TELA Bio (TELA) 10-K 30 Mar 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 20, 2020	Jun. 30, 2019
Document and Entity Information
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Entity Registrant Name	TELA Bio, Inc.
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Well Known Seasoned Issuer	No
Entity Voluntary Filers	No
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 Public Float			$ 0
Entity Common Stock, Shares Outstanding		11,407,243
Entity Central Index Key	0001561921
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 45,302	$ 17,278
Short-term investments	9,285
Accounts receivable, net	2,836	1,298
Inventory	4,603	4,348
Prepaid expenses and other assets	2,308	330
Total current assets	64,334	23,254
Property and equipment, net	677	758
Intangible assets, net	2,911	3,215
Total assets	67,922	27,227
Current liabilities:
Accounts payable	3,171	3,421
Accrued expenses	3,533	5,153
Other current liabilities	9	985
Total current liabilities	6,713	9,559
Long-term debt with related party	30,243	29,733
Preferred stock warrant liability		1,640
Other long-term liabilities	4	5
Total liabilities	36,960	40,937
Redeemable convertible preferred stock		124,150
Stockholders' equity (deficit):
Preferred stock; $0.001 par value: 10,000,000 shares authorized; no shares issued and outstanding
Common stock; $0.001 par value: 200,000,000 shares authorized; 11,406,976 and 296,624 shares issued and 11,406,221 and 295,712 shares outstanding at December 31, 2019 and 2018, respectively	11
Additional paid‑in capital	198,829
Accumulated other comprehensive loss	(19)
Accumulated deficit	(167,859)	(137,860)
Total stockholders' equity (deficit)	30,962	(137,860)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	$ 67,922	27,227
Series A Redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock		33,112
Series B Redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock		$ 91,038

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Preferred stock, Par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, Par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	11,406,976	296,629
Common stock, shares outstanding (in shares)	11,406,221	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)	0	22,501,174
Preferred stock, shares outstanding (in shares)	0	22,501,174
Series B Redeemable convertible preferred stock
Preferred stock, shares authorized (in shares)	82,891,619	82,891,619
Preferred stock, shares issued (in shares)	0	63,032,500
Preferred stock, shares outstanding (in shares)	0	63,032,500

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements of Operations and Comprehensive Loss
Revenue	$ 15,446	$ 8,274	$ 4,245
Cost of revenue (excluding amortization of intangible assets)	5,870	4,547	1,713
Amortization of intangible assets	304	785
Gross profit	9,272	2,942	2,532
Operating expenses:
Sales and marketing	18,060	13,646	8,712
General and administrative	6,223	4,899	4,958
Research and development	4,151	4,339	5,786
Gain on litigation settlement		(2,160)
Total operating expenses	28,434	20,724	19,456
Loss from operations	(19,162)	(17,782)	(16,924)
Other (expense) income:
Interest expense	(3,609)	(1,802)	(4,558)
Loss on extinguishment of debt		(1,822)
Change in fair value of preferred stock warrant liability	(5)	244	54
Other income	351	70	94
Total other (expense) income	(3,263)	(3,310)	(4,410)
Net loss	(22,425)	(21,092)	(21,334)
Accretion of redeemable convertible preferred stock to redemption value	(7,783)	(8,823)	(5,893)
Net loss attributable to common stockholders	$ (30,208)	$ (29,915)	$ (27,227)
Net loss per common share, basic and diluted	$ (17.10)	$ (101.41)	$ (93.26)
Weighted average common shares outstanding, basic and diluted	1,766,412	294,988	291,963
Comprehensive loss:
Foreign currency translation adjustment	$ (15)
Unrealized loss on short-term investments	(4)
Comprehensive loss	$ (22,444)	$ (21,092)	$ (21,334)

Consolidated Statements of Rede

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Series A Redeemable convertible preferred stock	Series B Redeemable convertible preferred stock	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit	Total
Balance at Beginning of period at Dec. 31, 2016	$ 28,811	$ 52,452
Balance at Beginning of period (in shares) at Dec. 31, 2016	22,501,174	39,543,222
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series B redeemable convertible preferred stock upon conversion of promissory notes (in shares)		6,951,175
Issuance of Series B redeemable convertible preferred stock upon conversion of promissory notes		$ 9,462
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $269, $206, $165 (in shares)		12,931,034
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $269, $206, $165		$ 14,731
Accretion of redeemable convertible preferred stock to redemption value	$ 2,129	3,764
Balance at Ending period at Dec. 31, 2017	$ 30,940	$ 80,409
Balance at Ending period (in shares) at Dec. 31, 2017	22,501,174	59,425,431
Balance at Beginning of period at Dec. 31, 2016						$ (81,174)	$ (81,174)
Balance at Beginning of period (in shares) at Dec. 31, 2016			286,432
Increase (Decrease) in Temporary Equity [Roll Forward]
Vesting of common stock previously subject to repurchase (in shares)			6,955
Vesting of common stock previously subject to repurchase				$ 31			$ 31
Exercise of stock options (in shares)			404				404
Exercise of stock options				2			$ 2
Stock-based compensation expense				197			197
Accretion of redeemable convertible preferred stock to redemption value				(230)		(5,663)	(5,893)
Net loss						(21,334)	(21,334)
Balance at Ending period at Dec. 31, 2017						(108,171)	(108,171)
Balance at Ending period (in shares) at Dec. 31, 2017			293,791
Increase (Decrease) in Temporary Equity [Roll Forward]
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $269, $206, $165 (in shares)		3,607,069
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $269, $206, $165		$ 3,978
Accretion of redeemable convertible preferred stock to redemption value	$ 2,172	6,651
Balance at Ending period at Dec. 31, 2018	$ 33,112	$ 91,038					$ 124,150
Balance at Ending period (in shares) at Dec. 31, 2018	22,501,174	63,032,500					0
Increase (Decrease) in Temporary Equity [Roll Forward]
Vesting of common stock previously subject to repurchase (in shares)			549
Vesting of common stock previously subject to repurchase				5			$ 5
Exercise of stock options (in shares)			1,377				1,377
Exercise of stock options				5			$ 5
Stock-based compensation expense				216			216
Accretion of redeemable convertible preferred stock to redemption value				(226)		(8,597)	(8,823)
Net loss						(21,092)	(21,092)
Balance at Ending period at Dec. 31, 2018						(137,860)	$ (137,860)
Balance at Ending period (in shares) at Dec. 31, 2018			295,717
Increase (Decrease) in Temporary Equity [Roll Forward]
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $269, $206, $165 (in shares)		12,527,956
Sale of Series B redeemable convertible preferred stock, net of stock issue costs of $269, $206, $165		$ 14,367
Accretion of redeemable convertible preferred stock to redemption value	$ 1,563	$ 6,220
Balance at Ending period (in shares) at Dec. 31, 2019	0	0					0
Increase (Decrease) in Temporary Equity [Roll Forward]
Vesting of common stock previously subject to repurchase (in shares)			628
Vesting of common stock previously subject to repurchase				4			$ 4
Exercise of stock options (in shares)			2,527				2,527
Exercise of stock options				14			$ 14
Issuance/Conversion of convertible preferred stock (in shares)	(22,501,174)	(75,560,456)	6,708,649
Issuance/Conversion of convertible preferred stock	$ (34,675)	$ (111,625)	$ 7	146,293			146,300
Issuance of stock			$ 4	50,625			50,629
Issuance of stock (in shares)			4,398,700
Unrealized loss on available for sales securities					$ (4)		(4)
Foreign currency translation adjustment					(15)		(15)
Stock-based compensation expense				457			457
Accretion of redeemable convertible preferred stock to redemption value				(209)		(7,574)	(7,783)
Conversion of outstanding preferred stock warrants				1,645			1,645
Net loss						(22,425)	(22,425)
Balance at Ending period at Dec. 31, 2019			$ 11	$ 198,829	$ (19)	$ (167,859)	$ 30,962
Balance at Ending period (in shares) at Dec. 31, 2019			11,406,221

Consolidated Statements of Re_2

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Series B Redeemable convertible preferred stock
Stock issue costs	$ 165	$ 206	$ 269

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (22,425)	$ (21,092)	$ (21,334)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	278	463	761
Noncash interest expense	523	712	2,113
Noncash loss on extinguishment of debt		1,469
Amortization of intangible assets	304	785
Inventory excess and obsolescence charge	1,591	2,224	452
Beneficial conversion feature upon conversion of promissory notes			1,408
Change in fair value of warrants	5	(244)	(54)
Stock-based compensation expense	457	216	197
Loss (gain) on sale of property and equipment		(2)	14
Change in operating assets and liabilities:
Accounts receivable	(1,528)	(541)	(578)
Inventory	(1,839)	(4,757)	(127)
Prepaid expenses and other assets	(1,977)	99	(58)
Restricted cash		24
Accounts payable	(773)	1,914	(748)
Accrued expenses and other liabilities	(118)	(1,194)	1,586
Foreign currency remeasurement gain	(21)
Net cash used in operating activities	(25,523)	(19,924)	(16,368)
Cash flows from investing activities:
Purchases of short-term investments	(9,284)
Payment for intangible asset	(2,500)	(1,500)
Purchase of property and equipment	(197)	(62)	(114)
Proceeds from sale of property and equipment		4	13
Net cash used in investing activities	(11,981)	(1,558)	(101)
Cash flows from financing activities:
Proceeds from initial public offering net of underwriting discounts, commissions and offering costs	51,151
Proceeds from issuance of long-term debt with related party		30,000
Proceeds from issuance of long‑term debt and preferred stock warrants		8,000	5,000
Repayment of long-term debt		(13,000)
Borrowings under revolving credit facility		5,732
Repayments of revolving credit facility		(5,732)
Proceeds from issuance of Series B redeemable convertible preferred stock, net of offering costs	14,367	3,978	14,731
Proceeds from issuance of convertible promissory notes and preferred stock warrants			7,386
Payment of deferred financing costs		(1,569)	(596)
Payment of capital lease obligations			(188)
Proceeds from exercise of stock options	14	5	2
Net cash provided by financing activities	65,532	27,414	26,335
Effect of exchange rate on cash	(4)
Net increase in cash and cash equivalents	28,024	5,932	9,866
Cash and cash equivalents, beginning of year	17,278	11,346	1,480
Cash and cash equivalents, end of year	45,302	17,278	11,346
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	3,086	1,090	329
Cash paid on loss on extinguishment of debt		353
Supplemental disclosures of noncash investing and financing activities:
Fair value of warrants issued in connection with equity and debt financing		187	1,751
Accretion of redeemable convertible preferred stock	7,783	8,823	5,893
Conversion of convertible preferred stock to common stock in connection with the initial public offering	146,300
Conversion of outstanding preferred stock warrants	1,645
Offering costs in accounts payable	522
Conversion of convertible promissory notes and accrued interest to Series B redeemable convertible preferred stock			8,054
Intangible assets in accrued expenses and other liabilities		2,500
Recognition of exit fee for debt discount		3,400
Issuance of common stock for early exercised stock options	4	$ 5	$ 31
Unrealized loss on short-term investments	$ 4

Background

Background	12 Months Ended
	Dec. 31, 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 (“OviTex”), which utilizes surgical reconstruction medical device technology licensed from a strategic partner, Aroa Biosurgery (“Aroa”), as described in Note 11, and on the research and development of additional medical devices with Aroa and on other internally developed technologies. In April 2019, the Company received 510(k) clearance from the U.S. Food and Drug Administration (“FDA”) for OviTex PRS Reinforced Tissue Matrix (“OviTex PRS”), which addresses unmet needs in plastic reconstruction surgery. The Company’s principal corporate office and research facility is located in Malvern, Pennsylvania.

