Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Jun. 30, 2019	Aug. 14, 2019
Document And Entity Information
Entity Registrant Name	REPLIMUNE GROUP, INC.
Entity Central Index Key	0001737953
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Entity Current Reporting Status	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		31,666,182
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019
Current assets:
Cash and cash equivalents	$ 38,364	$ 25,704
Short-term investments	82,435	109,107
Research and development incentives receivable	2,410	2,474
Prepaid expenses and other current assets	4,529	3,696
Total current assets	127,738	140,981
Property, plant and equipment, net	963	12,159
Research and development incentives receivable - long term	613
Restricted cash	1,636	1,186
Long term prepaid rent	11,901
Right-to-use asset	690
Total assets	143,541	154,326
Current liabilities:
Accounts payable	10,830	7,084
Accrued expenses and other current liabilities	1,829	2,801
Lease liabilities, current	394
Total current liabilities	13,053	9,885
Financing obligation		6,561
Deferred rent, net of current portion		24
Lease liabilities, non-current	336
Total liabilities	13,389	16,470
Commitments and contingencies (Note 11)
Stockholders' Equity:
Common stock, $0.001 par value; 150,000,000 shares authorized as of June 30, 2019 and March 31, 2019; 31,663,701 and 31,656,950 shares issued and outstanding as of June 30, 2019 and March 31, 2019	32	32
Additional paid-in capital	200,473	198,645
Accumulated deficit	(69,181)	(59,766)
Accumulated other comprehensive loss	(1,172)	(1,055)
Total stockholders' equity	130,152	137,856
Total liabilities and stockholders' equity	$ 143,541	$ 154,326

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2019	Mar. 31, 2019
CONDENSED CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized	150,000,000	150,000,000
Common stock, issued	31,663,701	31,656,950
Common stock, outstanding	31,663,701	31,656,950

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating expenses:
Research and development	$ 7,457	$ 3,936
General and administrative	3,450	1,943
Total operating expenses	10,907	5,879
Loss from operations	(10,907)	(5,879)
Other income (expense):
Research and development incentives	621	438
Investment income	687	227
Change in fair value of warrant liability		(5,450)
Other income (expense), net	91	620
Total other income (expense), net	1,399	(4,165)
Net loss	(9,508)	(10,044)
Net loss attributable to common shareholders	$ (9,508)	$ (10,044)
Net loss per share attributable to common shareholders, basic and diluted (in dollars per share)	$ (0.30)	$ (2.02)
Weighted average common shares outstanding-basic and diluted (in shares)	31,661,430	4,981,227

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Net loss	$ (9,508)	$ (10,044)
Other comprehensive income (loss):
Foreign currency translation loss	(182)	(847)
Net unrealized gain on short-term investments, net of tax	65	35
Comprehensive loss	$ (9,625)	$ (10,856)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Convertible preferred stock	Common stock	Additional paid-in capital	Accumulated deficit	Accumulated other comprehensive loss	Total
Balance at Mar. 31, 2018	$ 86,361	$ 5	$ 1,097	$ (28,932)	$ (238)	$ (28,068)
Balance (in shares) at Mar. 31, 2018	1,925,968	5,007,485
Increase (decrease) in Stockholders' Equity
Foreign currency translation adjustment					(847)	(847)
Unrealized gain on short-term investments					35	35
Stock-based compensation expense			225			225
Net loss				(10,044)		(10,044)
Balance at Jun. 30, 2018	$ 86,361	$ 5	1,322	(38,976)	(1,050)	(38,699)
Balance (in shares) at Jun. 30, 2018	1,925,968	5,007,485
Balance at Mar. 31, 2019		$ 32	198,645	(59,766)	(1,055)	137,856
Balance (in shares) at Mar. 31, 2019		31,656,950
Increase (decrease) in Stockholders' Equity
Foreign currency translation adjustment					(182)	(182)
Unrealized gain on short-term investments					65	65
Exercise of stock options			18			$ 18
Exercise of stock options (in shares)		6,751				6,751
Stock-based compensation expense			1,810			$ 1,810
Net loss				(9,508)		(9,508)
Balance at Jun. 30, 2019		$ 32	$ 200,473	(69,181)	$ (1,172)	130,152
Balance (in shares) at Jun. 30, 2019		31,663,701
Increase (decrease) in Stockholders' Equity
Impact of adoption of ASC 842				$ 93		$ 93

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net loss	$ (9,508)	$ (10,044)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,810	225
Depreciation and amortization	42	33
Change in fair value of warrant liability		5,450
Net amortization of premiums and discounts on short-term investments	(436)	(121)
Changes in operating assets and liabilities:
Research and development incentives receivable	(621)	(438)
Prepaid expenses and other current assets	(847)	(220)
Operating lease right-of-use-assets	85
Long term prepaid rent	(6,895)
Accounts payable	3,764	(259)
Accrued expenses and other current liabilities	(885)	(1,479)
Operating lease liabilities	(91)
Deferred rent		(6)
Net cash used in operating activities	(13,582)	(6,859)
Cash flows from investing activities:
Purchases of property, plant and equipment	(362)	(116)
Purchase of short-term investments	(18,486)	(10,744)
Proceeds from sales and maturities of short-term investments	45,659	15,750
Net cash provided by investing activities	26,811	4,890
Cash flows from financing activities:
Payment of issuance costs		(195)
Exercise of stock options	18
Net cash provided by (used in) financing activities	18	(195)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(137)	(731)
Net increase (decrease) in cash, cash equivalents and restricted cash	13,110	(2,895)
Cash, cash equivalents and restricted cash at beginning of period	26,890	17,661
Cash, cash equivalents and restricted cash at end of period	40,000	14,766
Supplemental disclosure of non-cash investing and financing activities:
Net unrealized gain on short term investments	65
Deferred offering costs included in accounts payable		1,149
Purchases of property and equipment included in accounts payable		$ 21
Lease assets obtained in exchange for new operating lease liabilities	$ 789

Nature of the business	3 Months Ended
Nature of the business	Jun. 30, 2019
Nature of the business
Nature of the business	1. Nature of the business Replimune Group, Inc. (the “Company”) is a clinical‑stage biotechnology company focused on the development of oncolytic immunotherapies to treat cancer. Replimune Limited (“Replimune UK”) was incorporated in 2015 under the laws of England, and was the sole shareholder of Replimune, Inc. (“Replimune US”), a Delaware corporation. On July 5, 2017, Replimune Group, Inc., a Delaware corporation, was incorporated and on July 10, 2017 the shareholders of Replimune UK effected a share‑for‑share exchange pursuant to which they exchanged their outstanding shares in Replimune UK for shares in Replimune Group, Inc., on a one‑for‑one basis. In addition, the holders of warrants and stock options to purchase Replimune UK capital stock canceled their warrants to purchase shares of series seed convertible preferred stock and stock options in Replimune UK and were issued replacement warrants to purchase shares of series seed convertible preferred stock and stock options to acquire Replimune Group, Inc. capital stock on a one‑for‑one basis. These transactions are collectively referred to as the reorganization. Upon completion of the reorganization, the historical consolidated financial statements of Replimune UK became the historical consolidated financial statements of Replimune Group, Inc. because the reorganization was accounted for similar to a reorganization of entities under common control due to the high degree of common ownership of Replimune UK and Replimune Group, Inc. and lack of economic substance to the transaction. The Company concluded that the reorganization resulted in no change in the material rights and preferences of each respective class of equity interests and no change in the fair value of each respective class of equity interests before and after the reorganization. On December 8, 2017, Replimune UK transferred all outstanding shares of its wholly owned subsidiary, Replimune US to Replimune Group, Inc. Replimune Group. Inc., a Delaware corporation, is the sole shareholder of Replimune UK, Replimune US and Replimune Securities Corporation, a Massachusetts corporation that was incorporated in November 2017. The Company is subject to risks and uncertainties common to early‑stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance and reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. Forward stock split On July 9, 2018, the Company effected a 1-for-9.94688 forward stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for each series of the Company’s Convertible Preferred Stock (see Note 7). Accordingly, all share and per share amounts for all periods presented in the accompanying consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this forward stock split and adjustment of the convertible preferred stock conversion ratios. Further, on July 9, 2018, the Company’s authorized shares of common stock were increased to 27,314,288. Accordingly, the authorized shares of common stock presented in the accompanying consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect the newly authorized shares of common stock. Initial public offering On July 24, 2018, the Company completed an initial public offering (“IPO”) of its common stock and issued and sold 6,700,000 shares of common stock at a public offering price of $15.00 per share, resulting in net proceeds of $93,465 after deducting underwriting discounts and commissions but before deducting offering costs of $2,157. Upon closing of the IPO, the Company’s outstanding convertible preferred stock automatically converted into shares of common stock (see Note 7). Upon conversion of the convertible preferred stock, the Company reclassified the carrying value of the convertible preferred stock to common stock and additional paid-in capital. The warrant to purchase shares of the Company’s series seed convertible preferred stock was converted into a warrant to purchase shares of the Company’s common stock upon the closing of the IPO. As a result, the warrant liability was remeasured a final time on the closing date of the IPO and reclassified to stockholders’ equity (deficit). Additionally, the Company repurchased 26,258 shares of class A common stock at a price equal to its par value upon the closing of the IPO. On July 30, 2018, the Company issued and sold an additional 707,936 shares of its common stock at the IPO price of $15.00 per share pursuant to the underwriters’ partial exercise of their option to purchase additional shares of common stock, resulting in additional net proceeds of $9,876 after deducting discounts and commissions and other offering expenses. Also, in connection with the completion of its IPO on July 24, 2018, the Company filed an amended and restated certificate of incorporation with the Secretary of State of the State of Delaware to authorize the issuance of up to 150,000,000 shares of common stock, par value $0.001 per share, and 10,000,000 shares of undesignated preferred stock, par value $0.001 per share. Basis of presentation The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has incurred recurring losses since its inception, including net losses of $9,508 and $10,044 for the three months ended June 30, 2019 and 2018, respectively. In addition, as of June 30, 2019, the Company had an accumulated deficit of $69,181. The Company expects to continue to generate operating losses for the foreseeable future. As of August 14, 2019, the issuance date of these consolidated financial statements, the Company expects that its cash and cash equivalents and short-term investments will be sufficient to fund its operating expenses and capital expenditure requirements through at least 12 months from the issuance of the consolidated financial statements. The future viability of the Company beyond that point is dependent on its ability to raise additional capital to finance its operations. If the Company is unable to obtain funding it could be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects, or it may be unable to continue operations. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all.

