Summary of Significant Accounting Policies (Policies)	9 Months Ended
Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company has prepared the accompanying financial statements in accordance with accounting principles generally accepted in the United States (“GAAP”).
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed balance sheet as of September 30, 2018, the condensed statements of operations and cash flows for the periods ended September 30, 2018 and 2017, and the statement of redeemable convertible preferred stock and stockholders’ deficit for the nine months ended September 30, 2018 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited financial statements and, in the opinion of management, reflect all adjustments necessary for the fair presentation of the Company’s financial position as of September 30, 2018 and the results of its operations and its cash flows for the periods ended September 30, 2018 and 2017. The financial data and other information disclosed in these notes related to the periods ended September 30, 2018 and 2017 are also unaudited. The results for the periods ended September 30, 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2018, any other interim periods or any future year or period.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed financial statements include, but are not limited to, the accrual of research and development expenses and the valuation of common stock, stock options, warrants and derivative instruments. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates or assumptions.
Segment Information	Segment Information The Company operates the business on the basis of a single reportable segment, which is the business of developing and commercializing prescription drug products. The Company’s chief operating decision-maker is the Chief Executive Officer (“CEO”), who evaluates the Company as a single operating segment.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. All cash and cash equivalents are held in U.S. financial institutions. Cash equivalents consist of an interest-bearing checking account. From time to time, amounts deposited exceed federally insured limits. The Company believes the associated credit risk to be minimal.
Deferred Offering Costs	Deferred Offering Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ deficit as a reduction of proceeds generated as a result of the offering. Should the planned equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the statements of operations. The Company recorded deferred offering costs of $0 and $397 as of December 31, 2017 and September 30, 2018, respectively, which is included in other long-term assets on the accompanying condensed balance sheet.
Classification and Accretion of Redeemable Convertible Preferred Stock	Classification and Accretion of Redeemable Convertible Preferred Stock The Company has classified the Series A Preferred outside of stockholders’ equity (deficit) because the shares contain certain redemption features that are not solely within the control of the Company. The carrying value of the Series A Preferred is accreted to its redemption value from the date of issuance through the earliest date of redemption.
Research and Development Expenses	Research and Development Expenses Research and development (“R&D”) expenses include both internal R&D activities and external contracted services. Internal R&D activity expenses include salaries, benefits and stock-based compensation and other costs to support the Company’s R&D operations. External contracted services include product development efforts including certain product licensor milestone payments, clinical trial activities, manufacturing and control-related activities and regulatory costs. R&D expenses are charged to operations as incurred. The Company reviews and accrues R&D expenses based on services performed and relies upon estimates of those costs applicable to the stage of completion of each project. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. Upfront payments and milestone payments made for the licensing of technology are expensed as R&D in the period in which they are incurred. Nonrefundable advance payments for goods or services to be received in the future for use in R&D activities are recorded as prepaid expenses and are expensed as the related goods are delivered or the services are performed.
Earnings (Loss) Per Share	Earnings (Loss) Per Share Basic net loss per common share is computed by dividing net loss attributable to common stockholders for the period by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders for the period by the weighted average number of common and common equivalent shares, such as Series A Preferred, unvested restricted stock, stock options and warrants, outstanding during the period. Common stock equivalents are excluded from the computation where their inclusion would be anti-dilutive. No such adjustments were made for 2017 or 2018 as the Company reported a net loss for the periods ended September 30, 2017 and 2018 as including the effects of common stock equivalents in the diluted EPS calculation would have been antidilutive (See Note 9).
Warrant Liability	Warrant Liability The Company estimates the fair value of certain warrants at each reporting period using Level 3 inputs. The estimates in valuation models are based, in part, on subjective assumptions, including but not limited to stock price volatility, the expected life of the warrants, the risk-free interest rate and the exercise price of the warrants, and could differ materially in the future. Changes in the fair value of the warrant liability during the period are recorded as a component of other income (expense). The Company will continue to adjust the fair value of the warrant liability at the end of each reporting period for changes in fair value until the earlier of the exercise or expiration of the applicable warrants, or when the number of shares issuable upon exercise of these warrants is fixed which occurred with the Company’s IPO in November 2018.