Verrica Pharmaceuticals (VRCA) 10-Q 7 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 07, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	VRCA
Entity Registrant Name	Verrica Pharmaceuticals Inc.
Entity Central Index Key	1,660,334
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		25,696,371

CONDENSED BALANCE SHEETS

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 103,149	$ 8,663
Prepaid expenses and other assets	1,441	420
Total current assets	104,590	9,083
Property, plant and equipment, net	112
Deposits	14
Total assets	104,716	9,083
Current liabilities:
Accounts payable	1,081	153
Accrued expenses	2,008	449
Accounts payable and accrued expenses-related party	36	14
Total current liabilities	3,125	616
Total liabilities	3,125	616
Commitments and Contingencies (Note 5)
Convertible preferred stock		15,508
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding as of June 30, 2018 and December 31, 2017
Common stock, $0.0001 par value; 200,000,000 and 33,236,900 shares authorized as of June 30, 2018 and December 31, 2017, respectively; 25,801,515 shares issued and 25,696,371 shares outstanding as of June 30, 2018 and 3,804,643 shares issued and 3,699,499 shares outstanding as of December 31, 2017, respectively	3
Treasury stock, at cost, 105,144 shares as of June 30, 2018 and December 31, 2017	0	0
Additional paid-in capital	121,856	5,394
Accumulated deficit	(20,268)	(12,435)
Total stockholders' equity (deficit)	101,591	(7,041)
Total liabilities, convertible preferred stock and stockholders' equity (deficit)	$ 104,716	9,083
Series A Convertible Preferred Stock [Member]
Current liabilities:
Convertible preferred stock		10,508
Stockholders' equity (deficit):
Total stockholders' equity (deficit)		10,508
Series B Convertible Preferred Stock [Member]
Current liabilities:
Convertible preferred stock		5,000
Stockholders' equity (deficit):
Total stockholders' equity (deficit)		$ 5,000

CONDENSED BALANCE SHEETS (Paren

CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	33,236,900
Commom stock, shares issued	25,801,515	3,804,643
Common stock, shares outstanding	25,696,371	3,699,499
Treasury stock, shares	105,144	105,144
Series A Convertible Preferred Stock [Member]
Convertible preferred stock, shares authorized	0	21,302,972
Convertible preferred stock, shares issued	0	21,302,972
Convertible preferred stock, shares outstanding	0	21,302,972
Series B Convertible Preferred Stock [Member]
Convertible preferred stock, shares authorized	0	1,937,984
Convertible preferred stock, shares issued	0	1,937,984
Convertible preferred stock, shares outstanding	0	1,937,984

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating expenses:
Research and development	$ 3,609	$ 977	$ 4,538	$ 1,493
General and administrative	2,503	118	3,489	172
Total operating expenses	6,112	1,095	8,027	1,665
Loss from operations	(6,112)	(1,095)	(8,027)	(1,665)
Other income
Interest income	153		194
Total other income	153		194
Net loss	$ (5,959)	$ (1,095)	$ (7,833)	$ (1,665)
Net loss per share, basic and diluted	$ (1.04)	$ (0.38)	$ (1.82)	$ (0.58)
Weighted average common shares outstanding, basic and diluted	5,751,326	2,850,471	4,308,996	2,849,891

CONDENSED STATEMENTS OF CONVERT

CONDENSED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - 6 months ended Jun. 30, 2018 - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock [Member]	Series B Convertible Preferred Stock [Member]	Series C Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Treasury Stock at Cost [Member]
Beginning Balance at Dec. 31, 2017	$ (7,041)	$ 10,508	$ 5,000			$ 5,394	$ (12,435)
Beginning Balance (shares) at Dec. 31, 2017		21,302,972	1,937,984		3,804,643
Stock-based compensation	1,583					1,583
Series C convertible preferred stock				$ 21,000
Series C convertible preferred stock (shares)				4,606,267
Issuance costs for Series C preferred				$ (7)
Conversion of preferred stock into common stock	36,501	$ (10,508)	$ (5,000)	$ (20,993)	$ 2	36,499
Conversion of preferred stock into common stock (shares)		(21,302,972)	(1,937,984)	(4,606,267)	16,246,872
Issuance of common stock in connection with IPO, net of offering costs	78,381				$ 1	78,380
Issuance of common stock in connection with IPO, net of offering costs (shares)					5,750,000
Net loss	(7,833)						(7,833)
Ending Balance at Jun. 30, 2018	$ 101,591				$ 3	$ 121,856	$ (20,268)	$ 0
Ending Balance (shares) at Jun. 30, 2018		0	0		25,801,515

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net loss	$ (7,833)	$ (1,665)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,583	3
Depreciation expense	5
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,035)	(375)
Accounts payable	573	303
Accrued expenses	851	48
Accounts payable and accrued expenses-related party	22	25
Net cash used in operating activities	(5,834)	(1,661)
Cash flows from investing activities
Purchases of property, plant and equipment	(111)
Net cash used in investing activities	(111)
Cash flows from financing activities
Proceeds from the issuance of common stock in connection with IPO	86,250
Net cash provided by financing activities	100,431	1,640
Net increase (decrease) in cash and cash equivalents	94,486	(21)
Cash and cash equivalents at the beginning of the period	8,663	527
Cash and cash equivalents at the end of the period	103,149	506
Supplemental disclosure of noncash investing and financing activities:
Fixed asset purchases accrued at period end	6
Issuance costs included in accounts payable and accrued expenses	1,057
Conversion of preferred stock into common stock	36,501
Series A Convertible Preferred Stock [Member]
Cash flows from financing activities
Proceeds received from subscription receivable / issuance of preferred stock		1,700
Payments of Stock Issuance Costs		$ (60)
Series C Convertible Preferred Stock [Member]
Cash flows from financing activities
Proceeds received from subscription receivable / issuance of preferred stock	21,000
Payments of Stock Issuance Costs	(7)
IPO [Member]
Cash flows from financing activities
Payments of Stock Issuance Costs	$ (6,812)

