Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2019	Aug. 09, 2019
[DocumentAndEntityInformationAbstract]
Entity Registrant Name	NextCure, Inc.
Entity Central Index Key	0001661059
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		22,714,765

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 192,689	$ 135,173
Restricted cash	873	460
Prepaid expenses and other current assets	2,959	152
Total current assets	196,521	135,785
Property and equipment, net	12,329	11,407
Other assets	4,200	436
Total assets	213,050	147,628
Current liabilities:
Accounts payable	1,990	2,483
Accrued liabilities	2,171	2,411
Deferred rent, current portion	6	28
Term loan, current portion	833	387
Deferred revenue, current portion	6,524	4,989
Total current liabilities	11,524	10,298
Deferred rent, net of current portion	322	242
Term loan, net of current portion	4,167	73
Deferred revenue, net of current portion	18,442	21,736
Total liabilities	34,455	32,349
Commitments and contingencies (Note 6)
Redeemable preferred stock:
Total redeemable preferred stock		162,223
Stockholders’ equity (deficit):
Preferred stock; par value of $0.001 per share, 10,000,000 and 0 shares authorized at June 30, 2019 and December 31, 2018. No shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively
Common stock, par value of $0.001 per share; 100,000,000 and 158,745,671 shares authorized at June 30, 2019 and December 31, 2018, respectively, 22,714,765 and 1,374,812 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	23	11
Additional paid-in capital	240,245	342
Accumulated deficit	(61,673)	(47,297)
Total stockholders’ equity (deficit)	178,595	(46,944)
Total liabilities, preferred stock and stockholders’ equity (deficit)	$ 213,050	147,628
Series A Preferred Stock
Redeemable preferred stock:
Total redeemable preferred stock		71,000
Series B Preferred Stock
Redeemable preferred stock:
Total redeemable preferred stock		$ 91,223

CONDENSED BALANCE SHEETS - (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Preferred stock, par value per share	$ 0.001	$ 0.001
Preferred stock, number of shares authorized	10,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.001	$ 0.001
Common stock, number of shares authorized	100,000,000	158,745,671
Common stock, shares issued	22,714,765	1,374,812
Common stock, shares outstanding	22,714,765	1,374,812
Series A Preferred Stock
Preferred stock, par value per share	$ 0.001	$ 0.001
Preferred stock, number of shares authorized	0	68,181,819
Preferred stock, shares issued	0	68,181,819
Preferred stock, shares outstanding	0	68,181,819
Series B Preferred Stock
Preferred stock, par value per share	$ 0.001	$ 0.001
Preferred stock, number of shares authorized	0	56,828,852
Preferred stock, shares issued	0	56,828,851
Preferred stock, shares outstanding	0	56,828,851

CONDENSED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
CONDENSED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Revenue	$ 1,402		$ 2,759
Type of Revenue [Extensible List]			nxtc:RelatedPartyMember
Operating expenses:
Research and development	7,643	$ 4,434	$ 14,156	$ 8,644
General and administrative	2,714	866	4,373	1,665
Total operating expenses	10,357	5,300	18,529	10,309
Loss from operations	(8,955)	(5,300)	(15,770)	(10,309)
Other income, net	734	69	1,394	82
Net loss	$ (8,221)	$ (5,231)	$ (14,376)	$ (10,227)
Net loss per share attributable to common stockholders—basic and diluted (in dollars per share)	$ (0.61)	$ (3.82)	$ (1.92)	$ (7.47)
Weighted average common shares outstanding—basic and diluted (in shares)	13,498,393	1,369,212	7,472,298	1,369,212

CONDENSED STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS’ DEFICIT - USD ($) $ in Thousands	Preferred Stock Series A Preferred Stock	Preferred Stock Series A-3 preferred stock	Preferred Stock Series B Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Series A Preferred Stock	Series B Preferred Stock	Total
Balance at the beginning at Dec. 31, 2017				$ 1	$ 84	$ (24,498)			$ (24,413)
Balance at the beginning (in shares) at Dec. 31, 2017				1,369,212
Balance at the beginning at Dec. 31, 2017	$ 40,000
Balance at the beginning (in shares) at Dec. 31, 2017	40,000,000
Increase (Decrease) in Stockholders' Deficit
Stock based compensation					24				24
Net loss						(4,996)			(4,996)
Balance at the end at Mar. 31, 2018				$ 1	108	(29,494)			(29,385)
Balance at the end (in shares) at Mar. 31, 2018				1,369,212
Balance at the end at Mar. 31, 2018	$ 40,000
Balance at the end (in shares) at Mar. 31, 2018	40,000,000
Balance at the beginning at Dec. 31, 2017				$ 1	84	(24,498)			(24,413)
Balance at the beginning (in shares) at Dec. 31, 2017				1,369,212
Balance at the beginning at Dec. 31, 2017	$ 40,000
Balance at the beginning (in shares) at Dec. 31, 2017	40,000,000
Increase (Decrease) in Stockholders' Deficit
Net loss									(10,227)
Balance at the end at Jun. 30, 2018				$ 1	132	(34,725)			(34,592)
Balance at the end (in shares) at Jun. 30, 2018				1,369,212
Balance at the end at Jun. 30, 2018	$ 71,000
Balance at the end (in shares) at Jun. 30, 2018	68,181,819
Balance at the beginning at Mar. 31, 2018				$ 1	108	(29,494)			(29,385)
Balance at the beginning (in shares) at Mar. 31, 2018				1,369,212
Balance at the beginning at Mar. 31, 2018	$ 40,000
Balance at the beginning (in shares) at Mar. 31, 2018	40,000,000
Increase (Decrease) in Stockholders' Deficit
Stock based compensation					24				24
Issuance of stock		$ 31,000
Issuance of stock (in shares)		28,181,819
Net loss						(5,231)			(5,231)
Balance at the end at Jun. 30, 2018				$ 1	132	(34,725)			(34,592)
Balance at the end (in shares) at Jun. 30, 2018				1,369,212
Balance at the end at Jun. 30, 2018	$ 71,000
Balance at the end (in shares) at Jun. 30, 2018	68,181,819
Balance at the beginning at Dec. 31, 2018				$ 1	352	(47,297)			$ (46,944)
Balance at the beginning (in shares) at Dec. 31, 2018				1,374,812					1,374,812
Balance at the beginning at Dec. 31, 2018	$ 71,000		$ 91,223				$ 71,000	$ 91,223	$ 162,223
Balance at the beginning (in shares) at Dec. 31, 2018	68,181,819		56,828,851
Increase (Decrease) in Stockholders' Deficit
Stock based compensation					383				383
Issuance of stock					4				4
Issuance of stock (in shares)				4,697
Net loss						(6,155)			(6,155)
Balance at the end at Mar. 31, 2019				$ 1	739	(53,452)			(52,712)
Balance at the end (in shares) at Mar. 31, 2019				1,379,509
Balance at the end at Mar. 31, 2019	$ 71,000		$ 91,223
Balance at the end (in shares) at Mar. 31, 2019	68,181,819		56,828,851
Balance at the beginning at Dec. 31, 2018				$ 1	352	(47,297)			$ (46,944)
Balance at the beginning (in shares) at Dec. 31, 2018				1,374,812					1,374,812
Balance at the beginning at Dec. 31, 2018	$ 71,000		$ 91,223				$ 71,000	$ 91,223	$ 162,223
Balance at the beginning (in shares) at Dec. 31, 2018	68,181,819		56,828,851
Increase (Decrease) in Stockholders' Deficit
Net loss									(14,376)
Balance at the end at Jun. 30, 2019				$ 23	240,245	(61,673)			$ 178,595
Balance at the end (in shares) at Jun. 30, 2019				22,714,765					22,714,765
Balance at the beginning at Mar. 31, 2019				$ 1	739	(53,452)			$ (52,712)
Balance at the beginning (in shares) at Mar. 31, 2019				1,379,509
Balance at the beginning at Mar. 31, 2019	$ 71,000		$ 91,223
Balance at the beginning (in shares) at Mar. 31, 2019	68,181,819		56,828,851
Increase (Decrease) in Stockholders' Deficit
Initial public offering, net of issuance costs of $9.4 million				$ 6	76,844				76,850
Initial public offering, net of issuance costs of $9.4 million (in shares)				5,750,000
Conversion of preferred stock to common stock	$ (71,000)		$ (91,223)	$ 15	162,208				162,223
Conversion of preferred stock to common stock (in shares)	(68,181,819)		(56,828,851)	15,560,569
Stock based compensation					412				412
Issuance of stock				$ 1	42				43
Issuance of stock (in shares)				24,687
Net loss						(8,221)			(8,221)
Balance at the end at Jun. 30, 2019				$ 23	$ 240,245	$ (61,673)			$ 178,595
Balance at the end (in shares) at Jun. 30, 2019				22,714,765					22,714,765

