TELA Bio (TELA) 10-Q 18 Dec 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Dec. 03, 2019
Document and Entity Information
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Entity Registrant Name	TELA Bio, Inc.
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		11,405,543
Entity Central Index Key	0001561921
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 10,701	$ 17,278
Accounts receivable	2,278	1,298
Inventory	4,272	4,348
Prepaid expenses and other	365	330
Total current assets	17,616	23,254
Property and equipment, net	716	758
Intangible assets, net	2,987	3,215
Deferred offering costs	1,731
Total assets	23,050	27,227
Current liabilities:
Accounts payable	1,701	3,421
Accrued expenses	3,600	5,153
Other current liabilities	1,008	985
Total current liabilities	6,309	9,559
Long-term debt with related party	30,108	29,733
Preferred stock warrant liability	1,644	1,640
Other long-term liabilities	5	5
Total liabilities	38,066	40,937
Redeemable convertible preferred stock	145,384	124,150
Stockholders' deficit:
Accumulated other comprehensive loss	(2)
Accumulated deficit	(160,398)	(137,860)
Total stockholders' deficit	(160,400)	(137,860)
Total liabilities, redeemable convertible preferred stock and stockholders' deficit	23,050	27,227
Series A Redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock	34,458	33,112
Series B Redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock	$ 110,926	$ 91,038

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, Par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	127,157,585	127,157,585
Common stock, shares issued (in shares)	298,992	296,629
Common stock, shares outstanding (in shares)	298,117	295,717
Series A Redeemable convertible preferred stock
Preferred stock, shares authorized (in shares)	22,501,174	22,501,174
Preferred stock, shares issued (in shares)	22,501,174	22,501,174
Preferred stock, shares outstanding (in shares)	22,501,174	22,501,174
Preferred stock, liquidation value	$ 34,458
Series B Redeemable convertible preferred stock
Preferred stock, shares authorized (in shares)	82,891,619	82,891,619
Preferred stock, shares issued (in shares)	75,560,456	63,032,500
Preferred stock, shares outstanding (in shares)	75,560,456	63,032,500
Preferred stock, liquidation value	$ 110,213

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Consolidated Statements of Operations and Comprehensive Loss
Revenue	$ 3,973	$ 2,212	$ 10,582	$ 5,847
Cost of revenue (excluding amortization of intangible assets)	1,293	769	4,045	3,224
Amortization of intangible assets	76	76	228	709
Gross profit	2,604	1,367	6,309	1,914
Operating expenses:
Sales and marketing	4,736	3,608	12,678	9,630
General and administrative	1,208	1,399	3,737	3,366
Research and development	516	1,044	3,230	3,362
Gain on litigation settlement		(2,160)		(2,160)
Total operating expenses	6,460	3,891	19,645	14,198
Loss from operations	(3,856)	(2,524)	(13,336)	(12,284)
Other (expense) income:
Interest expense	899	309	2,725	1,037
Loss on extinguishment of debt				(615)
Change in fair value of preferred stock warrant liability	34	17	(4)	191
Other income	55	10	172	44
Total other (expense) income	(810)	(282)	(2,557)	(1,417)
Net loss	(4,666)	(2,806)	(15,893)	(13,701)
Accretion of redeemable convertible preferred stock to redemption value	(2,058)	(1,871)	(6,843)	(6,848)
Net loss attributable to common stockholders	$ (6,724)	$ (4,677)	$ (22,736)	$ (20,549)
Net loss per common share, basic and diluted	$ (22.58)	$ (15.84)	$ (76.62)	$ (69.70)
Weighted average common shares outstanding, basic and diluted	297,750	295,228	296,743	294,823
Comprehensive loss:
Net loss	$ (4,666)	$ (2,806)	$ (15,893)	$ (13,701)
Foreign currency translation adjustment	1		(2)
Comprehensive loss	$ (4,665)	$ (2,806)	$ (15,895)	$ (13,701)