Organization and Description of

Organization and Description of Business Operations	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business Operations	Note 1—Organization and Description of Business Operations Verrica Pharmaceuticals Inc. (the “Company”) was formed on July 3, 2013 and is incorporated in the State of Delaware. The Company is a clinical-stage medical dermatology company focused on identifying, developing and commercializing innovative pharmaceutical products for the treatment of skin diseases with significant unmet needs, with an initial focus on addressing molluscum contagiosum. Reverse Stock Split On June 4, 2018, the Company effected a 1.714-for-one All share and per share amounts, including stock options, have been retroactively adjusted in these condensed financial statements for all periods presented to reflect the 1.714-for-one 1.714-for-one Liquidity and Capital Resources The Company has incurred substantial operating losses since inception and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of June 30, 2018, the Company had an accumulated deficit of $20.3 million. On February 20, 2018 and March 7, 2018, the Company issued an aggregate of 4,606,267 shares of Series C convertible preferred stock, at an issuance price of $4.559 per share, for gross proceeds of $21.0 million. On June 19, 2018, the Company completed an initial public offering (“IPO”) of its common stock, which resulted in the issuance and sale of 5,750,000 shares of its common stock at a public offering price of $15.00 per share, generating net proceeds of $78.4 million after deducting underwriting discounts and other offering costs. Upon the closing of the IPO, all outstanding shares of the Company’s Series A, Series B and Series C convertible preferred stock were automatically converted into 16,246,872 shares of the Company’s common stock. In addition, upon the closing of the IPO, the Company’s amended and restated certificate of incorporation authorized the Company to issue up to 200,000,000 shares of common stock, $0.0001 par value per share, and 10,000,000 shares of preferred stock, $0.0001 par value per share, all of which shares of preferred stock will be undesignated.

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	Note 2—Significant Accounting Policies Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) as determined by Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) for interim financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim condensed financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. They may not include all of the information and footnotes required by GAAP for complete financial statements. Therefore, these financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto for the year ended December 31, 2017 included in the Company’s final prospectus for its IPO dated as of June 14, 2018 and filed with the Securities and Exchange Commission (the “SEC”) on June 15, 2018 pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended. The results of operations for any interim periods are not necessarily indicative of the results that may be expected for the entire fiscal year or any other interim period. 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 and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The most significant estimates in the Company’s financial statements relate to the valuation of common stock and stock options. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results may differ materially and adversely from these estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected. Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with original maturities of 90 days or less at acquisition to be cash equivalents. Cash and cash equivalents include cash held in banks and money market mutual funds. Concentrations of Credit Risk and Off-Balance Cash and cash equivalents are financial instruments that are potentially subject to concentrations of credit risk. The Company’s cash and cash equivalents are deposited in accounts at large financial institutions, and amounts may exceed federally insured limits. The Company believes it is not exposed to significant credit risk due to the financial strength of the depository institutions in which the cash and cash equivalents are held. The Company has no financial instruments with off-balance Research and Development Costs The Company’s research and development expenses consist primarily of costs associated with the Company’s clinical trials, salaries, payroll taxes, employee benefits, and equity-based compensation charges for those individuals involved in ongoing research and development efforts. Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Fair Value Measurement ASC 820, Fair Value Measurements The accounting guidance classifies fair value measurements in one of the following three categories for disclosure purposes: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Inputs other than Level 1 prices for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and values determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. Included in cash and cash equivalents as of June 30, 2018 is a money market fund with a carrying value and fair value of $103.0 million based upon a Level 1 fair value assessment. The carrying amounts for the Company’s other financial instruments approximate fair values. Stock-Based Compensation The Company expenses stock-based compensation to employees and board members over the requisite service period based on the estimated grant-date fair value of the awards. The Company accounts for forfeitures as they occur. Stock-based awards with graded-vesting schedules are recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model, and the assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the statements of operations based upon the underlying individual’s role at the Company. Stock-based compensation for non-employee Income Taxes Income taxes are recorded in accordance with ASC 740, Income Taxes The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit would more likely than not be realized assuming examination by the taxing authority. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company recognizes any interest and penalties accrued related to unrecognized tax benefits as income tax expense. Net Loss Per Share Net loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net loss per share excludes the potential impact of Series A, Series B and Series C Preferred Stock, common stock options and unvested shares of restricted stock because their effect would be anti-dilutive due to the Company’s net loss. Since the Company had a net loss in each of the periods presented, basic and diluted net loss per common share are the same. The table below provides potential shares outstanding that were not included in the computation of diluted net loss per common share, as the inclusion of these securities would have been anti-dilutive: As of June 30, 2018 2017 Shares issuable upon conversion of Series A Preferred — 12,428,773 Shares issuable upon exercise of stock options 1,383,582 90,429 Non-vested 848,859 848,859 Recently Adopted Accounting Pronouncements In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting Recently Issued Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) right-of-use In June 2018, the FASB issued ASU No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Note 3—Related Party Transactions Prior to the IPO, the Company was controlled by PBM VP Holdings, LLC (“PBM VP Holdings”), an affiliate of PBM Capital Group, LLC. Paul B. Manning, who is the President and Chief Executive Officer of PBM Capital Group, LLC and the current chairman of the Company’s Board of Directors (the “Board”), and certain entities affiliated with Mr. Manning, continue to be the Company’s largest shareholder on a collective basis. On December 2, 2015, the Company entered into a Services Agreement (a “SA”) with PBM Capital Group, LLC. Pursuant to the terms of the SA, which had an initial term of twelve months (and was automatically renewable for successive monthly periods), PBM Capital Group, LLC rendered advisory and consulting services to the Company. Services provided under the SA included certain business development, operations, technical, contract, accounting and back office support services. In consideration for these services, the Company was obligated to pay PBM Capital Group, LLC a monthly management fee of $2,500. On March 29, 2018, the Company amended the SA with PBM Capital Group, LLC, effective as of April 1, 2018. Pursuant to the terms of the SA, as amended, which has an initial term of twelve months (and is automatically renewable for successive monthly periods), PBM Capital Group, LLC will render advisory and consulting services to the Company. Services provided under the SA may include certain business development, operations, technical, contract, accounting and back office support services. In consideration for these services, the Company is obligated to pay PBM Capital Group, LLC a monthly management fee of $50,000. The SA, as amended, provides for the termination by the Company with 30 days advance notice or a mutually agreed upon effective date for transition as individual services are cancelled with a corresponding reduction in the monthly management fee. For the three months ended June 30, 2018 and 2017, the Company incurred expenses under the SA of $150,000 and $7,500, respectively, which were primarily included in general and administrative expenses. For the six months ended June 30, 2018 and 2017, the Company incurred expenses under the SA of $157,500 and $15,000, respectively, which were primarily included in general and administrative expenses. As of June 30, 2018 and December 31, 2017, the Company had a payable due to PBM Capital Group, LLC and its affiliates of $36,000 and $14,000, respectively.