CONDENSED STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS’ DEFICIT (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2019
Initial public offering issuance costs		$ 9,400
Common stock, par value per share		$ 0.001
Series A-3 preferred stock
Initial public offering issuance costs	$ 0

CONDENSED STATEMENTS OF CASH FLOWS - USD ($)	6 Months Ended
CONDENSED STATEMENTS OF CASH FLOWS - USD ($)	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net loss	$ (14,376,000)	$ (10,227,000)
Adjustments to reconcile net loss to net cash provided by (used) in operating activities:
Depreciation and amortization	1,145,000	763,000
Stock-based compensation	795,000	48,000
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(2,815,000)	(114,000)
Accounts payable	(493,000)	512,000
Accrued liabilities and other current liabilities	(182,000)	(707,000)
Deferred revenue	(1,759,000)	(35,000)
Net cash used in operating activities	(17,685,000)	(9,760,000)
Cash flows from investing activities:
Purchase of property and equipment	(2,067,000)	(853,000)
Net cash used in investing activities	(2,067,000)	(853,000)
Cash flows from financing activities:
Proceeds from initial public offering, net of issuance costs	77,264,000
Proceeds from issuance of preferred stock, net of issuance costs		31,000,000
Proceeds from issuance of common stock	43,000
Proceeds from the term loan	4,540,000
Payments of the term loan		(200,000)
Net cash provided by financing activities	81,847,000	30,800,000
Net increase in cash, cash equivalents and restricted cash	62,095,000	20,187,000
Cash, cash equivalents and restricted cash—beginning of year	135,633,000	9,287,000
Cash, cash equivalents and restricted cash—end of period	197,728,000	29,474,000
Supplemental disclosures of cash flow information:
Cash paid for interest	80,000	$ 12,000
Supplemental disclosures of noncash investing and financing activities:
Purchase of property and equipment included in accrued liabilities	75,000
Deferred financing costs in accrued liabilities	154,000
Conversion of convertible preferred stock into common stock	$ 162,223,000

Nature of the Business	6 Months Ended
Nature of the Business	Jun. 30, 2019
Nature of the Business
Nature of the Business	1. Nature of the Business Organization NextCure, Inc. (“NextCure” or the “Company”) was incorporated in Delaware in September 2015 and is headquartered in Beltsville, Maryland. The Company is a clinical-stage biopharmaceutical company committed to discovering and developing novel, first‑in‑class immunomedicines to treat cancer and other immune‑related diseases by restoring normal immune function. Through its proprietary Functional, Integrated, NextCure Discovery in Immuno‑Oncology (“FIND‑IO”) platform, the Company studies various immune cells in order to discover and understand targets and structural components of immune cells and their functional impact in order to develop immunomedicines. Since inception, the Company has devoted substantially all of its efforts and financial resources to organizing and staffing the Company, identifying business development opportunities, raising capital, securing intellectual property rights related to the Company’s product candidates, building and optimizing the Company’s manufacturing capabilities and conducting discovery, research and development activities for the Company’s product candidates, discovery programs and its FIND‑IO platform. Initial Public Offering On May 13, 2019, the Company closed its initial public offering (“IPO”), in which the Company issued and sold 5,750,000 shares of common stock at a public offering price of $15.00 per share, for net proceeds to the Company of approximately $77.0 million after deducting underwriting discounts and commissions of $6.0 million and offering expenses of approximately $3.4 million. In preparation for the IPO, on May 3, 2019, the Company effected a one-for-8.0338 reverse stock split of its issued and outstanding common stock. The par value and authorized shares of common stock were not adjusted as a result of the reverse stock split. All of the share and per share information presented in the accompanying financial statements has been adjusted to reflect the reverse common stock split on a retroactive basis for all periods and as of all dates presented. Upon the closing of the IPO, on May 13, 2019, all of the outstanding shares of the Company’s convertible preferred stock automatically converted into 15,560,569 shares of common stock at the applicable conversion ratio then in effect. Subsequent to the closing of the IPO, there were no shares of preferred stock outstanding. Upon the closing of the IPO, on May 13, 2019, the Company’s certificate of incorporation was amended and restated to provide for 100,000,000 authorized shares of common stock with a par value of $0.001 per share and 10,000,000 authorized shares of preferred stock with a par value of $0.001 per share. Liquidity The Company has not generated any revenue to date from product sales and does not expect to generate any revenues from product sales in the foreseeable future. Through June 2019, the Company has funded its operations primarily with proceeds from the sale of preferred stock and proceeds from the Company’s agreement with Eli Lilly and Company (Note 5) and proceeds from the IPO. The Company expects to incur additional operating losses and negative operating cash flows for the foreseeable future.

