Equillium (EQ) 10-Q 15 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 13, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	EQ
Entity Registrant Name	EQUILLIUM, INC.
Entity Central Index Key	1,746,466
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock Shares Outstanding		17,376,236

Balance Sheets

Balance Sheets - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 4,982,505	$ 7,103,553
Prepaid expenses and other current assets	77,805	45,813
Total current assets	5,060,310	7,149,366
Property and equipment, net	31,887	2,077
Deferred offering costs	1,329,350
Total assets	6,421,547	7,151,443
Current liabilities:
Accounts payable	1,230,262	243,741
Accrued expenses	1,449,492	325,079
Total current liabilities	2,679,754	568,820
Long-term convertible promissory notes	10,321,940	6,994,847
Long-term convertible promissory notes, related party	1,274,784	1,064,019
Biocon anti-dilution right	2,375,109	775,842
Other non-current liabilities	148,724
Total liabilities	16,800,311	9,403,528
Commitments and contingencies
Stockholders' deficit:
Common stock, $0.0001 par value; 43,100,000 shares authorized at December 31, 2017 and September 30, 2018 (unaudited); 10,708,074 and 11,130,446 shares issued and outstanding as of December 31, 2017 and September 30, 2018 (unaudited), respectively	166	124
Additional paid-in capital	141,526	9,665
Accumulated deficit	(10,520,456)	(2,261,874)
Total stockholders' deficit	(10,378,764)	(2,252,085)
Total liabilities and stockholders' deficit	$ 6,421,547	$ 7,151,443

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	43,100,000	43,100,000
Common stock, shares issued	11,130,446	10,708,074
Common stock, shares outstanding	11,130,446	10,708,074

Statement of Operations (Unaudi

Statement of Operations (Unaudited) - USD ($)	3 Months Ended		7 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2018
Operating expenses:
Research and development	$ 1,222,296	$ 49,949	$ 851,313	$ 2,425,213
General and administrative	1,003,584	33,762	220,935	1,962,276
Total operating expenses	2,225,880	83,711	1,072,248	4,387,489
Loss from operations	(2,225,880)	(83,711)	(1,072,248)	(4,387,489)
Other expense (income):
Interest expense	1,221,100	15,123	22,192	2,329,296
Interest income	(27,544)			(57,470)
Change in fair value of Biocon anti-dilution right	1,496,987	42,191	61,078	1,599,267
Total other expense (income)	2,690,543	57,314	83,270	3,871,093
Net loss and comprehensive loss	$ (4,916,423)	$ (141,025)	$ (1,155,518)	$ (8,258,582)
Net loss per share, basic and diluted	$ (0.44)	$ (0.01)	$ (0.16)	$ (0.76)
Weighted-average common shares outstanding, basic and diluted	11,078,840	10,708,074	7,127,537	10,835,483

Statements of Cash Flows (unaud

Statements of Cash Flows (unaudited) - USD ($)	7 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2018
Operating activities:
Net loss	$ (1,155,518)	$ (8,258,582)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization		3,709
Stock-based compensation		131,355
Deferred rent		487
Non-cash interest expense	22,192	2,329,296
Change in fair value of Biocon anti-dilution right	61,078	1,599,267
Non-cash research license expense	615,091
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(28,057)	(31,992)
Accounts payable	33,269	351,997
Accrued expenses	184,528	175,181
Net cash used in operating activities	(267,417)	(3,699,282)
Investing activities:
Purchases of property and equipment		(25,381)
Net cash used in investing activities		(25,381)
Financing activities:
Proceeds from issuance of convertible promissory notes, net		1,599,012
Proceeds from issuance of convertible promissory notes related party, net	1,000,000
Proceeds from issuance of common stock	100
Proceeds from exercise of stock options, including early exercise		199,210
Costs paid in connection with initial public offering		(194,607)
Net cash provided by financing activities	1,000,100	1,603,615
Net decrease in cash and cash equivalents	732,683	(2,121,048)
Cash and cash equivalents at beginning of period		7,103,553
Cash and cash equivalents at end of period	732,683	4,982,505
Supplemental disclosures of noncash activities:
Issuance of common stock to Biocon for license	9,689
Amounts included in accounts payable for purchases of property and equipment		8,138
Deferred initial public offering costs included in accounts payable and accrued expenses		1,134,743
Cash flow noncash investing and financing activities	$ 9,689	$ 1,142,881