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2018
Payables and Accruals [Abstract]
Accrued Expenses	Note 4—Accrued Expenses Accrued expenses consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017 Compensation and related costs $ 508 $ 49 Clinical trials and drug development 184 233 Initial Public Offering costs 697 — Consulting - former Chief Scientific Officer 382 — Professional fees 53 129 Other 184 38 Total accrued expenses $ 2,008 $ 449

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 5—Commitments and Contingencies Litigation As of June 30, 2018 and December 31, 2017, there was no litigation against the Company. Purchase Order On March 22, 2018, the Company executed a purchase order with a supplier, denominated in Chinese yuan, pursuant to which the Company agreed to purchase approximately $2.3 million of crude cantharidin material. As of June 30, 2018, the Company purchased approximately $0.5 million of crude cantharidin material under this purchase order. On July 16, 2018, the Company entered into a supply agreement with the supplier. The executed purchase order is covered under the terms of the supply agreement. Refer to ‘Note 8 – Subsequent Event’ for further description of the supply agreement. Agreements with Former Chief Scientific Officer On May 31, 2018, the Company and the former Chief Scientific Officer (“CSO”) executed a transition agreement to resign from employment as well as a Consulting Agreement (the “Consulting Agreement”) that began upon the closing of the IPO. The Consulting Agreement provides for cash payments to the former CSO of $29,375 per month for the first 12 months of the agreement. After the first 12 months, the former CSO will receive $300 per hour for each hour of consulting services provided. The Company accrued $0.4 million as of June 30, 2018 under this Consulting Agreement.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2018
Federal Home Loan Banks [Abstract]
Stockholders' Equity	Note 6—Stockholders’ Equity Common Stock The Company has authorized 200,000,000 and 33,236,900 shares of common stock, $0.0001 par value per share, as of June 30, 2018 and December 31, 2017, respectively. Each share of common stock is entitled to one voting right. Common stock owners are entitled to dividends when funds are legally available and declared by the Board. On June 19, 2018, the Company completed an IPO of its common stock, which resulted in the issuance and sale of 5,750,000 shares of its common stock at a public offering price of $15.00 per share, generating net proceeds of $78.4 million after deducting underwriting discounts and other offering costs. The shares commenced trading on the Nasdaq Global Market on June 15, 2018 under the ticker symbol “VRCA.” Restricted Stock Pursuant to an Amended and Restated Stock Purchase Agreement (the “Amended and Restated Agreement”) between the Company and the former CSO, 848,859 shares held by the former CSO are subject to repurchase at $0.0001 per share. These shares will be released from the repurchase option on the earliest to occur of (i) a change in control, (ii) regulatory approval of the Company’s new drug application for cantharidin, (iii) commercial sale of products and (iv) a covered termination, as defined in the Amended and Restated Agreement. Convertible Preferred Stock On December 2, 2015, the Company issued an aggregate of 21,302,972 shares of Series A Preferred Stock to fourteen investors for cash consideration of $1.9 million, conversion of previously outstanding notes payable and accrued interest of $0.5 million and a stock subscription receivable of $8.5 million. The Company incurred aggregate issuance costs of $0.4 million, related to the issuance of the Series A Preferred Stock and subsequent settlement of the stock subscription receivable. PBM VP Holdings paid the Company $0.5 million during the year ended December 31, 2016, and $8.0 million during the year ended December 31, 2017 to settle the stock subscription receivable. Upon the closing of the IPO on June 19, 2018, all outstanding shares of the Company’s Series A Preferred Stock were automatically converted into 12,428,773 shares of the Company’s common stock. On December 15, 2017, the Company issued and sold an aggregate of 1,937,984 shares of Series B Preferred Stock, at an issuance price of $2.58 per share, for gross proceeds of $5.0 million. The Company did not incur any issuance costs for the Series B Preferred Stock. Upon the closing of the IPO on June 19, 2018, all outstanding shares of the Company’s Series B Preferred Stock were automatically converted into 1,130,679 shares of the Company’s common stock. On February 20, 2018 and March 7, 2018, the Company issued and sold an aggregate of 4,606,267 shares of Series C Preferred Stock, at an issuance price of $4.559 per share, for aggregate gross proceeds of $21.0 million. Upon the closing of the IPO on June 19, 2018, all outstanding shares of the Company’s Series C Preferred Stock were automatically converted into 2,687,420 shares of the Company’s common stock. The Company classified its Convertible Preferred Stock outside of stockholders’ deficit because redemption of the Convertible Preferred Stock, upon a deemed liquidation event, was not solely within the Company’s control.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Note 7—Stock-Based Compensation In June 2018, the Board adopted and approved the 2018 Equity Incentive Plan (the “IPO Plan”), which amended and restated the Company’s prior 2013 Equity Incentive Plan (the “2013 Plan”) and became effective in connection with the IPO pricing on June 19, 2018. Prior to the effectiveness of the IPO Plan, the 2013 Plan provided for the grant of share-based awards to employees, directors and consultants of the Company. As a result of the effectiveness of the IPO Plan, no further grants may be made under the 2013 Plan. The IPO Plan provides for the grant of incentive stock options to employees, and for the grant of nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance-based stock awards and other forms of stock awards to employees, including officers, consultants and directors. The IPO Plan also provides for the grant of performance-based cash awards to employees, including officers, consultants and directors. The Company has initially reserved 3,738,199 shares of common stock for issuance under the IPO Plan, which is the sum of (1) 2,198,198 new shares, plus (2) the number of shares reserved for issuance under the 2013 Plan at the time the IPO Plan became effective, plus (3) any shares subject to outstanding stock options or other stock awards that would have otherwise returned to the 2013 Plan (such as upon the expiration or termination