Risks and Liquidity

Risks and Liquidity	12 Months Ended
	Dec. 31, 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 $167.9 million as of December 31, 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 $50.6 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	12 Months Ended
	Dec. 31, 2019
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	(3) Summary of Significant Accounting Policies Basis of Presentation and Principals of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). The consolidated financial statements include the accounts of TELA Bio, Inc. and its wholly owned subsidiary TELA Bio Limited. All intercompany accounts and transactions have been eliminated in consolidation. 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 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. Segments Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision‑making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one segment. Concentration of Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. The Company places its cash with high‑credit‑quality financial institutions and invests in money market funds, government agency securities and corporate debt securities. The Company has established guidelines relative to credit ratings and maturities that seek to maintain safety and liquidity. As described in Note 11, the Company has licensed patents and other intellectual property from Aroa. As part of this agreement, Aroa is also the sole manufacturer of the Company’s products. The inability of Aroa to fulfill supply requirements of the Company could materially impact future operating results. A change in the relationship with Aroa, or an adverse change in their business, could materially impact future operating results. Cash and Cash Equivalents The Company considers cash equivalents to be highly liquid investments with maturities of three months or less from the date of purchase. Cash equivalents consist of investments in a money market fund. The Company’s cash and cash equivalents are carried at the fair value of the investment based on quoted market prices. Short-Term Investments Short-term investments consist of investments in corporate debt securities with a maturity of greater than three months when acquired. The Company classifies these investments as available-for-sale securities. These investments are reported at fair value with the related unrealized gains and losses included in accumulated other comprehensive loss, a component of stockholders’ equity. The Company evaluates its investments for other-than-temporary impairment by reviewing factors such as the length of time and extent to which fair value has been below cost basis and the Company’s ability and intent to hold the investment for a period of time which may be sufficient for anticipated recovery of the market value. There were no other-than-temporary impairments in 2019. Short-term investments consisted of the following at December 31, 2019 (in thousands): Estimated Amortization/ Unrealized Fair Cost Accretion Gains/(Losses) Value Corporate debt securities $ 9,284 $ 5 $ (4) $ 9,285 Inventory Inventory consists of finished goods and is identified and tracked by lot and stated at the lower of cost or net realizable value, with cost being determined on a first‑in, first‑out basis. The Company periodically analyzes its inventory levels and writes down inventory that has become obsolete or that has a cost basis in excess of its expected net realizable value based on expected customer demand. As of December 31, 2019 and 2018, the Company had $1.1 million and $0.8 million, respectively, in inventory consigned to others. Property and Equipment Property and equipment are stated at the aggregate cost incurred to acquire and place the asset in service. Expenditures for routine maintenance and repairs are charged to expense as incurred and costs of improvements and renewals are capitalized. Depreciation is provided over the estimated useful lives of the assets using the straight‑line method. Intangible Assets Upfront payments and milestone payments due related to licenses or commercialization rights prior to future economic benefit being established are recorded as research and development expenses. Milestone payments due related to licenses or commercialization rights after future economic benefit is established are recorded as intangible assets. In 2018, the Company recorded $4.0 million in intangible assets as it became probable that the Company would make these payments. In 2019 and 2018, the Company recorded $0.3 million and $0.8 million, respectively, of amortization expense related to intangible assets. At December 31, 2019, the remaining life of intangible assets was 9.6 years. The Company anticipates recognizing amortization expense of $0.3 million for the next five years and $1.4 million thereafter. Long‑Lived Assets Long‑lived assets, such as property and equipment and intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If circumstances require a long‑lived asset or asset group be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by such asset or asset group to its carrying value. If the carrying value of the long‑lived asset or asset group exceeds the undiscounted cash flows, an impairment is recognized to the extent the carrying value exceeds its fair value. Fair value is determined using various valuation techniques, including discounted cash flow models, quoted market values, and third‑party independent appraisals, as considered necessary. No impairment losses were recognized during the year ended December 31, 2019, 2018 or 2017. Debt Issuance Costs Debt issuance costs incurred in connection with debt (Note 6) are amortized to interest expense over the term of the respective financing arrangement using the effective‑interest method, and debt issuance costs incurred under the revolver are amortized to interest expense over the term of the respective financing arrangement using the straight‑line method. Debt issuance costs, net of related amortization are deducted from the carrying value of the related debt. 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 Company determined that the new guidance did not have a material impact on its revenue recognition practices as it does not provide customers with price concessions, rebates, volume discounts or other such reductions for which an estimated transaction price must be determined and then allocated to specific deliverables. 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 product shipped to a customer 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. There are no incremental costs of obtaining a contract that would rise to or enhance an asset other than product costs, which are a component of inventory. 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. The following table presents revenue disaggregated (in thousands): Year ended December 31, OviTex $ 14,041 OviTex PRS 1,405 Total revenue $ 15,446 Sales of OviTex accounted for all of the Company’s revenue for the years ended December 31, 2018 and 2017. 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. Research and Development Research and development costs are charged to expense as incurred and consist primarily of salaries, benefits, and other related costs, including stock‑based compensation for personnel serving in the research and development functions as well as payments to Aroa and related supply and manufacturing costs. At the end of the reporting period, the Company compares payments made to third‑party service providers to the estimated progress toward completion of the research or development objectives. Such estimates are subject to change as additional information becomes available. Depending on the timing of payments to the service providers and the progress that the Company estimates has been made as a result of the service provided, the Company may record net prepaid or accrued expense relating to these costs. Costs incurred in obtaining patent and other intellectual property licenses for which there are no alternative future uses are charged to expense as incurred. Stock‑Based Compensation The Company accounts for stock‑based awards in accordance with provisions of ASC Topic 718, Compensation—Stock Compensation , under which the Company recognizes the grant‑date fair value of stock‑based awards issued to employees and nonemployee board members as compensation expense on a straight‑line basis over the vesting period of the award while awards containing a performance condition are recognized as expense when the achievement of the performance criteria is considered probable. The Company accounts for stock‑based compensation for awards granted to nonemployee consultants by revaluing the award over the vesting period of the awards. The Company uses the Black‑Scholes option pricing model to determine the grant‑date fair value of stock options. The Company estimates forfeitures that it expects will occur and adjusts expense for actual forfeitures in the periods they occur. Income Taxes Income taxes are accounted for under the asset‑and‑liability method as required by ASC Topic 740 (“ASC 740”), Income Taxes . Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period corresponding to the enactment date. Under ASC 740, a valuation allowance is required when it is more likely than not all or some portion of the deferred tax assets will not be realized through generating sufficient future taxable income. ASC Subtopic 740‑10 (“ASC 740‑10”), Accounting for Uncertainty of Income Taxes , defines the criterion an individual tax position must meet for any part of the benefit of the tax position to be recognized in consolidated financial statements prepared in conformity with GAAP. The Company may recognize the tax benefit from an uncertain tax position only if it is more likely than not such tax position will be sustained on examination by the taxing authorities, based solely on the technical merits of the respective tax position. The tax benefits recognized in the consolidated financial statements from such a tax position should be measured based on the largest benefit having a greater than 50% likelihood of being realized upon ultimate settlement with the tax authority. In accordance with the disclosure requirements of ASC 740‑10, the Company’s policy on income statement classification of interest and penalties related to income tax obligations is to include such items as part of total interest expense and other expense, respectively. 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 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 OrbiMed Credit Facility (Note 6), it is impractical to determine the fair value of the debt. Items measured at fair value on a recurring basis included the Company’s preferred stock warrants. The warrants were carried at their estimated fair value. The Company follows the provisions of 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 as of December 31, 2019 and 2018 (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) December 31, 2019: Assets: Cash equivalents – money market fund $ 34,918 $ — $ — Cash equivalents – corporate debt securities $ — $ 8,850 $ — Cash equivalents – government agency securities $ — $ 1,000 $ — Short-term investments – corporate debt securities $ — $ 9,285 $ — 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 (in thousands): January 1, 2017 $ — Fair value of warrants issued – Convertible promissory notes 1,408 Fair value of warrants issued – Notes payable 343 Change in fair value of warrants (54) December 31, 2017 1,697 Fair value of warrants issued – MidCap Credit Facility 187 Change in fair value of warrants (244) December 31, 2018 1,640 Change in fair value of warrants 5 Conversion into common stock warrants (1,645) December 31, 2019 $ — The fair value of the warrants at November 13, 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 57.5 % 57.4 % 57.5 % Risk-free interest rate 2.04 % 1.79 % 1.79 % Remaining contractual term in years 8.4 7.2 7.4 The fair value of the warrants at December 31, 2018 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 58.1 % 57.0 % 57.4 % Risk‑free interest rate 2.69 % 2.64 % 2.64 % Remaining contractual term in years 9.3 8.1 8.3 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 entitled the holders of such shares to participate in distributions but contractually did not require the holders of such shares to participate in losses of the Company. 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 as of December 31, 2019 and 2018, as they would be antidilutive. Years ended December 31, 2019 2018 Series A redeemable convertible preferred stock — 911,336 Series B redeemable convertible preferred stock — 2,552,919 Stock options (including shares subject to repurchase) 1,421,697 490,134 Series B redeemable convertible preferred stock warrants — 88,556 Common stock warrants 88,556 — Total 1,510,253 4,042,945 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 November 2016, the FASB issued ASU No. 2016‑18, Consolidated Statement of Cash Flows: Restricted Cash . The amendments address diversity in practice that exists in the classification and presentation of changes in restricted cash and require that a consolidated statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The standard was effective for the Company beginning January 1, 2019. The Company’s adoption of this standard did not have a material impact on the Company’s consolidated financial statements. 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 adoption of this guidance is not expected to be material to the Company’s 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 adoption of this guidance is not expected to be material to the Company’s consolidated financial statements and related disclosures.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2019
Property and Equipment
Property and Equipment	(4) Property and Equipment Property and equipment consisted of the following (in thousands): December 31, Asset description Estimated useful lives 2019 2018 Lab equipment 5 Years $ 2,250 $ 2,203 Furniture and fixtures 5 Years 112 110 Computer equipment and software 3 Years 508 398 Leasehold improvements Lesser of useful life or lease term 1,328 1,290 Total 4,198 4,001 Less accumulated depreciation and amortization (3,521) (3,243) Property and equipment, net $ 677 $ 758 The cost of property and equipment at both December 31, 2019 and 2018 includes $0.2 million of equipment located at Aroa. Depreciation expense was $0.3 million, $0.5 million and $0.8 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2019
Accrued Expenses
Accrued Expenses	(5) Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, 2019 2018 Compensation and related benefits $ 2,310 $ 1,760 Interest 41 42 Professional fees 641 552 Accrued milestone payments — 2,500 Research and development expenses 35 133 Other 506 166 $ 3,533 $ 5,153