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based compensation under the provisions of the Financial Accounting Standards Board (the “FASB”) Accounting Standards Codification (“ASC”) — 718 Compensation — Stock Compensation. The guidance under ASC 718 requires companies to estimate the fair value of the stock-based compensation awards on the date of grant for employees and directors and record expense over the related service periods, which are generally the vesting period of the equity awards. Awards for consultants are accounted for under ASC 505-50 — Equity Based Payments to Non-Employees. Compensation expense is recognized over the period during which services are rendered by such consultants and non-employees until completed. At the end of each financial reporting period prior to completion of the service, the fair value of these awards is remeasured using the then-current fair value of the Company’s common stock and updated assumption inputs in the Black-Scholes-Merton option-pricing model (“BSM”). The Company estimates the fair value of stock-based option awards to its employees and directors using the BSM. The BSM requires the input of subjective assumptions, including the expected stock price volatility, the calculation of expected term, forfeitures and the fair value of the underlying common stock on the date of grant, among other inputs. The risk-free interest rate was determined from the implied yields for zero-coupon U.S. government issues with a remaining term approximating the expected life of the options or warrants. Dividends on common stock are assumed to be zero for the BSM valuation of the stock options. The expected term of stock options granted is based on vesting periods and the contractual life of the options. Expected volatilities are based on comparable companies’ historical volatility, which management believes represents the most accurate basis for estimating expected future volatility under the current conditions. The Company accounts for forfeitures as they occur.
Fair Value Measurements	Fair Value Measurements We measure certain of our assets and liabilities at fair value. Fair value represents the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value accounting requires characterization of the inputs used to measure fair value into a three-level fair value hierarchy as follows: *Level 1* — Inputs based on quoted prices in active markets for identical assets or liabilities. An active market is a market in which transactions occur with sufficient frequency and volume to provide pricing information on an ongoing basis. *Level 2* — Observable inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent from the entity. *Level 3* — Unobservable inputs that reflect the entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available. Fair value measurements are classified based on the lowest level of input that is significant to the measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of the assets and liabilities and their placement within the fair value hierarchy levels. The determination of the fair values stated below takes into account the market for the Company’s financials, assets and liabilities, the associated credit risk and other factors as required. The Company considers active markets as those in which transactions for the assets or liabilities occur in sufficient frequency and volume to provide pricing information on an ongoing basis. The carrying amounts of cash and cash equivalents, accounts payable and accrued liabilities approximate their fair values due to the short-term maturities of these instruments. The fair values of the Company’s warrant liability at inception and for subsequent mark-to-market fair value measurements are based on management’s valuation model and expectations with respect to the method and timing of settlement. The Company has determined that the warrant liability fair values are classified as Level 3 measurements within the fair value hierarchy.
Impact of New Accounting Pronouncements	Impact of New Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02 (Topic 842) – Leases, which requires the lease rights and obligations arising from lease contracts, including existing and new arrangements, with terms more than 12 months to be recognized as assets and liabilities on the balance sheet. Recognition, measurement and presentation of expenses will depend on classification as a finance or operating lease. The amendments also require certain quantitative and qualitative disclosures about leasing arrangements. ASU 2016-02 is effective for reporting periods beginning after December 15, 2018 with early adoption permitted. While the Company is still evaluating ASU 2016-02, the Company expects the adoption of ASU 2016-02 will not have a material effect on the Company’s financial condition from the recognition of the lease rights and obligations as assets and liabilities. The Company is currently evaluating ASU 2016-02 to determine the effect on the Company’s results of operations and cash flows. In June 2018, the FASB issued ASU 2018-07, Compensation — Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting, which simplifies the accounting for nonemployee share-based payment transactions. The amendments specify that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. ASU 2018-07 will be effective for financial statements issued for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years with early adoption permitted (but no sooner than the adoption of Topic 606). The Company is currently evaluating ASU 2018-07 to determine the effect on the Company’s financial statements. In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, Disclosure Update and Simplification, amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders’ equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders’ equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of operations is required to be filed. This final rule became effective on November 5, 2018. On September 25, 2018, the SEC released guidance advising that it will not object to a registrant adopting the requirement to include changes in stockholders’ equity in the Form 10-Q for the first quarter beginning after the effective date of the rule. The Company does not expect the adoption of SEC Release No. 33-10532 to have a material impact on its financial position, results of operations and related disclosures. The Company anticipates adopting SEC Release No. 33-10532 in its Form 10-Q filing for the quarter ending March 31, 2019.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2018