of a stock award prior to exercise). The number of shares of common stock reserved for issuance under the IPO Plan will automatically increase on January 1 each year, for a period of ten years, from January 1, 2019 through January 1, 2028, by 4% of the total number of shares of the Company’s common stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares as may be determined by the Board. As of June 30, 2018, 2,112,719 shares were available for grant under the IPO Plan. Stock Options The Company’s employee stock options generally vest as follows: 25% after 12 months of continuous services and the remaining 75% on a ratable basis over a 36-month In January 2017, the Company granted 17,502 common stock options to an employee, subject to the terms and conditions of the 2013 Plan above. The stock options are subject to time vesting requirements through 2021, are nontransferable, and have term expiration dates set to expire in January 2027. At June 30, 2018, 6,199 of these options had vested. On December 22, 2017, the Board granted a stock option award for 724,315 shares of common stock to the Company’s Chief Executive Officer (“CEO Stock Option Grant”) subject to the Board’s approval of a valuation report as to the value of the Company common stock. On February 12, 2018, the Board determined that the exercise price of the CEO Stock Option Grant would be equal to the greater of 1) $3.75 per share or 2) the Board’s approval of a valuation report as to the value of the Company common stock as of February 12, 2018. On March 28, 2018, the Board approved the valuation of the Company’s common stock of $6.52 per share as of February 12, 2018, which set the exercise price for 878,923 options (including 724,315 to the Company’s Chief Executive Officer and 154,608 to other employees granted by the Board on December 22, 2017 and February 12, 2018, respectively) and established an accounting grant date. On February 12, 2018, the Board approved stock option awards to employees for 186,696 options to acquire common stock, with the exercise price of these awards to be established at the fair value of the Company’s common stock as of February 26, 2018 for 113,768 options and March 5, 2018 for 72,928 options. On April 24, 2018, the Board approved the valuation of the Company’s common stock of $6.86 per share as of February 26, 2018 and March 5, 2018, which set the exercise price for the 186,696 options. On April 24, 2018, the Board also approved the valuation of the Company’s common stock of $8.73 per share as of April 4, 2018, which set the exercise price for 87,514 options that were approved by the Board on March 20, 2018. An accounting grant date for these awards was established upon approval by the Board of these valuation reports on the Company’s common stock as of the applicable dates on April 24, 2018. The fair value of each employee and non-employee non-employees Prior to the Company’s IPO, in order to determine the fair value, the Company considered, among other things, contemporaneous valuations of the Company’s common stock, the Company’s business, financial condition and results of operations, including related industry trends affecting its operations; the likelihood of achieving a liquidity event, such as an initial public offering, or IPO, or sale, given prevailing market conditions; the lack of marketability of the Company’s common stock; the market performance of comparable publicly traded companies; and U.S. and global economic and capital market conditions. The grant date fair value of employee stock option awards is determined using the Black-Scholes option-pricing model. The following assumptions were used during the three and six months ended June 30, 2018 and 2017 to estimate the fair value of employee stock option awards: For the three months ended June 30, For the six months ended June 30, 2018 2017* 2018 2017 Exercise price $6.86 - $15.00 — $6.52 - $15.00 $0.90 Risk-free rate of interest 2.83% - 2.95% — 2.58% - 2.95% 1.92% - 2.23% Expected term (years) 6.12 — 6.11 6.25 Expected stock price volatility 71.18% - 83.67% — 70.58% - 83.67% 79.02% - 79.12% Weighted average estimated fair value share price $7.52 — $6.53 $0.12 Dividend yield — — — — * The Company did not grant stock options during the three months ended June 30, 2017 Non-employee non-employees non-employee non-employee The following table summarizes the Company’s employee stock option activity under the 2013 Plan and the IPO Plan for the six months ended June 30, 2018: Weighted average Weighted average remaining contractual Aggregate intrinsic Number of shares exercise price life (in years) value Outstanding as of December 31, 2017 17,502 $ 0.90 Options granted 1,293,153 7.64 Outstanding as of June 30, 2018 1,310,655 $ 7.55 9.7 $ 15,967,862 Options vested and exercisable as of June 30, 2018 6,199 $ 0.90 8.5 $ 116,727 The following table summarizes the Company’s non-employee Weighted average Weighted average remaining contractual Aggregate intrinsic Number of shares exercise price life (in years) value Outstanding as of December 31, 2017 72,927 $ 0.90 Options granted — — Outstanding as of June 30, 2018 72,927 $ 0.90 7.8 $ 1,373,215 Options vested and exercisable as of June 30, 2018 48,620 $ 0.90 7.8 $ 915,515 The aggregate intrinsic value in the above table is calculated as the difference between fair value of the Company’s common stock price and the exercise price of the stock options. The weighted average grant date fair value per share for the employee stock option grants during the six months ended June 30, 2018 and 2017 was $6.53 and $0.12, respectively. As of June 30, 2018, the total unrecognized compensation related to unvested employee and non-employee stock Restricted Stock The following table summarizes restricted stock award activities for the six months ended June 30, 2018: Weighted Average Grant Date Fair Number of Shares Value Nonvested at December 31, 2017 848,859 $ 0.33 Granted — — Nonvested at June 30, 2018 848,859 $ 0.33 As of June 30, 2018, the total unrecognized compensation expense related to the nonvested shares was $0.3 million. No compensation expense has been recognized for these nonvested shares as these shares are performance-based and the triggering event was not determined to be probable as of June 30, 2018. Stock-based compensation expense has been reported in the Company’s condensed statements of operations for the three and six months ended June 30, 2018 and 2017 as follows (in thousands): For the three months ended June 30, For the six months ended June 30, 2018 2017 2018 2017 Research and development $ 350 $ 2 $ 467 $ 3 General and administrative 1,071 — 1,116 — Total stock-based compensation $ 1,421 $ 2 $ 1,583 $ 3