Consolidated Statements of Rede

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Deficit - USD ($) $ in Thousands	Series A Redeemable convertible preferred stock	Series B Redeemable convertible preferred stock	Common stock	Additional paid in capital [Member]	Accumulated other comprehensive loss	Accumulated deficit	Total
Balance at Beginning of period at Dec. 31, 2017						$ (108,171)	$ (108,171)
Balance at Beginning of period (in shares) at Dec. 31, 2017			293,791
Vesting of common stock previously subject to repurchase				$ 3			3
Vesting of common stock previously subject to repurchase (in shares)			448
Exercise of stock options				6			6
Exercise of stock options (in shares)			1,157
Stock-based compensation expense				169			169
Accretion of redeemable convertible preferred stock to redemption value				(178)		(6,670)	(6,848)
Net loss						(13,701)	(13,701)
Balance at Ending period at Sep. 30, 2018						(128,542)	(128,542)
Balance at Ending period (in shares) at Sep. 30, 2018			295,396
Balance at Beginning of period at Dec. 31, 2017	$ 30,940	$ 80,409
Balance at Beginning of period (in shares) at Dec. 31, 2017	22,501,174	59,425,431
Increase (Decrease) in Temporary Equity [Roll Forward]
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $26, $141, $151		$ 1,349
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $26, $141, $151 (in shares)		1,294,069
Accretion of redeemable convertible preferred stock to redemption value	$ 1,718	$ 5,130
Balance at Ending period at Sep. 30, 2018	$ 32,658	$ 86,888
Balance at Ending period (in shares) at Sep. 30, 2018	22,501,174	60,719,500
Balance at Beginning of period at Jun. 30, 2018						(123,928)	(123,928)
Balance at Beginning of period (in shares) at Jun. 30, 2018			295,125
Vesting of common stock previously subject to repurchase				1			1
Vesting of common stock previously subject to repurchase (in shares)			126
Exercise of stock options				1			1
Exercise of stock options (in shares)			145
Stock-based compensation expense				61			61
Accretion of redeemable convertible preferred stock to redemption value				63		(1,808)	(1,871)
Net loss						(2,806)	(2,806)
Balance at Ending period at Sep. 30, 2018						(128,542)	(128,542)
Balance at Ending period (in shares) at Sep. 30, 2018			295,396
Balance at Beginning of period at Jun. 30, 2018	$ 32,205	$ 85,470
Balance at Beginning of period (in shares) at Jun. 30, 2018	22,501,174	60,719,500
Increase (Decrease) in Temporary Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value	$ 453	$ 1,418
Balance at Ending period at Sep. 30, 2018	$ 32,658	$ 86,888
Balance at Ending period (in shares) at Sep. 30, 2018	22,501,174	60,719,500
Balance at Beginning of period at Dec. 31, 2018						(137,860)	(137,860)
Balance at Beginning of period (in shares) at Dec. 31, 2018			295,717
Vesting of common stock previously subject to repurchase				3			3
Vesting of common stock previously subject to repurchase (in shares)			508
Exercise of stock options				12			$ 12
Exercise of stock options (in shares)			1,892				1,892
Foreign currency translation adjustment					$ (2)		$ (2)
Stock-based compensation expense				183			183
Accretion of redeemable convertible preferred stock to redemption value				(198)		(6,645)	(6,843)
Net loss						(15,893)	(15,893)
Balance at Ending period at Sep. 30, 2019					(2)	(160,398)	(160,400)
Balance at Ending period (in shares) at Sep. 30, 2019			298,117
Balance at Beginning of period at Dec. 31, 2018	$ 33,112	$ 91,038					124,150
Balance at Beginning of period (in shares) at Dec. 31, 2018	22,501,174	63,032,500
Increase (Decrease) in Temporary Equity [Roll Forward]
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $26, $141, $151		$ 14,391
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $26, $141, $151 (in shares)		12,527,956
Accretion of redeemable convertible preferred stock to redemption value	$ 1,346	$ 5,497
Balance at Ending period at Sep. 30, 2019	$ 34,458	$ 110,926					145,384
Balance at Ending period (in shares) at Sep. 30, 2019	22,501,174	75,560,456
Balance at Beginning of period at Jun. 30, 2019					(3)	(153,744)	(153,747)
Balance at Beginning of period (in shares) at Jun. 30, 2019			297,502
Vesting of common stock previously subject to repurchase				2			2
Vesting of common stock previously subject to repurchase (in shares)			202
Exercise of stock options				4			4
Exercise of stock options (in shares)			413
Foreign currency translation adjustment					1		1
Stock-based compensation expense				64			64
Accretion of redeemable convertible preferred stock to redemption value				$ (70)		(1,988)	(2,058)
Net loss						(4,666)	(4,666)
Balance at Ending period at Sep. 30, 2019					$ (2)	$ (160,398)	(160,400)
Balance at Ending period (in shares) at Sep. 30, 2019			298,117
Balance at Beginning of period at Jun. 30, 2019	$ 34,005	$ 107,058
Balance at Beginning of period (in shares) at Jun. 30, 2019	22,501,174	73,587,014
Increase (Decrease) in Temporary Equity [Roll Forward]
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $26, $141, $151		$ 2,263
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $26, $141, $151 (in shares)		1,973,442
Accretion of redeemable convertible preferred stock to redemption value	$ 453	$ 1,605
Balance at Ending period at Sep. 30, 2019	$ 34,458	$ 110,926					$ 145,384
Balance at Ending period (in shares) at Sep. 30, 2019	22,501,174	75,560,456

Consolidated Statements of Re_2

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Deficit (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Series B Redeemable convertible preferred stock
Stock issue costs	$ 26	$ 141	$ 151

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (15,893)	$ (13,701)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	206	393
Noncash loss on extinguishment of debt		513
Noncash interest expense	395	398
Amortization of intangible assets	228	709
Inventory excess and obsolescence charge	1,093	1,550
Change in fair value of warrants	4	(191)
Stock-based compensation expense	183	169
Changes in operating assets and liabilities:
Accounts receivable	(983)	(475)
Inventory	(1,023)	(3,287)
Prepaid expenses and other assets	(35)	125
Accounts payable	(2,470)	1,178
Accrued expenses and other liabilities	(44)	(1,541)
Net cash used in operating activities	(18,339)	(14,160)
Cash flows from investing activities:
Payment for intangible asset	(2,500)
Purchase of property and equipment	(164)	(42)
Net cash used in investing activities	(2,664)	(42)
Cash flows from financing activities:
Proceeds from issuance of long-term debt and preferred stock warrants		8,000
Repayment of long-term debt		(5,000)
Borrowings under revolving credit facility		4,912
Repayments of revolving credit facility		(3,668)
Proceeds from issuance of Series B redeemable preferred stocks, net	14,415	1,349
Payment of deferred financing costs		(830)
Proceeds from exercise of stock options	12	6
Net cash provided by financing activities	14,427	4,769
Effect of exchange rate on cash	(1)
Net decrease in cash and cash equivalents	(6,577)	(9,433)
Cash and cash equivalents, beginning of period	17,278	11,346
Cash and cash equivalents, end of period	10,701	1,913
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	2,330	639
Cash paid on loss on extinguishment of debt		102
Supplemental disclosures of noncash investing and financing activities:
Fair value of warrants issued in connection with equity and debt financing		187
Accretion of redeemable convertible preferred stock to redemption value	(6,843)	(6,848)
Intangible assets in accrued expenses and other liabilities		4,000
Deferred Series B equity costs in accounts payable and accrued expenses	24
Deferred offering costs in accounts payable and accrued expenses	1,731
Issuance of common stock for early exercised stock options	$ 3	$ 3

Background

Background	9 Months Ended
	Sep. 30, 2019
Background
Background	(1) Background TELA Bio, Inc. (the “Company”) was incorporated in the state of Delaware on April 17, 2012 and wholly owns TELA Bio Limited, a company incorporated in the United Kingdom. The Company is focused on the commercialization and sale of OviTex Reinforced Tissue Matrix, which utilizes surgical reconstruction medical device technology licensed from a strategic partner and on the research and development of additional medical devices with this strategic partner and on other internally developed technologies. In April 2019, the Company received 510(k) clearance from the United States Food and Drug Administration (“FDA”) for OviTex PRS Reinforced Tissue Matrix (“OviTex PRS”), which addresses unmet needs in plastic and reconstructive surgery. The Company’s principal corporate office and research facility is located in Malvern, Pennsylvania.