Summary of significant accounting policies

3 Months Ended

Jun. 30, 2019

Summary of significant accounting policies

Summary of significant accounting policies

2. Summary of significant accounting policies

Principles of consolidation

The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America , or GAAP, and include the accounts of the Company and its wholly owned subsidiaries, Replimune UK, Replimune US and Replimune Securities Corporation, after elimination of all intercompany accounts and transactions. The consolidated financial statements reflect the capital as if Replimune Group, Inc. had been in existence for all periods presented.

Use of estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual for research and development expenses and the valuation of common stock and stock‑based awards. The Company bases its estimates on historical experience, known trends and other market‑specific or other relevant factors that it believe to be reasonable under the circumstances. Estimates are periodically reviewed in light of reasonable changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates or assumptions.

Unaudited interim financial information

The accompanying consolidated balance sheet as of June 30, 2019, the consolidated statements of operations, of comprehensive loss and of cash flows for the three months ended June 30, 2019 and 2018 and the consolidated statement of convertible preferred stock and stockholders’ equity (deficit) as of June 30, 2019 and 2018 are unaudited. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of June 30, 2019 and the results of its operations and its cash flows for the three months ended June 30, 2019 and 2018. The financial data and other information disclosed in these consolidated notes related to the three months ended June 30, 2019 and 2018 are unaudited. The results for the three months ended June 30, 2019 are not necessarily indicative of results to be expected for the year ending March 31, 2020, any other interim periods or any future year or period. The financial information included herein should be read in conjunction with the financial statements and notes in the Company's Annual Report on Form 10-K for the year ended March 31, 2019.

During the three months ended June 30, 2019, there have been no changes to the Company’s significant accounting policies as described in the Company's Annual Report on Form 10-K for the year ended March 31, 2019, except as described below.

Recently Adopted Accounting Pronouncements

In June 2018, the FASB issued (“ASU 2018-07”), Compensation — Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. ASU 2018-17 expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. ASU 2018-17 also clarifies that Topic 718 does not apply to share-based payments used to effectively provide (1) financing to the issuer or (2) awards granted in conjunction with selling goods or services to customers as part of a contract accounted for under Revenue from Contracts with Customers (Topic 606). The guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted. The Company adopted ASU 2018-17 on April 1, 2019. The adoption of ASU 2018-17 did not have a material impact on the Company’s consolidated financial statements.

In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815) I. Accounting for Certain Financial Instruments with Down Round Features II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception (“ASU 2017-11”). Part I applies to entities that issue financial instruments such as warrants, convertible debt or convertible preferred stock that contain down-round features. Part II replaces the indefinite deferral for certain mandatorily redeemable noncontrolling interests and mandatorily redeemable financial instruments of nonpublic entities contained within Accounting Standards Codification (“ASC”) Topic 480 with a scope exception and does not impact the accounting for these mandatorily redeemable instruments. ASU 2017-11 is required to be adopted for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. The Company adopted ASU 2017-11 on April 1, 2019. The adoption of ASU 2017-11 did not have a material impact on the Company’s consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which supersedes FASB Topic 840, Leases (Topic 840) and provides principles for the recognition, measurement, presentation and disclosure of leases for both lessees and lessors. The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases. In January 2018, the FASB issued ASU 2018-01, Leases (Topic 842) Land Easement Practical Expedient for Transition to Topic 842, which amends ASU 2016-02 to provide entities an optional transition practical expedient to not evaluate under Topic 842 existing or expired land easements that were not previously accounted for as leases under the current leases guidance in Topic 842. An entity that elects this practical expedient should evaluate new or modified land easements under Topic 842 beginning at the date that the entity adopts Topic 842. In July 2018, the FASB also issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, which provides an optional transition method that allows entities to elect to apply the standard prospectively at its effective date, versus recasting the prior periods presented.

The Company adopted ASU 2016-02, Leases (“ASU 2016-02”), as amended, on April 1, 2019, which supersedes the current leasing guidance and upon adoption, requires lessees to recognize right-to-use assets and lease liabilities on the balance sheet for all leases with terms longer than 12 months. Leases are classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. Upon the adoption of the guidance, operating leases are capitalized on the balance sheet at the present value of lease payments. The balance sheet amount recorded for existing leases at the date of adoption of ASU 2016-02 was calculated using the applicable incremental borrowing rate at the date of adoption.

The Company adopted ASU 2016-02, including several practical expedients on April 1, 2019. The Company elected the available package of practical expedients which allows the Company to not reassess previous accounting conclusions around whether arrangements are or contain leases, the classification of leases, and the treatment of initial direct costs. The Company also made an accounting policy election to utilize the short-term lease exemption, whereby leases with a term of 12 months or less will not follow the recognition and measurement requirements of the new standard. Upon adoption, the Company recognized total right-of-use assets of $789, with corresponding liabilities of $837 on the consolidated balance sheets. Additionally, the Company derecognized $11,514 of construction in progress assets and $6,561 of financing obligations and recorded long term prepaid rent of $5,006 on the consolidated balance sheet (see Note 11).

The following table summarizes the financial impact on the Company’s condensed consolidated balance sheet upon the adoption of ASU 2016-02 and the cumulative effect adjustment on April 1, 2019:


	March 31,				April 1,
	2019		Adjustments		2019
Property, plant, and equipment, net	$	12,159	$	(11,514)	$	645
Right-to-use asset	$	—	$	789	$	789
Long term prepaid rent	$	—	$	5,006	$	5,006
Lease liabilities, current	$	—	$	388	$	388
Lease liabilities, non-current	$	—	$	449	$	499
Accrued expenses and other current liabilities	$	2,801	$	(24)	$	2,777
Deferred rent, net of current portion	$	24	$	(24)	$	—
Financing obligation	$	6,561	$	(6,561)	$	—
Accumulated deficit	$	(59,766)	$	93	$	(59,673)

Recently Issued Accounting Pronouncements

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). The amendments in this ASU require certain existing disclosure requirements in Topic 820 to be modified or removed, and certain new disclosure requirements to be added to the Topic. In addition, this ASU allows entities to exercise more discretion when considering fair value measurement disclosures. ASU 2018-13 will be effective for the Company beginning April 1, 2020 with early adoption permitted. The Company is in the process of evaluating the impact of ASU 2018-13 on its consolidated financial statements and disclosures.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326). The standard changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. Financial assets measured at amortized cost will be presented at the net amount expected to be collected by using an allowance for credit losses. In April 2019, the FASB issued ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, which clarifies and corrects certain unintended applications of the guidance contained in each of the amended Topics. Additionally, in May 2019, the FASB issued ASU No. 2019-05, Financial Instruments – Credit Losses (Topic 326), which provides an option to irrevocably elect to measure certain individual financial assets at fair value instead of amortized cost. The standard is effective for fiscal years and interim periods beginning after December 15, 2019. Early adoption is permitted for all periods beginning after December 15, 2018. The Company is currently in the process of evaluating the impact the standard will have on its consolidated financial statements.