Organization and Accounting Pro

Organization and Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Accounting Pronouncements	1. Organization and Accounting Pronouncements Description of Business Equillium, Inc. (the “Company”) was incorporated in the state of Delaware on March 16, 2017. The Company is engaged in the research and development of products for severe autoimmune and inflammatory, or immuno-inflammatory, disorders with high unmet medical need. The Company has devoted substantially all of its efforts to organizing and staffing the company, business planning, raising capital, in-licensing rights to EQ001, conducting preclinical research, filing its initial IND and preparing to commence clinical development of EQ001. In addition, the Company has a limited operating history, has not generated revenues from its principal operations, and the sales and income potential of its business is unproven. The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the Securities and Exchange commission (SEC) related to a quarterly report on Form 10-Q. Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations. The unaudited interim financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The operating results presented in these unaudited financial statements are not necessarily indicative of the results that may be expected for any future periods. These unaudited financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto for the year ended December 31, 2017 included in the Company’s final prospectus filed with the SEC on October 10, 2018 relating to the Company’s Registration Statement on Form S-1 (File No. 333-227387) for its initial public offering (IPO). In October 2018, the Company implemented a 1-for-8.62 forward stock split of its outstanding common stock. The accompanying financial statements give retroactive effect to the forward split for all periods presented. In October 2018, the Company completed an initial public offering, or IPO, selling 4,670,000 shares of common stock at an offering price of $14.00 per share. The Company received net proceeds of approximately $58.7 million, after deducting underwriting discounts, commissions and estimated offering-related transaction costs. In November 2018, the Company sold an aggregate of 445,097 shares of common stock pursuant to the underwriters’ partial exercise of their option to purchase additional shares Recent Accounting Pronouncements In February 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-02, Leases (Topic 842), In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (Topic 230) In June 2018, the FASB issued ASU 2018-07, Improvements to Non-Employee Share-Based Payment Accounting (Topic 718) Revenue from Contracts with Customers (Topic 606)

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The Company’s financial statements are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of the Company’s financial statements requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the financial statements and accompanying notes. Management evaluates its estimates on an ongoing basis. Although estimates are based on the Company’s historical experience, knowledge of current events, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Concentration of Credit Risk Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. Comprehensive Loss The Company is required to report all components of comprehensive loss, including net loss, in the financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized gains and losses on investments and foreign currency gains and losses. Comprehensive loss is the same as the net loss for the nine months ended September 30, 2018 (unaudited) and for the period March 16, 2017 (inception) through September 20, 2017 (unaudited). Fair Value of Financial Instruments The carrying amounts of all prepaid and other current assets, accounts payable, accrued expenses, and debt are considered to be representative of their respective fair values because of the short-term nature of those instruments. Deferred Initial Public Offering Costs Costs incurred in connection with the IPO primarily consist of direct incremental legal, printing and accounting fees. IPO costs are capitalized as incurred and will be offset against proceeds upon consummation of the offering. In the event the offering had been terminated or abandoned, deferred IPO costs would have been expensed in the period such determination had been made. As of September 30, 2018 (unaudited) and December 31, 2017, there was $1.3 million and $0, respectively, of deferred IPO costs included in other long-term assets on the Company’s balance sheets. Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally two to five years, or the remaining term of the lease). Accrued Research and Development Expense The Company is required to estimate its expenses resulting from its obligations under contracts with vendors, consultants and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical or clinical study as measured by the timing of various aspects of the study or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and other key personnel as to the progress of studies, or other services being conducted. During the course of a study, the Company adjusts its rate of expense recognition if actual results differ from its estimates. Research and Development Research and development expenses include salaries, benefits, costs to third-party contractors to perform research and development activities, and associated overhead expenses. Research and development costs are expensed as incurred. Patent Costs The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses in the statement of operations. Debt Costs The Company capitalizes related debt issuance costs and amortizes them over the life of the loan using the effective interest method. Conversion discounts on the Company’s convertible promissory notes based on a future round of financing are recognized as additional interest expense over the life of the debt using the effective interest method. Deferred Rent Deferred rent consists of the difference between cash payments and the recognition of rent expense on a straight-line basis for the facilities the Company leases. The Company’s leases for its facilities provide for fixed increases in minimum annual rental payments. The total amount of rental payments due over the lease terms are being charged to rent expense ratably over the life of the leases. Biocon Anti-Dilution Right The Company has committed to issue to Biocon SA (together with Biocon Limited, “Biocon”) additional shares of common stock to maintain Biocon’s ownership interest at 19.5% of the diluted Company shares outstanding (as defined in the License Agreements (as defined below)) until the Company has received aggregate cumulative gross proceeds from sales of equity securities of $15.0 million (“Biocon Anti-Dilution Right”). As an obligation exists to issue a variable number of shares and that obligation is not indexed to the Company’s common stock, the Biocon Anti-Dilution Right has been classified as a liability in the accompanying balance sheet. The Biocon Anti-Dilution Right is recorded at fair value using the precedent transaction method. The fair value of the Biocon Anti-Dilution Right is re-measured at each financial reporting period with any changes in fair value recognized as a component of other expense (income). Stock-Based Compensation Stock-based compensation expense represents the cost of the grant date fair value of employee and non-employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis, net of actual forfeitures during the period. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model. The exercise price for all stock options granted was at the estimated fair value of the underlying common stock as determined on the date of grant by the Company’s Board of Directors. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities include outstanding stock options under the Company’s equity incentive plan and have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Three months ended September 30, Nine Months Ended September 30, Period March 16, 2017 (inception) through September 30, 2018 2017 2018 2017 (unaudited) (unaudited) Common stock options 434,280 - 434,280 - Total 434,280 - 434,280 -