Risks and Liquidity

Risks and Liquidity	9 Months Ended
	Sep. 30, 2019
Risks and Liquidity
Risks and Liquidity	(2) Risks and Liquidity The Company’s operations to date have focused on commercializing products, developing and acquiring technology and assets, business planning, raising capital and organization and staffing. The Company has incurred recurring losses and negative cash flows from operations since inception and has an accumulated deficit of $160.4 million as of September 30, 2019. The Company anticipates incurring additional losses until such time, if ever, it can generate sufficient revenue from its products to cover its expenses and has limited resources available to fund current commercialization and research and development activities. In November 2019, the Company closed its initial public offering (“IPO”) in which the Company issued and sold 4,398,700 shares of its common stock at a public offering price of $13.00 per share, including 398,700 shares of the Company’s common stock sold pursuant to the underwriters’ option to purchase additional shares. The Company received net proceeds of $50.7 million after deducting underwriting discounts, commissions and other offering expenses. The operations of the Company are subject to certain risks and uncertainties including, among others, uncertainty of product development, technological uncertainty, commercial acceptance of any developed products, alternative competing technologies, dependence on collaborative partners, uncertainty regarding patents and proprietary rights, comprehensive government regulations, and dependence on key personnel.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	(3) Summary of Significant Accounting Policies The Company’s complete summary of significant accounting policies can be found in “Note 3, Summary of Significant Accounting Policies” in the audited consolidated financial statements included in the Company’s Prospectus dated November 7, 2019 filed with the SEC. Any reference in these notes to applicable guidance is meant to refer to generally accepted accounting principles (“GAAP”) in the United States as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). Interim Financial Statements The accompanying unaudited interim consolidated financial statements have been prepared from the books and records of the Company in accordance with GAAP for interim financial information and Rule 10‑01 of Regulation S‑X promulgated by the SEC, which permits reduced disclosures for interim periods. All adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the accompanying consolidated balance sheets and statements of operations and comprehensive loss, redeemable convertible preferred stock and stockholders’ deficit, and cash flows have been made. Although these interim consolidated financial statements do not include all of the information and footnotes required for complete annual consolidated financial statements, management believes the disclosures are adequate to make the information presented not misleading. Unaudited interim results of operations and cash flows are not necessarily indicative of the results that may be expected for the full year. Unaudited interim consolidated financial statements and footnotes should be read in conjunction with the audited consolidated financial statements and footnotes included in the Prospectus. Reverse Stock Split The Company effected a one-for-24.69 reverse stock split of its common stock on October 28, 2019. The reverse stock split combined approximately 25 shares of the Company's issued and outstanding common stock into one share of common stock and correspondingly adjusted the conversion price of its redeemable convertible preferred stock. No fractional shares were issued in connection with the reverse stock split. Any fractional share resulting from the reverse stock split was rounded down to the nearest whole share, and in lieu of any fractional shares, the Company will pay in cash to the holders of such fractional shares an amount equal to the fair value, as determined by the board of directors, of such fractional shares. All common stock, per share and related information presented in the unaudited interim consolidated financial statements and accompanying notes have been retroactively adjusted to reflect the reverse stock split. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant judgments are employed in estimates used to determine the fair value of redeemable convertible preferred stock, preferred stock warrant liability and stock‑based awards issued, and recoverability of the carrying value of the Company’s inventory. As future events and their effects cannot be determined with precision, actual results may differ significantly from these estimates. Deferred Offering Costs The Company capitalizes certain legal, accounting, and other third‑party fees that are directly associated with in‑process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs will be recorded as a reduction of additional paid‑in capital generated as a result of the offering. Should the equity financing no longer be considered probable of being consummated, all deferred offering costs would be charged to operating expenses in the consolidated statement of operations. Deferred offering costs were $1.7 million at September 30, 2019. Revenue Recognition The Company accounts for revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers , which was adopted on January 1, 2019, using the modified retrospective method. The adoption of this guidance had no cumulative adjustment to the Company’s consolidated financial statements as of the adoption date. Under ASC Topic 606, an entity recognizes revenue when its customer obtains control of the promised good, in an amount that reflects the consideration that the entity expects to be entitled in exchange for those goods. The Company performs the following five steps to recognize revenue under ASC Topic 606: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract, and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only recognizes revenue when it is probable that it will collect the consideration to which it is entitled in exchange for the goods or services that will be transferred to the customer. A significant portion of the Company’s revenue is generated from sales representatives or from consigned inventory maintained at hospitals. Revenue from the sale of consigned products is recognized when control is transferred to the customer, which occurs at the time the product is used in a surgical procedure. For product that is not held on consignment, the Company recognizes revenue when control transfers to the customer which occurs at the time the product is shipped or delivered. For all of the Company’s contracts, the only identified performance obligation is providing the product to the customer. Payment terms with customers do not exceed one year and, therefore, the Company does not account for a financing component in its arrangements. The Company expenses incremental costs of obtaining a contract with a customer (e.g., sales commissions) when incurred as the period of benefit is less than one year. Fees charged to customers for shipping are recognized as revenue. Prior to the adoption