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt
Debt	(6) Debt Long‑term debt consisted of the following at December 31, 2019 and 2018 (in thousands): December 31, 2019 2018 OrbiMed Term Loan (related party) $ 30,000 $ 30,000 End of term charge 3,000 3,000 Unamortized end of term charge and issuance costs (2,757) (3,267) Long-term debt with related party $ 30,243 $ 29,733 OrbiMed Term Loan (Related Party) In November 2018, the Company entered into a senior secured term loan facility (“OrbiMed Credit Facility”) with OrbiMed Royalty Opportunities II, LP (“OrbiMed”), a related party as the lender is affiliated with a stockholder of the Company, which consists of up to $35.0 million in term loans (“OrbiMed Term Loans”). 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 (described below) and will use the remaining proceeds to fund operations and capital expenditures. The Company elected not to borrow Tranche 2 prior to its expiration on December 31, 2019. Pursuant to the OrbiMed Credit Facility, 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 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 Loan matures 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 December 31, 2019, the interest rate was 9.75%. 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 $0.3 million of third party and lender fees, which along with the End of Term Charge of $3.0 million 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 2019 and 2018 was $3.6 million and $0.6 million, respectively. MidCap Credit Facility In April 2018, the Company entered into a $14.0 million debt financing transaction (“MidCap Credit Facility”) with MidCap Financial (“MidCap”), which consisted of a $3.5 million revolving credit facility (“Revolver”) and $10.5 million in term loans (“MidCap Term Loans”). The Term Loans consisted of two tranches, an $8.0 million Tranche 1 (“MidCap Tranche 1”) and a $2.5 million Tranche 2 (“MidCap Tranche 2”). In April 2018, the Company borrowed $8.0 million of MidCap Tranche 1 and used the majority of the proceeds to repay the note payable outstanding. In conjunction with the closing of the MidCap Tranche 1 term loans, the Company issued MidCap warrants to purchase 206,897 shares of the Company’s Series B redeemable convertible preferred stock at an exercise price of $1.16 per share. The warrants have a contractual term equal to the earlier of a change in control or 10 years. The estimated fair value of the warrants of $0.2 million (determined using the Black‑Scholes option pricing model), along with $0.8 million of third‑party and lender fees (including $0.4 million of End of Term Charge) incurred with the issuance of the debt, were recorded as the End of Term Charge and debt issuance costs and were being recognized as interest expense over the life of the Tranche 1 term loan using the effective‑interest method. The MidCap Term Loans and the Revolver bore interest at a rate equal to one‑month LIBOR plus 7.0% and one‑month LIBOR plus 3.75%, respectively, until the aggregate principal, interest, and End of Term Charge totaling $0.4 million were paid with part of the proceeds received from the OrbiMed Credit Facility. As a result of these payments, a $1.2 million loss on extinguishment was recorded during the year ended December 31, 2018. Interest expense associated with the Midcap Credit Facility recorded during 2018 was $0.6 million. Note Payable In March 2017, the Company entered into a Loan and Security Agreement (“Loan Agreement”) and borrowed $5.0 million (“Note A”). Note A bore interest at 9.45% until the aggregate principal, interest, and other termination fees were paid with part of the proceeds received from the MidCap Credit Facility. As a result of these payments, a $0.6 million loss on extinguishment was recorded during the year ended December 31, 2018. Interest expense associated with Note A recorded during both the years ended December 31, 2018 and 2017 was $0.4 million. In connection with the Loan Agreement, the Company granted 387,932 Series B warrants with an original term of 10 years with an exercise price of $1.16 per share. Convertible Promissory Note In January 2017, the Company issued $7.4 million of secured, convertible promissory notes (the “Convertible Notes”), together with warrants, primarily to holders of the Company’s Series B redeemable convertible stock (“Series B”). The Convertible Notes bore interest at the rate of 12%. The Convertible Notes were secured by a lien on all assets of the Company, including intellectual property and cash, and were scheduled to mature in October 2017. The principal amount of the Convertible Notes and accrued interest thereon of $0.7 million converted into 6,951,175 shares of the Company’s Series B in connection with the sale of Series B to a new investor in October 2017 (Note 7). The purchasers of the Convertible Notes also received a 10‑year warrant to purchase shares of the Company’s Series B, with the number of shares issuable upon warrant exercise equal to 25% of the note principal divided by $1.16, or 1,591,864 warrants. The exercise price of the warrants is $1.16 per share. The estimated fair value of the warrants of $1.4 million (determined using the Black‑Scholes option pricing model) was recorded as a debt discount and was fully amortized to interest expense during 2017 over the term of the Convertible Notes. In addition, in accordance with the applicable FASB accounting guidance, after considering the allocation of a portion of the proceeds to the warrants, the Company determined that the Convertible Notes contained a beneficial conversion feature (“BCF”). The BCF existed at the date of the issuance of the Convertible Notes due to the fact that the original carrying value of the Convertible Notes, after allocation of the proceeds, would be less than the purchase price of the series of preferred stock paid by investors in the next qualified or nonqualified financing, as defined. During the year ended December 31, 2017, the BCF of $1.4 million was fully recognized as additional interest expense. Debt issuance costs of $0.1 million were incurred and were recorded as a discount on the carrying value of the debt, and amortized to interest expense in 2017 through the date of conversion of the Convertible Notes.

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit)	12 Months Ended
	Dec. 31, 2019
Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit)
Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit)	(7) Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) Initial Public Offering In November 2019, the Company closed its 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 $50.6 million after deducting underwriting discounts, commissions and other offering expenses. In addition, immediately prior to the closing of the IPO, all of the Company’s outstanding shares of redeemable convertible preferred stock, including accrued dividends payable 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. Preferred Stock Prior to the IPO, all of the Company’s redeemable convertible preferred stock was classified outside of stockholders’ deficit because the shares contain certain redemption features that were not solely within the control of the Company. At the time of issuance, the redeemable convertible preferred stock was recorded at its issuance price, less issuance costs. Throughout 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 at $1.16 per share for aggregate gross proceeds of $14.5 million. Transaction fees of $0.2 million were recorded as a reduction of the carrying value of the Series B. Throughout 2018, the Company entered into various stock purchase agreements with new and existing investors pursuant to which the Company sold an aggregate 3,607,069 shares of the Company’s Series B at $1.16 per share for aggregate gross proceeds of $4.2 million. Transaction fees of $0.2 million were recorded as a reduction of the carrying value of the Series B. In October 2017, the Company entered into a stock purchase agreement with a strategic corporate investor pursuant to which the Company sold 12,931,034 shares of the Company’s Series B at $1.16 per share for aggregate gross proceeds of $15.0 million. Transaction fees of $0.3 million were recorded as a reduction of the carrying value of the Series B. Concurrent with this financing, a total of 6,951,175 shares of Series B were issued upon conversion of the Convertible Notes plus accrued interest on such notes (Note 6). Warrants The Company had the following warrants outstanding to purchase common stock at December 31, 2019: Exercise Expiration Outstanding price dates Common stock warrants issued to MidCap 8,379 $ 28.65 Common stock warrants issued to note payable holders 15,712 28.65 Common stock warrants issued to convertible promissory note holders 64,465 $ 28.65 88,556

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Stock-Based Compensation
Stock-Based Compensation	(8) Stock‑Based Compensation The Company has two equity incentive plans: the 2012 Stock Incentive Plan and the 2019 Equity Incentive Plan. New awards can only be granted under the 2019 Equity Incentive Plan (the “Plan”). At December 31, 2019, 323,715 shares were available for future issuances. The Plan provides for the grant of incentive stock options, nonqualified stock options, restricted stock awards, restricted stock units 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 agreements 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): Year ended December 31, 2019 2018 2017 Sales and marketing $ 164 $ 68 $ 44 General and administrative 225 115 116 Research and development 68 33 37 Total stock‑based compensation $ 457 $ 216 $ 197 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, 2017 282,331 $ 5.77 Granted 84,587 5.93 Exercised (404) 5.19 Early exercised (830) 5.93 Canceled/forfeited (14,770) 5.87 Outstanding at December 31, 2017 350,914 5.81 Granted 152,016 5.93 Exercised (1,377) 5.57 Early exercised (427) 5.93 Canceled/forfeited (11,904) 5.93 Outstanding at December 31, 2018 489,222 5.84 Granted 978,415 12.51 Exercised (2,527) 5.93 Early exercised (471) 5.93 Canceled/forfeited (43,697) 8.58 Outstanding at December 31, 2019 1,420,942 $ 10.35 8.75 Vested and expected to vest at December 31, 2019 1,317,047 $ 10.23 8.68 Exercisable at December 31, 2019 345,881 $ 5.87 6.18 The 2012 Stock Incentive Plan and the 2019 Equity Incentive Plan provide the holders of stock options an election to early exercise prior to vesting. The Company had 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 December 31, 2019, $4,000 of proceeds from early exercised options are recognized as a current liability in other current liabilities in the accompanying consolidated balance sheet. The following table summarizes activity relating to early exercise of stock options: Number of shares Unvested balance at January 1, 2017 7,159 Early exercised 830 Vested (6,955) Unvested balance at December 31, 2018 1,034 Early exercised 427 Vested (549) Unvested balance at December 31, 2018 912 Early exercised 471 Vested (628) Unvested balance at December 31, 2019 755 The weighted average grant‑date fair value per share of options granted was $6.81, $1.08 and $0.54 for the years ended December 31, 2019, 2018 and 2017, respectively. The aggregate intrinsic value of options exercised was nominal for the year ended December 31, 2019. As of December 31, 2019, the total unrecognized compensation expense related to unvested employee and nonemployee stock option awards was $5.7 million, which is expected to be recognized in expense over a weighted‑average period of approximately 3.4 years. 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 require 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 Securities and Exchange Commission. 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: Year ended December 31, 2019 2018 2017 Expected dividend yield — — — Expected volatility 55.9 % 56.5 % 50.0 % Risk‑free interest rate 1.82 % 2.77 % 2.07 % Expected term 6.24 Years 6.25 Years 6.25 Years