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: 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 for similar assets and liabilities in active markets, 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 liability. 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). At September 30, 2018 (unaudited) and December 31, 2017, the Company did not have financial assets that are measured at fair value on a recurring basis. The carrying amounts of the Company’s financial instruments, including cash and cash equivalents, prepaid and other current assets, accounts payable, and accrued liabilities, approximate fair value due to their short maturities. The Company believes the fair value of its convertible promissory notes approximates its carrying value. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. The Company estimated the fair value of its Biocon Anti-Dilution Right (see Note 5) at the time of issuance and remeasures it at each reporting date using the precedent transaction method. The precedent transaction method was applied to solve for the enterprise value of the Company under two scenarios: with the Biocon Anti-Dilution Right and without the Biocon Anti-Dilution Right. The resulting difference in the enterprise value under these two scenarios is the estimated fair value of the Biocon Anti-Dilution Right. The estimates used to determine the enterprise value of the Company are based, in part, on subjective assumptions and could differ materially in the future. Fluctuations in the fair value of the Biocon Anti-Dilution Right are impacted by unobservable inputs, most significantly the estimated fair value of the Company and probability of achieving different financing scenarios. If the Company does not receive proceeds from an equity financing, the fair value of the Biocon Anti-Dilution Right would be zero. Alternatively, if an equity financing results in gross proceeds of $15.0 million or greater, the fair value of the Biocon Anti-Dilution Right could be as high as $3.2 million. Changes in the estimated fair value of the Company and the probability of achieving different financing scenarios can have a significant impact on the fair value of the Biocon Anti-Dilution Right. Financial liabilities measured at fair value on a recurring basis consist of the Biocon Anti-Dilution Right. As of September 30, 2018 (unaudited) and December 31, 2017, the carrying amount of the Biocon Anti-Dilution Right was $2.4 million and $0.8 million, respectively, which approximates fair value and was determined based upon Level 3 inputs. As of September 30, 2018 (unaudited) and December 31, 2017, the Company did not hold any Level 1 or Level 2 financial liabilities that are recorded at fair value on a recurring basis. The following table presents activity for the Biocon Anti-Dilution Right measured at fair value using Level 3 unobservable inputs as of September 30, 2018 (unaudited) and December 31, 2017: Fair Value Measurements at Reporting Date Using Significant Unobservable Inputs (Level 3) Balance at March 16, 2017 (inception) $ - Issuance of Biocon Anti-Dilution Right 605,402 Changes in fair value reflected as change in fair value of Biocon Anti-Dilution Right 170,440 Balance at December 31, 2017 775,842 Changes in fair value reflected as change in fair value of Biocon Anti-Dilution Right 1,599,267 Balance at September 30, 2018 (unaudited) $ 2,375,109 In connection with the October 2018 IPO, the Company issued to Biocon 228,060 shares of common stock in full satisfaction of the Biocon Anti-Dilution Right. Accordingly, the Company will record in the 4 th

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2018
Accrued Liabilities Current [Abstract]
Accrued Expenses	4. Accrued Expenses Accrued expenses consist of the following: September 30, December 31, 2018 2017 (unaudited) Accrued payroll and other employee benefits $ 326,165 $ 15,548 Accrued interest 478,822 88,372 Preclinical studies 58,229 36,000 Accrued taxes - 184,527 Other accruals 586,276 632 Accrued expenses $ 1,449,492 $ 325,079

Collaboration and License Agree

Collaboration and License Agreement	9 Months Ended
	Sep. 30, 2018
Collaboration And License Agreement [Abstract]
Collaboration and License Agreement	5. Collaboration and License Agreement In May 2017, the Company entered into a collaboration and license agreement, clinical supply agreement, investor rights agreement, and common stock purchase agreement (collectively “License Agreements”) with Biocon. Pursuant to the License Agreements, Biocon granted the Company an exclusive license in the United States and Canada (“Company Territory”) to develop, make, have made, use, sell, have sold, offer for sale, import and otherwise exploit EQ001 and any pharmaceutical composition or preparation containing or comprising EQ001 (“Biocon Product”) that uses Biocon technology or Biocon know-how. Pursuant to the License Agreements, Biocon agreed to be the Company’s exclusive supplier of EQ001 clinical drug product for up to three concurrent orphan drug clinical indications at no cost until the Company’s first U.S. regulatory approval and all other clinical drug product at cost. In consideration of the rights granted to the Company by Biocon, the Company issued Biocon shares of its common stock equal to 19.5% of its outstanding shares at the time of the execution of the License Agreements. Biocon also has a Biocon Anti-Dilution Right (see Note 2) which is recorded at fair value using the precedent transaction method (see Note 3) and was determined to be $605,402 at the time of issuance. As an obligation exists to issue a variable number of shares and such obligation is not indexed to the Company’s common stock, the Biocon Anti-Dilution Right has been classified as a liability in the accompanying balance sheet. The fair value of the Biocon Anti-Dilution Right is re-measured at each financial reporting period with any changes in fair value being recognized as a component of other expense (income). As of September 30, 2018 (unaudited) and December 31, 2017, the fair value of the Biocon Anti-Dilution Right was $2,375,109 and $775,842, respectively. In addition, the Company is obligated to pay Biocon up to an aggregate of $30 million in regulatory milestone payments upon the achievement of certain regulatory approvals and up to an aggregate of $565 million in sales milestone payments upon the achievement of first commercial sale of product and specified levels of product sales. The Company is also required to pay quarterly tiered royalties based on a percentage from the mid-single digits to sub-teen double-digits of net sales of Biocon Products, subject to adjustments in certain circumstances. Biocon is also required to pay the Company royalties at comparable percentages for sales of EQ001 outside of the Company Territory if the approvals in such geographies included or referenced the Company’s data. To date, the Company has not made or received payments in connection with the milestones or royalties within the agreement.

