 is effective for fiscal years and interim periods within those fiscal years, beginning after December 15, 2015 . Early adoption is permitted for financial statements that have not been previously issued. A company should apply the new guidance on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Upon transition, a company is required to comply with the applicable disclosures for a change in an accounting principle. The guidance only affects the presentation of debt issuance costs in the balance sheet and has no impact on results of operations. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, which addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, and early adoption is not permitted. The Company does not expect that adoption of ASU 2016-01 will have a significant impact on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which requires that lease arrangements longer than twelve months result in an entity recognizing an asset and liability. The updated guidance is effective for interim and annual periods beginning after December 15, 2018, and early adoption is permitted. The Company is currently evaluating the impact of the updated guidance on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-08, Principal versus Agent Considerations - Reporting Revenue Gross versus Net. This ASU clarifies the revenue recognition implementation guidance for preparers on certain aspects of principal versus agent consideration. The amendments in this ASU are effective for annual periods beginning after December 15, 2017 and for interim periods therein. The Company is in the process of evaluating the impact of the adoption of this standard on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation, which is intended to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for annual periods beginning after December 15, 2016, and interim periods therein. Early application is permitted. The Company is currently evaluating the impact of this guidance on its consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses, to require the measurement of expected credit losses for financial instruments held at the reporting date based on historical experience, current conditions and reasonable forecasts. The main objective of this ASU is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years; the ASU allows for early adoption as of the beginning of an interim or annual reporting period beginning after December 15, 2018. The Company is currently assessing the impact that this standard will have on its consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Statements of Cash Flows – Classifications of Certain Cash Receipts and Cash Payments, to clarify how companies present and classify certain cash receipts and cash payments in the statement of cash flows. The ASU is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years; the ASU allows for early adoption. The Company is currently assessing the impact that this standard will have on its consolidated financial statements.

Composition of Certain Financia

Composition of Certain Financial Statement Items	9 Months Ended
	Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Composition of Certain Financial Statement Items	NOTE C. COMPOSITION OF CERTAIN FINANCIAL STATEMENT ITEMS Inventories September 30, December 31, (in thousands) 2016 2015 Finished goods $ 2,699 $ 2,014 Work in process 1,431 388 Raw materials 1,763 1,487 Total $ 5,893 $ 3,889 Property and Equipment September 30, December 31, (in thousands) 2016 2015 Furniture and office equipment $ 791 $ 533 Computer hardware and software 2,721 2,187 Laboratory equipment 4,019 2,915 Tooling and molds 1,463 1,243 Leasehold improvements 1,905 583 $ 10,899 $ 7,461 Less accumulated depreciation and amortization (4,940 ) (3,766 ) Property and equipment in progress 531 431 Total $ 6,490 $ 4,126 Depreciation and amortization expense was $0.5 million and $0.3 million during the three months ended September 30, 2016 and 2015, respectively, and $1.2 million and $0.7 million during the nine months ended September 30, 2016 and 2015, respectively. Intangible Assets September 30, December 31, (in thousands) 2016 2015 Technologies $ 6,000 $ — Trade name 350 — $ 6,350 $ — Less accumulated amortization (111 ) — Total $ 6,239 $ — In connection with the XeroGel acquisition, the Company acquired the technology-based intangible assets described in the above table and the XeroGel trade name. The technologies are amortized over a useful life of approximately 14 years, based on the remaining useful life of the licenses acquired as management plans to fully utilize the technologies over the full useful life, and the trade name is amortized over a useful life of 20 years. Amortization expense was $0.1 million during the three and nine months ended September 30, 2016 and zero during the three and nine months ended September 30, 2015. Future amortization expense related to intangible assets with definite lives is projected as follows: (in thousands) 2016 (remaining) $ 109 2017 436 2018 436 2019 436 2020 436 2021 436 2022 and thereafter 3,950 Total $ 6,239 Accrued Expenses September 30, December 31, (in thousands) 2016 2015 Compensation and commissions payable $ 6,531 $ 3,898 Royalty payable 1,640 1,800 Other accrued expenses (1) 2,197 1,297 Total $ 10,368 $ 6,995 (1)

Liquidity and Business Risks

Liquidity and Business Risks	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Liquidity and Business Risks	NOTE D. LIQUIDITY AND BUSINESS RISKS As of September 30, 2016, the Company had cash, cash equivalents and short-term investments of $39.2 million and an accumulated deficit of $143.5 million. In February 2015, the Company completed its IPO by issuing 5.3 million shares of common stock at an offering price of $17.00 per share, for net proceeds of approximately $81.0 million, after deducting underwriting discounts and commissions and offering expenses. Prior to the IPO, the Company financed its operations with a combination of revenue, private placements of convertible preferred securities and amounts borrowed under its credit facility. The Company expects that its cash and cash equivalents, short-term investments and anticipated revenue will be sufficient to fund its operations through at least the next twelve months.