of ASC Topic 606, revenue was recognized when persuasive evidence of an arrangement existed, the price was fixed or determinable, delivery had occurred, and there was a reasonable assurance of collection of the sales proceeds. Revenue for products sold to a customer was recognized when the product was shipped to the customer, at which time title passed to the customer. In the case of consigned inventory, revenue was recognized when the product was utilized in a surgical procedure. Fair value of financial instruments Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction among market participants. Fair value determination in accordance with applicable accounting guidance requires that a number of significant judgments are made. Additionally, fair value is used on a nonrecurring basis to evaluate assets for impairment or as required for disclosure purposes by applicable accounting guidance on disclosures about fair value of financial instruments. Depending on the nature of the assets and liabilities, various valuation techniques and assumptions are used when estimating fair value. The carrying amounts of certain of the Company’s financial instruments, including cash and cash equivalents, accounts receivable, prepaid expenses and other assets, and accounts payable are shown at cost, which approximates fair value due to the short‑term nature of these instruments. Due to the related‑party relationship of our credit facility (the “OrbiMed Credit Facility”) with OrbiMed Royalty Opportunities IP, LP (“OrbiMed”) (Note 5), it is impractical to determine the fair value of the debt. Items measured at fair value on a recurring basis include the Company’s preferred stock warrants. The warrants are carried at their estimated fair value. The Company follows the provisions of FASB ASC Topic 820, Fair Value Measurement , for financial assets and liabilities measured on a recurring basis. The guidance requires fair value measurements be classified and disclosed in one of the following three categories: · Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. · Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liabilities. · Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). The following fair value hierarchy table presents information about each major category of the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands): Fair value measurement at reporting date using Quoted prices in active markets Significant other Significant for identical observable unobservable assets inputs inputs (Level 1) (Level 2) (Level 3) September 30, 2019 Assets: Cash equivalents – money market fund $ 9,470 $ — $ — Liability: Warrant liability $ — $ — $ 1,644 December 31, 2018 Assets: Cash equivalents – money market fund $ 16,002 $ — $ — Liability: Warrant liability $ — $ — $ 1,640 A rollforward of the warrant liability (Level 3 measurement) is as follows: January 1, 2019 $ 1,640 Change in fair value of warrants 4 September 30, 2019 $ 1,644 The fair value of the warrants at September 30, 2019 was determined using the Black‑Scholes option pricing model with the following assumptions: Convertible MidCap Credit promissory Facility notes Notes payable Expected dividend yield — — — Expected volatility 57.46 % 57.40 % 57.19 % Risk‑free interest rate 1.65 % 1.62 % 1.62 % Remaining contractual term in years 8.6 7.3 7.5 Net loss per share Basic and diluted net loss per common share is determined by dividing net loss attributable to common stockholders by the weighted‑average shares of common stock outstanding during the reporting period. The Company’s outstanding redeemable convertible preferred stock contractually entitles the holders of such shares to participate in distributions but contractually does not require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders since dilutive shares are not assumed to have been issued if their effect is antidilutive. Therefore, the weighted‑average shares used to calculate both basic and diluted loss per share are the same. The following potentially dilutive securities have been excluded from the computation of diluted weighted‑average shares outstanding for the periods presented, as they would be antidilutive. September 30, 2019 2018 Series A redeemable convertible preferred stock 911,336 911,336 Series B redeemable convertible preferred stock 3,060,302 2,459,245 Stock options (including shares subject to repurchase) 552,605 472,450 Series B redeemable convertible preferred stock warrants 88,556 88,556 Total 4,612,799 3,931,587 Amounts in the above table reflect the common stock equivalents of the noted instrument. Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases , which requires a lessee to record a right-of-use asset and a corresponding lease liability on the balance sheet for all leases with terms longer than 12 months. A modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial application. An entity may choose to use either (1) its effective date or (2) the beginning of the earliest comparative period presented in the consolidated financial statements as its date of initial application. If an entity chooses the second option, the transition requirements for existing leases also apply to leases entered into between the date of initial application and the effective date. The standard is effective for the Company beginning January 1, 2021, with early adoption permitted. The Company plans to adopt this standard on January 1, 2021 and is currently evaluating the expected impact that the standard could have on its consolidated financial statements and related disclosures. In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718) Improvements to Nonemployee Share-Based Payment Accounting . The amendments in this update expand the scope of Topic 718 to include stock-based payment transactions for acquiring goods and services from nonemployees. Under this ASU, an entity should apply the requirements of Topic 718 to nonemployee awards except for specific guidance on inputs to an option pricing model and the attribution of costs (i.e., the period of time over which stock-based payment awards vest and the pattern of cost recognition over that period). The guidance is effective for the Company beginning January 1, 2020, with early adoption permitted. The Company is currently evaluating the effect that this guidance will have on its consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU No. 2018-13, Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurements, which changes the fair value measurement disclosure requirements of ASC Topic 820. The goal of the ASU is to improve the effectiveness of ASC Topic 820's disclosure requirements. The standard is effective for the Company beginning January 1, 2020. The Company is currently evaluating the potential impact of the adoption of this standard on its related disclosures.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2019
Accrued Expenses
Accrued Expenses	(4) Accrued Expenses Accrued expenses consisted of the following (in thousands): September 30, December 31, 2019 2018 Compensation and related benefits $ 1,755 $ 1,760 Interest — 42 Professional fees 1,207 552 Accrued milestone payments — 2,500 Research and development expenses 35 133 Other 603 166 $ 3,600 $ 5,153