Convertible Promissory Notes

Convertible Promissory Notes	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Convertible Promissory Notes	6. Convertible Promissory Notes In May 2017, the Company issued $1,000,000 in convertible promissory notes to its founders (“Founder Notes”). The Founder Notes accrued interest at a rate of 6% a year and mature one year from issuance. The Founder Notes are convertible at the option of the holder upon a Qualified Financing (as defined below). In October 2017, November 2017, April 2018, and June 2018, the Company entered into note purchase agreements whereby the Company agreed to issue and investors (the “Noteholders”) agreed to purchase $9,407,474 in convertible promissory notes (the “Convertible Promissory Notes”). As part of the October 2017 Convertible Promissory Notes, the Founder Notes were amended and restated on terms matching the Convertible Promissory Notes and the then outstanding principal and accrued interest thereunder was included as the principal amount of each such amended and restated Convertible Promissory Note. The Convertible Promissory Notes accrue interest at a rate of 6% per year and mature two years from their issuance. The Convertible Promissory Notes automatically convert into equity securities sold pursuant to a qualified financing (“Qualified Financing”) transaction from which the Company receives total gross proceeds of not less than $15 million at a conversion price equal to 90% of the per share price paid by investors for such securities if the closing of the financing occurs on or prior to the six month anniversary of the issuance of Convertible Promissory Notes or at a conversion price equal to 80% of the per share price paid by investors for such securities if the closing of the financing occurs after the six month anniversary of the issuance of Convertible Promissory Notes. In connection with the October 2018 IPO, the Convertible Promissory Notes converted into 878,834 shares of common stock. The Company recorded interest expense of $2,329,296 and $22,192 using the effective-interest method for the nine months ended September 30, 2018 (unaudited) and the period March 16, 2017 (inception) through September 30, 2017 (unaudited), respectively, in relation to stated interest and the estimated discount at which the Convertible Promissory Notes will convert. The following is a summary of all debt obligations recorded on the balance sheet at September 30, 2018 and December 31, 2017: September 30, December 31, 2018 2017 (unaudited) Convertible Promissory Notes $ 9,407,474 $ 7,807,474 Accrued discount 2,189,250 251,392 Total notes payable $ 11,596,724 $ 8,058,866

Stockholders' Deficit

Stockholders' Deficit	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Stockholders’ Deficit	7. Stockholders’ Deficit During 2017, the Company issued 8,620,000 shares of common stock to founders at a price of $0.00001 per share and 2,088,074 shares of common stock to Biocon as partial consideration for the License Agreements (Note 5). The shares issued to Biocon were valued at $0.005 per share, resulting in $9,689 of research license expense. Stock Options In December 2017, the Company adopted the 2017 Equity Incentive Plan (the “Plan”). The Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, and other stock awards. As of September 30, 2018 (unaudited) and December 31, 2017, the number of shares reserved under the Plan was 1,189,773. There were 333,121 and 1,189,773 shares available for grant under the Plan as of September 30, 2018 (unaudited) and December 31, 2017, respectively. Options granted under the Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant. The exercise price of each option shall be determined by the Board of Directors based on the estimated fair value of the Company’s stock on the date of the option grant. The exercise price shall not be less than 100% of the fair market value of the Company’s common stock at the time the option is granted. Most option grants generally vest 25% on the first anniversary of the original vesting commencement date, with the balance vesting monthly over the remaining three years and early exercise is permitted. A summary of the Company’s stock option activity under the Plan is as follows: Shares Weighted- Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at December 31, 2017 - $ - - $ - Granted 856,652 3.60 9.82 8,223,638 Exercised 422,372 0.48 9.71 4,721,915 Cancelled - - - - Outstanding at September 30, 2018 (unaudited) 434,280 3.60 9.92 3,501,724 Total cash received from the exercise of stock options was approximately $0.2 million and $0 as of September 30, 2018 (unaudited) and December 31, 2017, respectively. Liability for Early Exercise of Restricted Stock Options All stock option grants under the 2017 Plan provide for exercise of the stock option prior to vesting. Shares of common stock issued upon exercise of unvested options are subject to repurchase by us at the respective original exercise price until vested. Consideration received for the exercise of unvested stock options is recorded as a liability and reclassified into equity as the related award vests. Stock-Based Compensation Expense The Company recorded stock-based compensation expense of $0.1 million and $0 for the three months ended September 30, 2018 and 2017 (unaudited), respectively, and $0.1 million and $0 for the nine months ended September 30, 2018 (unaudited) and for the period March 16, 2017 (inception) through September 30, 2017 (unaudited), respectively. The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows: Nine Months Ended September 30, Period March 16, 2017 (Inception) Through September 30 2018 2017 Weighted-average grant date fair value $5.77 - Risk-free interest rate 2.77% - 2.93% - Expected volatility 88.29% - Expected term (in years) 5.91 - Expected dividend yield 0.00% - 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 volatility. Due to the Company’s limited operating history and lack of company-specific historical or implied volatility as a private company, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available. 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 of the time-to-vesting and the contractual life of the options. Expected dividend yield. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not intend to pay dividends. Forfeitures . The Company reduces stock-based compensation expense for actual forfeitures during the period. As of September 30, 2018 (unaudited) and December 31, 2017, the unrecognized compensation cost related to outstanding employee and nonemployee options was $4,808,531 and $0, respectively, and is expected to be recognized as expense over approximately 3.48 years and 0 years, respectively. Common Stock Reserved for Future Issuance Common stock reserved for future issuance consists of the following as of September 30, 2018 and December 31, 2017: September 30, December 31, 2018 2017 (unaudited) Stock options issued and outstanding 434,280 - Authorized for future stock awards or options grants 1,090,392 1,189,773 Total 1,524,672 1,189,773