Fair value of financial assets and liabilities

3 Months Ended

Jun. 30, 2019

Fair value of financial assets and liabilities

Fair value of financial assets and liabilities

3. Fair value of financial assets and liabilities

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis:


	Fair Value Measurements as of
	June 30, 2019 Using:
	Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	—	$	447	$	—	$	447
Commercial paper		—		36,927		—		36,927
US Government Agency bonds		—		12,970		—		12,970
US Treasury bonds		—		28,188		—		28,188
Corporate debt securities		—		4,350		—		4,350
	$	—	$	82,882	$	—	$	82,882


	Fair Value Measurements as of
	March 31, 2019 Using:
	Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	—	$	2,676	$	—	$	2,676
Commercial paper		—		46,687		—		46,687
US Government Agency bonds		—		20,884		—		20,884
US Treasury bonds		—		41,057		—		41,057
Corporate debt securities		—		8,467		—		8,467
	$	—	$	119,771	$	—	$	119,771

During the three months ended June 30, 2019 and 2018, there were no transfers between levels.

Valuation of cash equivalents and short‑term investments

Money market funds, commercial paper, US Treasury bonds and corporate debt securities were valued by the Company using quoted prices in active markets for similar securities, which represent a Level 2 measurement within the fair value hierarchy.

Valuation of Warrant Liability

The warrant liability is related to the warrants to purchase shares of series seed convertible preferred stock (see Note 7). The fair value of the warrant liability was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. Upon the closing of the IPO in July 2018, the warrant to purchase shares of the Company’s series seed convertible preferred stock was converted into a warrant to purchase shares of the Company’s common stock. As a result, the warrant liability was remeasured a final time on the closing date of the IPO and reclassified to stockholders’ equity (deficit).

The Company used the Black-Scholes option-pricing model, which incorporated assumptions and estimates, to value the warrant liability. Key estimates and assumptions impacting the fair value measurement include (i) the expected term of the warrants, (ii) the risk-free interest rate, (iii) the expected dividend yield, (iv) expected volatility of the price of the underlying series seed convertible preferred stock and (v) the fair value of the series seed convertible preferred stock on the valuation date. The Company estimated the fair value per share of the underlying series seed convertible preferred stock based, in part, on the results of third-party valuations and additional factors deemed relevant. The risk-free interest rate was determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the warrants. The Company estimated a 0% expected dividend yield based on the fact that the Company has never paid or declared dividends and does not intend to do so in the foreseeable future. Prior to July 2018, the Company was a private company and accordingly, lacked company-specific historical and implied volatility information of its stock, the expected stock volatility was based on the historical volatility of publicly traded peer companies for a term equal to the remaining expected term of the warrants.

Based on the terms and conditions of the warrant, upon closing of the Company’s IPO in July 2018, the warrant to purchase shares of the Company’s series seed convertible preferred stock was converted into a warrant to purchase shares of the Company’s common stock. On that date, the Company remeasured the warrant liability to fair value and reclassified the total carrying value to additional paid-in capital. The Company performed the final remeasurement of the warrant liability using the IPO price of $15.00 per share and recorded the change in fair value as a component of other income (expense), net in the consolidated statement of operations.

The following assumptions were used to measure the fair market value of the warrant liability as of June 30, 2018:


	Three Months Ended
	June 30, 2018
Risk-free interest rate		2.68	%
Expected dividend yield		0	%
Expected term (in years)		7.3
Expected volatility		64.4	%
Fair value of series seed preferred stock	$	15.00

The following table presents a roll forward of the warrant liability:


	Warrant
	Liability
Balance at March 31, 2018	$	1,642
Change in fair value		5,450
Balance at June 30, 2018	$	7,092

- 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

Short-term investments

3 Months Ended

Jun. 30, 2019

Short-term investments

Short-term investments

4. Short‑term investments

Short‑term investments by investment type consisted of the following:


	June 30, 2019
			Gross		Gross
	Amortized		unrealized		unrealized
	cost		gains		losses		Fair value
Commercial paper	$	36,890	$	37	$	—	$	36,927
US Government agency bonds		12,963		7		—		12,970
US Treasury bonds		28,155		33		—		28,188
Corporate debt securities		4,347		3		—		4,350
	$	82,355	$	80	$	—	$	82,435


	March 31, 2019
			Gross		Gross
	Amortized		unrealized		unrealized
	cost		gains		losses		Fair value
Commercial paper	$	46,687	$	2	$	(2)	$	46,687
US Government agency bonds		15,889		4		—		15,893
US Treasury bonds		38,047		13		—		38,060
Corporate debt securities		8,469		—		(2)		8,467
	$	109,092	$	19	$	(4)	$	109,107

Property, plant and equipment, net

3 Months Ended

Jun. 30, 2019

Property, plant and equipment, net

Property, plant and equipment, net

5. Property, plant and equipment, net

Property, plant and equipment, net consisted of the following:


	June 30,		March 31,
	2019		2019
Leasehold improvements	$	154	$	154
Construction in progress		443		124
Build-to-suit lease asset		—		11,514
Office equipment		49		49
Computer equipment		144		138
Plant and laboratory equipment		619		584
		1,409		12,563
Less: Accumulated depreciation and amortization		(446)		(404)
	$	963	$	12,159

Depreciation and amortization expense was $42 and $33 for the three months ended June 30, 2019 and 2018, respectively.

Build-to-suit lease asset, as of March 31, 2019, included $11,514 capitalized in connection with the Company's build-to-suit lease accounting. Upon transition to ASC 842, the Company determined that it did not control the build-to-suit lease asset and the arrangement has been accounted for under ASC 842 guidance. Upon the adoption of ASC 842, the Company derecognized $11,514 of construction in progress and $6,561 of financing obligations and recorded long term prepaid rent of $5,006 on the consolidated balance sheet (see Note 11).

Accrued expenses and other current liabilities

3 Months Ended

Jun. 30, 2019

Accrued expenses and other current liabilities.

Accrued expenses and other current liabilities

6. Accrued expenses and other current liabilities

Accrued expenses and other current liabilities consisted of the following:


	June 30,		March 31,
	2019		2019
Accrued research and development costs	$	777	$	530
Accrued compensation and benefits costs		660		1,510
Accrued professional fees		260		464
Deferred rent		—		24
Other		132		273
	$	1,829	$	2,801

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Jun. 30, 2019
Stockholders' Equity
Stockholders' Equity	7. Stockholders’ Equity Common Stock As of June 30, 2019 and March 31, 2019, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue up to 150,000,000 shares of common stock, par value $0.001 per share. As of June 30, 2019 and March 31, 2019, the Company had reserved 8,449,932 and 6,873,744 shares of common stock for the exercise of outstanding stock options, the number of shares remaining available for grant under the Company's 2018 Omnibus Incentive Compensation Plan and the Company's Employee Stock Purchase Plan (see Note 8) and the exercise of the outstanding warrants to purchase shares of common, respectively. Undesignated Preferred Stock As of June 30, 2019 and March 31, 2019, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue up to 10,000,000 shares of undesignated preferred stock, par value $0.001 per share. There were no undesignated preferred shares issued or outstanding as of June 30, 2019 or March 31, 2019. Convertible Preferred Stock The Company has issued series seed convertible preferred stock (the “series seed preferred stock”), series A convertible preferred stock (the “series A preferred stock”) and series B convertible preferred stock (the “series B preferred stock”). The series seed preferred stock, series A preferred stock and series B preferred stock are collectively referred to as the “preferred stock.” In connection with the closing of the IPO, the preferred stock converted into 19,157,360 shares of common stock on a 1:9.94688 basis. There was no preferred stock outstanding as of June 30, 2019. Preferred Stock Warrants In connection with the issuance of the series seed preferred stock, the Company issued to the holders of the series seed preferred stock warrants for the purchase of 50,000 shares of series seed preferred stock, which became fully vested and exercisable in the year of issuance. The warrants to purchase shares of series seed preferred stock were issued at an exercise price of $10.00 per share and expire on the earlier of September 16, 2025 or a qualified change of control event. The issuance date fair value of the warrants to purchase shares of series seed preferred stock was $391 and was recorded as a liability with a corresponding reduction in the carrying value of the series seed preferred stock. The Company recognized a loss of $0 and $5,450 in change in fair value of warrant liability within total other income (expense), net in the consolidated statements of operations for the three months ended June 30, 2019 and 2018, respectively, related to the change in fair value of the warrant liability. Upon the closing of the Company’s IPO in July 2018, all outstanding convertible preferred stock was converted into common stock and the series seed preferred stock warrants became exercisable for common stock instead of series seed preferred stock. As a result, the warrant liability was remeasured a final time on the closing date of the IPO and reclassified to stockholders’ equity.