Long-term Debt

Long-term Debt	9 Months Ended
	Sep. 30, 2019
Long-term Debt
Long-term Debt	(5) Long‑term Debt Long‑term debt consisted of the following (in thousands): September 30, December 31, 2019 2018 OrbiMed Term Loan (related party) $ 30,000 $ 30,000 End of term charge 3,000 3,000 Unamortized issuance costs (2,892) (3,267) Long‑term debt $ 30,108 $ 29,733 OrbiMed Term Loan (Related Party) Pursuant to the OrbiMed Credit Facility, which consists of up to $35.0 million in term loans (the “OrbiMed Term Loans”) the Company provided a first priority security interest in all existing and future acquired assets, excluding intellectual property and certain other assets, owned by the Company. The OrbiMed Term Loans consist of two tranches, a $30.0 million Tranche 1 (“Tranche 1”) and a $5.0 million Tranche 2 (“Tranche 2”). In November 2018, the Company borrowed $30.0 million of Tranche 1 and used a portion of the proceeds to repay the MidCap Credit Facility and will use the remaining proceeds to fund operations and capital expenditures. The Company is eligible to borrow Tranche 2 until December 31, 2019, as the Company’s consolidated revenue on a trailing six‑month basis equaled or exceeded $7.5 million. The OrbiMed Credit Facility contains a negative pledge on intellectual property owned by the Company. The OrbiMed Credit Facility also contains customary indemnification obligations and customary events of default, including, among other things, (i) nonpayment, (ii) breach of warranty, (iii) nonperformance of covenants and obligations, (iv) default on other indebtedness, (v) judgments, (iv) change of control, (vii) bankruptcy and insolvency, (viii) impairment of security, (ix) key permit events, (x) key person event, (xi) regulatory matters, (xii) and key contracts. In addition, the Company must maintain a minimum cash balance of $2.0 million. In the event of default under the OrbiMed Credit Facility, the Company would be required to pay interest on principal and all other due and unpaid obligations at the current rate in effect plus 3%. The OrbiMed Term Loans mature on November 16, 2023 and bear interest at a rate equal to 7.75% plus the greater of one‑month LIBOR or 2.0%. At September 30, 2019, the interest rate was 9.86%. The Company is required to make 60 monthly interest payments beginning on November 30, 2018, with the entire principal payment due at maturity. The OrbiMed Term Loans have a prepayment penalty equal to 10.0% of the prepaid principal amount prior to the second anniversary of the Term Loans, 5.0% of the prepaid principal amount after the second anniversary but prior to the third anniversary and 2.5% of the prepaid principal amount after the third anniversary. The Company is also required to pay an exit fee at the time of maturity or prepayment event equal to 10.0% of all principal borrowings (the “End of Term Charge”) and an administration fee equal to $10,000 on the last day of each quarter until all obligations have been paid in full. In conjunction with the closing of the OrbiMed Term Loans, the Company incurred $3.3 million of third‑party and lender fees, which along with the end of term charge were recorded as debt issuance costs, and are being recognized as interest expense over the term of the loan using the effective‑interest method. Interest expense associated with the OrbiMed Credit Facility recorded during the nine months ended September 30, 2019 was $2.7 million, $0.4 million was related to the amortization of debt issuance costs.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock and Stockholders’ Deficit	9 Months Ended
	Sep. 30, 2019
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Redeemable Convertible Preferred Stock and Stockholders’ Deficit	(6) Redeemable Convertible Preferred Stock and Stockholders’ Deficit Preferred Stock During the nine months ended September 30, 2019, the Company entered into various stock purchase agreements with new and existing investors pursuant to which the Company sold an aggregate 12,527,956 shares of the Company’s Series B redeemable convertible preferred stock (“Series B”) at $1.16 per share for aggregate gross proceeds of $14.5 million. Transaction fees of $0.1 million were recorded as a reduction of the carrying value of the Series B. Warrants The Company had the following warrants outstanding to purchase Series B at September 30, 2019: Exercise Expiration Outstanding price dates Preferred stock warrants issued to MidCap 206,897 $ 1.16 Preferred stock warrants issued to note payable holders 387,932 $ 1.16 Preferred stock warrants issued to convertible promissory note holders 1,591,864 $ 1.16 2,186,693 The Company accounts for its warrants to purchase shares of redeemable convertible preferred stock as liabilities as they are exercisable for a redeemable instrument. The Company adjusted the liability for changes in fair value until the consummation of the Company’s IPO. In connection with the IPO, the Company’s outstanding shares of preferred stock including accrued dividends payable were converted into an aggregate of 6,708,649 shares of common stock, and the Company’s outstanding warrants to purchase shares of preferred stock were automatically converted into warrants to purchase an aggregate of 88,556 shares of common stock.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2019
Stock-Based Compensation
Stock-Based Compensation	(7) Stock‑Based Compensation In 2012, the Company adopted the 2012 Stock Incentive Plan (the “Plan”), which was later amended and restated, pursuant to which 30,738 shares were available for future issuances as of September 30, 2019. The Plan provides for the grant of incentive stock options, nonqualified stock options, restricted stock awards, and/or stock appreciation rights to employees, directors, and other persons, as determined by the Company’s board of directors. The Company’s stock options vest based on the terms in each award agreement and generally vest over four years and have a term of 10 years. The Company estimates forfeitures that it expects will occur and adjusts expense for actual forfeitures in the periods they occur. The Company measures employee and nonemployee stock‑based awards at grant‑date fair value and records compensation expense on a straight‑line basis over the vesting period of the award. The Company recorded stock‑based compensation expense in the following expense categories of its accompanying consolidated statements of operations (in thousands): Three months ended Nine months ended September 30, 2019 September 30, 2019 2019 2018 2019 2018 Sales and marketing $ 31 $ 21 $ 61 $ 51 General and administrative 29 32 101 90 Research and development 4 8 21 28 Total stock‑based compensation $ 64 $ 61 $ 183 $ 169 The following table summarizes stock option activity for the Plan: Weighted average Weighted remaining Number of average exercise contractual term shares price per share (years) Outstanding at January 1, 2019 489,222 $ 5.84 Granted 86,485 7.54 Exercised (1,892) 5.93 Early exercised (471) 5.93 Canceled/forfeited (21,614) 6.98 Outstanding at September 30, 2019 551,730 6.07 7.29 Vested and expected to vest at September 30, 2019 551,730 $ 6.07 7.29 Exercisable at September 30, 2019 461,414 $ 5.47 5.63 The 2012 Plan provides the holders of stock options an election to early exercise prior to vesting. The Company has the right, but not the obligation, to repurchase early exercised options without transferring any appreciation to the employee if the employee terminates employment before the end of the original vesting period. The repurchase price is the lesser of the original exercise price or the then fair value of the common stock. At September 30, 2019, $5,000 of proceeds from early exercised options are recognized as a current liability in accrued expenses in the accompanying balance sheet. The following table summarizes activity relating to early exercise of stock options: Number of shares Unvested balance at January 1, 2019 912 Early exercised 471 Vested (508) Unvested balance at September 30, 2019 875 The weighted average grant‑date fair value per share of options granted was $4.55 during the nine months ended September 30, 2019. The aggregate intrinsic value of options exercised was nominal for the nine months ended September 30, 2019. As of September 30, 2019, the total unrecognized compensation expense related to unvested employee and nonemployee stock option awards was $0.4 million, which is expected to be recognized in expense over a weighted‑average period of approximately 2.61 years. In connection with the IPO, the Company adopted the TELA Bio, Inc. 2019 Equity Incentive Plan, under which 1,215,067 shares were reserved for issuance. Estimating Fair Value of Stock Options The fair value of each grant of stock options was determined by the Company using the methods and assumptions discussed below. Certain of these inputs are subjective and generally requires judgment to determine. Expected term – The expected term of stock options represents the weighted average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term as provided by the SEC. The simplified method calculates the expected term as the average time to vesting and the contractual life of the options. Expected volatility – Due to the Company’s limited operating history and lack of company‑specific historical or implied volatility, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available. Risk‑free interest rate – The risk‑free rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options. Expected dividend – The Company has not paid and does not intend to pay dividends. The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below: Nine months ended September 30, 2019 Expected dividend yield — Expected volatility 55.95 % Risk‑free interest rate 2.12 % Expected term 6.25 Years