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	8. Subsequent Events In October 2018, the Company implemented a 1-for-8.62 forward stock split of its outstanding common stock. The accompanying financial statements give retroactive effect to the forward split for all periods presented. In October 2018, the Company completed an initial public offering, or IPO, selling 4,670,000 shares of common stock at an offering price of $14.00 per share. The Company received net proceeds of approximately $58.7 million, after deducting underwriting discounts, commissions and estimated offering-related transaction costs. In connection with the IPO, the convertible promissory notes and Biocon Anti-Dilution feature automatically converted into an aggregate of 1,106,894 shares of common stock. In November 2018, pursuant to the Underwriting Agreement, the Underwriters elected to purchase a total of an additional 445,097 shares of common stock of the Company, resulting in net proceeds of approximately $5.8 million

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-02, Leases (Topic 842), In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (Topic 230) In June 2018, the FASB issued ASU 2018-07, Improvements to Non-Employee Share-Based Payment Accounting (Topic 718) Revenue from Contracts with Customers (Topic 606)
Use of Estimates	Use of Estimates The Company’s financial statements are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of the Company’s financial statements requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the financial statements and accompanying notes. Management evaluates its estimates on an ongoing basis. Although estimates are based on the Company’s historical experience, knowledge of current events, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.
Comprehensive Loss	Comprehensive Loss The Company is required to report all components of comprehensive loss, including net loss, in the financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized gains and losses on investments and foreign currency gains and losses. Comprehensive loss is the same as the net loss for the nine months ended September 30, 2018 (unaudited) and for the period March 16, 2017 (inception) through September 20, 2017 (unaudited).
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of all prepaid and other current assets, accounts payable, accrued expenses, and debt are considered to be representative of their respective fair values because of the short-term nature of those instruments.
Deferred Initial Public Offering Costs	Deferred Initial Public Offering Costs Costs incurred in connection with the IPO primarily consist of direct incremental legal, printing and accounting fees. IPO costs are capitalized as incurred and will be offset against proceeds upon consummation of the offering. In the event the offering had been terminated or abandoned, deferred IPO costs would have been expensed in the period such determination had been made. As of September 30, 2018 (unaudited) and December 31, 2017, there was $1.3 million and $0, respectively, of deferred IPO costs included in other long-term assets on the Company’s balance sheets.
Property and Equipment	Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally two to five years, or the remaining term of the lease).
Accrued Research and Development Expense	Accrued Research and Development Expense The Company is required to estimate its expenses resulting from its obligations under contracts with vendors, consultants and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical or clinical study as measured by the timing of various aspects of the study or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and other key personnel as to the progress of studies, or other services being conducted. During the course of a study, the Company adjusts its rate of expense recognition if actual results differ from its estimates.
Research and Development	Research and Development Research and development expenses include salaries, benefits, costs to third-party contractors to perform research and development activities, and associated overhead expenses. Research and development costs are expensed as incurred.
Patent Costs	Patent Costs The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses in the statement of operations.
Debt Costs	Debt Costs The Company capitalizes related debt issuance costs and amortizes them over the life of the loan using the effective interest method. Conversion discounts on the Company’s convertible promissory notes based on a future round of financing are recognized as additional interest expense over the life of the debt using the effective interest method.
Deferred Rent	Deferred Rent Deferred rent consists of the difference between cash payments and the recognition of rent expense on a straight-line basis for the facilities the Company leases. The Company’s leases for its facilities provide for fixed increases in minimum annual rental payments. The total amount of rental payments due over the lease terms are being charged to rent expense ratably over the life of the leases.
Biocon Anti-Dilution Right	Biocon Anti-Dilution Right The Company has committed to issue to Biocon SA (together with Biocon Limited, “Biocon”) additional shares of common stock to maintain Biocon’s ownership interest at 19.5% of the diluted Company shares outstanding (as defined in the License Agreements (as defined below)) until the Company has received aggregate cumulative gross proceeds from sales of equity securities of $15.0 million (“Biocon Anti-Dilution Right”). As an obligation exists to issue a variable number of shares and that obligation is not indexed to the Company’s common stock, the Biocon Anti-Dilution Right has been classified as a liability in the accompanying balance sheet. The Biocon Anti-Dilution Right is recorded at fair value using the precedent transaction method. The fair value of the Biocon Anti-Dilution Right is re-measured at each financial reporting period with any changes in fair value recognized as a component of other expense (income).
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation expense represents the cost of the grant date fair value of employee and non-employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis, net of actual forfeitures during the period. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model. The exercise price for all stock options granted was at the estimated fair value of the underlying common stock as determined on the date of grant by the Company’s Board of Directors.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities include outstanding stock options under the Company’s equity incentive plan and have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Three months ended September 30, Nine Months Ended September 30, Period March 16, 2017 (inception) through September 30, 2018 2017 2018 2017 (unaudited) (unaudited) Common stock options 434,280 - 434,280 - Total 434,280 - 434,280 -