Stock-Based Compensation

3 Months Ended

Jun. 30, 2019

Stock-Based Compensation

Stock-Based Compensation

8. Stock‑Based Compensation

2015 Enterprise Management Incentive Share Option Plan

The 2015 Enterprise Management Incentive Share Option Plan of Replimune UK (the “2015 Plan”) provided for Replimune UK to grant incentive stock options, non‑statutory stock options, stock awards, stock units, stock appreciation rights and other stock‑based awards. Incentive stock options are granted only to the Company’s employees, including officers and directors who are also employees. Non‑statutory stock options are granted to employees, members of the board of directors, outside advisors and consultants of the Company.

2017 Equity Compensation Plan

In July 2017, in conjunction with the reorganization, the 2015 Plan was terminated, and all awards were cancelled with replacement awards issued under the 2017 Equity Compensation Plan (the “2017 Plan”). Subsequent to the reorganization, no additional grants will be made under the 2015 Plan and any outstanding awards under the 2015 Plan will continue with their original terms. The Company concluded that the cancellation of the 2015 Plan and issuance of replacement awards under the 2017 Plan was a modification with no change in the material rights and preferences and therefore no recorded change in the fair value of each respective award.

The Company’s 2017 Plan provides for the Company to grant incentive stock options or non‑statutory stock options, stock awards, stock units, stock appreciation rights and other stock‑based awards. Incentive stock options may be granted only to the Company’s employees, including officers and directors who are also employees. Restricted stock awards and non‑statutory stock options may be granted to employees, officers, members of the board of directors, advisors and consultants of the Company. The maximum number of common shares that may be issued under the 2017 Plan was 2,659,885 as of June 30, 2019, of which 0 remained available for future grants as of June 30, 2019. Shares with respect to which awards have expired, terminated, surrendered or cancelled under the 2017 Plan without having been fully exercised will be available for future awards under the 2018 Plan. In addition, shares of common stock that are tendered to the Company by a participant to exercise an award are added to the number of shares of common stock available for the grant of awards.

2018 Omnibus Incentive Compensation Plan

On July 9, 2018, the Company’s board of directors adopted, and the Company’s stockholders approved the 2018 Omnibus Incentive Compensation Plan (the “2018 Plan”), which became effective immediately prior to the effectiveness of the registration statement for the Company’s initial public offering. The 2018 Plan provides for the issuance of incentive stock options, non-qualified stock options, stock awards, stock units, stock appreciation rights and other stock-based awards. The number of shares initially reserved for issuance under the 2018 Plan is 3,617,968 shares, which is equal to the sum of (i) 3,486,118 shares of the Company’s common stock, plus (ii) the number of shares of the Company’s common stock reserved for issuance under the 2017 Plan that remain available as of the effective date of the 2018 Plan (not to exceed 131,850 shares of the Company’s common stock). If any options or stock appreciation rights, including outstanding options and stock appreciation rights granted under the 2017 Plan (up to 2,520,247 shares), terminate, expire, or are canceled, forfeited, exchanged, or surrendered without having been exercised, or if any stock awards, stock units or other stock-based awards, including outstanding awards granted under the 2017 Plan, are forfeited, terminated, or otherwise not paid in full in shares of common stock, the shares of the Company’s common stock subject to such grants will be available for purposes of our 2018 Plan. On April 1, 2019, the board of directors of the Company approved an increase of 1,266,370 shares reserved for the 2018 Plan. As of June 30, 2019, 2,442,339 shares remained available for future grants under the 2018 Plan.

The 2015 Plan, the 2017 Plan and the 2018 Plan was administered by the board of directors or, at the discretion of the board of directors, by a committee of the board of directors. However, the board of directors shall administer and approve all grants made to non-employee directors. The exercise prices, vesting and other restrictions are determined at the discretion of the board of directors, except that the exercise price per share of incentive stock options may not be less than 100% of the fair market value of the common stock on the date of grant (or 110% of fair value in the case of an award granted to employees who hold more than 10% of the total combined voting power of all classes of stock at the time of grant) and the term of stock options may not be greater than five years for an incentive stock option granted to a 10% stockholder and greater than ten years for all other options granted. Stock options awarded under both plans expire ten years after the grant date, unless the board of directors sets a shorter term. Vesting periods for both plans are determined at the discretion of the board of directors. Incentive stock options granted to employees and non-statutory options granted to employees, officers, members of the board of directors, advisors, and consultants of the Company typically vest over four years.

Employee Stock Purchase Plan

On July 9, 2018, the Company’s board of directors adopted and the Company’s stockholders approved the Employee Stock Purchase Plan (the “ESPP”), which became effective immediately prior to the effectiveness of the registration statement for the Company’s initial public offering. The total shares of common stock initially reserved for issuance under the ESPP is limited to 348,612 shares. In addition, as of the first trading day of each fiscal year during the term of the ESPP (excluding any extensions), an additional number of shares of the Company’s common stock equal to 1% of the total number of shares outstanding on the last trading day in the immediately preceding fiscal year or 697,224 shares, whichever is less (or such lesser amount as determined by the Company’s board of directors) will be added to the number of shares authorized under the ESPP. In accordance, on April 1, 2019, the board of directors of the Company approved an increase of 316,569 shares reserved for the ESPP. If the total number of shares of common stock to be purchased pursuant to outstanding purchase rights on any particular date exceed the number of shares then available for issuance under the ESPP, then the plan administrator will allocate the available shares pro-rata and refund any excess payroll deductions or other contributions to participants.

Stock option valuation

The fair value of stock option grants is estimated using the Black-Scholes option-pricing model. The Company lacks company-specific historical and implied volatility information. Therefore, it estimated its expected stock volatility based on the historical volatility of a publicly traded set of peer companies. For options with service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.

The following table presents, on a weighted-average basis, the assumptions that the Company used to determine the grant-date fair value of stock options granted to employees and directors:


	Three Months Ended
	June 30,
	2019
Risk-free interest rate	2.34	%
Expected term (in years)	6.0
Expected volatility	71	%
Expected dividend yield	0	%

The Company did not grant any stock options during the three months ended June 30, 2018.

Stock options

The following table summarizes the Company’s stock option activity:


		Weighted		Weighted
		Average		Average	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term (Years)	Value
Outstanding as of March 31, 2019	3,721,784	$	7.14	8.61	$	30,150
Granted	1,130,035		15.42	9.77
Exercised	(6,751)		2.64
Outstanding as of June 30, 2019	4,845,068		9.08	8.58	$	28,488
Options exercisable as of March 31, 2019	1,278,330	$	2.51	7.75	$	16,249
Options exercisable as of June 30, 2019	1,417,945		2.54	7.53	$	17,895

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock.

The total fair value of options vested during the three months ended June 30, 2019 and 2018 was $211 and $45, respectively.

As of June 30, 2019, there were no outstanding unvested service‑based stock options held by non‑employees.

Stock‑Based Compensation

Stock‑based compensation expense was classified in the consolidated statements of operations as follows:


	Three Months Ended
	June 30,
	2019		2018
Research and development	$	841	$	126
General and administrative		969		99
	$	1,810	$	225

As of June 30, 2019, total unrecognized compensation cost related to the unvested stock‑based awards was $21,265, which is expected to be recognized over a weighted average period of 2.42 years.