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2019

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited condensed financial statements as of June 30, 2019 and for the three and six months ended June 30, 2019 and 2018 have been prepared by the Company in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these condensed financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto as of and for the year ended December 31, 2018, which are included in the Company’s final prospectus that forms a part of the Company’s Registration Statement on Form S-1 (Reg. No. 333-230837) (the “Registration Statement”), as filed with the SEC pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended, on May 9, 2019.

The unaudited interim condensed financial statements have been prepared on the same basis as the audited financial statements. In the opinion of management, the accompanying unaudited interim condensed financial statements contain all adjustments necessary for a fair statement of the Company’s financial position as of June 30, 2019 and condensed results of operations and cash flows for the three and six months ended June 30, 2019 and 2018. Such adjustments are of a normal and recurring nature. The results of operations for the three and six months ended June 30, 2019 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2019.

Use of Estimates

The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to accrued expenses, revenue recognition, the valuation of equity‑based compensation, including incentive stock options, common stock and restricted common stock, as well as income taxes. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Restricted Cash

The Company is required, as a condition of its Term Loan (Note 7), to maintain cash collateral on deposit in a segregated money market bank account equal to the principal portion of the Term Loan, as determined on a quarterly basis. The bank may restrict withdrawals or transfers by or on behalf of the Company that would violate this requirement. The required reserve totaled $5.0 million as of June 30, 2019. This amount is presented as restricted cash on the accompanying balance sheet.

The following table reconciles cash and cash equivalents and restricted cash per the balance sheet to the statement of cash flows (in thousands):


	June 30,		December 31,
	2019		2018
		(unaudited)
Cash and cash equivalents	$	192,689	$	135,173
Restricted cash (including $4,200 in other assets)		5,039		460
Total	$	197,728	$	135,633

Revenue Recognition

The Company has adopted Accounting Standards Codification Topic 606, Revenue from Contracts with Customers (“ASC 606”). Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, the Company performs the following five steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect consideration to which it is entitled in exchange for the goods or services it transfers to the customer.

The Company evaluates customer options for material rights or options to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement.

Performance obligations are promised goods or services in a contract to transfer a distinct good or service to the customer and are considered distinct when (i) the customer can benefit from the good or service on its own or together with other readily available resources and (ii) the promised good or service is separately identifiable from other promises in the contract. In assessing whether promised goods or services are distinct, the Company considers factors such as the stage of development of the underlying intellectual property, the capabilities of the customer to develop the intellectual property on its own or whether the required expertise is readily available and whether the goods or services are integral to or dependent on other goods or services in the contract.

The Company estimates the transaction price based on the amount expected to be received for transferring the promised goods or services in the contract. Consideration generally may include fixed consideration or variable consideration. Should an arrangement include variable consideration, the Company will evaluate the amount of potential payments and the likelihood that the payments will be received. The Company will utilize either the most likely amount method or expected amount method to estimate the amount expected to be received based on which method best predicts the amount expected to be received. The amount of variable consideration that is included in the transaction price may be constrained and will be included in the transaction price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period.

The Company’s contracts may include development and regulatory milestone payments which would be assessed under the most likely amount method and constrained if it is probable that a significant revenue reversal would occur. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, will not be considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments would be recorded on a cumulative catch-up basis, which would affect collaboration revenues in the period of adjustment.

For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company will recognize revenue at the later of (i) when the related sales occur and (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied).

The Company allocates the transaction price based on the estimated stand-alone selling price of each of the performance obligations. The Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the stand-alone selling price for service obligations, which may include other comparable transactions, pricing considered in negotiating the transaction and the estimated costs. Additionally, in determining the standalone selling price for material rights, the Company may reference comparable transactions, clinical trial success probabilities and estimates of option exercise likelihood. Variable consideration will be allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated are consistent with the amounts the Company would expect to receive for the satisfaction of each performance obligation.

The consideration allocated to each performance obligation is recognized as revenue when control is transferred for the related goods or services. For performance obligations which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Upfront payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying condensed balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional.

Recently Issued Accounting Pronouncements

The Company qualifies as an emerging growth company (“EGC”) as defined under the Jumpstart Our Business Startups Act (the “JOBS Act”). Using exemptions provided under the JOBS Act provided to EGCs, the Company has elected to defer compliance with new or revised financial accounting standards until it is required to comply with such standards.

In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”). The new guidance requires lessees to record most leases on their balance sheets and recognize the related expenses on their income statements in a manner similar to current practice. ASU 2016-02 states that a lessee would recognize a lease liability for the obligation to make lease payments and a right-to-use asset for the right to use the underlying asset for the lease term. The standard is effective for the Company January 1, 2020. Early adoption is permitted. The Company is currently evaluating the effect of this standard on its financial statements.

In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606. The amendment clarifies that certain transactions between collaborative arrangement participants should be accounted for as revenue under Topic 606 when the collaborative arrangement participant is a customer in the context of a unit of account. In those situations, all the guidance in Topic 606 should be applied, including recognition, measurement, presentation and disclosure requirements. The amendment also adds unit of account guidance in Topic 808 to align with the guidance in Topic 606 (that is, a distinct good or service) when an entity is assessing whether the collaborative arrangement or a part of the arrangement is within the scope of Topic 606. Lastly, the amendment requires that in a transaction with a collaborative arrangement participant that is not directly related to sales to third parties, presenting the transaction together with revenue recognized under Topic 606 is precluded if the collaborative arrangement participant is not a customer. For public business entities, the amendments are effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The Company is currently evaluating these clarifications in the accounting and presentation for its collaborative arrangements within the scope of Topic 808 but does not expect it will have any impact.

Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2019

Fair Value of Financial Instruments

Fair Value of Financial Instruments

3. Fair Value of Financial Instruments

The Company has certain financial assets recorded at fair value, which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements.

Level 1—Quoted market prices in active markets for identical assets or liabilities.

Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves.

Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use.

To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

The following tables set forth the fair value of the Company’s financial assets by level within the fair value hierarchy (in thousands):

As of June 30, 2019

(unaudited)

Fair Value Measurement Based on

Significant

Quoted Prices in

Other

Significant

Carrying

Fair

Active Markets

Observable

Unobservable

Assets

Amount

Value

(Level 1)

Inputs (Level 2)

Inputs (Level 3)

Money market funds (cash equivalents)

5,000

—

As of December 31, 2018

Fair Value Measurement Based on

Significant

Quoted Prices in

Other

Significant

Carrying

Fair

Active Markets

Observable

Unobservable

Assets

Amount

Value

(Level 1)

Inputs (Level 2)

Inputs (Level 3)

Money market funds (cash equivalents)

5,000

—

The Company did not transfer any assets measured at fair value on a recurring basis between levels during the three and six months ended June 30, 2019.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Property and Equipment, Net

6 Months Ended

Jun. 30, 2019

Property and Equipment, Net

Property and Equipment, Net

4. Property and Equipment, Net

Property and equipment consist of the following (in thousands):


	June 30,		December 31,
	2019		2018
		(unaudited)
Research equipment	$	9,348	$	7,787
Leasehold improvements		5,065		4,825
Computer equipment		360		167
Furniture and fixtures		93		70
Construction in progress		1,077		1,027
Property and equipment, gross		15,943		13,876
Less: accumulated depreciation and amortization		(3,614)		(2,469)
Property and equipment, net	$	12,329	$	11,407

Construction in progress at June 30, 2019 consists of the costs incurred for research equipment and for the build-out of additional lab and office space and at December 31, 2018 consists of the costs incurred for the build-out of a manufacturing suite at the Company’s headquarters in Beltsville, Maryland.

Depreciation and amortization expense was $582,000 and $1,145,000 for the three and six months ended June 30, 2019, respectively, and $387,000 and $763,000 for the three and six months ended June 30, 2018, respectively.

Agreement with Eli Lilly and Company

6 Months Ended

Jun. 30, 2019

Agreement with Eli Lilly and Company

Agreement with Eli Lilly and Company

5. Agreement with Eli Lilly and Company

On November 2, 2018, the Company entered into a multi-year research and development collaboration agreement (the “Lilly Agreement”) with Eli Lilly and Company (“Lilly”), pursuant to which the Company will use its proprietary FIND-IO platform to identify novel oncology targets for additional collaborative research and drug discovery by the Company and Lilly. Under the Lilly Agreement, Lilly and the Company have granted one another an equal number of exclusive options to research, develop, manufacture and commercialize compounds and products directed to oncology targets identified through the Lilly Agreement. Both Lilly and the Company have all options remaining eligible for exercise. The research collaboration with Lilly will be managed by a joint steering committee formed by an equal number of members from the Company and Lilly and will expire upon the earlier of the exercise of all options granted to Lilly or four years from the date of the agreement, subject to certain extensions. The Company considers Lilly to be a related party based on Lilly’s equity investment in the Company as discussed below.

During the research term under the Lilly Agreement, as a part of target discovery, the Company will be responsible for providing Lilly with oncology targets identified using the Company’s FIND-IO platform. From the targets provided by the Company, Lilly may select targets to advance to target validation using criteria developed by both parties. Following completion of the agreed upon target validation plan with respect to a given target, either party may propose to advance that target to compound discovery. For each target that has been advanced to compound discovery, Lilly will have the option to obtain an exclusive license with respect to the compounds and products directed to the target. If Lilly does not exercise its option with respect to a given target or has previously exercised all of its options, the Company will have the option to obtain licenses with respect to compounds and products directed to that target. Following option exercise by a party, the development and commercialization of any products directed to the target will be conducted by the exercising party. The exercising party must use commercially reasonable efforts to develop, seek regulatory approval for and commercialize any such products under mutually agreed upon work plans.

In November 2018, the Company received an upfront, non-refundable payment of $25.0 million under the Lilly Agreement and a concurrent $15.0 million equity investment. In addition, the Company will receive quarterly research and development support payments during a portion of the research term as well as option exercise fees upon option exercises by Lilly.

Pursuant to the Lilly Agreement, Lilly may owe an aggregate of up to $1.4 billion in development and regulatory milestones and sales milestones. Additionally, Lilly will pay mid to high single-digit royalties on net sales for all products directed to each target optioned by Lilly. Upon the Company’s exercise of an option with respect to a given target, the Company will pay Lilly an option exercise payment and may become obligated to milestone and royalty payments. The company may owe an aggregate of up to $710.0 million in development and regulatory milestones and sales milestones.

Upon the adoption of ASC 606, the Company evaluated the Lilly Agreement under the provisions of ASC 606 and concluded that Lilly is a customer prior to the exercise of its option to obtain an exclusive license with respect to the compounds and products directed to a target that has been advanced to compound discovery. The Company identified the following material promises under the Lilly Agreement: (i) a limited research license to conduct activities under the research collaboration; (ii) research and development services together with the provision of a data package in connection with Lilly’s option; (iii) various governance obligations, most notably participation on the joint steering committee; and (iv) rights related to an optional term extension by Lilly. The Company evaluated Lilly’s option to obtain an exclusive license with respect to the compounds and products directed to a target that has been advanced to compound discovery and concluded that the option was not issued at a significant and incremental discount, and therefore does not provide material rights. As such, they are excluded as performance obligations at the outset of the arrangement. The Company determined that the research license was not capable of being distinct and the related research and development services and governance activities are not distinct in the context of the contract and, as such, the Company determined that these promises should be combined into a single performance obligation, resulting in a total of two performance obligations under the Lilly Agreement; one for research and development services and one for the right related to an optional term extension by Lilly.