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Three months ended September 30, Nine Months Ended September 30, Period March 16, 2017 (inception) through September 30, 2018 2017 2018 2017 (unaudited) (unaudited) Common stock options 434,280 - 434,280 - Total 434,280 - 434,280 -

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Summary of Activity for the Biocon Anti-Dilution Right Measured at Fair Value Using Level 3 Unobservable Inputs	The following table presents activity for the Biocon Anti-Dilution Right measured at fair value using Level 3 unobservable inputs as of September 30, 2018 (unaudited) and December 31, 2017: Fair Value Measurements at Reporting Date Using Significant Unobservable Inputs (Level 3) Balance at March 16, 2017 (inception) $ - Issuance of Biocon Anti-Dilution Right 605,402 Changes in fair value reflected as change in fair value of Biocon Anti-Dilution Right 170,440 Balance at December 31, 2017 775,842 Changes in fair value reflected as change in fair value of Biocon Anti-Dilution Right 1,599,267 Balance at September 30, 2018 (unaudited) $ 2,375,109

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2018
Accrued Liabilities Current [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following: September 30, December 31, 2018 2017 (unaudited) Accrued payroll and other employee benefits $ 326,165 $ 15,548 Accrued interest 478,822 88,372 Preclinical studies 58,229 36,000 Accrued taxes - 184,527 Other accruals 586,276 632 Accrued expenses $ 1,449,492 $ 325,079

Convertible Promissory Notes (T

Convertible Promissory Notes (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Summary of All Debt Obligations Recorded on Balance Sheet	The following is a summary of all debt obligations recorded on the balance sheet at September 30, 2018 and December 31, 2017: September 30, December 31, 2018 2017 (unaudited) Convertible Promissory Notes $ 9,407,474 $ 7,807,474 Accrued discount 2,189,250 251,392 Total notes payable $ 11,596,724 $ 8,058,866

Stockholders' Deficit (Tables)

Stockholders' Deficit (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Summary of Stock Option Activity	A summary of the Company’s stock option activity under the Plan is as follows: Shares Weighted- Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at December 31, 2017 - $ - - $ - Granted 856,652 3.60 9.82 8,223,638 Exercised 422,372 0.48 9.71 4,721,915 Cancelled - - - - Outstanding at September 30, 2018 (unaudited) 434,280 3.60 9.92 3,501,724
Summary of Weighted-Average Assumptions Used to Determine Fair Value of Stock Option Grants	The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows: Nine Months Ended September 30, Period March 16, 2017 (Inception) Through September 30 2018 2017 Weighted-average grant date fair value $5.77 - Risk-free interest rate 2.77% - 2.93% - Expected volatility 88.29% - Expected term (in years) 5.91 - Expected dividend yield 0.00% -
Summary of Reserved Shares of Common Stock for Future Issuance	Common stock reserved for future issuance consists of the following as of September 30, 2018 and December 31, 2017: September 30, December 31, 2018 2017 (unaudited) Stock options issued and outstanding 434,280 - Authorized for future stock awards or options grants 1,090,392 1,189,773 Total 1,524,672 1,189,773