Related-Party Transactions

Related-Party Transactions	9 Months Ended
	Sep. 30, 2019
Related-Party Transactions
Related-Party Transactions	(8) Related‑Party Transactions On November 16, 2018, the Company entered into a senior secured term loan facility with OrbiMed, an entity affiliated with an owner of a material amount of the Company’s outstanding voting securities. The terms of the debt and related components are further described in more detail in Note 5.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Summary of Significant Accounting Policies
Interim Financial Statements	Interim Financial Statements The accompanying unaudited interim consolidated financial statements have been prepared from the books and records of the Company in accordance with GAAP for interim financial information and Rule 10‑01 of Regulation S‑X promulgated by the SEC, which permits reduced disclosures for interim periods. All adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the accompanying consolidated balance sheets and statements of operations and comprehensive loss, redeemable convertible preferred stock and stockholders’ deficit, and cash flows have been made. Although these interim consolidated financial statements do not include all of the information and footnotes required for complete annual consolidated financial statements, management believes the disclosures are adequate to make the information presented not misleading. Unaudited interim results of operations and cash flows are not necessarily indicative of the results that may be expected for the full year. Unaudited interim consolidated financial statements and footnotes should be read in conjunction with the audited consolidated financial statements and footnotes included in the Prospectus.
Reverse Stock Split	Reverse Stock Split The Company effected a one-for-24.69 reverse stock split of its common stock on October 28, 2019. The reverse stock split combined approximately 25 shares of the Company's issued and outstanding common stock into one share of common stock and correspondingly adjusted the conversion price of its redeemable convertible preferred stock. No fractional shares were issued in connection with the reverse stock split. Any fractional share resulting from the reverse stock split was rounded down to the nearest whole share, and in lieu of any fractional shares, the Company will pay in cash to the holders of such fractional shares an amount equal to the fair value, as determined by the board of directors, of such fractional shares. All common stock, per share and related information presented in the unaudited interim consolidated financial statements and accompanying notes have been retroactively adjusted to reflect the reverse stock split.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant judgments are employed in estimates used to determine the fair value of redeemable convertible preferred stock, preferred stock warrant liability and stock‑based awards issued, and recoverability of the carrying value of the Company’s inventory. As future events and their effects cannot be determined with precision, actual results may differ significantly from these estimates.
Deferred Offering Costs	Deferred Offering Costs The Company capitalizes certain legal, accounting, and other third‑party fees that are directly associated with in‑process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs will be recorded as a reduction of additional paid‑in capital generated as a result of the offering. Should the equity financing no longer be considered probable of being consummated, all deferred offering costs would be charged to operating expenses in the consolidated statement of operations. Deferred offering costs were $1.7 million at September 30, 2019.
Revenue Recognition	Revenue Recognition The Company accounts for revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers , which was adopted on January 1, 2019, using the modified retrospective method. The adoption of this guidance had no cumulative adjustment to the Company’s consolidated financial statements as of the adoption date. Under ASC Topic 606, an entity recognizes revenue when its customer obtains control of the promised good, in an amount that reflects the consideration that the entity expects to be entitled in exchange for those goods. The Company performs the following five steps to recognize revenue under ASC Topic 606: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract, and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only recognizes revenue when it is probable that it will collect the consideration to which it is entitled in exchange for the goods or services that will be transferred to the customer. A significant portion of the Company’s revenue is generated from sales representatives or from consigned inventory maintained at hospitals. Revenue from the sale of consigned products is recognized when control is transferred to the customer, which occurs at the time the product is used in a surgical procedure. For product that is not held on consignment, the Company recognizes revenue when control transfers to the customer which occurs at the time the product is shipped or delivered. For all of the Company’s contracts, the only identified performance obligation is providing the product to the customer. Payment terms with customers do not exceed one year and, therefore, the Company does not account for a financing component in its arrangements. The Company expenses incremental costs of obtaining a contract with a customer (e.g., sales commissions) when incurred as the period of benefit is less than one year. Fees charged to customers for shipping are recognized as revenue. Prior to the adoption of ASC Topic 606, revenue was recognized when persuasive evidence of an arrangement existed, the price was fixed or determinable, delivery had occurred, and there was a reasonable assurance of collection of the sales proceeds. Revenue for products sold to a customer was recognized when the product was shipped to the customer, at which time title passed to the customer. In the case of consigned inventory, revenue was recognized when the product was utilized in a surgical procedure.
Fair value of financial instruments	Fair value of financial instruments Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction among market participants. Fair value determination in accordance with applicable accounting guidance requires that a number of significant judgments are made. Additionally, fair value is used on a nonrecurring basis to evaluate assets for impairment or as required for disclosure purposes by applicable accounting guidance on disclosures about fair value of financial instruments. Depending on the nature of the assets and liabilities, various valuation techniques and assumptions are used when estimating fair value. The carrying amounts of certain of the Company’s financial instruments, including cash and cash equivalents, accounts receivable, prepaid expenses and other assets, and accounts payable are shown at cost, which approximates fair value due to the short‑term nature of these instruments. Due to the related‑party relationship of our credit facility (the “OrbiMed Credit Facility”) with OrbiMed Royalty Opportunities IP, LP (“OrbiMed”) (Note 5), it is impractical to determine the fair value of the debt. Items measured at fair value on a recurring basis include the Company’s preferred stock warrants. The warrants are carried at their estimated fair value. The Company follows the provisions of FASB ASC Topic 820, Fair Value Measurement , for financial assets and liabilities measured on a recurring basis. The guidance requires fair value measurements be classified and disclosed in one of the following three categories: · Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. · Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liabilities. · Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). The following fair value hierarchy table presents information about each major category of the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands): Fair value measurement at reporting date using Quoted prices in active markets Significant other Significant for identical observable unobservable assets inputs inputs (Level 1) (Level 2) (Level 3) September 30, 2019 Assets: Cash equivalents – money market fund $ 9,470 $ — $ — Liability: Warrant liability $ — $ — $ 1,644 December 31, 2018 Assets: Cash equivalents – money market fund $ 16,002 $ — $ — Liability: Warrant liability $ — $ — $ 1,640 A rollforward of the warrant liability (Level 3 measurement) is as follows: January 1, 2019 $ 1,640 Change in fair value of warrants 4 September 30, 2019 $ 1,644 The fair value of the warrants at September 30, 2019 was determined using the Black‑Scholes option pricing model with the following assumptions: Convertible MidCap Credit promissory Facility notes Notes payable Expected dividend yield — — — Expected volatility 57.46 % 57.40 % 57.19 % Risk‑free interest rate 1.65 % 1.62 % 1.62 % Remaining contractual term in years 8.6 7.3 7.5
Net loss per share	Net loss per share Basic and diluted net loss per common share is determined by dividing net loss attributable to common stockholders by the weighted‑average shares of common stock outstanding during the reporting period. The Company’s outstanding redeemable convertible preferred stock contractually entitles the holders of such shares to participate in distributions but contractually does not require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders since dilutive shares are not assumed to have been issued if their effect is antidilutive. Therefore, the weighted‑average shares used to calculate both basic and diluted loss per share are the same. The following potentially dilutive securities have been excluded from the computation of diluted weighted‑average shares outstanding for the periods presented, as they would be antidilutive. September 30, 2019 2018 Series A redeemable convertible preferred stock 911,336 911,336 Series B redeemable convertible preferred stock 3,060,302 2,459,245 Stock options (including shares subject to repurchase) 552,605 472,450 Series B redeemable convertible preferred stock warrants 88,556 88,556 Total 4,612,799 3,931,587 Amounts in the above table reflect the common stock equivalents of the noted instrument.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Summary of Significant Accounting Policies
Schedule of fair value of assets and liabilities measured on recurring basis	The following fair value hierarchy table presents information about each major category of the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands): Fair value measurement at reporting date using Quoted prices in active markets Significant other Significant for identical observable unobservable assets inputs inputs (Level 1) (Level 2) (Level 3) September 30, 2019 Assets: Cash equivalents – money market fund $ 9,470 $ — $ — Liability: Warrant liability $ — $ — $ 1,644 December 31, 2018 Assets: Cash equivalents – money market fund $ 16,002 $ — $ — Liability: Warrant liability $ — $ — $ 1,640
Schedule of warrant liability	January 1, 2019 $ 1,640 Change in fair value of warrants 4 September 30, 2019 $ 1,644
Schedule of fair value of warrants	Convertible MidCap Credit promissory Facility notes Notes payable Expected dividend yield — — — Expected volatility 57.46 % 57.40 % 57.19 % Risk‑free interest rate 1.65 % 1.62 % 1.62 % Remaining contractual term in years 8.6 7.3 7.5
Schedule of dilutive securities excluded	September 30, 2019 2018 Series A redeemable convertible preferred stock 911,336 911,336 Series B redeemable convertible preferred stock 3,060,302 2,459,245 Stock options (including shares subject to repurchase) 552,605 472,450 Series B redeemable convertible preferred stock warrants 88,556 88,556 Total 4,612,799 3,931,587