Short-Term Investments

Short-Term Investments	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
SHORT-TERM INVESTMENTS	NOTE E. SHORT-TERM INVESTMENTS The Company determines the appropriate classification of its investments at the time of purchase and revaluates such determinations at each balance sheet date. Marketable securities are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. Marketable securities for which the Company does not have the intent or ability to hold to maturity are classified as available-for-sale. Marketable securities classified as available-for-sale are carried at fair market value, with the unrealized gains and losses included in the determination of comprehensive income and reported in stockholders’ equity. The following is a summary of the available-for-sale investments by type of instrument, which are included in short-term investments in the consolidated balance sheet as of September 30, 2016 and December 31, 2015. Unrealized Unrealized Gain in Losses in Accumulated Accumulated Other Other Amortized Comprehensive Comprehensive Estimated September 30, 2016 (in thousands) Cost Income (Loss) Income (Loss) Fair Value Commercial paper $ 7,734 $ 12 $ — $ 7,746 Corporate bonds 8,725 — (3 ) 8,722 Foreign assets 7,498 1 — 7,499 Total available-for-sale securities $ 23,957 $ 13 $ (3 ) $ 23,967 Unrealized Unrealized Gain in Losses in Accumulated Accumulated Other Other Amortized Comprehensive Comprehensive Estimated December 31, 2015 (in thousands) Cost Income (Loss) Income (Loss) Fair Value Commercial paper $ 9,482 $ 10 $ — $ 9,492 Corporate bonds 19,605 — (19 ) 19,586 Government bonds 1,999 — — 1,999 Foreign assets 7,140 — (7 ) 7,133 Total available-for-sale securities $ 38,226 $ 10 $ (26 ) $ 38,210 Based on an evaluation of securities that have been in a loss position, the Company did not recognize any other-than-temporary impairment charges during the nine months ended September 30, 2016. The Company considered various factors, including a credit and liquidity assessment of the underlying securities and the Company’s intent and ability to hold the underlying securities until the estimated date of recovery of its amortized cost. As of September 30, 2016 and December 31, 2015, available-for-sale maturities as noted in the table above mature in one year or less.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE F. FAIR VALUE MEASUREMENTS As of September 30, 2016 and December 31, 2015, the carrying amounts of cash and cash equivalents, receivables, accounts payable and accrued expenses approximated their estimated fair values because of the short-term nature of these financial instruments. Goodwill and intangible assets acquired are stated at fair value based upon the acquisition valuation. Fair value is defined as the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three categories: • Level 1: Quoted market prices in active markets for identical assets or liabilities. • Level 2: Includes other than Level 1 inputs that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs for which all significant inputs are observable or can be corroborated by observable market data for substantially the full term of the asset or liabilities. • Level 3: Unobservable inputs that are supported by little or no market activities, which would require the Company to develop its own assumptions. Short-term Investments The following is a summary of available-for-sale investments by type of instrument measured at fair value on a recurring basis at September 30, 2016 and December 31, 2015, respectively. September 30, 2016 (in thousands) Level 1 Level 2 Level 3 Total Commercial paper $ — $ 7,746 $ — $ 7,746 Corporate bonds — 8,722 — 8,722 Foreign assets — 7,499 — 7,499 Total $ — $ 23,967 $ — $ 23,967 December 31, 2015 (in thousands) Level 1 Level 2 Level 3 Total Commercial paper $ — $ 9,492 $ — $ 9,492 Corporate bonds — 19,586 — 19,586 Government bonds — 1,999 — 1,999 Foreign assets — 7,133 — 7,133 Total $ — $ 38,210 $ — $ 38,210 There were no transfers in or out of Level 1, Level 2 or Level 3 fair value measurement during the three and nine months ended September 30, 2016. Convertible Preferred Stock Warranty Liability The following table sets forth a summary of the changes in the estimated fair value of the Company’s convertible preferred stock warrants, which represent financial instruments that were categorized as Level 3, according to the three-level fair value hierarchy. Nine Months Ended September 30, (in thousands) 2016 2015 Beginning of the period $ — $ 291 Issued — — Exercised — — Expired — — Reclassified to equity (1) — (648 ) Change in fair value — 357 End of the period $ — $ — (1) In connection with the closing of the IPO in February 2015, warrants to purchase shares of convertible preferred stock were converted to warrants to purchase shares of common stock, resulting in the reclassification of the related convertible preferred stock warrant liability to additional paid-in-capital. The fair market value of the convertible preferred stock prior to the IPO was determined using the option pricing method and the probability weighted expected return method. The fair value of the convertible preferred stock warrant liability was determined using the Black-Scholes option pricing model with the following assumptions: Nine Months Ended September 30, 2016 2015 Expected life in years N/A 7.5 Risk-free interest rate N/A 1.6 % Expected dividend yield N/A 0.0 % Expected volatility N/A 56 %

Debt

Debt	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Debt	NOTE G. DEBT The Company has a credit facility (the “credit facility”) with Oxford Finance LLC under the terms of an amended and restated loan and security agreement, which was amended most recently in May 2015. Under the credit facility, the Company could borrow up to a total of $25.0 million in three tranches at a fixed rate of 9.40%. The first tranche of $15.0 million, including the refinance of $7.5 million in debt previously outstanding, was borrowed in December 2013. In connection with the funding of the first tranche, the Company paid a prorated final payment fee on the original credit facility of $0.1 million. The second tranche of up to $5.0 million was available through December 31, 2014, all of which was borrowed during the three months ended December 31, 2014. The third tranche of up to $5.0 million was available at any time through December 31, 2015, subject to certain six-month revenue milestones. Although the specified revenue milestones for the third tranche were achieved, the Company elected not to borrow additional funds. The credit facility matures and all amounts borrowed thereunder are due on December 1, 2018. As a result of achieving certain funding and revenue milestones provided for in the credit facility in December 2015, the Company was permitted to extend the interest-only period through January 2017. Beginning February 2017, the Company will make 23 equal monthly payments of principal and interest in the amount of approximately $1.0 million each. In addition to the principal and interest payments, under the credit facility the Company is required to pay a final payment fee of 7.15% on all amounts outstanding under the credit facility, which is being accrued over the credit facility term and will be due at the earlier of maturity or prepayment. If the Company repays the entire amount borrowed under the credit facility prior to maturity, the Company will also be required to pay a prepayment fee equal to 0.75% with respect to the principal amount that is prepaid. As of September 30, 2016 and December 31, 2015, the Company had borrowed and had outstanding $20.0 million of debt under the credit facility. As of September 30, 2016 and December 31, 2015, the carrying amount of debt approximated fair value because the fixed interest rate approximates current market rates of interest available in the market. The fair value of the Company’s debt is considered a Level 3 measurement.

Convertible Preferred Stock

Convertible Preferred Stock	9 Months Ended
	Sep. 30, 2016
Temporary Equity Disclosure [Abstract]
Convertible Preferred Stock	NOTE H. CONVERTIBLE PREFERRED STOCK In connection with the IPO in February 2015, 44.3 million shares of convertible preferred stock were converted into 11.4 million shares of common stock, resulting in the reclassification of the related redeemable convertible preferred stock of $91.6 million to common stock and additional paid-in-capital.