The transaction price at the outset of the arrangement was determined to be $32.7 million, comprised of the upfront fee received from Lilly, quarterly research and development support payments to be received from Lilly during a portion of the research term and an equity investment premium as determined by the Company with reference to a valuation of the Company’s preferred stock prepared by an unrelated third-party valuation firm in accordance with the guidance provided by the American Institute of Certified Public Accountants Practice Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation.

The transaction price was allocated to the two performance obligations based on their relative standalone selling price determined with reference to the Company’s estimated costs attendant to the obligations. Revenue allocated to the research and development performance obligation is being recognized as the research and development services are provided using an input method according to research and development costs incurred to date compared to estimated total research and development costs. The transfer of control occurs over this time period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. Revenue allocated to Lilly’s right related to an optional term extension is deferred until the right is exercised or lapses, and will subsequently be recognized accordingly.

While the Lilly Agreement was executed in November 2018, the Company’s performance initiated in January 2019. Under the Lilly Agreement, the Company recognized revenue of $1.4 million and $2.8 million for the three and six months ended June 30, 2019, respectively. As of June 30, 2019, deferred revenue included in the Company’s balance sheets comprised the following (in thousands):


	June 30,		December 31,
	2019		2018
		(unaudited)
Deferred revenue, beginning of period	$	26,725	$	—
Up-front payment		—		25,000
Attributed premium on the proceeds from Lilly’s investment in the Company		—		1,725
Research and development support billing		1,000		—
Revenue from research and development arrangement recognized		(2,759)		—
Total deferred revenue, end of period		24,966		26,725
Less: Deferred revenue, current portion		(6,524)		(4,989)
Deferred revenue, non-current portion	$	18,442	$	21,736

Commitments and Contingencies

6 Months Ended

Jun. 30, 2019

Commitments and Contingencies

Commitments and Contingencies

6. Commitments and Contingencies

Operating Leases

The Company subleases its facilities under a non‑cancelable operating sublease agreement. The sublease commenced on February 9, 2016 and, as amended, expires on August 31, 2025. The Company is also responsible for its prorated share of the sublandlord’s operating expense.

On January 30, 2019, the Company entered into a new lease to be used for office and laboratory space, which the Company took possession of in June 2019. The new lease expires in March 2030 and will also cover the Company’s existing space after expiration of the Company’s current lease. Base rent for the first 10 months is abated, after which the base rent of the lease is $19,650 per month, with an increase in annual rent of 3.0% in each subsequent year of the lease term. In connection with this lease, the Company executed a letter of credit of $39,000, which has not been drawn down on.

On March 15, 2019, the Company entered into an amended and restated sublease that covers the Company’s existing space plus additional square footage to be used as office space, which the Company took possession of upon entering into the amended and restated sublease. The total remaining commitment under the amended and restated sublease is approximately $2.7 million.

The future minimum payments for the operating leases are as follows (in thousands):


Remainder of the year	$	193
2020		675
2021		819
2022		868
2023		860
Thereafter		6,897
Total future minimum payments	$	10,312

Rent expense incurred under operating leases was approximately $87,000 and $190,000 for the three and six months ended June 30, 2019, respectively, and $101,000 and $201,000 for the three and six months ended June 30, 2018, respectively.

Legal Proceedings

The Company, from time to time, may be party to litigation arising in the ordinary course of business. The Company is not a party to any litigation or legal proceedings, nor is management aware of any pending or threatened litigation that, in the opinion of the Company’s management, are likely to have a material adverse effect on the Company’s business. At each reporting date, the Company evaluates whether a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses the costs related to its legal proceedings as incurred.

Term Loan

6 Months Ended

Jun. 30, 2019

Term Loan

Term Loan

7. Term Loan

In April 2016, the Company entered into a $1.0 million term loan with a commercial bank (the “Term Loan”). On January 25, 2019, the Company amended the Term Loan to increase the Company’s borrowing capacity to $5.0 million, which amount remains secured by the Company’s certificates of deposit, money market account, investment property and deposit or investment accounts. As amended, the Term Loan bears interest at the greater of the prime rate less 1% and 4.25%. The effective interest rate was 4.5% for the three and six months ended June 30, 2019. The effective interest rate was 3.79% and 3.66% for the three and six months ended June 30, 2018, respectively. Under the Term Loan, the Company is required to make monthly interest‑only payments through January 2020 and is required to make 36 equal monthly payments of principal plus accrued interest thereafter through January 2023.

Future maturities of the Term Loan as of June 30, 2019 are as follows (in thousands):


Remainder of the year	$	—
2020		1,528
2021		1,667
2022		1,667
2023		138
Total		5,000
Less: current portion of term loan		(833)
Term loan, net of current portion	$	4,167

Interest expense under the Term Loan was approximately $57,000 and $99,000 for the three and six months ended June 30, 2019, respectively, and $6,000 and $13,000 for the three and six months ended June 30, 2018, respectively.

Stock-Based Compensation

6 Months Ended

Jun. 30, 2019

Stock-Based Compensation

Stock-Based Compensation

8. Stock‑Based Compensation

Employee Equity Plans

The NextCure, Inc. 2015 Omnibus Incentive Plan (the "2015 Plan") provides for the Company to grant incentive stock options or nonqualified stock options, restricted stock awards, unrestricted stock awards or restricted stock units to employees, consultants and directors of the Company. The 2015 Plan is administered by the board of directors, or at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting and other restrictions are determined at the discretion of the board of directors or its committee if so delegated, except that the exercise price per share of the stock options may not be less than 100% of the fair market value of a share of the Company's common stock on the date of grant and the term of the stock options may not be greater than 10 years.

On May 3, 2019, the Company’s stockholders approved the NextCure, Inc. 2019 Omnibus Incentive Plan (the ‘‘2019 Plan’’), which became effective on May 8, 2019, the date on which the Registration Statement was declared effective (the “Effective Date”). The 2019 Plan replaces the 2015 Plan as the Company’s board of directors (the “Board”) determined not to make additional awards under the 2015 Plan following the effectiveness of the 2019 Plan. The 2019 Plan provides for the grant of awards of options, stock appreciation rights, restricted stock, restricted stock units, deferred stock units, unrestricted stock, dividend equivalent rights, other equity-based awards and cash bonus awards to the Company’s officers, employees, non-employee directors and other key persons (including consultants). The number of shares of common stock reserved for issuance under the 2019 Plan is 2,900,000 plus the number of shares of stock related to awards outstanding under the 2015 Plan that subsequently terminate by expiration or forfeiture, cancellation or otherwise without the issuance of such shares. The number of shares reserved for issuance under the 2019 Plan will automatically increase on January 1, 2020 and each January 1st thereafter during the term of the 2019 Plan by 4% of the number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year or such lesser number of shares determined by the Board.