Net loss per share

3 Months Ended

Jun. 30, 2019

Net loss per share

Net loss per share

9. Net loss per share

Basic and diluted net loss per share attributable to common stockholders was calculated as follows:


	Three Months Ended
	June 30,
	2019		2018
Numerator:
Net loss attributable to common stockholders	$	(9,508)	$	(10,044)
Denominator:
Weighted average common shares outstanding, basic and diluted		31,661,430		4,981,227
Net loss per share attributable to common stockholders, basic and diluted	$	(0.30)	$	(2.02)

The Company’s potentially dilutive securities, which include stock options, convertible preferred stock and warrants to purchase shares of series seed preferred stock, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Common A stock has been excluded from the computation of diluted net loss per share because the shares have nominal economic participation rights. 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 the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti‑dilutive effect:


	Three Months Ended
	June 30,
	2019	2018
Options to purchase common stock	4,845,068	2,502,530
Convertible preferred stock (as converted to common stock)	—	19,157,360
Warrants to purchase convertible preferred stock (as converted to common stock)	497,344	497,344
	5,342,412	22,157,234

Significant agreements	3 Months Ended
Significant agreements	Jun. 30, 2019
Significant agreements
Significant agreements	10. Significant agreements Agreement with Bristol-Myers Squibb Company In February 2018, the Company entered into an agreement with Bristol-Myers Squibb Company (“BMS”). Pursuant to the agreement, BMS will provide to the Company, at no cost, a compound for use in the Company’s ongoing clinical trial. Under the agreement, the Company will sponsor, fund and conduct the clinical trial in accordance with an agreed-upon protocol. BMS granted the Company a non-exclusive, non-transferrable, royalty-free license (with a right to sublicense) under its intellectual property to its compound in the clinical trial and agreed to manufacture and supply its compound, at its cost and for no charge to the Company, for use in the clinical trial. Unless earlier terminated, the agreement will remain in effect until (i) the completion of the clinical trial, (ii) all related clinical trial data have been delivered to both parties and (iii) the completion of any statistical analyses and bioanalyses contemplated by the clinical trial protocol or any analysis otherwise agreed upon by the parties. The agreement may be terminated by either party (i) in the event of an uncured material breach by the other party, (ii) in the event the other party is insolvent or in bankruptcy proceedings or (iii) for safety reasons. Upon termination, the licenses granted to the Company to use BMS’s compound in the clinical trial will terminate. As of June 30, 2019, the Company had not incurred any costs and does not expect to incur future costs in connection with this agreement. Agreement with Regeneron Pharmaceuticals, Inc. In May 2018, the Company entered into an agreement with Regeneron Pharmaceuticals, Inc. (“Regeneron”). The Company and Regeneron are each independently developing compounds for the treatment of certain tumor types. Pursuant to the agreement, the Company and Regeneron will undertake one or more clinical trials using a combination of the compounds being developed by each entity. Under the agreement, each study will be conducted under terms set out in a separately agreed upon study plan that will identify the name of the sponsor and which party will manage the particular clinical trial, and include the protocol, the budget and a schedule of clinical obligations. In June 2018, under the terms of the agreement between the Company and Regeneron, the parties agreed to the first study plan. The Company and Regeneron have agreed to the protocol, budget, sample testing and clinical obligations schedule under the study plan. Development and supply costs associated with the study plan will be split equally between the Company and Regeneron. Pursuant to the terms of the agreement, each party granted the other party a non-exclusive license under its respective intellectual property and agreed to contribute the necessary resources needed to fulfill its respective obligations, in each case, under the terms of the agreed-upon or to-be agreed upon study plans. Development costs of a particular clinical trial will be split equally between the Company and Regeneron. The agreement may be terminated by either party if (i) there is no active study plan for which a final study report has not been completed, (ii) the parties have not entered into a study plan for an additional clinical trial within a period of time after the delivery of the most recent final study report or (iii) in the event of a material breach. The Company will account for costs incurred as part of the study, including costs to supply compounds for use in the study, as research and development expenses within the consolidated statement of operations. The Company will recognize any amounts received from Regeneron in connection with this agreement as an offset to research and development expense within the consolidated statement of operations. Under the terms of the agreement, on a quarterly basis the Company and Regeneron true-up costs of the study and make corresponding payments to the party that incurred the majority of the costs. During the three months ended June 30, 2019 or 2018, the Company did not make any payments under the terms of the agreement to Regeneron. During the three months ended June 30, 2019 and 2018, the Company received payments under the terms of the agreement to Regeneron of $337 and $0, respectively. As of June 30, 2019 and March 31, 2019, the Company recorded $912 and $337 of receivables from Regeneron in connection with this agreement in prepaid expenses and other current assets in the consolidated balance sheet, respectively, with an offset to research and development expenses on the consolidated statement of operations.

Commitments and contingencies

3 Months Ended

Jun. 30, 2019

Commitments and contingencies

Commitments and contingencies

11. Commitments and contingencies

Operating Leases

In December 2015, the Company entered into a lease agreement for office space in Woburn, Massachusetts, which expires on March 30, 2021. The Company has the option to extend the lease agreement for successive periods of five years. Monthly lease payments, inclusive of base rent and ancillary charges, total $7. Monthly base rent is subject to increase each year in proportion to the Consumer Price Index.

In April 2016, the Company entered into a lease agreement for office and laboratory space in Abingdon, England, which expires on April 3, 2026. The Company has the right to terminate the lease as of April 4, 2021 upon at least nine months’ prior written notice. Monthly lease payments are inclusive of base rent, ancillary charges, non‑rent shared tenant occupancy costs and the respective value added tax to be paid. Monthly lease payments include base rent of approximately $23 through December 3, 2016 and $31 thereafter. Monthly base rent is subject to increase after April 2021 in proportion to the Retail Price Index.

In June 2018, the Company entered into an agreement to lease approximately 63,000 square feet of office, manufacturing and laboratory space within a previously occupied building with approximately 106,000 square feet of rentable space in Framingham, Massachusetts. Pursuant to the lease agreement, the lease term commenced in December 2018, subject to the landlord completing certain agreed upon landlord improvements. The rent commencement date and lease commencement date is estimated to be eight months after the commencement of the lease term. The initial lease term is ten years from the rent commencement date and includes two optional five year extensions. Annual lease payments during the first year are $2,373 with increases of 3.0% each year.

Upon transition to ASC 842, the Company determined that it did not control the build-to-suit lease asset and the arrangement has been accounted for under ASC 842 guidance. Upon the adoption of ASC 842, the Company derecognized $11,514 of construction in progress and $6,561 of financing obligations and recorded long term prepaid rent of $5,006 on the consolidated balance sheet as landlord owned tenant improvements were determined to be lease payments and included as prepaid rent on the balance sheet.

In June 2019, the Company entered into an agreement to lease approximately 18,700 square feet of office space in Woburn, Massachusetts. Pursuant to the lease agreement, the lease term is estimated to commence in August 2019. The rent commencement date is to be one month after the commencement of the lease term. The initial lease term is ten years from the rent commencement date and includes an optional five year extension. Annual lease payments during the first year are $488 with increases of approximately 1.6% each year.

The Company determines if an arrangement is a lease at inception. Operating leases are included in our balance sheet as right-of-use assets from operating leases, current operating lease liabilities and long-term operating lease liabilities. Certain of the Company’s lease agreements contain renewal options; however, the Company does not recognize right-of-use assets or lease liabilities for renewal periods unless it is determined that the Company is reasonably certain of renewing the lease at inception or when a triggering event occurs. As the Company’s leases do not provide an implicit rate, the Company estimated the incremental borrowing rate in calculating the present value of the lease payments. Since the Company elected to account for each lease component and its associated non-lease components as a single combined lease component, all contract consideration was allocated to the combined lease component. Some of the Company’s lease agreements contain rent escalation clauses (including index-based escalations). The Company recognizes the minimum rental expense on a straight-line basis based on the fixed components of a lease arrangement. The Company amortizes this expense over the term of the lease beginning with the date of initial possession, which is the date the Company can enter the leased space and begin to make improvements in preparation for its intended use. Variable lease components represent amounts that are not fixed in nature and are not tied to an index or rate, and are recognized as incurred.