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit)	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stockholders' Equity (Deficit)	NOTE I. STOCKHOLDERS’ EQUITY Preferred Stock The Company’s amended and restated certificate of incorporation authorizes 10.0 million shares of preferred stock. As of September 30, 2016, no shares of preferred stock were outstanding. Common Stock The Company’s amended and restated certificate of incorporation authorizes 200.0 million shares of common stock. As of September 30, 2016, 18.9 million shares of common stock were outstanding. 2015 Incentive Award Plan In December 2014, the Company’s Board of Directors adopted, and in January 2015 the Company’s stockholders approved, the Entellus Medical, Inc. 2015 Incentive Award Plan (the “2015 Plan”). The 2015 Plan became effective in connection with the IPO, at which time the Company ceased making awards under the Entellus Medical, Inc. 2006 Stock Incentive Plan. Under the 2015 Plan, the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units and certain other awards to individuals who are employees, officers, directors or consultants of the Company. A total of 1,345,570 shares of common stock were initially reserved for issuance under the 2015 Plan. In addition, the number of shares available for issuance under the 2015 Plan is annually increased by an amount equal to the lesser of (A) 875,000 shares, (B) 4% of the outstanding shares of the Company’s common stock as of the last day of the immediately preceding fiscal year or (C) an amount determined by the Company’s Board of Directors. In the first quarter of 2016, in accordance with this “evergreen” provision, the number of shares available under the 2015 Plan was increased by 751,750 shares resulting in a total of 2,097,320 shares of common stock available for issuance under the 2015 Plan. A summary of the Company’s stock option and restricted stock unit activity and related information is as follows: September 30, 2016 Weighted Average Aggregate Weighted Remaining Intrinsic Average Contractual Value (shares in thousands) Options Exercise Price Term ($000) Outstanding, January 1, 2016 2,583 $ 11.79 8.5 years $ 16,377 Granted 905 16.10 Exercised (51 ) 2.11 Cancelled — — Forfeited (62 ) 16.87 Outstanding, September 30, 2016 3,375 $ 13.00 8.2 years $ 32,142 Exercisable 1,278 $ 9.20 7.2 years $ 16,981 The aggregate pre-tax intrinsic value of options exercised was $0.8 million and $2.7 million for the nine months ended September 30, 2016 and 2015, respectively. The aggregate pre-tax intrinsic value was calculated as the difference between the exercise prices of the underlying options and the estimated fair value of the common stock on the date of exercise or September 30, 2016. The total cash received by the Company upon the exercise of options was $0.1 million and $0.3 million during the nine months ended September 30, 2016 and 2015, respectively. During the nine months ended September 30, 2016, the Company issued restricted stock units (“RSUs”) covering 11,771 shares of common stock at a per share weighted average fair value of $16.99. Employee Stock Purchase Plan In December 2014, the Company’s Board of Directors adopted, and in January 2015 the Company’s stockholders approved, the Entellus Medical, Inc. 2015 Employee Stock Purchase Plan (“ESPP”). Under the ESPP, the Company has set two six-month offering periods during each calendar year, one beginning January 1 and ending on June 30, and the other beginning July 1 and ending on December 31, during which employees can choose to have up to 20% of their eligible compensation withheld to purchase less than 2,000 shares of the Company’s common stock during each offering period. The purchase price of the shares is 85% of the market price on the first or last trading day of the offering period, whichever is lower. A total of 200,000 shares of common stock were initially reserved for issuance under the ESPP. In addition, the number of shares available for issuance under the ESPP will be annually increased on the first day of each fiscal year during the term of the ESPP, beginning with the 2016 fiscal year, by an amount equal to the lesser of (A) 1% of the shares of the Company’s common stock outstanding on the date of the adoption of the plan or (B) a lesser amount determined by the Company’s Board of Directors. In the first quarter of 2016, in accordance with the “evergreen” provision, the number of shares available for grant under the ESPP increased in the amount of 16,488 shares, resulting in a total of 216,488 shares of common stock reserved for issuance under the ESPP. During the three and nine months ended September 30, 2016, the Company issued less than 0.1 million shares of its common stock to participants under the ESPP. During the three months ended September 30, 2016 and September 30, 2015, the Company recognized less than $0.1 million and zero in stock-based compensation expense related to the ESPP, respectively, and $0.2 million and zero during the nine months ended September 30, 2016 and September 30, 2015, respectively.

Stock Based Compensation Expens

Stock Based Compensation Expense	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation Expense	NOTE J. STOCK-BASED COMPENSATION EXPENSE Stock-based compensation expense is reflected in the Condensed Consolidated Statements of Operations and Comprehensive Loss for the three and nine months ended September 30, 2016 and 2015, as follows: Three Months Ended Nine Months Ended September 30, September 30, (in thousands) 2016 2015 2016 2015 Cost of goods sold $ 30 $ 18 $ 77 $ 40 Selling and marketing 536 203 1,470 428 Research and development 149 71 413 171 General and administrative 821 408 2,100 1,137 Total $ 1,536 $ 700 $ 4,060 $ 1,776 The Company estimates the fair value of stock-based compensation expense on the date of grant using the Black-Scholes option-pricing model. The Black-Scholes model determines the fair value of stock-based payment awards based on the fair market value of the Company’s common stock on the date of grant and is affected by assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the fair market value of the Company’s common stock, volatility over the expected term of the awards and actual and projected employee stock option exercise behaviors. The Company has opted to use the “simplified method” for estimating the expected term of options, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the option. Due to the Company’s limited operating history and a lack of company-specific historical and implied volatility data, the Company has based its estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. The historical volatility data was computed using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of the share-based payments. The Company will continue to analyze the historical stock price volatility and expected term assumptions as more historical data for the Company’s common stock becomes available. The risk-free rate assumption is based on the U.S. Treasury instruments with maturities similar to the expected term of the Company’s stock options. The expected dividend assumption is based on the Company’s history of not paying dividends and its expectation that it will not declare dividends for the foreseeable future. As stock-based compensation expense recognized in the financial statements is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates. Forfeitures are estimated based on estimated future employee turnover and historical experience. The fair value of the options granted to employees or directors during the nine months ended September 30, 2016 and 2015 was estimated as of the grant date using the Black-Scholes model assuming the weighted average assumptions listed in the following table: Nine Months Ended September 30, 2016 2015 Expected life in years 6.0 6.0 Risk-free interest rate 1.6 % 1.7 % Expected dividend yield 0 % 0 % Expected volatility 51 % 70 % Weighted average fair value $ 7.93 $ 25.70 The fair value of the ESPP options granted to employees during the three and nine months ended September 30, 2016 and 2015 was estimated as of the grant date using the Black-Scholes model assuming the weighted average assumptions listed in the following table: Nine Months Ended September 30, 2016 2015 Expected life in years 0.5 — Risk-free interest rate 0.4 % — Expected dividend yield 0 % — Expected volatility 49 % — Weighted average fair value $ 5.30 $ —

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	NOTE K. INCOME TAXES The Company did not record a federal, state or foreign income tax benefit for its losses for the three and nine months ended September 30, 2016 and 2015 due to its conclusion that a valuation allowance is required against its net deferred tax assets excluding the deferred tax liability related to its tax deductible goodwill acquired in connection with the XeroGel acquisition.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Earnings Per Share	NOTE L. EARNINGS PER SHARE Basic net loss per share is computed by dividing the net loss by the weighted average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of shares of common stock and dilutive potential shares of common stock outstanding during the period. Because the Company has reported a net loss for all periods presented, diluted net loss per share is the same as basic net loss per share for those periods as all potentially dilutive shares consisting of stock options, warrants, RSUs and ESPP shares were antidilutive in those periods. The following table sets forth the computation of the Company’s net loss per share: Three Months Ended Nine Months Ended September 30, September 30, (in thousands) 2016 2015 2016 2015 Net loss $ (9,519 ) $ (6,071 ) $ (21,412 ) $ (13,287 ) Weighted average common stock outstanding 18,855 18,738 18,827 16,688 Net loss per share, basic and diluted $ (0.50 ) $ (0.32 ) $ (1.14 ) $ (0.80 ) The following potentially dilutive securities outstanding have been excluded from the computations of diluted earnings per share because such securities have an antidilutive impact due to losses reported: September 30, (in thousands) 2016 2015 Common stock warrants 38 38 Common stock options 3,375 2,231 Restricted stock units 12 — Common stock ESPP 20 — Total 3,445 2,269