Organization and Accounting P_2

Organization and Accounting Pronouncements - Additional Information (Details)	Nov. 15, 2018USD ($)shares	Oct. 31, 2018USD ($)$ / sharesshares	Sep. 30, 2017USD ($)	Sep. 30, 2018
Organization And Accounting Pronouncements [Line Items]
Date of incorporation				Mar. 16, 2017
State of incorporation				Delaware
Proceeds from issuance of common stock			$ 100
Subsequent Event | Underwriters Option
Organization And Accounting Pronouncements [Line Items]
Sale of stock | shares	445,097
Proceeds from issuance of common stock	$ 5,800,000
Subsequent Event | Common Stock
Organization And Accounting Pronouncements [Line Items]
Forward stock split, conversion ratio		8.62
Subsequent Event | Common Stock | IPO
Organization And Accounting Pronouncements [Line Items]
Sale of stock | shares		4,670,000
Sale of stock, per share | $ / shares		$ 14
Net proceeds, after deducting underwriting discounts, commissions and related transaction costs		$ 58,700,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	May 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Deferred offering costs	$ 1,329,350
Collaboration and License Agreement | Biocon Anti-Dilution Right
Summary Of Significant Accounting Policies [Line Items]
Percentage of common stock outstanding shares issued in consideration for collaboration and license agreement	19.50%		19.50%
Aggregate cumulative gross proceeds from sales of equity securities to be received	$ 15,000,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful lives	2 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful lives	5 years
IPO | Other Long-Term Assets
Summary Of Significant Accounting Policies [Line Items]
Deferred offering costs	$ 1,300,000	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	434,280	434,280
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	434,280	434,280

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended			7 Months Ended	9 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2018	Oct. 31, 2018	Dec. 31, 2017	Mar. 16, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Financial Liabilities transfer level 1 to level 2		$ 0			$ 0
Financial Liabilities transfer level 2 to level 1		0			0
Financial Liabilities transfer Into Level 3					0
Financial Liabilities transfer out of Level 3					0
Biocon anti-dilution right		$ 2,375,109			$ 2,375,109		$ 775,842
Common stock, shares issued		11,130,446			11,130,446		10,708,074
Change in fair value of Biocon anti-dilution right		$ 1,496,987	$ 42,191	$ 61,078	$ 1,599,267
Biocon | Subsequent Event | IPO
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Common stock, shares issued						228,060
Biocon Anti-Dilution Right | Scenario, Forecast
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Change in fair value of Biocon anti-dilution right	$ 800,000
Fair Value, Measurements, Recurring | Biocon Anti-Dilution Right
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Biocon anti-dilution right		2,375,109			2,375,109		$ 775,842	$ 0
Fair Value, Measurements, Recurring | Biocon Anti-Dilution Right | Minimum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of Biocon anti-dilution right		0			0
Fair Value, Measurements, Recurring | Biocon Anti-Dilution Right | Maximum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of Biocon anti-dilution right		$ 3,200,000			$ 3,200,000

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Activity for the Biocon Anti-Dilution Right Measured at Fair Value Using Level 3 Unobservable Inputs (Details) - USD ($)	9 Months Ended	10 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at March 16, 2017 (inception)	$ 775,842
Balance at December 31, 2017	2,375,109	$ 775,842
Fair Value, Measurements, Recurring | Biocon Anti-Dilution Right
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at March 16, 2017 (inception)	775,842
Issuance of liability		605,402
Changes in fair value	1,599,267	170,440
Balance at December 31, 2017	$ 2,375,109	$ 775,842

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Accrued Liabilities Current [Abstract]
Accrued payroll and other employee benefits	$ 326,165	$ 15,548
Accrued interest	478,822	88,372
Preclinical studies	58,229	36,000
Accrued taxes		184,527
Other accruals	586,276	632
Accrued expenses	$ 1,449,492	$ 325,079

Collaboration And License Agr_2

Collaboration And License Agreements - Additional Information (Details) - USD ($)	1 Months Ended
	May 31, 2017	Sep. 30, 2018	Dec. 31, 2017
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Fair value of the liability		$ 2,375,109	$ 775,842
Collaboration and License Agreement | Maximum | Biocon
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory milestone payments	$ 30,000,000
Sales milestone payments	$ 565,000,000
Collaboration and License Agreement | Biocon Anti-Dilution Right
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of common stock outstanding shares issued in consideration for collaboration and license agreement	19.50%	19.50%
Issuance of liability	$ 605,402
Fair value of the liability		$ 2,375,109	$ 775,842

Convertible Promissory Notes -

Convertible Promissory Notes - Additional Information (Details) - USD ($)	1 Months Ended			3 Months Ended		7 Months Ended	9 Months Ended
	Oct. 31, 2018	Jun. 30, 2018	May 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2018
Debt Instrument [Line Items]
Interest expense				$ 1,221,100	$ 15,123	$ 22,192	$ 2,329,296
Convertible Promissory Notes
Debt Instrument [Line Items]
Accrued interest rate		6.00%
Mature period		2 years
Interest expense						$ 22,192	2,329,296
Convertible Promissory Notes | Minimum
Debt Instrument [Line Items]
Gross proceeds from convertible promissory notes conversion, converted equity securities amount to be received				$ 15,000,000			$ 15,000,000
Convertible Promissory Notes | IPO | Subsequent Event
Debt Instrument [Line Items]
Convertible promissory notes converted into common stock	878,834
Convertible Promissory Notes | Closing of Financing Occurs on or Prior to Six Month Anniversary of Issuance of Convertible Promissory Notes
Debt Instrument [Line Items]
Convertible promissory notes conversion price, percentage of per share price paid by investors for such securities							90.00%
Convertible Promissory Notes | Closing of Financing Occurs After Six Month Anniversary of Issuance of Convertible Promissory Notes
Debt Instrument [Line Items]
Convertible promissory notes conversion price, percentage of per share price paid by investors for such securities							80.00%
Convertible Promissory Notes | Founder Notes
Debt Instrument [Line Items]
Convertible promissory notes issued			$ 1,000,000
Accrued interest rate			6.00%
Mature period			1 year
Convertible Promissory Notes | Note Purchase Agreements
Debt Instrument [Line Items]
Convertible promissory notes issued		$ 9,407,474