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Employee Benefit Plans
Employee Benefit Plans	(9) Employee Benefit Plans 401(k) Defined Contribution Plan The Company sponsors a 401(k) defined‑contribution plan covering all employees. Participants are permitted to contribute up to 100% of their eligible annual pretax compensation up to an established federal limit on aggregate participant contributions. Discretionary profit‑sharing contributions made by the Company, if any, are determined annually by the board of directors. To date, the Company has not made discretionary profit‑sharing contributions under the 401(k) plan but effective January 1, 2020, the Company will match 50% of employees’ contributions up to 6%, subject to a maximum annual amount. Participants are immediately vested in their own contributions to the plan and are fully vested in discretionary profit sharing made by the Company after three years of service. 2019 Employee Stock Purchase Plan In November 2019, the Company adopted the 2019 Employee Stock Purchase Plan (the “ESPP”) with a total of 107,887 shares reserved for future issuance under the ESPP. In addition, subject to prior approval by the Company’s board of directors, the number of shares authorized and reserved for issuance under the ESPP will be increased annually equal to the least of (i) 107,887 shares of common stock, (ii) 1% of the shares outstanding on the final day of the immediately preceding calendar year, and (iii) such smaller number of shares as determined by the board of directors. The ESPP provides the opportunity to purchase the Company’s common stock at a 5% discount to the market price through payroll deductions. As of December 31, 2019, no shares have been issued under the ESPP.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Taxes
Income Taxes	(10) Income Taxes The Company has incurred losses since inception. Deferred tax assets and liabilities are determined based on the differences between the financial statement carrying amounts and tax bases of assets and liabilities using enacted tax rates in effect for years in which differences are expected to reverse. Significant components of the Company’s deferred tax assets for federal income taxes as of December 31, 2019 and 2018 consisted of the following (in thousands): December 31, 2019 2018 Deferred tax assets Net operating loss carryforwards $ 32,704 $ 26,993 Research and development credits 853 701 Depreciation and amortization 578 825 Accrued LifeCell settlement — 252 Accrued expenses and other 259 191 Inventory reserve 417 425 Gross deferred tax asset 34,811 29,387 Valuation allowance (34,811) (29,387) Net deferred tax asset $ — $ — The Company does not have unrecognized tax benefits as of December 31, 2019 and 2018. The Company recognizes interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. The Company’s net operating loss (“NOL”) carryforwards for federal and state income tax purposes consisted of the following (in thousands): December 31, 2019 2018 NOL carryforwards Federal $ 122,925 $ 99,939 State 106,062 91,797 The NOL carryforwards begin expiring in 2032 for federal purposes and in 2026 for state income tax purposes. The Company recorded a valuation allowance on the deferred tax assets as of December 31, 2019 and 2018 because of the uncertainty of their realization. The valuation allowance increased by $5.4 million for the year ended December 31, 2019 mainly due to losses incurred and by $5.5 million for the years ended December 31, 2018, mainly due to losses incurred and the reduction in the tax rate. In December 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted. The Tax Act includes a number of changes to existing U.S. tax laws that impact the Company, most notably a reduction of the U.S. corporate income tax rate from 34% to 21% for tax years beginning after December 31, 2017. The Tax Act also provided for a onetime transition tax on certain foreign earnings and the acceleration of depreciation for certain assets placed into service after September 27, 2017 as well as prospective changes beginning in 2018, including repeal of the domestic manufacturing deduction, acceleration of tax revenue recognition, capitalization of research and development expenditures, additional limitations on executive compensation, and limitations on the deductibility of interest. Utilization of the net operating losses and general business tax credits carryforwards may be subject to a substantial limitation under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, if changes in ownership of the company have occurred previously or occur in the future. Ownership changes may limit the amount of net operating losses and general business tax credits carryforwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of 5% shareholders in the stock of a corporation by more than 50 percentage points over a three‑year period. If the Company experiences a Section 382 ownership change, the tax benefits related to the NOL carryforwards may be further limited or lost. The Company has not performed an analysis under Section 382 and cannot predict or otherwise determine whether there would be any limitation to the amount of net operating losses and general business tax credits carryforwards that can be utilized. A reconciliation of income tax benefit at the statutory federal income tax rate and as reflected in the consolidated financial statements is as follows: Year ended December 31, 2019 2018 2017 Rate reconciliation Federal tax benefit at statutory rate (21.0) % (21.0) % (34.0) % State rate, net of federal benefit (2.9) (4.7) (5.2) Permanent differences 0.4 0.5 5.5 Change in federal rate — — 48.0 Research and development (0.7) (0.8) — Change in valuation allowance 24.2 26.3 (15.1) Other — (0.3) 0.8 Total tax provision — % — % — % The Company files income tax returns in the U.S. federal jurisdiction and various state jurisdictions. Tax years 2016 and forward remain open for examination for federal tax purposes and tax years 2016 and forward remain open for examination for the Company’s more significant state tax jurisdictions. To the extent utilized in future years’ tax returns net operating loss carryforwards at December 31, 2018 will remain subject to examination until the respective tax year is closed.