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE M. COMMITMENTS AND CONTINGENCIES Operating Leases As of September 30, 2016, the Company has three leased facilities under operating lease agreements. The Company entered into a 41-month lease in February 2012, effective April 1, 2012, for its corporate headquarters. The Company entered into a 50-month lease on June 30, 2014, effective July 1, 2014, for additional distribution space in a second facility. On February 26, 2015, the Company exercised its right to extend the lease term of its manufacturing and corporate facility for an additional three years through August 2018. On June 30, 2015, the Company entered into amendments to each of these two lease agreements, among other things, to expand the space occupied by the Company at the property at which the Company’s corporate headquarters are located, and to extend the term of each lease agreement through June 2021, with an option to extend for an additional term through June 2024. In connection with the XeroGel acquisition, the Company assumed a lease agreement for manufacturing facility space in Hayward, California through August 31, 2017. Rental payments on operating leases are charged to expense on a straight-line basis over the period of the lease. The lease agreements require the Company to pay executory costs such, as real estate taxes, insurance and repairs, and include renewal and escalation clauses. Approximate minimum annual future obligations which include monthly contractual lease payments under operating leases with initial terms in excess of one year, are as follows: (in thousands) 2016 (remaining) $ 111 2017 430 2018 394 2019 388 2020 389 2021 197 Total $ 1,909 Total lease expense was approximately $0.2 million and $0.1 million for the three months ended September 30, 2016 and 2015, respectively, and $0.5 million and $0.3 million for the nine months ended September 30, 2016 and 2015, respectively. Other Commitment In June 2016, the Company entered into an Amended and Restated Fiagon NA Distribution Agreement (the “Fiagon Distribution Agreement”) with Fiagon NA Corporation (“Fiagon”) in which the Company was granted exclusive distribution rights in the U.S. and Canada for Fiagon Image Guidance Systems (“Fiagon IGS”) and certain components, parts and related ancillary products i) to hospitals, ii) to ENT physicians in the office, clinic, and surgery centers, and iii) under ENT healthcare system contracts. The terms of the Fiagon Distribution Agreement require the Company to purchase minimum quantities of Fiagon IGS and certain other disposable products through August 9, 2020 in order for the Company to retain exclusive distribution rights.

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Preparation	Basis of Preparation The financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”). The interim financial data as of September 30, 2016 is unaudited and is not necessarily indicative of the results for a full year. In the opinion of the Company’s management, the interim data includes only normal and recurring adjustments necessary for a fair statement of the Company’s financial results for the three and nine months ended September 30, 2016 and 2015. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to SEC rules and regulations relating to interim financial statements. The accompanying condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 that has been filed with the SEC.
Initial Public Offering	Initial Public Offering In February 2015, the Company completed its initial public offering (“IPO”) by issuing 5.3 million shares of common stock, at an offering price of $17.00 per share, for net proceeds of approximately $81.0 million, after deducting underwriting discounts, commissions and offering expenses payable by the Company. In connection with the IPO, the Company’s outstanding shares of convertible preferred stock were automatically converted into an aggregate of 11.4 million shares of common stock, and the Company’s outstanding warrants to purchase shares of convertible preferred stock were automatically converted into warrants to purchase up to an aggregate of less than 0.1 million shares of common stock, resulting in the reclassification of the related redeemable convertible preferred stock warrant liability of $0.6 million to additional paid-in-capital.
1-for-4 Reverse Stock Split	1-for-4 Reverse Stock Split In connection with the IPO, the Company’s board of directors and stockholders approved a reverse stock split of the Company’s common stock on a 1-for-4 basis. The reverse stock split became effective on January 12, 2015. The par value of the common stock was not adjusted as a result of the reverse stock split. Adjustments corresponding to the reverse stock split were made to the ratio at which the convertible preferred stock converted into common stock immediately prior to the closing of the IPO. Accordingly, all share and per share amounts for all periods presented in these financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect the reverse stock split and adjustment of the preferred stock’s conversion ratios.
Business Combination	Business Combination On June 29, 2016, the Company acquired and entered into an exclusive license for the XeroGel™ assets with CogENT Therapeutics, LLC for $11.0 million in cash (the “XeroGel acquisition”). T (in thousands) Purchase Price Allocation Technologies $ 6,000 Trade names 350 Tangible assets 323 Total identifiable assets 6,673 Goodwill $ 4,327 The Company incurred transaction costs in connection with the acquisition of approximately $0.3 million for the nine months ended September 30, 2016, which are included in general and administrative expenses. The estimated fair value of the net assets acquired is preliminary and subject to change. While the Company uses its best estimates and assumptions as a part of the purchase price allocation process to accurately value assets acquired at the acquisition date, its estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, the Company may record adjustments to the assets acquired, with the corresponding offset to goodwill. Under the terms of the XeroGel acquisition agreements, the Company became the manufacturer of XeroGel and will continue to market and sell XeroGel to hospitals, offices and ambulatory surgery centers. Prior to the transaction, the Company was the exclusive distributor of XeroGel in the United States. The distribution agreement between the two parties was terminated in connection with the transaction. As a result of the XeroGel acquisition, the Company began recognizing all XeroGel revenue on a gross basis effective June 29, 2016. The Company has concluded that the XeroGel acquisition was not material for purposes of including pro forma information in this report and therefore has not provided any such information herein.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill represents the excess of the purchase price over the fair value of net assets acquired in a business combination. Intangible assets are recorded at their estimated fair value at the date of acquisition. In the year following the period in which identified intangible assets become fully amortized, the fully amortized balances are removed from the gross asset and accumulated amortization amounts. Goodwill is not amortized, but is instead subject to impairment testing. Intangible assets with finite lives are amortized using a straight-line method over their respective useful lives.
Goodwill Impairment Policy	Goodwill Impairment Policy The Company chose November 1 as the date to assess its On an annual basis, or more frequently upon the occurrence of certain events, the Company will test for goodwill impairment using a three-step process. T The second step is to identify a potential impairment by comparing the calculated fair value of a reporting unit with its carrying amount. The fair value of a reporting unit is determined based on a discounted cash flow analysis and further analyzed using other methods of valuation. A discounted cash flow analysis requires the Company to make various assumptions, including assumptions about future cash flows, growth rates and discount rates. The assumptions about future cash flows and growth rates are based on the Company’s long-term projections. In addition, an assumed terminal value is used to project future cash flows beyond base years. Assumptions used in the Company’s impairment testing will be consistent with the Company’s internal forecasts and operating plans. The Company’s discount rate will be based on its debt and equity balances, adjusted for current market conditions and investor expectations of return on its equity. If the fair value of a reporting unit exceeds its carrying amount, there will be no impairment. If the calculated fair value is less than the carrying value, the third step of the goodwill impairment test compares the implied fair value of the reporting unit’s goodwill with its carrying amount. To the extent the carrying amount of the reporting unit’s goodwill exceeds its implied fair value, a write-down of the reporting unit’s goodwill would be necessary.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reported period. Actual results could differ from those estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers. This standard will eliminate the transaction and industry specific revenue recognition guidance under current U.S. GAAP and replace it with a principles based approach for determining revenue recognition. The new guidance is effective for annual and interim periods beginning after December 15, 2017. The Company is in the process of evaluating the impact of this standard on its consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance, which changes the presentation of debt issuance costs in financial statements. Under ASU 2015-03, an entity presents such costs in the balance sheet as a direct deduction from the related debt liability rather than as an asset. Amortization of the costs is reported as interest expense. ASU 2015-03 is effective for fiscal years and interim periods within those fiscal years, beginning after December 15, 2015 . Early adoption is permitted for financial statements that have not been previously issued. A company should apply the new guidance on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Upon transition, a company is required to comply with the applicable disclosures for a change in an accounting principle. The guidance only affects the presentation of debt issuance costs in the balance sheet and has no impact on results of operations. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, which addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, and early adoption is not permitted. The Company does not expect that adoption of ASU 2016-01 will have a significant impact on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which requires that lease arrangements longer than twelve months result in an entity recognizing an asset and liability. The updated guidance is effective for interim and annual periods beginning after December 15, 2018, and early adoption is permitted. The Company is currently evaluating the impact of the updated guidance on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-08, Principal versus Agent Considerations - Reporting Revenue Gross versus Net. This ASU clarifies the revenue recognition implementation guidance for preparers on certain aspects of principal versus agent consideration. The amendments in this ASU are effective for annual periods beginning after December 15, 2017 and for interim periods therein. The Company is in the process of evaluating the impact of the adoption of this standard on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation, which is intended to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for annual periods beginning after December 15, 2016, and interim periods therein. Early application is permitted. The Company is currently evaluating the impact of this guidance on its consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses, to require the measurement of expected credit losses for financial instruments held at the reporting date based on historical experience, current conditions and reasonable forecasts. The main objective of this ASU is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years; the ASU allows for early adoption as of the beginning of an interim or annual reporting period beginning after December 15, 2018. The Company is currently assessing the impact that this standard will have on its consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, Statements of Cash Flows – Classifications of Certain Cash Receipts and Cash Payments, to clarify how companies present and classify certain cash receipts and cash payments in the statement of cash flows. The ASU is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years; the ASU allows for early adoption. The Company is currently assessing the impact that this standard will have on its consolidated financial statements.