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2019
Accrued Expenses
Accrued Expenses	Accrued expenses consisted of the following (in thousands): September 30, December 31, 2019 2018 Compensation and related benefits $ 1,755 $ 1,760 Interest — 42 Professional fees 1,207 552 Accrued milestone payments — 2,500 Research and development expenses 35 133 Other 603 166 $ 3,600 $ 5,153

Long-term Debt (Table)

Long-term Debt (Table)	9 Months Ended
	Sep. 30, 2019
Long-term Debt
Schedule of long term debt	Long‑term debt consisted of the following (in thousands): September 30, December 31, 2019 2018 OrbiMed Term Loan (related party) $ 30,000 $ 30,000 End of term charge 3,000 3,000 Unamortized issuance costs (2,892) (3,267) Long‑term debt $ 30,108 $ 29,733

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock and Stockholders’ Deficit (Tables)	9 Months Ended
	Sep. 30, 2019
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Schedule of Redeemable Convertible Preferred Stock and Stockholders’ Deficit	Exercise Expiration Outstanding price dates Preferred stock warrants issued to MidCap 206,897 $ 1.16 Preferred stock warrants issued to note payable holders 387,932 $ 1.16 Preferred stock warrants issued to convertible promissory note holders 1,591,864 $ 1.16 2,186,693

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Stock-Based Compensation
Schedule of stock based compensation expense categories in statement of operations	The Company recorded stock‑based compensation expense in the following expense categories of its accompanying consolidated statements of operations (in thousands): Three months ended Nine months ended September 30, 2019 September 30, 2019 2019 2018 2019 2018 Sales and marketing $ 31 $ 21 $ 61 $ 51 General and administrative 29 32 101 90 Research and development 4 8 21 28 Total stock‑based compensation $ 64 $ 61 $ 183 $ 169
Schedule of stock option activity	Weighted average Weighted remaining Number of average exercise contractual term shares price per share (years) Outstanding at January 1, 2019 489,222 $ 5.84 Granted 86,485 7.54 Exercised (1,892) 5.93 Early exercised (471) 5.93 Canceled/forfeited (21,614) 6.98 Outstanding at September 30, 2019 551,730 6.07 7.29 Vested and expected to vest at September 30, 2019 551,730 $ 6.07 7.29 Exercisable at September 30, 2019 461,414 $ 5.47 5.63
Schedule of activity relating to early exercise of stock options	Number of shares Unvested balance at January 1, 2019 912 Early exercised 471 Vested (508) Unvested balance at September 30, 2019 875
Schedule of weighted average assumptions	Nine months ended September 30, 2019 Expected dividend yield — Expected volatility 55.95 % Risk‑free interest rate 2.12 % Expected term 6.25 Years

Risks and Liquidity (Details)

Risks and Liquidity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	Nov. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Unusual Risk or Uncertainty [Line Items]
Accumulated deficit		$ (160,398)	$ (137,860)
Received net proceeds of after deducting underwriting discounts, commissions and other offering expenses	$ 50,700
IPO
Unusual Risk or Uncertainty [Line Items]
Number of shares issued and sold	4,398,700
Public offering price per share	$ 13
Over-Allotment Option
Unusual Risk or Uncertainty [Line Items]
Number of shares issued and sold	398,700

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Reverse Stock Split (Details)	Oct. 28, 2019shares
Summary of Significant Accounting Policies
Reverse stock split ratio	0.04
Number of shares are combined into one share	25
Number of fractional shares issued	0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Deferred offering costs (Details) $ in Thousands	Sep. 30, 2019USD ($)
Summary of Significant Accounting Policies
Deferred Offering Costs	$ 1,731

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Fair value of financial instruments (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Level 1 | Money market funds
Fair value of financial instruments
Cash equivalents	$ 9,470	$ 16,002
Level 3 | Warrants
Fair value of financial instruments
Warrant liability	$ 1,644	$ 1,640

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Warrant liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Summary of Significant Accounting Policies
Beginning balance			$ 1,640
Change in fair value of warrants	$ (34)	$ (17)	4	$ (191)
Ending balance	$ 1,644		$ 1,644

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Fair value of warrant (Details)	Sep. 30, 2019
MidCap Credit Facility
Fair value of the warrants
Remaining contractual term in years	8 years 7 months 6 days
Convertible promissory notes
Fair value of the warrants
Remaining contractual term in years	7 years 3 months 18 days
Notes payable
Fair value of the warrants
Remaining contractual term in years	7 years 6 months
Expected volatility | MidCap Credit Facility
Fair value of the warrants
Fair value of warrants	0.5746
Expected volatility | Convertible promissory notes
Fair value of the warrants
Fair value of warrants	0.5740
Expected volatility | Notes payable
Fair value of the warrants
Fair value of warrants	0.5719
Risk-free interest rate | MidCap Credit Facility
Fair value of the warrants
Fair value of warrants	0.0165
Risk-free interest rate | Convertible promissory notes
Fair value of the warrants
Fair value of warrants	0.0162
Risk-free interest rate | Notes payable
Fair value of the warrants
Fair value of warrants	0.0162