Convertible Promissory Notes _2

Convertible Promissory Notes - Summary of All Debt Obligations Recorded on Balance Sheet (Details) - Convertible Promissory Notes - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Convertible Promissory Notes	$ 9,407,474	$ 7,807,474
Accrued discount	2,189,250	251,392
Total notes payable	$ 11,596,724	$ 8,058,866

Stockholders' Deficit - Additio

Stockholders' Deficit - Additional Information (Details) - USD ($)	3 Months Ended		7 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Research and development	$ 1,222,296	$ 49,949	$ 851,313	$ 2,425,213
Number of shares reserved for issuance	1,524,672			1,524,672	1,189,773
Share-based Compensation expense	$ 100,000	$ 0	$ 0	$ 100,000
2017 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares reserved for issuance	1,189,773			1,189,773	1,189,773
Shares available for granted	333,121			333,121	1,189,773
2017 Equity Incentive Plan | Common Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period				10 years
Minimum options exercise price as percentage of fair market value of common stock				100.00%
Cash received from the exercise of stock options				$ 200,000	$ 0
2017 Equity Incentive Plan | Common Stock Options | Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage				25.00%
Vesting period				3 years
2017 Equity Incentive Plan | Employee And Non Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to outstanding options	$ 4,808,531			$ 4,808,531	$ 0
Expected recognition period of unrecognized compensation cost				3 years 5 months 23 days	0 years
Founder Notes | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Sale of stock					8,620,000
Sale of stock, per share					$ 0.00001
Collaboration and License Agreement | Biocon Limited
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Research and development					$ 9,689
Collaboration and License Agreement | Biocon Limited | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Sale of stock					2,088,074
Sale of stock, per share					$ 0.005

Stockholders' Deficit - Summary

Stockholders' Deficit - Summary of Stock Option Activity (Details) - 2017 Equity Incentive Plan	9 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted | shares	856,652
Number of Shares, Exercised | shares	422,372
Number of Shares, Ending Balance | shares	434,280
Weighted Average Exercise Price, Granted | $ / shares	$ 3.60
Weighted Average Exercise Price, Exercised | $ / shares	0.48
Weighted Average Exercise Price, Ending Balance | $ / shares	$ 3.60
Weighted Average Remaining Contractual Term, Granted	9 years 9 months 25 days
Weighted Average Remaining Contractual Term, Exercised	9 years 8 months 15 days
Weighted Average Remaining Contractual Term, Outstanding	9 years 11 months 1 day
Aggregate Intrinsic Value, Outstanding | $	$ 3,501,724
Granted | $	8,223,638
Exercised | $	$ 4,721,915

Stockholders' Deficit - Summa_2

Stockholders' Deficit - Summary of Weighted-Average Assumptions Used to Determine Fair Value of Stock Option Grants (Details)	9 Months Ended
	Sep. 30, 2018$ / shares
Equity [Abstract]
Weighted-average grant date fair value	$ 5.77
Risk-free interest rate, minimum	2.77%
Risk-free interest rate, maximum	2.93%
Expected volatility	88.29%
Expected term (in years)	5 years 10 months 28 days
Expected dividend yield	0.00%

Stockholders' Deficit - Summa_3

Stockholders' Deficit - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Sep. 30, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	1,524,672	1,189,773
Stock Options Issued and Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	434,280
Authorized for Future Stock Awards or Options Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	1,090,392	1,189,773

Subsequent Events - Additional

Subsequent Events - Additional Information (Details)	Nov. 15, 2018USD ($)shares	Oct. 31, 2018USD ($)$ / sharesshares	Sep. 30, 2017USD ($)
Subsequent Event [Line Items]
Proceeds from issuance of common stock | $			$ 100
Subsequent Event | Underwriters Option
Subsequent Event [Line Items]
Sale of stock | shares	445,097
Proceeds from issuance of common stock | $	$ 5,800,000
Subsequent Event | Common Stock
Subsequent Event [Line Items]
Forward stock split, conversion ratio		8.62
Subsequent Event | Common Stock | IPO
Subsequent Event [Line Items]
Sale of stock | shares		4,670,000
Sale of stock, price per share | $ / shares		$ 14
Net proceeds, after deducting underwriting discounts, commissions and related transaction costs | $		$ 58,700,000
Subsequent Event | Common Stock | IPO | Convertible Promissory Notes and Biocon Anti-Dilution Feature
Subsequent Event [Line Items]
Conversion of convertible securities, shares of common stock issued | shares		1,106,894