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Schedule of Preliminary Purchase Price Allocation	The preliminary purchase price allocation is as follows: (in thousands) Purchase Price Allocation Technologies $ 6,000 Trade names 350 Tangible assets 323 Total identifiable assets 6,673 Goodwill $ 4,327

Composition of Certain Financ21

Composition of Certain Financial Statement Items (Tables)	9 Months Ended
	Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Inventories	Inventories September 30, December 31, (in thousands) 2016 2015 Finished goods $ 2,699 $ 2,014 Work in process 1,431 388 Raw materials 1,763 1,487 Total $ 5,893 $ 3,889
Schedule of Property and Equipment	Property and Equipment September 30, December 31, (in thousands) 2016 2015 Furniture and office equipment $ 791 $ 533 Computer hardware and software 2,721 2,187 Laboratory equipment 4,019 2,915 Tooling and molds 1,463 1,243 Leasehold improvements 1,905 583 $ 10,899 $ 7,461 Less accumulated depreciation and amortization (4,940 ) (3,766 ) Property and equipment in progress 531 431 Total $ 6,490 $ 4,126
Schedule of Intangible Assets	Intangible Assets September 30, December 31, (in thousands) 2016 2015 Technologies $ 6,000 $ — Trade name 350 — $ 6,350 $ — Less accumulated amortization (111 ) — Total $ 6,239 $ —
Future Amortization Expense Related to Intangible Assets	Future amortization expense related to intangible assets with definite lives is projected as follows: (in thousands) 2016 (remaining) $ 109 2017 436 2018 436 2019 436 2020 436 2021 436 2022 and thereafter 3,950 Total $ 6,239
Schedule of Accrued Expenses	Accrued Expenses September 30, December 31, (in thousands) 2016 2015 Compensation and commissions payable $ 6,531 $ 3,898 Royalty payable 1,640 1,800 Other accrued expenses (1) 2,197 1,297 Total $ 10,368 $ 6,995 (1)

Short-Term Investments (Tables)

Short-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Summary of Investments by Type of Instrument	The following is a summary of the available-for-sale investments by type of instrument, which are included in short-term investments in the consolidated balance sheet as of September 30, 2016 and December 31, 2015. Unrealized Unrealized Gain in Losses in Accumulated Accumulated Other Other Amortized Comprehensive Comprehensive Estimated September 30, 2016 (in thousands) Cost Income (Loss) Income (Loss) Fair Value Commercial paper $ 7,734 $ 12 $ — $ 7,746 Corporate bonds 8,725 — (3 ) 8,722 Foreign assets 7,498 1 — 7,499 Total available-for-sale securities $ 23,957 $ 13 $ (3 ) $ 23,967 Unrealized Unrealized Gain in Losses in Accumulated Accumulated Other Other Amortized Comprehensive Comprehensive Estimated December 31, 2015 (in thousands) Cost Income (Loss) Income (Loss) Fair Value Commercial paper $ 9,482 $ 10 $ — $ 9,492 Corporate bonds 19,605 — (19 ) 19,586 Government bonds 1,999 — — 1,999 Foreign assets 7,140 — (7 ) 7,133 Total available-for-sale securities $ 38,226 $ 10 $ (26 ) $ 38,210