Contingencies and Commitments

Contingencies and Commitments	12 Months Ended
	Dec. 31, 2019
Contingencies and Commitments
Contingencies and Commitments	(11) Contingencies and Commitments Legal Proceedings On November 18, 2016, the Company and LifeCell Corporation (“LifeCell”) agreed to settle litigation initiated by LifeCell in March 2015 related to LifeCell’s complaints alleging (i) that the Company misappropriated LifeCell’s trade secrets and proprietary information and hired various former LifeCell employees allegedly in violation of their noncompetition covenants and nonsolicitation agreements and (ii) that the Company infringed U.S. Patent No. 6,143,293, (the 293 patent), which LifeCell had recently purchased from Carnegie Mellon University. Both cases have been dismissed with prejudice. As part of this settlement, LifeCell agreed not to sue the Company, either directly or through a person acting at its request or with its involvement for patent infringement, trade secret misappropriation, breach of an assignment obligation, unfair competition, unjust enrichment, tortious interference with contract and prospective economic advantage, civil conspiracy, or like causes of action with respect to OviTex. Also, as part of this settlement agreement, among other provisions, the Company agreed to pay LifeCell $1.0 million within 30 days of the execution of the settlement agreement and up to an additional $3.0 million based upon the Company achieving set revenue milestones for its OviTex product family. As of December 31, 2019, all amounts have been paid. The estimated present value of the future revenue milestone payments was $1.0 million at December 31, 2018 was recorded in other current liabilities in the accompanying consolidated balance sheets, based on when the payments were expected to be made at each respective balance sheet date. Noncash interest expense of $20,000, $0.2 million and $0.3 million was recorded during 2019, 2018 and 2017 respectively, for the change in estimated present value of the future revenue milestone payments. Legal and other costs incurred in defense of the Company was charged to expense as incurred and totaled $0.4 million for the year ended December 31, 2017 and were recorded in general and administrative expenses in the accompanying consolidated statement of operations. No legal defense costs were incurred subsequent to December 31, 2017. On February 12, 2016, the Company filed suit against National Union Fire Insurance Company of Pittsburgh, Pennsylvania (“National Union”), the former carrier for the Company’s Directors & Officers and Employment Practices Liability Insurance. The complaint charged National Union with breach of contract and failure to reimburse the Company for defense costs it incurred in the LifeCell litigation discussed above that the Company believes are covered under the insurance policy sold by National Union. The complaint sought reimbursement of $5.0 million, the full limit of the policy, as well as reimbursement of the Company’s costs pursuing the action against National Union. In 2018, the Company settled the suit and received $2.4 million and paid its broker $0.2 million and recognized the net amount of $2.2 million as a gain on litigation settlement in the Company’s consolidated statement of operations during the year ended December 31, 2018. From time to time, the Company may be a party to various other lawsuits, claims, and other legal proceedings that arise in the ordinary course of its business. While the outcomes of these matters are uncertain, management does not expect that the ultimate costs to resolve these matters will have a material adverse effect on the Company’s financial position, results of operations, or cash flows. Agreements with Aroa In August 2012, the Company entered into a License, Product Development, and Supply Umbrella Agreement (“Aroa Agreement”) with Aroa. The Aroa Agreement provides the Company a license to patent rights and other intellectual property related to Aroa’s products and technologies for use in certain indications and expires on the later of August 3, 2022 or expiration of the last patent covering the products (currently July 30, 2029). The Company has the right to extend the term of the agreement by an additional 10 years following the expiration of the last patent covering the products on commercially reasonable terms to be negotiated by the parties. This agreement initially limited the Company’s license rights to the U.S. but was subsequently amended in March 2013 to include the European Union and certain former Union of Soviet Socialist Republic satellite nations. The financial terms of this Aroa Agreement, as amended, include (i) the payment of $1.0 million and the issuance of 74,316 shares of the Company’s common stock valued at $0.3 million concurrent with the closing of the December 2012 financing, (ii) the payment of $1.0 million upon the amendment of the Aroa Agreement in March 2013, and (iii) the payment of $1.0 million upon the approval by the U.S. Food and Drug Administration (“FDA”) of the use of Aroa’s product for certain indications (paid in June 2013). All amounts paid were recorded at the time within in‑process research and development expense in the consolidated statements of operations as the Company believes that the technology licensed from Aroa required substantial additional development efforts and had no alternative future uses to the Company. In April 2014, the Company submitted a new 510(k) application to the FDA incorporating the licensed technologies, as well as technology licensed from a second strategic partner. The Aroa Agreement also requires future payments aggregating up to $4.0 million upon the achievement of U.S. and European cumulative product sales targets. In 2018, it became probable that the Company would be issued CE Mark approval to sell OviTex in Europe by the European Medical Agency, and the Company recognized a $1.0 million liability and a corresponding developed right intangible asset related to this milestone payment owed to Aroa. Of this amount, $0.5 million was paid in 2018 and the remaining $0.5 million was paid in 2019. With respect to the sales milestone payments in the North American territory, a payment of $1.0 million and $2.0 million are due when cumulative product sales in the North American territory reach certain amounts. In 2018, it became probable that the Company would achieve the sales milestones in the North American territory, and, as such, the Company recorded a liability of $3.0 million and a corresponding developed technology right intangible asset. The Company paid $1.0 million to Aroa in 2018 related to one of the cumulative product sales targets and the remaining $2.0 million in 2019. With respect to the sales milestone payments in the European territory, a payment of $1.0 million is due when cumulative product net sales in the European territory reach certain amounts. Other key terms of the amended Aroa agreement in addition to those disclosed above are as follows: · The transfer price for product produced by Aroa was increased from 150% of Aroa’s cost of goods sold to 200% of the cost of goods sold, with the quarterly true‑up amount continuing to equal 27% of the Company’s net sales of the licensed product reduced by transfer price payments previously made for the respective quarter. The purchase commitments aggregate to $11.0 million for the North American territory over a five‑year period, consisting of $2.0 million in total in years one and two, $2.0 million in year three, $3.0 million in year four, and $4.0 million in year five. The purchase commitments aggregate to $2.8 million for the European territory over a five‑year period, consisting of $0.5 million in total in years one and two, $0.5 million in year three, $0.8 million in year four, and $1.0 million in year five. In addition, the Company continues to be required to pay a make whole payment if the required minimum purchase commitments for each territory for the corresponding contract years are not made. As of December 31, 2019, the Company has met its purchase commitments and no make whole payments are required for those periods. The period for the purchase commitments for the North American territory for years four and five end in June 2020 and June 2021, respectively. Upon a change in control of the Company (as defined in the amended agreement), the annual minimum amounts will be extended for a sixth year with a $5.0 million minimum amount for the North American territory and $1.0 million minimum amount for the European territory. If a change in control of the Company occurs prior to the first product launch in the applicable territory, then the annual minimum requirements shall commence upon such change in control. If the make whole payments, if any, are not made by the Company after a notice and cure period, then the license will convert to a nonexclusive basis in the territory for which the payment was required but not made. · Separate product development/launch goals and extension rights exist for a breast reconstruction product, as well as other products in specified indications for use. With respect to the breast reconstruction product, the goal was to file an investigational device exemption with the FDA for the North American territory by December 28, 2017, 18 months after the commercial launch of OviTex in the North American territory. The Company met this deadline with the filing of an investigational device exemption (IDE) application with the FDA on November 22, 2017. The Company extended the European deadline and paid $0.5 million. Concurrent with the extension payment, the Company agreed to assume responsibility in obtaining regulatory approval in Europe with a new regulatory filing deadline of June 30, 2020. The Company expects to meet the filing deadline and that no further extension payments will be required. · Provisions exist for the Company to step in and operate Aroa’s plant if a supply failure occurs and is not cured within a set timeframe. Under the amended agreement, the criteria for a supply failure was modified to mean a failure by Aroa to timely supply, during any consecutive 60‑day period, at least 75% of the products ordered by the Company under binding purchase orders. During the period that the Company steps in and assumes manufacturing responsibility, it shall not be required to purchase product from or pay transfer prices to Aroa, the annual minimums shall be proportionately reduced to reflect the lack of supply responsibility by Aroa and the Company shall pay a royalty of 6% of net sales in lieu of 27% of net sales of the licensed products. · The Company is responsible for the payment of 50% of the capital costs of any manufacturing expansion plan agreed upon by the parties, provided that any such payments made by the Company will be offset against future revenue sharing amounts payable (revenue share of 27% of the Company’s net sales of the licensed product). The Company expects to enter into similar milestone‑based agreements with its strategic partner for both product territories and new products in order to expand and extend its product portfolio. As of December 31, 2019, the Company had $8.3 million in purchase commitments with Aroa. Employment Agreements The Company entered into employment agreements with key personnel providing for compensation and severance in certain circumstances, as defined in the respective employment agreements. Operating Leases The Company leases office and laboratory space in Malvern, Pennsylvania under a noncancelable lease, which expires in May 2021. The facility lease agreement has annual scheduled payment increases. The Company is recognizing the rent expense on a straight‑line basis over the lease term. The Company recognized rent expense of $0.3 million for each of the years ended December 31, 2019, 2018 and 2017. The future minimum lease payments under the facility operating lease agreement as of December 31, 2019 are as follows (in thousands): 2020 $ 217 2021 92 $ 309