Basis of Presentation

The Company has prepared the accompanying financial statements in accordance with accounting principles generally accepted in the United States (“GAAP”).

Unaudited Interim Financial Information

Unaudited Interim Financial Information

The accompanying condensed balance sheet as of September 30, 2018, the condensed statements of operations and cash flows for the periods ended September 30, 2018 and 2017, and the statement of redeemable convertible preferred stock and stockholders’ deficit for the nine months ended September 30, 2018 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited financial statements and, in the opinion of management, reflect all adjustments necessary for the fair presentation of the Company’s financial position as of September 30, 2018 and the results of its operations and its cash flows for the periods ended September 30, 2018 and 2017. The financial data and other information disclosed in these notes related to the periods ended September 30, 2018 and 2017 are also unaudited. The results for the periods ended September 30, 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2018, any other interim periods or any future year or period.

Use of Estimates

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed financial statements include, but are not limited to, the accrual of research and development expenses and the valuation of common stock, stock options, warrants and derivative instruments. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates or assumptions.

Segment Information

Segment Information

The Company operates the business on the basis of a single reportable segment, which is the business of developing and commercializing prescription drug products. The Company’s chief operating decision-maker is the Chief Executive Officer (“CEO”), who evaluates the Company as a single operating segment.

Cash and Cash Equivalents

Cash and Cash Equivalents

The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. All cash and cash equivalents are held in U.S. financial institutions. Cash equivalents consist of an interest-bearing checking account. From time to time, amounts deposited exceed federally insured limits. The Company believes the associated credit risk to be minimal.

Deferred Offering Costs

Deferred Offering Costs

The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ deficit as a reduction of proceeds generated as a result of the offering. Should the planned equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the statements of operations. The Company recorded deferred offering costs of $0 and $397 as of December 31, 2017 and September 30, 2018, respectively, which is included in other long-term assets on the accompanying condensed balance sheet.

Classification and Accretion of Redeemable Convertible Preferred Stock

Classification and Accretion of Redeemable Convertible Preferred Stock

The Company has classified the Series A Preferred outside of stockholders’ equity (deficit) because the shares contain certain redemption features that are not solely within the control of the Company. The carrying value of the Series A Preferred is accreted to its redemption value from the date of issuance through the earliest date of redemption.

Research and Development Expenses

Research and Development Expenses

Research and development (“R&D”) expenses include both internal R&D activities and external contracted services. Internal R&D activity expenses include salaries, benefits and stock-based compensation and other costs to support the Company’s R&D operations. External contracted services include product development efforts including certain product licensor milestone payments, clinical trial activities, manufacturing and control-related activities and regulatory costs. R&D expenses are charged to operations as incurred. The Company reviews and accrues R&D expenses based on services performed and relies upon estimates of those costs applicable to the stage of completion of each project. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates.

Upfront payments and milestone payments made for the licensing of technology are expensed as R&D in the period in which they are incurred. Nonrefundable advance payments for goods or services to be received in the future for use in R&D activities are recorded as prepaid expenses and are expensed as the related goods are delivered or the services are performed.

Earnings (Loss) Per Share

Earnings (Loss) Per Share

Basic net loss per common share is computed by dividing net loss attributable to common stockholders for the period by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders for the period by the weighted average number of common and common equivalent shares, such as Series A Preferred, unvested restricted stock, stock options and warrants, outstanding during the period. Common stock equivalents are excluded from the computation where their inclusion would be anti-dilutive. No such adjustments were made for 2017 or 2018 as the Company reported a net loss for the periods ended September 30, 2017 and 2018 as including the effects of common stock equivalents in the diluted EPS calculation would have been antidilutive (See Note 9).

Warrant Liability

Warrant Liability

The Company estimates the fair value of certain warrants at each reporting period using Level 3 inputs. The estimates in valuation models are based, in part, on subjective assumptions, including but not limited to stock price volatility, the expected life of the warrants, the risk-free interest rate and the exercise price of the warrants, and could differ materially in the future. Changes in the fair value of the warrant liability during the period are recorded as a component of other income (expense). The Company will continue to adjust the fair value of the warrant liability at the end of each reporting period for changes in fair value until the earlier of the exercise or expiration of the applicable warrants, or when the number of shares issuable upon exercise of these warrants is fixed which occurred with the Company’s IPO in November 2018.