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	Note 8—Subsequent Event On July 16, 2018, the Company entered into a supply agreement, pursuant to which the supplier has agreed to supply naturally-sourced cantharidin to the Company for a specified fixed price. Naturally-sourced cantharidin is the raw material used to manufacture the active pharmaceutical ingredient (“API”) in VP-102,

Significant Accounting Polici15

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) as determined by Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) for interim financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim condensed financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. They may not include all of the information and footnotes required by GAAP for complete financial statements. Therefore, these financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto for the year ended December 31, 2017 included in the Company’s final prospectus for its IPO dated as of June 14, 2018 and filed with the Securities and Exchange Commission (the “SEC”) on June 15, 2018 pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended. The results of operations for any interim periods are not necessarily indicative of the results that may be expected for the entire fiscal year or any other interim 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 and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The most significant estimates in the Company’s financial statements relate to the valuation of common stock and stock options. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results may differ materially and adversely from these estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected.
Segments	Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with original maturities of 90 days or less at acquisition to be cash equivalents. Cash and cash equivalents include cash held in banks and money market mutual funds.
Concentrations of Credit Risk and Off-Balance Sheet Risk	Concentrations of Credit Risk and Off-Balance Cash and cash equivalents are financial instruments that are potentially subject to concentrations of credit risk. The Company’s cash and cash equivalents are deposited in accounts at large financial institutions, and amounts may exceed federally insured limits. The Company believes it is not exposed to significant credit risk due to the financial strength of the depository institutions in which the cash and cash equivalents are held. The Company has no financial instruments with off-balance
Research and Development Costs	Research and Development Costs The Company’s research and development expenses consist primarily of costs associated with the Company’s clinical trials, salaries, payroll taxes, employee benefits, and equity-based compensation charges for those individuals involved in ongoing research and development efforts. Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made.
Fair Value Measurement	Fair Value Measurement ASC 820, Fair Value Measurements The accounting guidance classifies fair value measurements in one of the following three categories for disclosure purposes: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Inputs other than Level 1 prices for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and values determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. Included in cash and cash equivalents as of June 30, 2018 is a money market fund with a carrying value and fair value of $103.0 million based upon a Level 1 fair value assessment. The carrying amounts for the Company’s other financial instruments approximate fair values.
Stock-Based Compensation	Stock-Based Compensation The Company expenses stock-based compensation to employees and board members over the requisite service period based on the estimated grant-date fair value of the awards. The Company accounts for forfeitures as they occur. Stock-based awards with graded-vesting schedules are recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model, and the assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the statements of operations based upon the underlying individual’s role at the Company. Stock-based compensation for non-employee
Income Taxes	Income Taxes Income taxes are recorded in accordance with ASC 740, Income Taxes The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit would more likely than not be realized assuming examination by the taxing authority. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company recognizes any interest and penalties accrued related to unrecognized tax benefits as income tax expense.
Net Loss Per Share	Net Loss Per Share Net loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net loss per share excludes the potential impact of Series A, Series B and Series C Preferred Stock, common stock options and unvested shares of restricted stock because their effect would be anti-dilutive due to the Company’s net loss. Since the Company had a net loss in each of the periods presented, basic and diluted net loss per common share are the same. The table below provides potential shares outstanding that were not included in the computation of diluted net loss per common share, as the inclusion of these securities would have been anti-dilutive: As of June 30, 2018 2017 Shares issuable upon conversion of Series A Preferred — 12,428,773 Shares issuable upon exercise of stock options 1,383,582 90,429 Non-vested 848,859 848,859
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) right-of-use In June 2018, the FASB issued ASU No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting

Significant Accounting Polici16

Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Schedule of Total Potential Shares Outstanding Including Anti-dilutive	The table below provides potential shares outstanding that were not included in the computation of diluted net loss per common share, as the inclusion of these securities would have been anti-dilutive: As of June 30, 2018 2017 Shares issuable upon conversion of Series A Preferred — 12,428,773 Shares issuable upon exercise of stock options 1,383,582 90,429 Non-vested 848,859 848,859