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Summary of Available for Sale Investments at Fair Value on Recurring Basis	The following is a summary of available-for-sale investments by type of instrument measured at fair value on a recurring basis at September 30, 2016 and December 31, 2015, respectively. September 30, 2016 (in thousands) Level 1 Level 2 Level 3 Total Commercial paper $ — $ 7,746 $ — $ 7,746 Corporate bonds — 8,722 — 8,722 Foreign assets — 7,499 — 7,499 Total $ — $ 23,967 $ — $ 23,967 December 31, 2015 (in thousands) Level 1 Level 2 Level 3 Total Commercial paper $ — $ 9,492 $ — $ 9,492 Corporate bonds — 19,586 — 19,586 Government bonds — 1,999 — 1,999 Foreign assets — 7,133 — 7,133 Total $ — $ 38,210 $ — $ 38,210
Summary of Changes in Estimated Fair Value of Company's Convertible Preferred Stock Warrants	The following table sets forth a summary of the changes in the estimated fair value of the Company’s convertible preferred stock warrants, which represent financial instruments that were categorized as Level 3, according to the three-level fair value hierarchy. Nine Months Ended September 30, (in thousands) 2016 2015 Beginning of the period $ — $ 291 Issued — — Exercised — — Expired — — Reclassified to equity (1) — (648 ) Change in fair value — 357 End of the period $ — $ — (1) In connection with the closing of the IPO in February 2015, warrants to purchase shares of convertible preferred stock were converted to warrants to purchase shares of common stock, resulting in the reclassification of the related convertible preferred stock warrant liability to additional paid-in-capital.
Summary of Fair Value of Convertible Preferred Stock Warrant Liability	The fair market value of the convertible preferred stock prior to the IPO was determined using the option pricing method and the probability weighted expected return method. The fair value of the convertible preferred stock warrant liability was determined using the Black-Scholes option pricing model with the following assumptions: Nine Months Ended September 30, 2016 2015 Expected life in years N/A 7.5 Risk-free interest rate N/A 1.6 % Expected dividend yield N/A 0.0 % Expected volatility N/A 56 %

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit) (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity and Related Information	A summary of the Company’s stock option and restricted stock unit activity and related information is as follows: September 30, 2016 Weighted Average Aggregate Weighted Remaining Intrinsic Average Contractual Value (shares in thousands) Options Exercise Price Term ($000) Outstanding, January 1, 2016 2,583 $ 11.79 8.5 years $ 16,377 Granted 905 16.10 Exercised (51 ) 2.11 Cancelled — — Forfeited (62 ) 16.87 Outstanding, September 30, 2016 3,375 $ 13.00 8.2 years $ 32,142 Exercisable 1,278 $ 9.20 7.2 years $ 16,981

Stock Based Compensation Expe25

Stock Based Compensation Expense (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-based Compensation Expense in Condensed Statements of Operations and Comprehensive Loss	Stock-based compensation expense is reflected in the Condensed Consolidated Statements of Operations and Comprehensive Loss for the three and nine months ended September 30, 2016 and 2015, as follows: Three Months Ended Nine Months Ended September 30, September 30, (in thousands) 2016 2015 2016 2015 Cost of goods sold $ 30 $ 18 $ 77 $ 40 Selling and marketing 536 203 1,470 428 Research and development 149 71 413 171 General and administrative 821 408 2,100 1,137 Total $ 1,536 $ 700 $ 4,060 $ 1,776
Summary of Weighted Average Assumptions Used in Black-Scholes Model in Estimating Fair Value of Option Granted	The fair value of the options granted to employees or directors during the nine months ended September 30, 2016 and 2015 was estimated as of the grant date using the Black-Scholes model assuming the weighted average assumptions listed in the following table: Nine Months Ended September 30, 2016 2015 Expected life in years 6.0 6.0 Risk-free interest rate 1.6 % 1.7 % Expected dividend yield 0 % 0 % Expected volatility 51 % 70 % Weighted average fair value $ 7.93 $ 25.70
Summary of Weighted Average Assumptions Used in Black-Scholes Model in Estimating Fair Value of ESPP Option Granted	The fair value of the ESPP options granted to employees during the three and nine months ended September 30, 2016 and 2015 was estimated as of the grant date using the Black-Scholes model assuming the weighted average assumptions listed in the following table: Nine Months Ended September 30, 2016 2015 Expected life in years 0.5 — Risk-free interest rate 0.4 % — Expected dividend yield 0 % — Expected volatility 49 % — Weighted average fair value $ 5.30 $ —

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Schedule of Net Loss Per Share	The following table sets forth the computation of the Company’s net loss per share: Three Months Ended Nine Months Ended September 30, September 30, (in thousands) 2016 2015 2016 2015 Net loss $ (9,519 ) $ (6,071 ) $ (21,412 ) $ (13,287 ) Weighted average common stock outstanding 18,855 18,738 18,827 16,688 Net loss per share, basic and diluted $ (0.50 ) $ (0.32 ) $ (1.14 ) $ (0.80 )
Schedule of Antidilutive Securities Outstanding Excluded from Computation of Earnings Per Share	The following potentially dilutive securities outstanding have been excluded from the computations of diluted earnings per share because such securities have an antidilutive impact due to losses reported: September 30, (in thousands) 2016 2015 Common stock warrants 38 38 Common stock options 3,375 2,231 Restricted stock units 12 — Common stock ESPP 20 — Total 3,445 2,269

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Summary of Annual Future Minimum Lease Payments	Approximate minimum annual future obligations which include monthly contractual lease payments under operating leases with initial terms in excess of one year, are as follows: (in thousands) 2016 (remaining) $ 111 2017 430 2018 394 2019 388 2020 389 2021 197 Total $ 1,909

Organization - Additional Infor

Organization - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of reportable segments	1

Summary of Significant Accoun29

Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Thousands	Jun. 29, 2016USD ($)	Jan. 12, 2015	Feb. 28, 2015USD ($)$ / sharesshares	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Accounting Policies [Line Items]
Proceeds from initial public offering, net of issuance costs					$ 80,953
Reverse stock split conversion ratio		0.25
Payments to acquire business in cash				$ 11,000
Debt Issuance Costs				131		$ 176
CogENT Therapeutics, LLC [Member]
Accounting Policies [Line Items]
Payments to acquire business in cash	$ 11,000
Business acquisition, transaction costs				$ 300
Initial Public Offering [Member]
Accounting Policies [Line Items]
Common stock, shares issued | shares			5,300,000
Common stock offering price per share | $ / shares			$ 17
Proceeds from initial public offering, net of issuance costs			$ 81,000
Number of common stock converted from preferred stock | shares			11,400,000
Preferred stock warrant liability reclassified			$ 600
Initial Public Offering [Member] | Maximum [Member]
Accounting Policies [Line Items]
Shares purchasable upon conversion of preferred stock | shares			100,000

Summary of Significant Accoun30

Summary of Significant Accounting Policies - Schedule of Preliminary Purchase Price Allocation (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 29, 2016
Business Acquisition [Line Items]
Goodwill	$ 4,327
CogENT Therapeutics, LLC [Member]
Business Acquisition [Line Items]
Tangible assets		$ 323
Total identifiable assets		6,673
Goodwill		4,327
CogENT Therapeutics, LLC [Member] | Technologies [Member]
Business Acquisition [Line Items]
Intangible assets		6,000
CogENT Therapeutics, LLC [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Intangible assets		$ 350

Composition of Certain Financ31

Composition of Certain Financial Statement Items - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Finished goods	$ 2,699	$ 2,014
Work in process	1,431	388
Raw materials	1,763	1,487
Total	$ 5,893	$ 3,889	[1]
[1]	Amounts derived from audited financial statements of Entellus Medical, Inc. included in its Annual Report on Form 10-K for the year ended December 31, 2015.