As of June 30, 2019, 2,689,725 shares were available for future issuance under the 2019 Plan.

Stock options granted under the 2015 Plan and 2019 Plan (together, the “Plans”) to employees generally vest over four years and expire after ten years.

A summary of stock option activity for awards under the Plans is presented below:


	Options Outstanding and Exercisable
				Weighted
		Weighted		Average	Aggregate
		Average		Remaining	Intrinsic
	Number of	Exercise		Contractual	Value(1)
	Shares	Price		Life (Years)	(in thousands)
Outstanding as of December 31, 2018	2,056,891	$	4.74	9.4	$	5,946
Granted	210,269	$	15.57	10.0
Exercised	(29,383)	$	1.49	8.7
Outstanding as of June 30, 2019	2,237,777	$	5.80	9.0	$	20,663
Vested and expected to vest as of June 30, 2019	2,237,777	$	5.80		$	20,663
Exercisable as of June 30, 2019	415,357	$	1.15		$	5,744

(1)

The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money at June 30, 2019 and December 31, 2018.

The weighted-average grant date fair value of stock options granted to employees for the six months ended June 30, 2019 was $9.86. The aggregate intrinsic value of stock options exercised during the six months ended June 30, 2019 was $396,400.

The Company’s potential dilutive securities, which as of June 30, 2019 include common stock options, have been excluded from the computation of diluted net loss per share as the effect would be anti‑dilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded 2,237,777 potential shares of common stock , presented based on amounts outstanding at period end, from the computation of diluted net loss per share attributable to common stockholders for the period indicated because including them would have had an anti‑dilutive effect.

On May 3, 2019, the Company’s stockholders approved the NextCure, Inc. 2019 Employee Stock Purchase Plan (the “ESPP”), which became effective on the Effective Date. The ESPP is intended to qualify as an “employee stock purchase plan” within the meaning of Section 423(b) of the Internal Revenue Code. A total of 240,000 shares of common stock were reserved for issuance under this plan. In addition, the number of shares of common stock that may be issued under the ESPP will automatically increase on January 1, 2020 and each January 1st thereafter until expiration of the ESPP, in an amount equal to the lesser of (i) 1% of the number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year, (ii) 480,000 shares of common stock and (iii) a number of shares of common stock determined by the administrator of the ESPP.

Stock‑Based Compensation

The Company recorded stock-based compensation expense of $412,000 and $795,000 for the three and six months ended June 30, 2019, respectively, and $24,000 and $48,000 for the three and six months ended June 30, 2018, respectively.

Stock‑based compensation expense recorded as research and development and general and administrative expenses is as follows (in thousands):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
		(unaudited)			(unaudited)
	2019		2018		2019		2018
Research and development	$	151	$	11	$	300	$	21
General and administrative		261		13		495		27
Total stock-based compensation expense	$	412	$	24	$	795	$	48

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2019
Income Taxes
Income Taxes	9. Income Taxes The Company did not record a provision or benefit for income taxes during the six months ended June 30, 2019. The Company continues to maintain a full valuation allowance against its deferred tax assets. The Company has evaluated the positive and negative evidence involving its ability to realize its deferred tax assets. Management has considered the Company’s history of cumulative net losses incurred since inception and its lack of any commercially ready products. It has concluded that it is more likely than not that the Company will not realize the benefits of the deferred tax assets including net operating loss carryforwards and research and development credits. Management reevaluates the positive and negative evidence at each reporting period. Under the provisions of Sections 382 and 383 of the Internal Revenue Code, certain substantial changes in the Company’s ownership may have limited, or may limit in the future, the amount of net operating loss and research and development credit carryforwards that can be used to reduce future income taxes.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2019

Summary of Significant Accounting Policies

Basis of Presentation

Use of Estimates

Restricted Cash

The following table reconciles cash and cash equivalents and restricted cash per the balance sheet to the statement of cash flows (in thousands):


	June 30,		December 31,
	2019		2018
		(unaudited)
Cash and cash equivalents	$	192,689	$	135,173
Restricted cash (including $4,200 in other assets)		5,039		460
Total	$	197,728	$	135,633

Revenue Recognition

Recently Issued Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2019

Summary of Significant Accounting Policies

Summary of reconciliation cash and cash equivalents and restricted cash per the balance sheet to the statement of cash flows

The following table reconciles cash and cash equivalents and restricted cash per the balance sheet to the statement of cash flows (in thousands):


	June 30,		December 31,
	2019		2018
		(unaudited)
Cash and cash equivalents	$	192,689	$	135,173
Restricted cash (including $4,200 in other assets)		5,039		460
Total	$	197,728	$	135,633

Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value of Financial Instruments

Summary of fair value of the Company’s financial assets

The following tables set forth the fair value of the Company’s financial assets by level within the fair value hierarchy (in thousands):

As of June 30, 2019

(unaudited)

Fair Value Measurement Based on

Significant

Quoted Prices in

Other

Significant

Carrying

Fair

Active Markets

Observable

Unobservable

Assets

Amount

Value

(Level 1)

Inputs (Level 2)

Inputs (Level 3)

Money market funds (cash equivalents)

5,000

—

As of December 31, 2018

Fair Value Measurement Based on

Significant

Quoted Prices in

Other

Significant

Carrying

Fair

Active Markets

Observable

Unobservable

Assets

Amount

Value

(Level 1)

Inputs (Level 2)

Inputs (Level 3)

Money market funds (cash equivalents)

5,000

—

Property and Equipment, Net (Tables)

6 Months Ended

Jun. 30, 2019

Property and Equipment, Net

Summary of property and equipment

Property and equipment consist of the following (in thousands):


	June 30,		December 31,
	2019		2018
		(unaudited)
Research equipment	$	9,348	$	7,787
Leasehold improvements		5,065		4,825
Computer equipment		360		167
Furniture and fixtures		93		70
Construction in progress		1,077		1,027
Property and equipment, gross		15,943		13,876
Less: accumulated depreciation and amortization		(3,614)		(2,469)
Property and equipment, net	$	12,329	$	11,407