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2019
Related-Party Transactions
Related-Party Transactions	(12) 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 6.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Summary of Significant Accounting Policies
Basis of Presentation and Principals of Consolidation	Basis of Presentation and Principals of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). The consolidated financial statements include the accounts of TELA Bio, Inc. and its wholly owned subsidiary TELA Bio Limited. All intercompany accounts and transactions have been eliminated in consolidation.
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 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.
Segments	Segments Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision‑making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one segment.
Concentration of Risk	Concentration of Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. The Company places its cash with high‑credit‑quality financial institutions and invests in money market funds, government agency securities and corporate debt securities. The Company has established guidelines relative to credit ratings and maturities that seek to maintain safety and liquidity. As described in Note 11, the Company has licensed patents and other intellectual property from Aroa. As part of this agreement, Aroa is also the sole manufacturer of the Company’s products. The inability of Aroa to fulfill supply requirements of the Company could materially impact future operating results. A change in the relationship with Aroa, or an adverse change in their business, could materially impact future operating results.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers cash equivalents to be highly liquid investments with maturities of three months or less from the date of purchase. Cash equivalents consist of investments in a money market fund. The Company’s cash and cash equivalents are carried at the fair value of the investment based on quoted market prices.
Short-Term Investments	Short-Term Investments Short-term investments consist of investments in corporate debt securities with a maturity of greater than three months when acquired. The Company classifies these investments as available-for-sale securities. These investments are reported at fair value with the related unrealized gains and losses included in accumulated other comprehensive loss, a component of stockholders’ equity. The Company evaluates its investments for other-than-temporary impairment by reviewing factors such as the length of time and extent to which fair value has been below cost basis and the Company’s ability and intent to hold the investment for a period of time which may be sufficient for anticipated recovery of the market value. There were no other-than-temporary impairments in 2019. Short-term investments consisted of the following at December 31, 2019 (in thousands): Estimated Amortization/ Unrealized Fair Cost Accretion Gains/(Losses) Value Corporate debt securities $ 9,284 $ 5 $ (4) $ 9,285
Inventory	Inventory Inventory consists of finished goods and is identified and tracked by lot and stated at the lower of cost or net realizable value, with cost being determined on a first‑in, first‑out basis. The Company periodically analyzes its inventory levels and writes down inventory that has become obsolete or that has a cost basis in excess of its expected net realizable value based on expected customer demand. As of December 31, 2019 and 2018, the Company had $1.1 million and $0.8 million, respectively, in inventory consigned to others.
Property and Equipment	Property and Equipment Property and equipment are stated at the aggregate cost incurred to acquire and place the asset in service. Expenditures for routine maintenance and repairs are charged to expense as incurred and costs of improvements and renewals are capitalized. Depreciation is provided over the estimated useful lives of the assets using the straight‑line method.
Intangible Assets	Intangible Assets Upfront payments and milestone payments due related to licenses or commercialization rights prior to future economic benefit being established are recorded as research and development expenses. Milestone payments due related to licenses or commercialization rights after future economic benefit is established are recorded as intangible assets. In 2018, the Company recorded $4.0 million in intangible assets as it became probable that the Company would make these payments. In 2019 and 2018, the Company recorded $0.3 million and $0.8 million, respectively, of amortization expense related to intangible assets. At December 31, 2019, the remaining life of intangible assets was 9.6 years. The Company anticipates recognizing amortization expense of $0.3 million for the next five years and $1.4 million thereafter.
Long-Lived Assets	Long‑Lived Assets Long‑lived assets, such as property and equipment and intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If circumstances require a long‑lived asset or asset group be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by such asset or asset group to its carrying value. If the carrying value of the long‑lived asset or asset group exceeds the undiscounted cash flows, an impairment is recognized to the extent the carrying value exceeds its fair value. Fair value is determined using various valuation techniques, including discounted cash flow models, quoted market values, and third‑party independent appraisals, as considered necessary. No impairment losses were recognized during the year ended December 31, 2019, 2018 or 2017.
Debt Issuance Costs	Debt Issuance Costs Debt issuance costs incurred in connection with debt (Note 6) are amortized to interest expense over the term of the respective financing arrangement using the effective‑interest method, and debt issuance costs incurred under the revolver are amortized to interest expense over the term of the respective financing arrangement using the straight‑line method. Debt issuance costs, net of related amortization are deducted from the carrying value of the related debt.
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 Company determined that the new guidance did not have a material impact on its revenue recognition practices as it does not provide customers with price concessions, rebates, volume discounts or other such reductions for which an estimated transaction price must be determined and then allocated to specific deliverables. 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 product shipped to a customer 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. There are no incremental costs of obtaining a contract that would rise to or enhance an asset other than product costs, which are a component of inventory. 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. The following table presents revenue disaggregated (in thousands): Year ended December 31, OviTex $ 14,041 OviTex PRS 1,405 Total revenue $ 15,446 Sales of OviTex accounted for all of the Company’s revenue for the years ended December 31, 2018 and 2017. 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.
Research and Development	Research and Development Research and development costs are charged to expense as incurred and consist primarily of salaries, benefits, and other related costs, including stock‑based compensation for personnel serving in the research and development functions as well as payments to Aroa and related supply and manufacturing costs. At the end of the reporting period, the Company compares payments made to third‑party service providers to the estimated progress toward completion of the research or development objectives. Such estimates are subject to change as additional information becomes available. Depending on the timing of payments to the service providers and the progress that the Company estimates has been made as a result of the service provided, the Company may record net prepaid or accrued expense relating to these costs. Costs incurred in obtaining patent and other intellectual property licenses for which there are no alternative future uses are charged to expense as incurred.
Stock-Based Compensation	Stock‑Based Compensation The Company accounts for stock‑based awards in accordance with provisions of ASC Topic 718, Compensation—Stock Compensation , under which the Company recognizes the grant‑date fair value of stock‑based awards issued to employees and nonemployee board members as compensation expense on a straight‑line basis over the vesting period of the award while awards containing a performance condition are recognized as expense when the achievement of the performance criteria is considered probable. The Company accounts for stock‑based compensation for awards granted to nonemployee consultants by revaluing the award over the vesting period of the awards. The Company uses the Black‑Scholes option pricing model to determine the grant‑date fair value of stock options. The Company estimates forfeitures that it expects will occur and adjusts expense for actual forfeitures in the periods they occur.
Income Taxes	Income Taxes Income taxes are accounted for under the asset‑and‑liability method as required by ASC Topic 740 (“ASC 740”), Income Taxes . Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period corresponding to the enactment date. Under ASC 740, a valuation allowance is required when it is more likely than not all or some portion of the deferred tax assets will not be realized through generating sufficient future taxable income. ASC Subtopic 740‑10 (“ASC 740‑10”), Accounting for Uncertainty of Income Taxes , defines the criterion an individual tax position must meet for any part of the benefit of the tax position to be recognized in consolidated financial statements prepared in conformity with GAAP. The Company may recognize the tax benefit from an uncertain tax position only if it is more likely than not such tax position will be sustained on examination by the taxing authorities, based solely on the technical merits of the respective tax position. The tax benefits recognized in the consolidated financial statements from such a tax position should be measured based on the largest benefit having a greater than 50% likelihood of being realized upon ultimate settlement with the tax authority. In accordance with the disclosure requirements of ASC 740‑10, the Company’s policy on income statement classification of interest and penalties related to income tax obligations is to include such items as part of total interest expense and other expense, respectively.
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 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 OrbiMed Credit Facility (Note 6), it is impractical to determine the fair value of the debt. Items measured at fair value on a recurring basis included the Company’s preferred stock warrants. The warrants were carried at their estimated fair value. The Company follows the provisions of 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 as of December 31, 2019 and 2018 (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) December 31, 2019: Assets: Cash equivalents – money market fund $ 34,918 $ — $ — Cash equivalents – corporate debt securities $ — $ 8,850 $ — Cash equivalents – government agency securities $ — $ 1,000 $ — Short-term investments – corporate debt securities $ — $ 9,285 $ — 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 (in thousands): January 1, 2017 $ — Fair value of warrants issued – Convertible promissory notes 1,408 Fair value of warrants issued – Notes payable 343 Change in fair value of warrants (54) December 31, 2017 1,697 Fair value of warrants issued – MidCap Credit Facility 187 Change in fair value of warrants (244) December 31, 2018 1,640 Change in fair value of warrants 5 Conversion into common stock warrants (1,645) December 31, 2019 $ — The fair value of the warrants at November 13, 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 57.5 % 57.4 % 57.5 % Risk-free interest rate 2.04 % 1.79 % 1.79 % Remaining contractual term in years 8.4 7.2 7.4 The fair value of the warrants at December 31, 2018 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 58.1 % 57.0 % 57.4 % Risk‑free interest rate 2.69 % 2.64 % 2.64 % Remaining contractual term in years 9.3 8.1 8.3
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 entitled the holders of such shares to participate in distributions but contractually did not require the holders of such shares to participate in losses of the Company. 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 as of December 31, 2019 and 2018, as they would be antidilutive. Years ended December 31, 2019 2018 Series A redeemable convertible preferred stock — 911,336 Series B redeemable convertible preferred stock — 2,552,919 Stock options (including shares subject to repurchase) 1,421,697 490,134 Series B redeemable convertible preferred stock warrants — 88,556 Common stock warrants 88,556 — Total 1,510,253 4,042,945 Amounts in the above table reflect the common stock equivalents of the noted instrument.
Recently Issued Accounting Pronouncement	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 November 2016, the FASB issued ASU No. 2016‑18, Consolidated Statement of Cash Flows: Restricted Cash . The amendments address diversity in practice that exists in the classification and presentation of changes in restricted cash and require that a consolidated statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The standard was effective for the Company beginning January 1, 2019. The Company’s adoption of this standard did not have a material impact on the Company’s consolidated financial statements. 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 adoption of this guidance is not expected to be material to the Company’s 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 adoption of this guidance is not expected to be material to the Company’s consolidated financial statements and related disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Summary of Significant Accounting Policies
Schedule Of Cash And Cash Equivalents And Short Term Investments	Short-term investments consisted of the following at December 31, 2019 (in thousands): Estimated Amortization/ Unrealized Fair Cost Accretion Gains/(Losses) Value Corporate debt securities $ 9,284 $ 5 $ (4) $ 9,285
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 as of December 31, 2019 and 2018 (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) December 31, 2019: Assets: Cash equivalents – money market fund $ 34,918 $ — $ — Cash equivalents – corporate debt securities $ — $ 8,850 $ — Cash equivalents – government agency securities $ — $ 1,000 $ — Short-term investments – corporate debt securities $ — $ 9,285 $ — December 31, 2018: Assets: Cash equivalents – money market fund $ 16,002 $ — $ — Liability: Warrant liability $ — $ — $ 1,640
Schedule of warrant liability	A rollforward of the warrant liability (Level 3 measurement) is as follows (in thousands): January 1, 2017 $ — Fair value of warrants issued – Convertible promissory notes 1,408 Fair value of warrants issued – Notes payable 343 Change in fair value of warrants (54) December 31, 2017 1,697 Fair value of warrants issued – MidCap Credit Facility 187 Change in fair value of warrants (244) December 31, 2018 1,640 Change in fair value of warrants 5 Conversion into common stock warrants (1,645) December 31, 2019 $ —
Disaggregation of Revenue	The following table presents revenue disaggregated (in thousands): Year ended December 31, OviTex $ 14,041 OviTex PRS 1,405 Total revenue $ 15,446
Schedule of fair value of warrants	The fair value of the warrants at November 13, 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 57.5 % 57.4 % 57.5 % Risk-free interest rate 2.04 % 1.79 % 1.79 % Remaining contractual term in years 8.4 7.2 7.4 The fair value of the warrants at December 31, 2018 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 58.1 % 57.0 % 57.4 % Risk‑free interest rate 2.69 % 2.64 % 2.64 % Remaining contractual term in years 9.3 8.1 8.3
Schedule of dilutive securities excluded	Years ended December 31, 2019 2018 Series A redeemable convertible preferred stock — 911,336 Series B redeemable convertible preferred stock — 2,552,919 Stock options (including shares subject to repurchase) 1,421,697 490,134 Series B redeemable convertible preferred stock warrants — 88,556 Common stock warrants 88,556 — Total 1,510,253 4,042,945

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property and Equipment
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): December 31, Asset description Estimated useful lives 2019 2018 Lab equipment 5 Years $ 2,250 $ 2,203 Furniture and fixtures 5 Years 112 110 Computer equipment and software 3 Years 508 398 Leasehold improvements Lesser of useful life or lease term 1,328 1,290 Total 4,198 4,001 Less accumulated depreciation and amortization (3,521) (3,243) Property and equipment, net $ 677 $ 758

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2019
Accrued Expenses
Accrued Expenses	Accrued expenses consisted of the following (in thousands): December 31, 2019 2018 Compensation and related benefits $ 2,310 $ 1,760 Interest 41 42 Professional fees 641 552 Accrued milestone payments — 2,500 Research and development expenses 35 133 Other 506 166 $ 3,533 $ 5,153

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt
Schedule of long term debt	Long‑term debt consisted of the following at December 31, 2019 and 2018 (in thousands): December 31, 2019 2018 OrbiMed Term Loan (related party) $ 30,000 $ 30,000 End of term charge 3,000 3,000 Unamortized end of term charge and issuance costs (2,757) (3,267) Long-term debt with related party $ 30,243 $ 29,733

Redeemable Convertible Prefer_2

Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) (Tables)	12 Months Ended
	Dec. 31, 2019
Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit)
Schedule of Redeemable Convertible Preferred Stock and Stockholders’ Deficit	Exercise Expiration Outstanding price dates Common stock warrants issued to MidCap 8,379 $ 28.65 Common stock warrants issued to note payable holders 15,712 28.65 Common stock warrants issued to convertible promissory note holders 64,465 $ 28.65 88,556

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Stock-Based Compensation
Schedule of stock based compensation expense categories in statement of operations	Year ended December 31, 2019 2018 2017 Sales and marketing $ 164 $ 68 $ 44 General and administrative 225 115 116 Research and development 68 33 37 Total stock‑based compensation $ 457 $ 216 $ 197
Schedule of stock option activity	Weighted average Weighted remaining Number of average exercise contractual term shares price per share (years) Outstanding at January 1, 2017 282,331 $ 5.77 Granted 84,587 5.93 Exercised (404) 5.19 Early exercised (830) 5.93 Canceled/forfeited (14,770) 5.87 Outstanding at December 31, 2017 350,914 5.81 Granted 152,016 5.93 Exercised (1,377) 5.57 Early exercised (427) 5.93 Canceled/forfeited (11,904) 5.93 Outstanding at December 31, 2018 489,222 5.84 Granted 978,415 12.51 Exercised (2,527) 5.93 Early exercised (471) 5.93 Canceled/forfeited (43,697) 8.58 Outstanding at December 31, 2019 1,420,942 $ 10.35 8.75 Vested and expected to vest at December 31, 2019 1,317,047 $ 10.23 8.68 Exercisable at December 31, 2019 345,881 $ 5.87 6.18
Schedule of activity relating to early exercise of stock options	Number of shares Unvested balance at January 1, 2017 7,159 Early exercised 830 Vested (6,955) Unvested balance at December 31, 2018 1,034 Early exercised 427 Vested (549) Unvested balance at December 31, 2018 912 Early exercised 471 Vested (628) Unvested balance at December 31, 2019 755
Schedule of weighted average assumptions	Year ended December 31, 2019 2018 2017 Expected dividend yield — — — Expected volatility 55.9 % 56.5 % 50.0 % Risk‑free interest rate 1.82 % 2.77 % 2.07 % Expected term 6.24 Years 6.25 Years 6.25 Years