Composition of Certain Financ32

Composition of Certain Financial Statement Items - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property plant and equipment, Gross	$ 10,899	$ 7,461
Less accumulated depreciation and amortization	(4,940)	(3,766)
Property and equipment in progress	531	431
Total	6,490	4,126	[1]
Furniture and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, Gross	791	533
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, Gross	2,721	2,187
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, Gross	4,019	2,915
Tooling and Molds [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, Gross	1,463	1,243
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, Gross	$ 1,905	$ 583
[1]	Amounts derived from audited financial statements of Entellus Medical, Inc. included in its Annual Report on Form 10-K for the year ended December 31, 2015.

Composition of Certain Financ33

Composition of Certain Financial Statement Items - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Finite Lived Intangible Assets [Line Items]
Depreciation and amortization of fixed assets	$ 0.5	$ 0.3	$ 1.2	$ 0.7
Amortization expenses	$ 0.1	$ 0	$ 0.1	$ 0
Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Useful life of Intangible asset			14 years
Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Useful life of Intangible asset			20 years

Composition of Certain Financ34

Composition of Certain Financial Statement Items - Schedule of Intangible Assets (Detail) $ in Thousands	Sep. 30, 2016USD ($)
Finite Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 6,350
Less accumulated amortization	(111)
Total	6,239
Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets, gross	6,000
Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 350

Composition of Certain Financ35

Composition of Certain Financial Statement Items - Future Amortization Expense Related to Intangible Assets (Detail) $ in Thousands	Sep. 30, 2016USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2016 (remaining)	$ 109
2,017	436
2,018	436
2,019	436
2,020	436
2,021	436
2022 and thereafter	3,950
Total	$ 6,239

Composition of Certain Financ36

Composition of Certain Financial Statement Items - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Payables And Accruals [Abstract]
Compensation and commissions payable	$ 6,531	$ 3,898
Royalty payable	1,640	1,800
Other accrued expenses	2,197	1,297
Accrued expenses, Total	$ 10,368	$ 6,995	[1]
[1]	Amounts derived from audited financial statements of Entellus Medical, Inc. included in its Annual Report on Form 10-K for the year ended December 31, 2015.

Liquidity and Business Risks -

Liquidity and Business Risks - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	9 Months Ended
	Feb. 28, 2015	Sep. 30, 2015	Sep. 30, 2016	Dec. 31, 2015	[1]
Subsidiary, Sale of Stock [Line Items]
Cash, cash equivalents and short-term investments			$ 39,200
Accumulated deficit			$ 143,470	$ 122,058
Proceeds from initial public offering, net of issuance costs		$ 80,953
Initial Public Offering [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock, shares issued	5.3
Common stock offering price per share	$ 17
Proceeds from initial public offering, net of issuance costs	$ 81,000
[1]	Amounts derived from audited financial statements of Entellus Medical, Inc. included in its Annual Report on Form 10-K for the year ended December 31, 2015.

Short-term Investments - Summar

Short-term Investments - Summary of Investments by Type of Instrument (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 23,957	$ 38,226
Unrealized Gain in Accumulated Other Comprehensive Income (Loss)	13	10
Unrealized Losses in Accumulated Other Comprehensive Income (Loss)	(3)	(26)
Estimated Fair Value	23,967	38,210
Short-term Investments [Member] | Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	7,734	9,482
Unrealized Gain in Accumulated Other Comprehensive Income (Loss)	12	10
Estimated Fair Value	7,746	9,492
Short-term Investments [Member] | Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	8,725	19,605
Unrealized Losses in Accumulated Other Comprehensive Income (Loss)	(3)	(19)
Estimated Fair Value	8,722	19,586
Short-term Investments [Member] | Foreign Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	7,498	7,140
Unrealized Gain in Accumulated Other Comprehensive Income (Loss)	1
Unrealized Losses in Accumulated Other Comprehensive Income (Loss)		(7)
Estimated Fair Value	$ 7,499	7,133
Short-term Investments [Member] | Government Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		1,999
Estimated Fair Value		$ 1,999

Short-term Investments - Additi

Short-term Investments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016USD ($)
Investments Debt And Equity Securities [Abstract]
Other-than-temporary impairment charges	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Available for Sale Investments at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	$ 23,967	$ 38,210
Fair Value, Measurements, Recurring [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	23,967	38,210
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	23,967	38,210
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	7,746	9,492
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member] | Level 2 [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	7,746	9,492
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	8,722	19,586
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member] | Level 2 [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	8,722	19,586
Fair Value, Measurements, Recurring [Member] | Foreign Assets [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	7,499	7,133
Fair Value, Measurements, Recurring [Member] | Foreign Assets [Member] | Level 2 [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments	$ 7,499	7,133
Fair Value, Measurements, Recurring [Member] | Government Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments		1,999
Fair Value, Measurements, Recurring [Member] | Government Bonds [Member] | Level 2 [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale investments		$ 1,999

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Transfer of assets between level 1, level 2 or level 3	$ 0	$ 0

Fair Value Measurements - Sum42

Fair Value Measurements - Summary of Changes in Estimated Fair Value of Company's Convertible Preferred Stock Warrants (Detail) - Convertible Preferred Stock Warrants [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Class of Warrant or Right [Line Items]
Beginning of the period	$ 291
Reclassified to equity	(648)
Change in fair value	$ 357

Fair Value Measurements - Sum43

Fair Value Measurements - Summary of Fair Value of Convertible Preferred Stock Warrant Liability (Detail)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
Expected life in years	0 years	7 years 6 months
Risk-free interest rate		1.60%
Expected dividend yield		0.00%
Expected volatility		56.00%

Debt - Additional Information (

Debt - Additional Information (Detail) - Credit Facility [Member]	May 19, 2015USD ($)Tranches	Feb. 28, 2017USD ($)Payment	Dec. 31, 2013USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 25,000,000
Line of credit facility, amount outstanding				$ 20,000,000	$ 20,000,000
Fixed interest floor rate	9.40%
Number of tranches | Tranches	3
Maturity date of debt instrument				Dec. 1, 2018
Credit facility final payment fee				7.15%
First Tranche [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding			$ 15,000,000
Payment fee			100,000
Third Tranche [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					$ 5,000,000
Prior to First Anniversary [Member]
Debt Instrument [Line Items]
Credit facility prepayment fee				0.75%
Scenario, Forecast [Member]
Debt Instrument [Line Items]
Number of equal monthly payments of principal and interest | Payment		23
Credit facility, equal monthly payments of principal and interest		$ 1,000,000
Scenario, Previously Reported [Member] | First Tranche [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding			$ 7,500,000
Maximum [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding						$ 5,000,000