Agreement with Eli Lilly and Company (Tables)

6 Months Ended

Jun. 30, 2019

Agreement with Eli Lilly and Company

Summary of deferred revenue included in the Company’s balance sheets

As of June 30, 2019, deferred revenue included in the Company’s balance sheets comprised the following (in thousands):


	June 30,		December 31,
	2019		2018
		(unaudited)
Deferred revenue, beginning of period	$	26,725	$	—
Up-front payment		—		25,000
Attributed premium on the proceeds from Lilly’s investment in the Company		—		1,725
Research and development support billing		1,000		—
Revenue from research and development arrangement recognized		(2,759)		—
Total deferred revenue, end of period		24,966		26,725
Less: Deferred revenue, current portion		(6,524)		(4,989)
Deferred revenue, non-current portion	$	18,442	$	21,736

Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2019

Commitments and Contingencies

Schedule of future minimum payments

The future minimum payments for the operating leases are as follows (in thousands):


Remainder of the year	$	193
2020		675
2021		819
2022		868
2023		860
Thereafter		6,897
Total future minimum payments	$	10,312

Term Loan (Tables)

6 Months Ended

Jun. 30, 2019

Term Loan

Schedule of future maturities

Future maturities of the Term Loan as of June 30, 2019 are as follows (in thousands):


Remainder of the year	$	—
2020		1,528
2021		1,667
2022		1,667
2023		138
Total		5,000
Less: current portion of term loan		(833)
Term loan, net of current portion	$	4,167

Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2019

Stock-Based Compensation

Summary of stock option activity


	Options Outstanding and Exercisable
				Weighted
		Weighted		Average	Aggregate
		Average		Remaining	Intrinsic
	Number of	Exercise		Contractual	Value(1)
	Shares	Price		Life (Years)	(in thousands)
Outstanding as of December 31, 2018	2,056,891	$	4.74	9.4	$	5,946
Granted	210,269	$	15.57	10.0
Exercised	(29,383)	$	1.49	8.7
Outstanding as of June 30, 2019	2,237,777	$	5.80	9.0	$	20,663
Vested and expected to vest as of June 30, 2019	2,237,777	$	5.80		$	20,663
Exercisable as of June 30, 2019	415,357	$	1.15		$	5,744

Summary of stock based compensation expense recorded

Stock‑based compensation expense recorded as research and development and general and administrative expenses is as follows (in thousands):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
		(unaudited)			(unaudited)
	2019		2018		2019		2018
Research and development	$	151	$	11	$	300	$	21
General and administrative		261		13		495		27
Total stock-based compensation expense	$	412	$	24	$	795	$	48

Nature of the Business - (Details) $ / shares in Units, $ in Thousands			6 Months Ended
	May 13, 2019 USD ($) $ / shares shares	May 03, 2019	Jun. 30, 2019 USD ($) $ / shares shares	Dec. 31, 2018 $ / shares shares
Nature of the Business
Reverse stock split ratio		0.1245
Proceeds from issuance of shares, net \| $			$ 77,264
Common stock, shares outstanding	15,560,569		22,714,765	1,374,812
Preferred stock, shares outstanding	0		0	0
Common stock, number of shares authorized	100,000,000		100,000,000	158,745,671
Common stock, par value per share \| $ / shares	$ 0.001		$ 0.001	$ 0.001
Preferred stock, number of shares authorized	10,000,000		10,000,000	0
Preferred stock, par value per share \| $ / shares	$ 0.001		$ 0.001	$ 0.001
IPO
Nature of the Business
Issuance of stock (in shares)	5,750,000
Share price \| $ / shares	$ 15.00
Proceeds from issuance of shares, net \| $	$ 77,000
Underwriting discounts and commissions \| $	6,000
Offering expenses \| $	$ 3,400

Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Restricted Cash
Restricted cash required reserve	$ 5,000
Reconciliation of cash and cash equivalents and restricted cash per the balance sheet to the statement of cash flows
Cash and cash equivalents	192,689	$ 135,173
Restricted cash (including $4,200 in other assets at June 30, 2019)	5,039	460
Restricted cash	873	460
Total	197,728	135,633	$ 29,474	$ 9,287
Other Assets, Noncurrent	$ 4,200	$ 436

Fair Value of Financial Instruments - (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair value of the Company’s financial assets
Assets transferred from level 1 to level 2	$ 0
Assets transferred from level 2 to level 1	0
Carrying Amount
Fair value of the Company’s financial assets
Money market funds (cash equivalents)	5,000	$ 5,000
Fair Value
Fair value of the Company’s financial assets
Money market funds (cash equivalents)	5,000	5,000
Fair Value \| Quoted Prices in Active Markets (Level 1)
Fair value of the Company’s financial assets
Money market funds (cash equivalents)	$ 5,000	$ 5,000

Property and Equipment, Net - (Details) - USD ($)	3 Months Ended		6 Months Ended
Property and Equipment, Net - (Details) - USD ($)	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Property and Equipment, Net
Property and equipment, gross	$ 15,943,000		$ 15,943,000		$ 13,876,000
Less: accumulated depreciation and amortization	(3,614,000)		(3,614,000)		(2,469,000)
Property and equipment, net	12,329,000		12,329,000		11,407,000
Depreciation and amortization expense	582,000	$ 387,000	1,145,000	$ 763,000
Research equipment
Property and Equipment, Net
Property and equipment, gross	9,348,000		9,348,000		7,787,000
Leasehold improvements
Property and Equipment, Net
Property and equipment, gross	5,065,000		5,065,000		4,825,000
Computer equipment
Property and Equipment, Net
Property and equipment, gross	360,000		360,000		167,000
Furniture and fixtures
Property and Equipment, Net
Property and equipment, gross	93,000		93,000		70,000
Construction in progress
Property and Equipment, Net
Property and equipment, gross	$ 1,077,000		$ 1,077,000		$ 1,027,000

Agreement with Eli Lilly and Company - Other (Details) $ in Thousands		3 Months Ended	6 Months Ended
	Nov. 02, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($) item	Jun. 30, 2018 USD ($)
Collaborative Arrangements
Equity investment				$ 31,000
Revenue		$ 1,402	$ 2,759
Lilly Agreement
Collaborative Arrangements
Period of expiry from date of agreement	4 years
Upfront non-refundable payment received	$ 25,000
Equity investment	15,000
The number of performance obligations. \| item			2
Revenue		$ 1,400	$ 2,800
Lilly Agreement \| Lilly
Collaborative Arrangements
Maximum development and regulatory milestones and sales milestone receivable	1,400,000
Maximum development and regulatory milestones and sales milestone payable upon option exercise	710,000
Transaction price	$ 32,700