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2018
Payables and Accruals [Abstract]
Accrued Expenses	Accrued expenses consisted of the following (in thousands): As of June 30, 2018 As of December 31, 2017 Compensation and related costs $ 508 $ 49 Clinical trials and drug development 184 233 Initial Public Offering costs 697 — Consulting - former Chief Scientific Officer 382 — Professional fees 53 129 Other 184 38 Total accrued expenses $ 2,008 $ 449

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2018
Assumptions Used to Estimate Fair Value of Employee Stock Option Awards	The grant date fair value of employee stock option awards is determined using the Black-Scholes option-pricing model. The following assumptions were used during the three and six months ended June 30, 2018 and 2017 to estimate the fair value of employee stock option awards: For the three months ended June 30, For the six months ended June 30, 2018 2017* 2018 2017 Exercise price $6.86 - $15.00 — $6.52 - $15.00 $0.90 Risk-free rate of interest 2.83% - 2.95% — 2.58% - 2.95% 1.92% - 2.23% Expected term (years) 6.12 — 6.11 6.25 Expected stock price volatility 71.18% - 83.67% — 70.58% - 83.67% 79.02% - 79.12% Weighted average estimated fair value share price $7.52 — $6.53 $0.12 Dividend yield — — — — * The Company did not grant stock options during the three months ended June 30, 2017
Schedule of Restricted Stock Awards Activites	The following table summarizes restricted stock award activities for the six months ended June 30, 2018: Weighted Average Grant Date Fair Number of Shares Value Nonvested at December 31, 2017 848,859 $ 0.33 Granted — — Nonvested at June 30, 2018 848,859 $ 0.33
Schedule of Stock Based Compensation Expense	Stock-based compensation expense has been reported in the Company’s condensed statements of operations for the three and six months ended June 30, 2018 and 2017 as follows (in thousands): For the three months ended June 30, For the six months ended June 30, 2018 2017 2018 2017 Research and development $ 350 $ 2 $ 467 $ 3 General and administrative 1,071 — 1,116 — Total stock-based compensation $ 1,421 $ 2 $ 1,583 $ 3
Employee Stock Options [Member]
Schedule of Stock Option Activity	The following table summarizes the Company’s employee stock option activity under the 2013 Plan and the IPO Plan for the six months ended June 30, 2018: Weighted average Weighted average remaining contractual Aggregate intrinsic Number of shares exercise price life (in years) value Outstanding as of December 31, 2017 17,502 $ 0.90 Options granted 1,293,153 7.64 Outstanding as of June 30, 2018 1,310,655 $ 7.55 9.7 $ 15,967,862 Options vested and exercisable as of June 30, 2018 6,199 $ 0.90 8.5 $ 116,727
Non-Employee Stock Option [Member]
Schedule of Stock Option Activity	The following table summarizes the Company’s non-employee Weighted average Weighted average remaining contractual Aggregate intrinsic Number of shares exercise price life (in years) value Outstanding as of December 31, 2017 72,927 $ 0.90 Options granted — — Outstanding as of June 30, 2018 72,927 $ 0.90 7.8 $ 1,373,215 Options vested and exercisable as of June 30, 2018 48,620 $ 0.90 7.8 $ 915,515

Organization and Description 19

Organization and Description of Business Operations - Additional Information (Detail) $ / shares in Units, $ in Thousands	Jun. 19, 2018USD ($)$ / sharesshares	Jun. 04, 2018shares	Mar. 07, 2018USD ($)$ / sharesshares	Feb. 20, 2018USD ($)$ / sharesshares	Jun. 30, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares
Description Of Business [Line Items]
Stock split conversion ratio		1.714
Stock split description		No fractional shares were issued in connection with the stock split.
Number of fractional shares issued		0
Accumulated deficit | $					$ (20,268)	$ (12,435)
Issuance of common stock in connection with IPO, net of offering costs | $					$ 86,250
Common stock, authorized	200,000,000				200,000,000	33,236,900
Common stock, par value | $ / shares	$ 0.0001				$ 0.0001	$ 0.0001
Preferred stock, authorized	10,000,000				10,000,000	10,000,000
Preferred stock, par value | $ / shares	$ 0.0001				$ 0.0001	$ 0.0001
IPO [Member]
Description Of Business [Line Items]
Convertible preferred stock share issued	5,750,000				2,198,198
Issuance of common stock in connection with IPO, net of offering costs | $	$ 78,400
Public offering price of common stock | $ / shares	$ 15
Conversion of preferred stock into common stock, shares	16,246,872
Series C Convertible Preferred Stock [Member]
Description Of Business [Line Items]
Convertible preferred stock share issued			4,606,267	4,606,267
Convertible preferred stock share issued price per share | $ / shares			$ 4.559	$ 4.559
Proceed from issuance of convertible preferred stock | $			$ 21,000	$ 21,000	$ 21,000

Significant Accounting Polici20

Significant Accounting Policies - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)Segment	Dec. 31, 2017USD ($)	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Significant Accounting Policies [Line Items]
Number of operating segment | Segment	1
Cash and cash equivalents at Carrying value	$ 103,149	$ 8,663	$ 506	$ 527
Money Market Funds [Member]
Significant Accounting Policies [Line Items]
Cash and cash equivalents at Carrying value	$ 103,000

Significant Accounting Polici21

Significant Accounting Policies - Schedule of Total Potential Shares Outstanding That Were Not Included in The Computation of Diluted Net Loss Per Common Share As Inclusion of These Securities Would Have Been Anti-Dilutive (Detail) - shares	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Employee Stock Options [Member]
Incremental Common Shares [Line Items]
Shares issuable upon exercise of stock options/ Non-vested shares under restricted stock grants	1,383,582	90,429
Restricted Stock [Member]
Incremental Common Shares [Line Items]
Shares issuable upon exercise of stock options/ Non-vested shares under restricted stock grants	848,859	848,859
Series A Convertible Preferred Stock [Member]
Incremental Common Shares [Line Items]
Shares issuable upon conversion of Preferred Stock		12,428,773