Stock-Based Compensation

Stock-Based Compensation

The Company accounts for stock-based compensation under the provisions of the Financial Accounting Standards Board (the “FASB”) Accounting Standards Codification (“ASC”) — 718 Compensation — Stock Compensation. The guidance under ASC 718 requires companies to estimate the fair value of the stock-based compensation awards on the date of grant for employees and directors and record expense over the related service periods, which are generally the vesting period of the equity awards. Awards for consultants are accounted for under ASC 505-50 — Equity Based Payments to Non-Employees. Compensation expense is recognized over the period during which services are rendered by such consultants and non-employees until completed. At the end of each financial reporting period prior to completion of the service, the fair value of these awards is remeasured using the then-current fair value of the Company’s common stock and updated assumption inputs in the Black-Scholes-Merton option-pricing model (“BSM”).

The Company estimates the fair value of stock-based option awards to its employees and directors using the BSM. The BSM requires the input of subjective assumptions, including the expected stock price volatility, the calculation of expected term, forfeitures and the fair value of the underlying common stock on the date of grant, among other inputs. The risk-free interest rate was determined from the implied yields for zero-coupon U.S. government issues with a remaining term approximating the expected life of the options or warrants. Dividends on common stock are assumed to be zero for the BSM valuation of the stock options. The expected term of stock options granted is based on vesting periods and the contractual life of the options. Expected volatilities are based on comparable companies’ historical volatility, which management believes represents the most accurate basis for estimating expected future volatility under the current conditions. The Company accounts for forfeitures as they occur.

Fair Value Measurements

Fair Value Measurements

We measure certain of our assets and liabilities at fair value. Fair value represents the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value accounting requires characterization of the inputs used to measure fair value into a three-level fair value hierarchy as follows:

Level 1 — Inputs based on quoted prices in active markets for identical assets or liabilities. An active market is a market in which transactions occur with sufficient frequency and volume to provide pricing information on an ongoing basis.

Level 2 — Observable inputs that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent from the entity.

Level 3 — Unobservable inputs that reflect the entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available.

Fair value measurements are classified based on the lowest level of input that is significant to the measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of the assets and liabilities and their placement within the fair value hierarchy levels. The determination of the fair values stated below takes into account the market for the Company’s financials, assets and liabilities, the associated credit risk and other factors as required. The Company considers active markets as those in which transactions for the assets or liabilities occur in sufficient frequency and volume to provide pricing information on an ongoing basis.

The carrying amounts of cash and cash equivalents, accounts payable and accrued liabilities approximate their fair values due to the short-term maturities of these instruments.

The fair values of the Company’s warrant liability at inception and for subsequent mark-to-market fair value measurements are based on management’s valuation model and expectations with respect to the method and timing of settlement. The Company has determined that the warrant liability fair values are classified as Level 3 measurements within the fair value hierarchy.

Impact of New Accounting Pronouncements

Impact of New Accounting Pronouncements

In February 2016, the FASB issued ASU 2016-02 (Topic 842) – Leases, which requires the lease rights and obligations arising from lease contracts, including existing and new arrangements, with terms more than 12 months to be recognized as assets and liabilities on the balance sheet. Recognition, measurement and presentation of expenses will depend on classification as a finance or operating lease. The amendments also require certain quantitative and qualitative disclosures about leasing arrangements. ASU 2016-02 is effective for reporting periods beginning after December 15, 2018 with early adoption permitted. While the Company is still evaluating ASU 2016-02, the Company expects the adoption of ASU 2016-02 will not have a material effect on the Company’s financial condition from the recognition of the lease rights and obligations as assets and liabilities. The Company is currently evaluating ASU 2016-02 to determine the effect on the Company’s results of operations and cash flows.

In June 2018, the FASB issued ASU 2018-07, Compensation — Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting, which simplifies the accounting for nonemployee share-based payment transactions. The amendments specify that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. ASU 2018-07 will be effective for financial statements issued for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years with early adoption permitted (but no sooner than the adoption of Topic 606). The Company is currently evaluating ASU 2018-07 to determine the effect on the Company’s financial statements.

In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, Disclosure Update and Simplification, amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders’ equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders’ equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of operations is required to be filed. This final rule became effective on November 5, 2018. On September 25, 2018, the SEC released guidance advising that it will not object to a registrant adopting the requirement to include changes in stockholders’ equity in the Form 10-Q for the first quarter beginning after the effective date of the rule. The Company does not expect the adoption of SEC Release No. 33-10532 to have a material impact on its financial position, results of operations and related disclosures. The Company anticipates adopting SEC Release No. 33-10532 in its Form 10-Q filing for the quarter ending March 31, 2019.