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Taxes
Summary of Significant components of the Company’s deferred tax assets	December 31, 2019 2018 Deferred tax assets Net operating loss carryforwards $ 32,704 $ 26,993 Research and development credits 853 701 Depreciation and amortization 578 825 Accrued LifeCell settlement — 252 Accrued expenses and other 259 191 Inventory reserve 417 425 Gross deferred tax asset 34,811 29,387 Valuation allowance (34,811) (29,387) Net deferred tax asset $ — $ —
Schedule of Company’s net operating loss (NOL) carryforwards	December 31, 2019 2018 NOL carryforwards Federal $ 122,925 $ 99,939 State 106,062 91,797
Schedule of reconciliation of income tax benefit	Year ended December 31, 2019 2018 2017 Rate reconciliation Federal tax benefit at statutory rate (21.0) % (21.0) % (34.0) % State rate, net of federal benefit (2.9) (4.7) (5.2) Permanent differences 0.4 0.5 5.5 Change in federal rate — — 48.0 Research and development (0.7) (0.8) — Change in valuation allowance 24.2 26.3 (15.1) Other — (0.3) 0.8 Total tax provision — % — % — %

Contingencies and Commitments (

Contingencies and Commitments (Tables)	12 Months Ended
	Dec. 31, 2019
Contingencies and Commitments
Schedule of future minimum lease payments under the facility operating lease agreement	The future minimum lease payments under the facility operating lease agreement as of December 31, 2019 are as follows (in thousands): 2020 $ 217 2021 92 $ 309

Risks and Liquidity (Details)

Risks and Liquidity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	Nov. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Unusual Risk or Uncertainty [Line Items]
Accumulated deficit		$ (167,859)	$ (137,860)
Received net proceeds of after deducting underwriting discounts, commissions and other offering expenses	$ 50,600
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 - Segments (Details)	12 Months Ended
	Dec. 31, 2019segment
Segments
Number of segments	1

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Short-Term Investments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Cash and Cash Equivalents [Line Items]
Other-than-temporary impairments	$ 0
Short-term Investments [Member]
Cash and Cash Equivalents [Line Items]
Cost	9,284
Amortization/ Accretion	5
Unrealized Gains/(Losses)	(4)
Estimated Fair Value	$ 9,285

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Inventory (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Inventory
Inventory consigned to others	$ 1.1	$ 0.8

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Intangible Assets
Intangible assets		$ 4,000
Amortization expense related to intangible assets	$ 304	$ 785
Remaining life of intangible assets	9 years 7 months 6 days
Intangible assets future amortization
Year 1	$ 300
Year 2	300
Year 3	300
Year 4	300
Year 5	300
Thereafter	$ 1,400

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Long-Lived Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Long-Lived Assets
Impairment of Long-Lived Assets	$ 0	$ 0

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Revenue Recognition (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Summary of Significant Accounting Policies
Incremental costs of obtaining a contract	$ 0

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Revenue Disaggregated (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 15,446	$ 8,274	$ 4,245
OviTex [Member]
Disaggregation of Revenue [Line Items]
Revenue	14,041
OviTex PRS [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 1,405

Summary of Significant Accou_12

Summary of Significant Accounting Policies - Fair value of financial instruments (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Level 1 | Money market funds
Fair value of financial instruments
Cash equivalents	$ 34,918	$ 16,002
Level 2 | Corporate debt securities
Fair value of financial instruments
Cash equivalents	8,850
Short-term investment – corporate debt securities	9,285
Level 2 | Agency securities
Fair value of financial instruments
Cash equivalents	$ 1,000
Level 3 | Warrants
Fair value of financial instruments
Warrant liability		$ 1,640

Summary of Significant Accou_13

Summary of Significant Accounting Policies - Warrant liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Beginning balance	$ 1,640	$ 1,697
Change in fair value of warrants	5	(244)	$ (54)
Conversion into common stock warrants	$ (1,645)
Ending balance		1,640	1,697
MidCap Credit Facility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Change in fair value of warrants		$ 187
Convertible promissory notes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Change in fair value of warrants			1,408
Notes payable
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Change in fair value of warrants			$ 343

Summary of Significant Accou_14

Summary of Significant Accounting Policies - Fair value of warrant (Details)	Nov. 13, 2019	Dec. 31, 2018
MidCap Credit Facility
Fair value of the warrants
Remaining contractual term in years	8 years 4 months 24 days	9 years 3 months 18 days
Convertible promissory notes
Fair value of the warrants
Remaining contractual term in years	7 years 2 months 12 days	8 years 1 month 6 days
Notes payable
Fair value of the warrants
Remaining contractual term in years	7 years 4 months 24 days	8 years 3 months 18 days
Expected volatility | MidCap Credit Facility
Fair value of the warrants
Fair value of warrants	57.5	58.1
Expected volatility | Convertible promissory notes
Fair value of the warrants
Fair value of warrants	57.4	57
Expected volatility | Notes payable
Fair value of the warrants
Fair value of warrants	57.5	57.4
Risk-free interest rate | MidCap Credit Facility
Fair value of the warrants
Fair value of warrants	2.04	2.69
Risk-free interest rate | Convertible promissory notes
Fair value of the warrants
Fair value of warrants	1.79	2.64
Risk-free interest rate | Notes payable
Fair value of the warrants
Fair value of warrants	1.79	2.64

Summary of Significant Accou_15

Summary of Significant Accounting Policies - Potentially dilutive securities (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	1,510,253	4,042,945
Stock Options
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	1,421,697	490,134
Series A
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares		911,336
Series B
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares		2,552,919
Series B Redeemable Convertible Preferred Stock Warrants
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares		88,556
Common Stock Warrants
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	88,556

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property and Equipment
Property and Equipment, Total	$ 4,198	$ 4,001
Less accumulated depreciation and amortization	(3,521)	(3,243)
Property and equipment, net	677	758
Depreciation expense	278	463	$ 761
Umbrella Agreement with Aroa
Property and Equipment
Property and Equipment, Total	200	200
Lab equipment
Property and Equipment
Property and Equipment, Total	$ 2,250	2,203
Estimated useful lives	5 years
Furniture and fixtures
Property and Equipment
Property and Equipment, Total	$ 112	110
Estimated useful lives	5 years
Computer equipment and software
Property and Equipment
Property and Equipment, Total	$ 508	398
Estimated useful lives	3 years
Leasehold improvements
Property and Equipment
Property and Equipment, Total	$ 1,328	$ 1,290

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Expenses
Compensation and related benefits	$ 2,310	$ 1,760
Interest	41	42
Professional fees	641	552
Accrued milestone payments		2,500
Research and development expenses	35	133
Other	506	166
Accrued Expenses, Total	$ 3,533	$ 5,153

Debt - Schedule of long term de

Debt - Schedule of long term debt (Details) - OrbiMed Term Loans (related party) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt
Long Term Debt	$ 30,000	$ 30,000
End of term charge	3,000	3,000
Unamortized issuance costs	(2,757)	(3,267)
Long-term debt	$ 30,243	$ 29,733

Debt - OrbiMed Term Loan (relat

Debt - OrbiMed Term Loan (related party) (Details)	12 Months Ended
	Dec. 31, 2019USD ($)tranche	Dec. 31, 2018USD ($)	Nov. 30, 2018USD ($)
OrbiMed Term Loans (related party)
Debt
Number of Tranches | tranche	2
Minimum Cash Balance	$ 2,000,000
Interest due to unpaid obligation	3.00%
Interest Rate (as a percent)	9.75%		7.75%
Number of Installment	60 months
Exit fee (as a percent)	10.00%
Administration Fees	$ 10,000
Debt issuance costs	300,000
Interest Expenses	$ 3,600,000	$ 600,000
OrbiMed Term Loans (related party) | Prior to second anniversary
Debt
Percentage of prepayment penalty on prepaid principal amount	10.00%
OrbiMed Term Loans (related party) | After second anniversary but prior to third anniversary
Debt
Percentage of prepayment penalty on prepaid principal amount	5.00%
OrbiMed Term Loans (related party) | After third anniversary
Debt
Percentage of prepayment penalty on prepaid principal amount	2.50%
OrbiMed Term Loans (related party) | LIBOR
Debt
Interest Rate (as a percent)	2.00%
OrbiMed Term Loans (related party) | Maximum
Debt
Debt Amount			$ 35,000,000
Tranche One
Debt
Debt Amount			30,000,000
Tranche Two
Debt
Debt Amount			$ 5,000,000

Debt - MidCap Credit Facility (

Debt - MidCap Credit Facility (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 30, 2018USD ($)tranche$ / sharesshares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Debt
Loss on extinguishment of debt			$ (1,822)
MidCap Credit Facility
Debt
Debt Amount	$ 14,000
Contractual term	10 years
Fair Value of warrants	$ 200
Third party and lender fees	800
End of Term Charge	400	$ 400
Loss on extinguishment of debt			1,200
Interest Expenses			$ 600
Revolver
Debt
Debt Amount	3,500
MidCap Term Loans
Debt
Debt Amount	$ 10,500
Number of Tranches | tranche	2
MidCap Tranche 1
Debt
Debt Amount	$ 8,000
MidCap Tranche 2
Debt
Debt Amount	$ 2,500
LIBOR | Revolver
Debt
Interest Rate		3.75%
LIBOR | MidCap Term Loans
Debt
Interest Rate		7.00%
Series B | MidCap Tranche 1
Debt
Warrants to purchase shares of the company | shares	206,897
Exercise Price | $ / shares	$ 1.16

Debt - Notes Payable (Details)

Debt - Notes Payable (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Debt
Loss on extinguishment of debt		$ (1,822)
Note A
Debt
Debt Amount				$ 5,000
Interest Rate (as a percent)				9.45%
Loss on extinguishment of debt		600
Interest Expenses		$ 400	$ 400
Series B Warrants
Debt
Number of warrants granted	387,932
Term of warrant	10 years
warrants exercise price	$ 1.16