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - PBM Capital Group, LLC [Member] - USD ($)	Dec. 02, 2015	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Schedule of Other Related Party Transactions [Line Items]
Services agreement initial term	12 months	12 months
Expenses incurred under services agreement		$ 150,000	$ 7,500	$ 157,500	$ 15,000
Due to related party		36,000		$ 36,000		$ 14,000
Service Agreement [Member]
Schedule of Other Related Party Transactions [Line Items]
Monthly management fee payable	$ 2,500
Amended Service Agreement [Member]
Schedule of Other Related Party Transactions [Line Items]
Monthly management fee payable		$ 50,000

Accrued Expenses - Accrued Expe

Accrued Expenses - Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accrued Liabilities, Current [Abstract]
Compensation and related costs	$ 508	$ 49
Clinical trials and drug development	184	233
Initial Public Offering costs	697	0
Consulting - former Chief Scientific Officer	382	0
Professional fees	53	129
Other	184	38
Total accrued expenses	$ 2,008	$ 449

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2018USD ($)$ / h	Mar. 22, 2018USD ($)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Litigation liability	$ 0		$ 0
Accrued expenses	2,008,000		$ 449,000
Former Chief Executive Officer [Member]
Loss Contingencies [Line Items]
Consulting agreement required cash payment per month	$ 29,375
Consulting payment per hour | $ / h	300
Accrued expenses	$ 400,000
Crude Cantharidin Material [Member]
Loss Contingencies [Line Items]
Purchase Commitment	$ 500,000	$ 2,300,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands	Jun. 19, 2018USD ($)$ / sharesshares	Mar. 07, 2018USD ($)$ / sharesshares	Feb. 20, 2018USD ($)$ / sharesshares	Dec. 15, 2017USD ($)$ / sharesshares	Dec. 02, 2015USD ($)Investorshares	Jun. 30, 2018USD ($)$ / sharesshares	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)
Common stock, authorized | shares	200,000,000					200,000,000		33,236,900
Common stock, par value | $ / shares	$ 0.0001					$ 0.0001		$ 0.0001
Common stock, voting right						1
Proceeds from initial public offering						$ 86,250
Repurchase of stocks | shares						105,144		105,144
Preferred stock shares issued | shares						0		0
Series A Convertible Preferred Stock [Member]
Preferred stock shares issued | shares					21,302,972
Proceeds from issuance of convertible preferred stock					$ 1,900
Conversion of notes payable and accrued interest					500
Preferred stock subscription receivable					8,500
Stock issuance cost					$ 400		$ 60
Proceeds from stock subscription receivable								$ 8,000
Number of investors | Investor					14
Gross proceed							$ 1,700
Series A Convertible Preferred Stock [Member] | PBMVP Holdings [Member]
Proceeds from stock subscription receivable									$ 500
Series C Convertible Preferred Stock [Member]
Common stock issued and sale | shares		4,606,267	4,606,267
Stock issuance cost						$ 7
Issuance price | $ / shares		$ 4.559	$ 4.559
Gross proceed		$ 21,000	$ 21,000			$ 21,000
Series B Convertible Preferred Stock [Member]
Common stock issued and sale | shares				1,937,984
Issuance price | $ / shares				$ 2.58
Gross proceed				$ 5,000
Amended and Restated Agreement [Member]
Repurchase of stocks | shares						848,859
Repurchase price | $ / shares						$ 0.0001
IPO [Member]
Common stock issued and sale | shares	5,750,000					2,198,198
Offering price | $ / shares	$ 15
Proceeds from initial public offering	$ 78,400
Stock issuance cost						$ 6,812
Conversion of preferred stock into common stock, shares | shares	16,246,872
IPO [Member] | Series A Preferred Stock [Member]
Conversion of preferred stock into common stock, shares | shares	12,428,773
IPO [Member] | Series B Preferred Stock [Member]
Conversion of preferred stock into common stock, shares | shares	1,130,679
IPO [Member] | Series C Preferred Stock [Member]
Conversion of preferred stock into common stock, shares | shares	2,687,420