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	1 Months Ended	9 Months Ended
	Feb. 28, 2015	Sep. 30, 2016
Temporary Equity [Line Items]
Preferred stock, conversion basis		In connection with the IPO in February 2015, 44.3 million shares of convertible preferred stock were converted into 11.4 million shares of common stock, resulting in the reclassification of the related redeemable convertible preferred stock of $91.6 million to common stock and additional paid-in-capital.
Number of preferred stock converted to common stock	44.3
Convertible preferred stock	$ 91.6
Initial Public Offering [Member]
Temporary Equity [Line Items]
Number of common stock converted from preferred stock	11.4

Stockholders' Equity (Deficit46

Stockholders' Equity (Deficit) - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended			9 Months Ended
	Jan. 31, 2015	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized		10,000,000			10,000,000		10,000,000
Preferred stock, shares outstanding		0			0		0
Common stock, shares authorized		200,000,000			200,000,000		200,000,000
Common stock, shares outstanding		18,863,000			18,863,000		18,794,000
Stock-based compensation		$ 1,536,000		$ 700,000	$ 4,060,000	$ 1,776,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance	200,000		216,488
Annual increase in shares available for grant			16,488
Weighted average fair value					$ 5.30
Increase in share reserve as percentage of shares of Common Stock outstanding on plan adoption date					1.00%
First offering date					Jan. 1, 2016
Stock-based compensation				$ 0	$ 200,000	0
Maximum percentage of compensation employees can withheld					20.00%
Purchase price as a percentage of market price					85.00%
Employee Stock Purchase Plan, Plan Description					Under the ESPP, the Company has set two six-month offering periods during each calendar year, one beginning January 1 and ending on June 30, and the other beginning July 1 and ending on December 31, during which employees can choose to have up to 20% of their eligible compensation withheld to purchase less than 2,000 shares of the Company’s common stock during each offering period. The purchase price of the shares is 85% of the market price on the first or last trading day of the offering period, whichever is lower.
Maximum [Member] | Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period shares		100,000			100,000
Stock-based compensation		$ 100,000
Shares of common stocks available for purchase by employee		2,000			2,000
2015 Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance	1,345,570		2,097,320
Annual increase in shares available for grant	875,000		751,750
Annual percentage increase in shares available for grant	4.00%
Aggregate pre-tax intrinsic value of options exercised					$ 800,000	2,700,000
Total cash received upon the exercise of options					$ 100,000	$ 300,000
2015 Incentive Award Plan [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares issued					11,771
Weighted average fair value					$ 16.99

Stockholders' Equity (Deficit47

Stockholders' Equity (Deficit) - Summary of Stock Option Activity and Related Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, Beginning balance	2,583
Options Granted	905
Options Exercised	(51)
Options Forfeited	(62)
Options outstanding, Ending balance	3,375	2,583
Options Exercisable, Ending balance	1,278
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Beginning balance	$ 11.79
Weighted Average Exercise Price, Granted	16.10
Weighted Average Exercise Price, Exercised	2.11
Weighted Average Exercise Price, Forfeited	16.87
Weighted Average Exercise Price, Ending balance	13	$ 11.79
Weighted Average Exercise Price, Exercisable	$ 9.20
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Term	8 years 2 months 12 days	8 years 6 months
Weighted Average Remaining Contractual Term, Exercisable	7 years 2 months 12 days
Aggregate Intrinsic Value	$ 32,142	$ 16,377
Aggregate Intrinsic Value Exercisable	$ 16,981

Stock Based Compensation Expe48

Stock Based Compensation Expense - Summary of Stock-Based Compensation Expense in Condensed Statements of Operations and Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,536	$ 700	$ 4,060	$ 1,776
Cost of Goods Sold [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	30	18	77	40
Selling and Marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	536	203	1,470	428
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	149	71	413	171
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 821	$ 408	$ 2,100	$ 1,137

Stock Based Compensation Expe49

Stock Based Compensation Expense - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested employee stock-based payment award	$ 15.5
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period for unearned stock-based compensation expense	3 years

Stock Based Compensation Expe50

Stock Based Compensation Expense - Summary of Weighted Average Assumptions Used in Black-Scholes Model in Estimating Fair Value of Option Granted (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life in years	6 months	0 years
Risk-free interest rate	0.40%
Expected dividend yield	0.00%
Expected volatility	49.00%
Weighted average fair value	$ 5.30
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life in years	6 years	6 years
Risk-free interest rate	1.60%	1.70%
Expected dividend yield	0.00%	0.00%
Expected volatility	51.00%	70.00%
Weighted average fair value	$ 7.93	$ 25.70

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Federal income tax benefit	$ 0	$ 0	$ 0	$ 0
State income tax benefit	0	0	0	0
Foreign income tax benefit	$ 0	$ 0	$ 0	$ 0

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net loss	$ (9,519)	$ (6,071)	$ (21,412)	$ (13,287)
Weighted average common stock outstanding	18,855	18,738	18,827	16,688
Net loss per share, basic and diluted	$ (0.50)	$ (0.32)	$ (1.14)	$ (0.80)

Earnings Per Share - Schedule53

Earnings Per Share - Schedule of Antidilutive Securities Outstanding Excluded from Computation of Earnings Per Share (Detail) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive potential common shares excluded from computation of diluted earning per share	3,445	2,269
Common Stock Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive potential common shares excluded from computation of diluted earning per share	38	38
Common Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive potential common shares excluded from computation of diluted earning per share	3,375	2,231
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive potential common shares excluded from computation of diluted earning per share	12
Common Stock ESPP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive potential common shares excluded from computation of diluted earning per share	20

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Feb. 26, 2015	Jun. 30, 2014	Feb. 29, 2012	Sep. 30, 2016USD ($)Facilities	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)Facilities	Sep. 30, 2015USD ($)
Commitments And Contingencies Disclosure [Abstract]
Number of leased facilities under operating lease agreement | Facilities				3		3
Operating leased facility, period		50 months	41 months
Operating leased facility, effective date		Jul. 1, 2014	Apr. 1, 2012
Operating leased facility, additional period	3 years
Operating leased facility, amendment description						On June 30, 2015, the Company entered into amendments to each of these two lease agreements, among other things, to expand the space occupied by the Company at the property at which the Company’s corporate headquarters are located, and to extend the term of each lease agreement through June 2021, with an option to extend for an additional term through June 2024.
Total lease expense | $				$ 0.2	$ 0.1	$ 0.5	$ 0.3

Commitment and Contingencies -

Commitment and Contingencies - Summary of Annual Future Minimum Lease Payments (Detail) $ in Thousands	Sep. 30, 2016USD ($)
Commitments And Contingencies Disclosure [Abstract]
2016 (remaining)	$ 111
2,017	430
2,018	394
2,019	388
2,020	389
2,021	197
Total minimum payment required	$ 1,909