	Three Months Ended
	June 30,
	2019
Lease cost	$	114
Total lease cost	$	114

The following table summarizes the maturity of the Company’s lease liabilities on an undiscounted cash flow basis and a reconciliation to the operating lease liabilities recognized on our balance sheet as of June 30, 2019:


Maturity lease liabilities	June 30, 2019
2020 (remaining nine months)	$	353
2021		471
Total lease payments		824
Less: interest		(94)
Total lease liabilities	$	730

The following disclosure is provided for periods prior to adoption of ASU 2016-02. Future annual minimum lease payment commitments as of March 31, 2019 were as follows, which included payments for the lease agreement in Framingham, Massachusetts which has not commenced under ASC 842, and therefore has not been recorded on the Company’s condensed consolidated balance sheet as of June 30, 2019:


Future annual minimum lease payment commitments:
2020	$	2,062
2021		2,901
2022		2,493
2023		2,568
2024		2,645
2025		2,725
Thereafter		12,770
	$	28,164

The following table provides lease disclosure as of and for the three months ended June 30, 2019:


Leases	June 30, 2019
Right-to-use asset	$	690

Long-term prepaid rent	$	11,901

Lease liabilities, current	$	394
Lease liabilities, non-current		336
Total lease liabilities	$	730

Other information
Cash paid for amounts included in the measurement of lease liabilities		119
Right-to-use asset obtained in exchange for new operating lease liabilities	$	789
Variable lease costs	$	—
Short term lease costs	$	—
Weighted-average remaining lease term - leases		1.8	years
Weighted-average discount rate - leases		15	%

The variable lease costs and short term lease costs were insignificant for the three months ended June 30, 2019.

Rent expense was $114 and $110 for the three months ended June 30, 2019 and 2018, respectively.

The company has not entered into any material financing leases as of June 30, 2019.

Manufacturing commitments

The Company has entered into an agreement with a contract manufacturing organization to provide clinical trial products. As of June 30, 2019 and March 31, 2019, the Company had committed to minimum payments under these arrangements totaling $3,784 and $4,694 through March 31, 2020, respectively.

Indemnification agreements

In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not aware of any claims under indemnification arrangements, and therefore it has not accrued any liabilities related to such obligations in its consolidated financial statements as of June 30, 2019 or March 31, 2019.

Legal Proceedings

The Company is not a party to any litigation and does not have contingency reserves established for any litigation liabilities.

Geographic Information

3 Months Ended

Jun. 30, 2019

Geographic Information

Geographic Information

12. Geographic Information

The Company operates in two geographic regions: the United States (Massachusetts) and the United Kingdom (Oxfordshire).

Information about the Company’s long-lived assets held in different geographic regions is presented in the table below:


	June 30, 2019		March 31, 2019
United States	$	452	$	11,648
United Kingdom		511		511
	$	963	$	12,159

Subsequent Events	3 Months Ended
Subsequent Events	Jun. 30, 2019
Subsequent Events
Subsequent Events	13. Subsequent Events ATM Program On August 8, 2019, the Company entered into a Sales Agreement (the “Sales Agreement”) with SVB Leerink LLC (the “Agent”), pursuant to which the Company may sell, from time to time, at its option, up to an aggregate amount of $75,000 of shares of the Company’s common stock, $0.001 par value per share (the “Shares”), through the Agent, as the Company’s sales agent. Any Shares to be offered and sold under the Sales Agreement will be issued and sold (i) by methods deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended or in negotiated transactions, if authorized by the Company and (ii) pursuant to, and only upon the effectiveness of, a registration statement on Form S-3 filed by the Company with the Securities and Exchange Commission on August 8, 2019 for an offering of up to $250,000 of various securities, including shares of the Company’s common stock, preferred stock, debt securities, warrants and/or units for sale to the public in one or more public offerings. Subject to the terms of the Sales Agreement, the Agent will use commercially reasonable efforts to sell the Shares from time to time, based upon the Company’s instructions (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company cannot provide any assurances that it will issue any Shares pursuant to the Sales Agreement. The Company will pay the Agent a commission of 3.0% of the gross proceeds from the sale of the Shares, if any. Term Loan Facility On August 7, 2019, (the “Closing Date”) the Company and certain of its affiliates entered into a Loan and Security Agreement (the “Loan Agreement”) with Hercules Capital, Inc. (“Hercules”) pursuant to which Hercules agreed to make available to the Company a secured term loan facility in the amount of $30,000 (the “Term Loan Facility”), subject to certain terms and conditions. The Company borrowed $10,000 under the Loan Agreement in one advance as a single tranche Term Loan on the Closing Date upon which the Company will pay a $225 facility charge. Advances under the Term Loan Facility bear interest at a rate per annum equal to the greater of either(i) the prime rate as reported in The Wall Street Journal plus 2.75%, and (ii) 8.75%. The Loan Agreement includes covenants, limitations, and events of default customary for similar facilities. The term of the Loan Agreement is four years, ending August 1, 2023. Interest is payable on a monthly basis until March 1, 2022 (the “Amortization Date”). After the Amortization Date, payments shall consist of equal monthly installments of principal and interest payable until the secured obligations are repaid in full. At any time the Company may prepay the principal of any advance pursuant to the terms of the Term Loan Facility subject to a prepayment charge equal to: 3.0%, if such advance is prepaid within the first twelve months following the Closing Date, 2.0%, if such advance is prepaid after twelve months but prior to twenty four months following the Closing Date, and 1.0%, if such advance is prepaid anytime thereafter. The Company will also pay a charge of equal to the product of 4.95% and the aggregate amount of any advance made pursuant to the terms of the Term Loan Facility. The Term Loan Facility is secured by substantially all of the Company’s assets, but excluding its intellectual property, and subject to certain exceptions and exclusions. The Loan Agreement contains customary covenants for transactions of this type and other covenants agreed to by the parties, including, among others, (i) the provision of delivery of annual and quarterly financial statements and insurance policies and (ii) restrictions on incurring debt, granting liens, making acquisitions, making loans, paying dividends, dissolving, and entering into leases and asset sales. The Loan Agreement also provides for customary events of default, including, among others, events of default relating to failure to make payment, bankruptcy, breach of covenants, breaches of representations and warranties, change of control, judgment and material adverse effects.

Summary of significant accounting policies (Policies)

3 Months Ended

Jun. 30, 2019

Summary of significant accounting policies

Principles of consolidation

Use of estimates

Unaudited interim financial information

Recently Adopted Accounting Pronouncements

The following table summarizes the financial impact on the Company’s condensed consolidated balance sheet upon the adoption of ASU 2016-02 and the cumulative effect adjustment on April 1, 2019:


	March 31,				April 1,
	2019		Adjustments		2019
Property, plant, and equipment, net	$	12,159	$	(11,514)	$	645
Right-to-use asset	$	—	$	789	$	789
Long term prepaid rent	$	—	$	5,006	$	5,006
Lease liabilities, current	$	—	$	388	$	388
Lease liabilities, non-current	$	—	$	449	$	499
Accrued expenses and other current liabilities	$	2,801	$	(24)	$	2,777
Deferred rent, net of current portion	$	24	$	(24)	$	—
Financing obligation	$	6,561	$	(6,561)	$	—
Accumulated deficit	$	(59,766)	$	93	$	(59,673)

Recently Issued Accounting Pronouncements

Summary of significant accounting policies (Tables)

3 Months Ended

Jun. 30, 2019

Summary of significant accounting policies

Summary of financial impact on condensed consolidated balance sheet upon the adoption of ASU 2016-02 and the cumulative effect adjustment


	March 31,				April 1,
	2019		Adjustments		2019
Property, plant, and equipment, net	$	12,159	$	(11,514)	$	645
Right-to-use asset	$	—	$	789	$	789
Long term prepaid rent	$	—	$	5,006	$	5,006
Lease liabilities, current	$	—	$	388	$	388
Lease liabilities, non-current	$	—	$	449	$	499
Accrued expenses and other current liabilities	$	2,801	$	(24)	$	2,777
Deferred rent, net of current portion	$	24	$	(24)	$	—
Financing obligation	$	6,561	$	(6,561)	$	—
Accumulated deficit	$	(59,766)	$	93	$	(59,673)

Fair value of financial assets and liabilities (Tables)

3 Months Ended

Jun. 30, 2019

Fair value of financial assets and liabilities

Schedule of company's financial assets and liabilities measured at fair value on a recurring basis