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Jun. 19, 2018	Apr. 24, 2018	Mar. 20, 2018	Mar. 05, 2018	Feb. 26, 2018	Feb. 12, 2018	Dec. 22, 2017	Jan. 31, 2017	Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017	Apr. 04, 2018	Mar. 28, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award stock option, shares granted										0
Exercise price of stock option grant													$ 0.90
Share price															$ 6.52
Risk-free rate of interest, minimum									2.83%			2.58%	1.92%
Risk-free rate of interest, maximum									2.95%			2.95%	2.23%
Expected stock price volatility, minimum									71.18%			70.58%	79.02%
Expected stock price volatility, maximum									83.67%			83.67%	79.12%
Expected dividend yield									0.00%	0.00%	[1]	0.00%	0.00%
Total unrecognized compensation									$ 0.3			$ 0.3
Non-Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award stock option, shares granted									0	0		0	0
Number of stock option award granted		186,696	87,514
Exercise price of stock option grant												$ 0
Exercise price of stock option grant				$ 6.86	$ 6.86				$ 0.90			$ 0.90		$ 8.73		$ 0.90
Risk-free rate of interest, minimum									2.68%	2.21%		2.33%	2.21%
Risk-free rate of interest, maximum									2.93%	2.40%		2.93%	2.48%
Expected stock price volatility, minimum									73.53%	78.84%		68.98%	78.84%
Expected stock price volatility, maximum									83.81%	79.07%		83.81%	79.12%
Expected dividend yield									0.00%	0.00%		0.00%	0.00%
Non-Employee Stock Option [Member] | Weighted Average [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share price									$ 17.77	$ 0.16		$ 17.77	$ 0.16
Employee Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted contractual term												10 years
Stock options expiration date												2028-06
Stock option vesting term, description												Through 2,022
Share based compensation arrangement by share based payment award stock option, shares granted								17,502				1,293,153
Stock option expiration date												2027-01
Stock option vesting term, description												Through 2,021
Stock options vested at grant									6,199			6,199
Number of stock option award granted						878,923
Exercise price of stock option grant												$ 7.64
Stock option exercised						186,696
Number of shares exercise price to be derived at fair value				72,928	113,768
Exercise price of stock option grant									$ 7.55			7.55				$ 0.90
Weighted average grant date fair value per share												$ 6.53	$ 0.12
Employee Stock Options [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of stock subject to vesting (as a percent)												25.00%
Stock vesting period												12 months
Employee Stock Options [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of stock subject to vesting (as a percent)												75.00%
Stock vesting period												12 months
Employee Stock Options [Member] | Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock option award granted							724,315
Exercise price of stock option grant						$ 3.75
Employee Stock Options [Member] | Other Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock option award granted						154,608
Employee And Non Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation									$ 7.2			$ 7.2
Weighted-average stock option recognize period												1 year 8 months 12 days
IPO [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for issuance									3,738,199			3,738,199
Shares issued	5,750,000											2,198,198
Annual Increase in number of common shares from January 1, 2019 through January 1, 2028												4.00%
Number of years reserved share increase												10 years
Shares available for grant									2,112,719			2,112,719
[1]	The Company did not grant stock options during the three months ended June 30, 2017

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used to Estimate Fair Value of Employee Stock Option Awards (Detail) - $ / shares	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	[1]	Jun. 30, 2018	Jun. 30, 2017
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]
Exercise price					$ 0.90
Risk-free rate of interest, minimum	2.83%			2.58%	1.92%
Risk-free rate of interest, maximum	2.95%			2.95%	2.23%
Expected term (years)	6 years 1 month 13 days			6 years 1 month 9 days	6 years 3 months
Expected stock price volatility, minimum	71.18%			70.58%	79.02%
Expected stock price volatility, maximum	83.67%			83.67%	79.12%
Weighted average estimated fair value share price	$ 7.52			$ 6.53	$ 0.12
Dividend yield	0.00%	0.00%		0.00%	0.00%
Minimum [Member]
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]
Exercise price	$ 6.86			$ 6.52
Maximum [Member]
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]
Exercise price	$ 15			$ 15
[1]	The Company did not grant stock options during the three months ended June 30, 2017

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Employee Stock Option Activity (Detail) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended
	Jan. 31, 2017	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Options granted		0
Weighted average exercise price, Options granted				$ 0.90
Employee Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Outstanding Beginning Balance			17,502
Number of shares, Options granted	17,502		1,293,153
Number of shares, Outstanding Ending Balance			1,310,655
Number of shares, Options vested and exercisable Ending Balance			6,199
Weighted average exercise price, Outstanding Beginning Balance			$ 0.90
Weighted average exercise price, Options granted			7.64
Weighted average exercise price, Outstanding Ending Balance			7.55
Weighted average exercise price, Options vested and exercisable Ending Balance			$ 0.90
Weighted average remaining contractual life (in years), Outstanding			9 years 8 months 12 days
Weighted average remaining contractual life (in years), Options vested and exercisable			8 years 6 months
Aggregate intrinsic value, Outstanding Ending Balance			$ 15,967,862
Aggregate intrinsic value, Options vested and exercisable Ending Balance			$ 116,727

Stock-Based Compensation - Sc29

Stock-Based Compensation - Schedule of Company's Non-Employee Stock Option Activity (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Options granted		0
Weighted average exercise price, Options granted				$ 0.90
Non-Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Outstanding Beginning Balance			72,927
Number of shares, Options granted	0	0	0	0
Number of shares, Outstanding Ending Balance	72,927		72,927
Number of shares, Options vested and exercisable Ending Balance	48,620		48,620
Weighted average exercise price, Outstanding Beginning Balance			$ 0.90
Weighted average exercise price, Options granted			0
Weighted average exercise price, Outstanding Ending Balance	$ 0.90		0.90
Weighted average exercise price, Options vested and exercisable Ending Balance	$ 0.90		$ 0.90
Number of shares, Weighted average remaining contractual life (in years) outstanding			7 years 9 months 18 days
Weighted average remaining contractual life (in years), Options vested and exercisable			7 years 9 months 18 days
Aggregate intrinsic value, Outstanding Ending Balance	$ 1,373,215		$ 1,373,215
Aggregate intrinsic value, Options vested and exercisable Ending Balance	$ 915,515		$ 915,515

Stock-Based Compensation - Sc30

Stock-Based Compensation - Schedule of Restricted Stock Awards Activites (Detail) - Restricted Stock [Member]	6 Months Ended
	Jun. 30, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested, Number of Shares, Beginning Balance | shares	848,859
Nonvested, Number of Shares, Granted | shares	0
Nonvested, Number of Shares, Ending Balance | shares	848,859
Nonvested, Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 0.33
Nonvested, Weighted Average Grant Date Fair Value, Granted | $ / shares	0
Nonvested, Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 0.33

Stock-Based Compensation - Sc31

Stock-Based Compensation - Schedule of Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 1,421	$ 2	$ 1,583	$ 3
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	350	$ 2	467	$ 3
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 1,071		$ 1,116

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail)	Jul. 16, 2018
Funing County Development Brucea Javanica Professional Cooperatives [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Supply agreement period	5 years