Agreement with Eli Lilly and Company - Deferred revenue included in balance sheets (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Deferred revenue
Deferred revenue from related party, beginning of period	$ 26,725
Up-front payment		$ 25,000
Attributed premium on the proceeds from Lilly’s investment in the Company		1,725
Research and development support billing	1,000
Revenue from research and development arrangement recognized	(2,759)
Total deferred revenue from related party, end of period	24,966	26,725
Deferred revenue, current portion	(6,524)	(4,989)
Deferred revenue, non-current portion	$ 18,442	$ 21,736

Commitments and Contingencies - Other (Details) - USD ($)		3 Months Ended		6 Months Ended
	Jan. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 15, 2019
Commitments and Contingencies
Period for which base rent is abated	10 months
Annual base rent per month after abatement	$ 19,650
Percentage of annual increase in lease rent	3.00%
Executed letter of credit	$ 39,000
Total remaining commitment under the amended and restated sublease						$ 2,700,000
Rent expenses operating leases		$ 87,000	$ 101,000	$ 190,000	$ 201,000

Commitments and Contingencies - Future Minimum Payments (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Future minimum payments:
Remainder of the year	$ 193
2020	675
2021	819
2022	868
2023	860
Thereafter	6,897
Total future minimum payments	$ 10,312

Term Loan - Other (Details)		3 Months Ended		6 Months Ended
Term Loan - Other (Details)	Jan. 25, 2019 USD ($) item	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Apr. 30, 2016 USD ($)
Face amount	$ 5,000,000					$ 1,000,000
Interest rate (as a percent)	4.25%	4.50%	3.79%	4.50%	3.66%
Number of equal monthly payments of principal plus accrued interest \| item	36
Interest expense		$ 57,000	$ 6,000	$ 99,000	$ 13,000
Prime rate \| Maximum
Spread (as a percent)	1.00%

Term Loan - Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Future maturities:
2020	$ 1,528
2021	1,667
2022	1,667
2023	138
Total	5,000
Less: current portion of term loan	(833)	$ (387)
Term loan, net of current portion	$ 4,167	$ 73

Stock-Based Compensation - Stock options (Details) - USD ($)			6 Months Ended
	May 03, 2019	Dec. 31, 2018	Jun. 30, 2019
2015 Plan
Number of Shares
Outstanding at the beginning			2,056,891
Granted			210,269
Exercised			(29,383)
Outstanding at the end		2,056,891	2,237,777
Vested and expected to vest at the end			2,237,777
Exercisable at the end			415,357
Weighted Average Exercise Price
Outstanding at the beginning (in dollars per share)			$ 4.74
Granted (in dollars per share)			15.57
Exercised (in dollars per share)			1.49
Outstanding at the end (in dollars per share)		$ 4.74	5.80
Vested and expected to vest at the end (in dollars per share)			5.80
Exercisable at the end (in dollars per share)			$ 1.15
Weighted Average Remaining Contractual Life (Years) And Aggregate Intrinsic Value
Outstanding (in years)		9 years 4 months 24 days	9 years
Granted (in years)			10 years
Exercised (in years)			8 years 8 months 12 days
Outstanding at the beginning (in dollars)			$ 5,946,000
Outstanding at the end (in dollars)		$ 5,946,000	20,663,000
Vested and expected to vest at the end (in dollars)			20,663,000
Exercisable at the end (in dollars)			$ 5,744,000
Weighted average grant date fair value per share of stock options granted			$ 9.86
Aggregate intrinsic value of stock options exercised			$ 396,400
2015 Plan \| Minimum
Stock Based Compensation
Share price of common stock on date of grant as a percent of fair market value of company stock (as a percent)			100.00%
2015 Plan \| Maximum
Stock Based Compensation
Term of awards			10 years
Omnibus Incentive Plan
Stock Based Compensation
Number of shares reserved for issuance under the plan	2,900,000
Annual increase in number of share reserved for issuance (as percent)	4.00%
2015 Plan and 2019 Employee Stock Purchase Plan
Stock Based Compensation
Vesting period			4 years
Expiration period			10 years
2019 Employee Stock Purchase Plan
Stock Based Compensation
Number of shares reserved for issuance under the plan	240,000		2,689,725
Annual increase in number of share reserved for issuance (as percent)	1.00%
Maximum annual increase in shares available for issuance under the plan	480,000
Option to purchase common stock
Stock Based Compensation
Antidilutive securities excluded from computation of diluted net loss per share			2,237,777

Stock-Based Compensation - Stock based compensation expense (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Stock based compensation expense
Total stock-based compensation expense	$ 412,000	$ 24,000	$ 795,000	$ 48,000
Research and development
Stock based compensation expense
Total stock-based compensation expense	151,000	11,000	300,000	21,000
General and administrative
Stock based compensation expense
Total stock-based compensation expense	$ 261,000	$ 13,000	$ 495,000	$ 27,000

Subsequent Events - (Details) - USD ($)	Aug. 02, 2019	Jan. 30, 2019
Subsequent Event
Period for which base rent is abated		10 months
Annual base rent per month after abatement		$ 19,650
Percentage of annual increase in lease rent		3.00%
Subsequent Event
Subsequent Event
Period for which base rent is abated	7 months
Annual base rent per month after abatement	$ 18,178
Percentage of annual increase in lease rent	3.00%

Subsequent Events	6 Months Ended
Subsequent Events	Jun. 30, 2019
Subsequent Events
Subsequent Events	10. Subsequent Events On August 2, 2019, the Company entered into a lease amendment for additional square feet to be used for office, laboratory and warehouse space, which the Company expects the landlord to deliver in April 2020. The amended lease is expected to expire on March 31, 2030. Base rent for the first seven months is abated with respect to the additional space, after which the base rent of the lease is $18,178 per month for that space, with an increase in annual rent of 3.0% in each subsequent year of the lease term.

Income Taxes - (Details) $ in Thousands	6 Months Ended
Income Taxes - (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Income Taxes
Provision or benefit from income taxes	$ 0