	Fair Value Measurements as of
	June 30, 2019 Using:
	Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	—	$	447	$	—	$	447
Commercial paper		—		36,927		—		36,927
US Government Agency bonds		—		12,970		—		12,970
US Treasury bonds		—		28,188		—		28,188
Corporate debt securities		—		4,350		—		4,350
	$	—	$	82,882	$	—	$	82,882


	Fair Value Measurements as of
	March 31, 2019 Using:
	Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	—	$	2,676	$	—	$	2,676
Commercial paper		—		46,687		—		46,687
US Government Agency bonds		—		20,884		—		20,884
US Treasury bonds		—		41,057		—		41,057
Corporate debt securities		—		8,467		—		8,467
	$	—	$	119,771	$	—	$	119,771

Schedule of unobservable inputs of the warrant liability upon the conversion date

The following assumptions were used to measure the fair market value of the warrant liability as of June 30, 2018:


	Three Months Ended
	June 30, 2018
Risk-free interest rate		2.68	%
Expected dividend yield		0	%
Expected term (in years)		7.3
Expected volatility		64.4	%
Fair value of series seed preferred stock	$	15.00

Schedule of roll forward of the warrant liability


	Warrant
	Liability
Balance at March 31, 2018	$	1,642
Change in fair value		5,450
Balance at June 30, 2018	$	7,092

Short-term investments (Tables)

3 Months Ended

Jun. 30, 2019

Short-term investments

Schedule of short-term investments


	June 30, 2019
			Gross		Gross
	Amortized		unrealized		unrealized
	cost		gains		losses		Fair value
Commercial paper	$	36,890	$	37	$	—	$	36,927
US Government agency bonds		12,963		7		—		12,970
US Treasury bonds		28,155		33		—		28,188
Corporate debt securities		4,347		3		—		4,350
	$	82,355	$	80	$	—	$	82,435


	March 31, 2019
			Gross		Gross
	Amortized		unrealized		unrealized
	cost		gains		losses		Fair value
Commercial paper	$	46,687	$	2	$	(2)	$	46,687
US Government agency bonds		15,889		4		—		15,893
US Treasury bonds		38,047		13		—		38,060
Corporate debt securities		8,469		—		(2)		8,467
	$	109,092	$	19	$	(4)	$	109,107

Property, plant and equipment, net (Tables)

3 Months Ended

Jun. 30, 2019

Property, plant and equipment, net

Schedule of property, plant and equipment, net


	June 30,		March 31,
	2019		2019
Leasehold improvements	$	154	$	154
Construction in progress		443		124
Build-to-suit lease asset		—		11,514
Office equipment		49		49
Computer equipment		144		138
Plant and laboratory equipment		619		584
		1,409		12,563
Less: Accumulated depreciation and amortization		(446)		(404)
	$	963	$	12,159

Accrued expenses and other current liabilities (Tables)

3 Months Ended

Jun. 30, 2019

Accrued expenses and other current liabilities.

Schedule of accrued expenses and other current liabilities


	June 30,		March 31,
	2019		2019
Accrued research and development costs	$	777	$	530
Accrued compensation and benefits costs		660		1,510
Accrued professional fees		260		464
Deferred rent		—		24
Other		132		273
	$	1,829	$	2,801

Stock-Based Compensation (Tables)

3 Months Ended

Jun. 30, 2019

Stock-Based Compensation

Summary of stock option activity


		Weighted		Weighted
		Average		Average	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term (Years)	Value
Outstanding as of March 31, 2019	3,721,784	$	7.14	8.61	$	30,150
Granted	1,130,035		15.42	9.77
Exercised	(6,751)		2.64
Outstanding as of June 30, 2019	4,845,068		9.08	8.58	$	28,488
Options exercisable as of March 31, 2019	1,278,330	$	2.51	7.75	$	16,249
Options exercisable as of June 30, 2019	1,417,945		2.54	7.53	$	17,895

Schedule of stock-Based Compensation expense


	Three Months Ended
	June 30,
	2019		2018
Research and development	$	841	$	126
General and administrative		969		99
	$	1,810	$	225

Employees stock options

Stock-Based Compensation

Schedule of assumptions used to determine the grant-date fair value of stock options granted


	Three Months Ended
	June 30,
	2019
Risk-free interest rate	2.34	%
Expected term (in years)	6.0
Expected volatility	71	%
Expected dividend yield	0	%

Net loss per share (Tables)

3 Months Ended

Jun. 30, 2019

Net loss per share

Schedule of calculation of basic and diluted net loss per share attributable to common stockholders


	Three Months Ended
	June 30,
	2019		2018
Numerator:
Net loss attributable to common stockholders	$	(9,508)	$	(10,044)
Denominator:
Weighted average common shares outstanding, basic and diluted		31,661,430		4,981,227
Net loss per share attributable to common stockholders, basic and diluted	$	(0.30)	$	(2.02)

Schedule of anti-dilutive securities excluded from the computation of diluted net loss per share attributable to common shareholders


	Three Months Ended
	June 30,
	2019	2018
Options to purchase common stock	4,845,068	2,502,530
Convertible preferred stock (as converted to common stock)	—	19,157,360
Warrants to purchase convertible preferred stock (as converted to common stock)	497,344	497,344
	5,342,412	22,157,234

Commitments and contingencies (Tables)

3 Months Ended

Jun. 30, 2019

Commitments and contingencies

Schedule of variable lease components


	Three Months Ended
	June 30,
	2019
Lease cost	$	114
Total lease cost	$	114

Summary of the maturity of company's lease liabilities


Maturity lease liabilities	June 30, 2019
2020 (remaining nine months)	$	353
2021		471
Total lease payments		824
Less: interest		(94)
Total lease liabilities	$	730

Schedule of future annual minimum lease payment commitments


Future annual minimum lease payment commitments:
2020	$	2,062
2021		2,901
2022		2,493
2023		2,568
2024		2,645
2025		2,725
Thereafter		12,770
	$	28,164

Schedule of additional information related to leases


Leases	June 30, 2019
Right-to-use asset	$	690

Long-term prepaid rent	$	11,901

Lease liabilities, current	$	394
Lease liabilities, non-current		336
Total lease liabilities	$	730

Other information
Cash paid for amounts included in the measurement of lease liabilities		119
Right-to-use asset obtained in exchange for new operating lease liabilities	$	789
Variable lease costs	$	—
Short term lease costs	$	—
Weighted-average remaining lease term - leases		1.8	years
Weighted-average discount rate - leases		15	%

Geographic Information (Tables)

3 Months Ended

Jun. 30, 2019

Geographic Information

Summary of company's long-lived assets held in different geographic regions


	June 30, 2019		March 31, 2019
United States	$	452	$	11,648
United Kingdom		511		511
	$	963	$	12,159

Nature of the business (Details) $ / shares in Units, $ in Thousands					3 Months Ended
	Jul. 30, 2018 USD ($) $ / shares shares	Jul. 24, 2018 USD ($) $ / shares shares	Jul. 09, 2018 shares	Jul. 10, 2017	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2018 USD ($)	Mar. 31, 2019 USD ($) $ / shares shares
Shares issued in exchange of shares in Replimune Group, Inc				1
Ratio of replacement warrants to capital stock				1
Forward stock split ratio for each common stock			0.100534
Common stock, authorized \| shares			27,314,288		150,000,000		150,000,000
Payment of initial public offering costs \| $						$ 195
Common stock, par value (in dollars per share) \| $ / shares					$ 0.001		$ 0.001
Repurchase of class A common stock upon closing of initial public offering (in shares) \| shares		26,258
Net loss \| $					$ (9,508)	$ (10,044)
Accumulated deficit \| $					$ (69,181)		$ (59,766)
IPO
Shares issued \| shares	707,936	6,700,000
Shares issued price (in dollars per share) \| $ / shares	$ 15.00	$ 15.00
Proceeds from issuance of common stock in initial public offering, net of underwriting fees and discounts \| $	$ 9,876	$ 93,465
Payment of initial public offering costs \| $		$ 2,157
Common stock, par value (in dollars per share) \| $ / shares		$ 0.001
Undesignated preferred stock, authorized \| shares		10,000,000			10,000,000		10,000,000
Preferred stock, Par Value (in dollars per share) \| $ / shares		$ 0.001			$ 0.001		$ 0.001
IPO \| Maximum
Common stock, authorized \| shares		150,000,000