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Potentially dilutive securities (Details) - shares	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	4,612,799	3,931,587
Stock Option
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	552,605	472,450
Warrants
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	88,556	88,556
Series A
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	911,336	911,336
Series B
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	3,060,302	2,459,245

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accrued Expenses
Compensation and related benefits	$ 1,755	$ 1,760
Interest		42
Professional fees	1,207	552
Accrued milestone payments		2,500
Research and development expenses	35	133
Other	603	166
Accrued Liabilities, Current, Total	$ 3,600	$ 5,153

Long-term Debt (Details)

Long-term Debt (Details) - OrbiMed Term Loans (related party) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Long-term Debt
OrbiMed Term Loan (related party)	$ 30,000	$ 30,000
End of term charge	3,000	3,000
Unamortized issuance costs	(2,892)	(3,267)
Long-term debt	$ 30,108	$ 29,733

Long-term Debt - Narratives (De

Long-term Debt - Narratives (Details)	9 Months Ended
	Sep. 30, 2019USD ($)tranche	Nov. 30, 2018USD ($)
OrbiMed Term Loans (related party)
Long-term Debt
Number of Tranches | tranche	2
Minimum Cash Balance	$ 2,000,000
Interest due to unpaid obligation	3.00%
Interest Rate (as a percent)	9.86%	7.75%
Number of Installment	60 months
Exit fee (as a percent)	10.00%
Administration Fees	$ 10,000
Debt issuance costs	3,300,000
Interest Expenses	2,700,000
Amortization of debt issuance costs	$ 400,000
OrbiMed Term Loans (related party) | Prior to second anniversary
Long-term Debt
Percentage of prepayment penalty on prepaid principal amount	10.00%
OrbiMed Term Loans (related party) | After second anniversary but prior to third anniversary
Long-term Debt
Percentage of prepayment penalty on prepaid principal amount	5.00%
OrbiMed Term Loans (related party) | After third anniversary
Long-term Debt
Percentage of prepayment penalty on prepaid principal amount	2.50%
OrbiMed Term Loans (related party) | One month LIBOR
Long-term Debt
Variable Interest Rate (as a percent)	2.00%
OrbiMed Term Loans (related party) | Minimum
Long-term Debt
Consolidated Revenue	$ 7,500,000
OrbiMed Term Loans (related party) | Maximum
Long-term Debt
Debt Amount	35,000,000
Tranche One
Long-term Debt
Debt Amount	30,000,000	$ 30,000,000
Tranche Two
Long-term Debt
Debt Amount	$ 5,000,000

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Stock and Stockholders’ Deficit (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	9 Months Ended
	Nov. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Issue price		$ 0.001	$ 0.001
Convertible Preferred Stock | IPO
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Aggregate of common stock	6,708,649
Warrants | IPO
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Aggregate of common stock	88,556
Series B
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Shares issued (in shares)		12,527,956
Issue price		$ 1.16
Gross proceeds		$ 14.5
Transaction Fee		$ 0.1

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Stock and Stockholders’ Deficit - Warrants outstanding (Details)	Sep. 30, 2019$ / sharesshares
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Warrants outstanding	2,186,693
MidCap Credit Facility | Warrants
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Warrants outstanding	206,897
warrants exercise price | $ / shares	$ 1.16
Notes payable | Warrants
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Warrants outstanding	387,932
warrants exercise price | $ / shares	$ 1.16
Convertible promissory notes | Warrants
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Warrants outstanding	1,591,864
warrants exercise price | $ / shares	$ 1.16

Stock-Based Compensation - Expe

Stock-Based Compensation - Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stock-Based Compensation
Total stock-based compensation	$ 64	$ 61	$ 183	$ 169
Sales and marketing
Stock-Based Compensation
Total stock-based compensation	31	21	61	51
General and administrative
Stock-Based Compensation
Total stock-based compensation	29	32	101	90
Research and development
Stock-Based Compensation
Total stock-based compensation	$ 4	$ 8	$ 21	$ 28

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - $ / shares	9 Months Ended
	Sep. 30, 2019
Number of shares
Balance at beginning of period	489,222
Granted	86,485
Exercised	(1,892)
Early exercised	(471)
Canceled/forfeited	(21,614)
Balance at end of period	551,730
Vested and expected to vest at end of period	551,730
Exercisable at end of period	461,414
Weighted average exercise price per share
Balance at beginning of period (in dollars per share)	$ 5.84
Granted ( in dollars per share)	7.54
Exercised (in dollars per share)	5.93
Early exercised (in dollars per share)	5.93
Canceled/forfeited (in dollars per share)	6.98
Balance at end of period (in dollars per share)	6.07
Vested and expected to vest at end of period (in dollars per share)	6.07
Exercisable at end of period (in dollars per share)	$ 5.47
Weighted average remaining contractual term
Weighted average remaining contractual term, outstanding	7 years 3 months 15 days
Weighted average remaining contractual term, Vested and expected to vest	7 years 3 months 15 days
Weighted average remaining contractual term, Exercisable	5 years 7 months 17 days

Stock-Based Compensation - Earl

Stock-Based Compensation - Early Exercise Of Stock Options (Details)	9 Months Ended
	Sep. 30, 2019shares
Stock-Based Compensation
Unvested balance at beginning of period	912
Early exercised	471
Vested	(508)
Unvested balance at end of period	875

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted average assumptions (Details)	9 Months Ended
	Sep. 30, 2019
Stock-Based Compensation
Expected volatility	55.95%
Risk-free interest rate	2.12%
Expected term	6 years 3 months

Stock-Based Compensation - Narr

Stock-Based Compensation - Narratives (Details)	9 Months Ended
	Sep. 30, 2019USD ($)$ / sharesshares
2012 Stock Incentive Plan
Stock-Based Compensation
Shares available for future issuance | shares	30,738
Vesting Period	4 years
Vesting Term	P10Y
Weighted Average Grant Date Fair Value per share | $ / shares	$ 4.55
Unrecognized compensation expense | $	$ 400,000
Weighted Average period for recognition of unrecognized expenses	2 years 7 months 10 days
2012 Stock Incentive Plan | Current Liability
Stock-Based Compensation
Proceeds from early exercise of option | $	$ 5,000
2019 Equity Incentive Plan
Stock-Based Compensation
Shares available for future issuance | shares	1,215,067