Debt - Convertible Promissory N

Debt - Convertible Promissory Note (Details) - Convertible promissory notes - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2017	Jan. 31, 2017
Debt
Interest Expenses		$ 1.4
Debt issuance costs		0.1
Series B
Debt
Debt Amount	$ 0.7		$ 7.4
Interest Rate (as a percent)			12.00%
Shares issued upon conversion	6,951,175
Term of warrant	10 years
Percent of Note Principal to be considered for shares issuable	25.00%
warrants exercise price	$ 1.16
Exercise price of the warrants	1,591,864
Fair Value of warrants		$ 1.4

Redeemable Convertible Prefer_3

Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - IPO (Details) $ / shares in Units, $ in Millions	1 Months Ended
	Nov. 30, 2019USD ($)$ / sharesshares
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Received net proceeds of after deducting underwriting discounts, commissions and other offering expenses | $	$ 50.6
IPO
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Number of shares issued and sold	4,398,700
Public offering price per share | $ / shares	$ 13
Over-Allotment Option
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Number of shares issued and sold	398,700
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

Redeemable Convertible Prefer_4

Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Issue price	$ 0.001	$ 0.001
Series B
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Shares issued (in shares)			12,931,034
Issue price			$ 1.16
Gross proceeds			$ 15
Transaction Fee			$ 0.3
Convertible Preferred Stock | Series B
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Shares issued (in shares)	12,527,956	3,607,069	6,951,175
Issue price	$ 1.16	$ 1.16
Gross proceeds	$ 14.5	$ 4.2
Transaction Fee	$ 0.2	$ 0.2

Redeemable Convertible Prefer_5

Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - Dividends (Details) - $ / shares	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Temporary Equity [Line Items]
Issue price	$ 0.001	$ 0.001
Series B
Temporary Equity [Line Items]
Issue price			$ 1.16

Redeemable Convertible Prefer_6

Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - Voting Rights (Details)	1 Months Ended
	Nov. 30, 2019shares
Warrants | IPO
Temporary Equity [Line Items]
Conversion of Stock, Shares Converted	88,556

Redeemable Convertible Prefer_7

Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - Warrants outstanding (Details)	Dec. 31, 2019$ / sharesshares
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Warrants outstanding	88,556
MidCap Credit Facility | Warrants
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Warrants outstanding	8,379
warrants exercise price | $ / shares	$ 28.65
Notes payable | Warrants
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Warrants outstanding	15,712
warrants exercise price | $ / shares	$ 28.65
Convertible promissory notes | Warrants
Redeemable Convertible Preferred Stock and Stockholders’ Deficit
Warrants outstanding	64,465
warrants exercise price | $ / shares	$ 28.65

Stock-Based Compensation - Expe

Stock-Based Compensation - Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Total stock-based compensation	$ 457	$ 216	$ 197
Sales and marketing
Stock-Based Compensation
Total stock-based compensation	164	68	44
General and administrative
Stock-Based Compensation
Total stock-based compensation	225	115	116
Research and development
Stock-Based Compensation
Total stock-based compensation	$ 68	$ 33	$ 37

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of shares
Balance at beginning of period	489,222	350,914	282,331
Granted	978,415	152,016	84,587
Exercised	(2,527)	(1,377)	(404)
Early exercised	(471)	(427)	(830)
Canceled/forfeited	(43,697)	(11,904)	(14,770)
Balance at end of period	1,420,942	489,222	350,914
Vested and expected to vest at end of period	1,317,047
Exercisable at end of period	345,881
Weighted average exercise price per share
Balance at beginning of period (in dollars per share)	$ 5.84	$ 5.81	$ 5.77
Granted ( in dollars per share)	12.51	5.93	5.93
Exercised (in dollars per share)	5.93	5.57	5.19
Early exercised (in dollars per share)	5.93	5.93	5.93
Canceled/forfeited (in dollars per share)	8.58	5.93	5.87
Balance at end of period (in dollars per share)	10.35	$ 5.84	$ 5.81
Vested and expected to vest at end of period (in dollars per share)	10.23
Exercisable at end of period (in dollars per share)	$ 5.87
Weighted average remaining contractual term
Weighted average remaining contractual term, outstanding	8 years 9 months
Weighted average remaining contractual term, Vested and expected to vest	8 years 8 months 5 days
Weighted average remaining contractual term, Exercisable	6 years 2 months 5 days

Stock-Based Compensation - Earl

Stock-Based Compensation - Early Exercise Of Stock Options (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Unvested balance at beginning of period	912	1,034	7,159
Early exercised	471	427	830
Vested	(628)	(549)	(6,955)
Unvested balance at end of period	755	912	1,034

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted average assumptions (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Expected volatility	55.90%	56.50%	50.00%
Risk-free interest rate	1.82%	2.77%	2.07%
Expected term	6 years 2 months 27 days	6 years 3 months	6 years 3 months

Stock-Based Compensation - Narr

Stock-Based Compensation - Narratives (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Vesting Period	3 years
2012 Stock Incentive Plan
Stock-Based Compensation
Vesting Period	4 years
Vesting Term	P10Y
Weighted Average Grant Date Fair Value per share	$ 6.81	$ 1.08	$ 0.54
Unrecognized compensation expense	$ 5,700,000
Weighted Average period for recognition of unrecognized expenses	3 years 4 months 24 days
2012 Stock Incentive Plan | Current Liability
Stock-Based Compensation
Proceeds from early exercise of option	$ 4,000
2019 Equity Incentive Plan
Stock-Based Compensation
Shares available for future issuance	323,715

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - shares	1 Months Ended	12 Months Ended
	Nov. 30, 2019	Dec. 31, 2019
Defined Contribution Plan Disclosure [Line Items]
Maximum contribution of participant (as a percent)		100.00%
Percentage of employer's contribution		50.00%
Percentage of employer's contribution to employees		6.00%
Participants vesting period		3 years
Employee Stock Purchase Plan 2019
Defined Contribution Plan Disclosure [Line Items]
Shares reserved for future issuance	107,887
Increase in number of shares	107,887
Increase in percentage of shares outstanding	1.00%
Discount on purchase of common stock	5.00%
Shares issued		0

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets
Net operating loss carryforwards	$ 32,704	$ 26,993
Research and development credits	853	701
Depreciation and amortization	578	825
Accrued LifeCell settlement		252
Accrued expenses and other	259	191
Inventory reserve	417	425
Gross deferred tax asset	34,811	29,387
Valuation allowance	(34,811)	(29,387)
Net deferred tax asset	$ 0	$ 0

Income Taxes - NOL carryforward

Income Taxes - NOL carryforwards (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Federal
Income Taxes
NOL carryforwards	$ 122,925	$ 99,939
State
Income Taxes
NOL carryforwards	$ 106,062	$ 91,797

Income Taxes - Rate reconciliat

Income Taxes - Rate reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Rate reconciliation
Federal tax benefit at statutory rate	21.00%	21.00%	34.00%
State rate, net of federal benefit	2.90%	4.70%	5.20%
Permanent differences	0.004	0.005	0.055
Change in federal rate			48.00%
Research and development	0.70%	0.80%
Change in valuation allowance	24.20%	26.30%	(15.10%)
Other		(0.30%)	0.80%
Total tax provision	0.00%	0.00%	0.00%

Income Taxes - Narratives (Deta

Income Taxes - Narratives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Unrecognized tax benefits	$ 0	$ 0
Increase (decrease) in valuation allowance	$ 5,400	$ 5,500
Corporate income tax rate	21.00%	21.00%	34.00%

Contingencies and Commitments_2

Contingencies and Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Gain on litigation settlement		$ 2,160
Litigation initiated by LifeCell
Loss Contingencies [Line Items]
Estimated present value of the future revenue milestone payments		1,000
Noncash interest expense	$ 20	200	$ 300
National Union Litigation
Loss Contingencies [Line Items]
Legal and other costs		0	$ 400
Damaged Sought	5,000
Damaged received		2,400
Payment to broker		200
Gain on litigation settlement		$ 2,200
Payment within 30 days of settlement agreement | Litigation initiated by LifeCell
Loss Contingencies [Line Items]
Amount awarded to other party	1,000
Payment upon company achieving set revenue milestones | Litigation initiated by LifeCell
Loss Contingencies [Line Items]
Amount awarded to other party	$ 3,000

Contingencies and Commitments -

Contingencies and Commitments - Agreement with Aroa (Details) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Apr. 30, 2014	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2012	Jul. 31, 2012
Contingencies and Commitments
Agreement extended term				10 years
Issuance of stock				$ 50,629
Umbrella Agreement with Aroa
Contingencies and Commitments
Payment for agreement	$ 4,000		$ 1,000
Issuance of stock (in shares)			74,316
Issuance of stock			$ 300
Payment for agreement			$ 1,000
Payment for agreement		$ 1,000
Percentage of transfer price						200.00%	150.00%
Increase in transfer price quarterly percentage				27.00%
Purchase commitments				$ 8,300
Number of days for product supply				60 days
Percentage of products ordered to be supplied				75.00%
Royalty percentage of net sales				6.00%
Capital cost payments				50.00%
Umbrella Agreement with Aroa | European territory
Contingencies and Commitments
Liability Recognized					$ 1,000
Developed right intangible asset					1,000
Payments made upon approval				$ 500	500
Sales milestone payments due					1,000
Purchase commitments				2,800
Purchase commitments due year one and two				500
Purchase commitments due year three				500
Purchase commitments due year four				800
Purchase commitments due year five				1,000
Purchase commitments due year Six				1,000
Payment for extending deadlines to file an investigational device exemption with the FDA				500
Umbrella Agreement with Aroa | North American territory
Contingencies and Commitments
Liability Recognized					3,000
Developed right intangible asset					3,000
Sales Milestone Payment				2,000	1,000
Sales milestone payments due					$ 2,000
Purchase commitments				11,000
Purchase commitments due year one and two				2,000
Purchase commitments due year three				2,000
Purchase commitments due year four				3,000
Purchase commitments due year five				4,000
Purchase commitments due year Six				$ 5,000

Contingencies and Commitments_3

Contingencies and Commitments - Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases, Operating [Abstract]
Operating Leases, Rent Expense	$ 300	$ 300	$ 300
2020	217
2021	92
Future minimum lease payments	$ 309