Summary of significant accounting policies (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Apr. 01, 2019	Mar. 31, 2019
Summary of significant accounting policies
Right-to-use asset	$ 690
lease liabilities	730
Property, plant and equipment, net	963		$ 12,159
Long term prepaid rent	11,901
Lease liabilities, current	394
Lease liabilities, non-current	336
Accrued expenses and other current liabilities	1,829		2,801
Deferred rent, net of current portion			24
Financing obligation			6,561
Accumulated deficit	(69,181)		$ (59,766)
ASU 2016-02
Summary of significant accounting policies
Right-to-use asset	789
lease liabilities	$ 837
Property, plant and equipment, net		$ 645
Right-to-use asset		789
Long term prepaid rent		5,006
Lease liabilities, current		388
Lease liabilities, non-current		499
Accrued expenses and other current liabilities		2,777
Accumulated deficit		(59,673)
ASU 2016-02 \| Adjustments
Summary of significant accounting policies
Property, plant and equipment, net		(11,514)
Right-to-use asset		789
Long term prepaid rent		5,006
Lease liabilities, current		388
Lease liabilities, non-current		449
Accrued expenses and other current liabilities		(24)
Deferred rent, net of current portion		(24)
Financing obligation		(6,561)
Accumulated deficit		$ 93

Fair value of financial assets and liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Fair value of financial assets and liabilities
Transfer from Leve 1 to Level 2, assets	$ 0	$ 0
Transfer from Leve 2 to Level 1, assets	0	0
Transfers into Level 3, assets	0	0
Transfer out of Level 3, assets	0	0
Transfer from Leve 1 to Level 2, liabilities	0	0
Transfer from Leve 2 to Level 1, liabilities	0	0
Transfers into Level 3, liabilities	0	0
Transfer out of Level 3, liabilities	0	$ 0
Recurring
Fair value of financial assets and liabilities
Assets fair value	82,882		$ 119,771
Level 2 \| Recurring
Fair value of financial assets and liabilities
Assets fair value	82,882		119,771
Money market funds \| Recurring
Fair value of financial assets and liabilities
Assets fair value	447		2,676
Money market funds \| Level 2 \| Recurring
Fair value of financial assets and liabilities
Assets fair value	447		2,676
Commercial paper \| Recurring
Fair value of financial assets and liabilities
Assets fair value	36,927		46,687
Commercial paper \| Level 2 \| Recurring
Fair value of financial assets and liabilities
Assets fair value	36,927		46,687
US Government agency bonds \| Recurring
Fair value of financial assets and liabilities
Assets fair value	12,970		20,884
US Government agency bonds \| Level 2 \| Recurring
Fair value of financial assets and liabilities
Assets fair value	12,970		20,884
US Treasury bonds \| Recurring
Fair value of financial assets and liabilities
Assets fair value	28,188		41,057
US Treasury bonds \| Level 2 \| Recurring
Fair value of financial assets and liabilities
Assets fair value	28,188		41,057
Corporate debt securities \| Recurring
Fair value of financial assets and liabilities
Assets fair value	4,350		8,467
Corporate debt securities \| Level 2 \| Recurring
Fair value of financial assets and liabilities
Assets fair value	$ 4,350		$ 8,467

Fair value of financial assets and liabilities - Unobservable inputs of the warrant liability (Details)	3 Months Ended
	Jun. 30, 2019 $ / shares	Jun. 30, 2018 $ / shares
Unobservable inputs of the warrant liability
Warrant liability fair value of series seed preferred stock (in dollars per share)	$ 15.00
Risk-free interest rate
Unobservable inputs of the warrant liability
Warrant liability inputs		2.68
Expected dividend yield
Unobservable inputs of the warrant liability
Warrant liability inputs		0
Expected term
Unobservable inputs of the warrant liability
Warrant liability expected term (in years)		7 years 3 months 18 days
Expected volatility
Unobservable inputs of the warrant liability
Warrant liability inputs		64.4
Fair value of series seed preferred stock
Unobservable inputs of the warrant liability
Warrant liability fair value of series seed preferred stock (in dollars per share)		$ 15.00

Fair value of financial assets and liabilities - Roll forward of the warrant liability (Details) - Warrant liability $ in Thousands	3 Months Ended
	Jun. 30, 2018 USD ($)
Roll forward of the warrant liability
Balance at beginning of the period	$ 1,642
Change in fair value	5,450
Balance at end of the period	$ 7,092

Short-term investments (Details) - Short-term investments - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019
Short-term investments
Amortized cost	$ 82,355	$ 109,092
Gross unrealized gains	80	19
Gross unrealized losses		(4)
Fair value	82,435	109,107
Commercial paper
Short-term investments
Amortized cost	36,890	46,687
Gross unrealized gains	37	2
Gross unrealized losses		(2)
Fair value	36,927	46,687
US Government agency bonds
Short-term investments
Amortized cost	12,963	15,889
Gross unrealized gains	7	4
Fair value	12,970	15,893
US Treasury bonds
Short-term investments
Amortized cost	28,155	38,047
Gross unrealized gains	33	13
Fair value	28,188	38,060
Corporate debt securities
Short-term investments
Amortized cost	4,347	8,469
Gross unrealized gains	3
Gross unrealized losses		(2)
Fair value	$ 4,350	$ 8,467

Property, plant and equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Apr. 01, 2019	Mar. 31, 2019
Property, plant and equipment, net
Property, Plant and Equipment, Gross, Total	$ 1,409			$ 12,563
Less: Accumulated depreciation and amortization	(446)			(404)
Property, plant and equipment , net	963			12,159
Depreciation and amortization expense	42	$ 33
Financing obligation				6,561
Long term prepaid rent	11,901
ASU 2016-02
Property, plant and equipment, net
Property, plant and equipment , net			$ 645
Lease capitalized asset			789
Long term prepaid rent			$ 5,006
Leasehold improvements
Property, plant and equipment, net
Property, Plant and Equipment, Gross, Total	154			154
Construction in Progress
Property, plant and equipment, net
Property, Plant and Equipment, Gross, Total	443			124
Build-to-suit lease asset
Property, plant and equipment, net
Property, plant and equipment , net				11,514
Office equipment
Property, plant and equipment, net
Property, Plant and Equipment, Gross, Total	49			49
Computer equipment
Property, plant and equipment, net
Property, Plant and Equipment, Gross, Total	144			138
Plant and laboratory equipment
Property, plant and equipment, net
Property, Plant and Equipment, Gross, Total	$ 619			$ 584

Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019
Accrued expenses and other current liabilities.
Accrued research and development costs	$ 777	$ 530
Accrued compensation and benefits costs	660	1,510
Accrued professional fees	260	464
Deferred rent		24
Other	132	273
Total	$ 1,829	$ 2,801

Stockholders' Equity (Details) - $ / shares	Jul. 24, 2018	Jun. 30, 2019	Mar. 31, 2019	Jul. 09, 2018
Stockholders' Equity
Shares authorized (in shares)		150,000,000	150,000,000	27,314,288
Par value (in dollars per share)		$ 0.001	$ 0.001
Repurchase of class A common stock upon closing of initial public offering (in shares)	26,258
IPO
Stockholders' Equity
Par value (in dollars per share)	$ 0.001
Undesignated preferred stock, authorized	10,000,000	10,000,000	10,000,000
Preferred stock, Par Value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Undesignated preferred shares issued		0	0
Undesignated preferred shares outstanding		0	0
Common stock
Stockholders' Equity
Shares authorized (in shares)		150,000,000	150,000,000
Par value (in dollars per share)		$ 0.001	$ 0.001
Common stock reserved for the conversion of outstanding shares of preferred stock		8,449,932	6,873,744
Maximum \| IPO
Stockholders' Equity
Shares authorized (in shares)	150,000,000

Stockholders' Equity - Convertible preferred stock (Details) $ in Thousands	Jul. 25, 2018 shares	Jun. 30, 2019 USD ($)
Convertible preferred stock
Conversion ratio	9.94688
Preferred stock outstanding \| $		$ 0
Common stock
Convertible preferred stock
Conversion of convertible preferred stock warrants into common stock warrants (in shares) \| shares	19,157,360

Stockholders' Equity - Preferred stock warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Preferred stock warrants
Loss from change in fair value of the warrant liability		$ 5,450
Series Seed preferred stock
Preferred stock warrants
Number of preferred stock warrants issued	50,000
Exercise price (in dollars per share)	$ 10.00
Fair value of the warrants to purchase shares of series seed preferred stock	$ 391
Other income (expense), net
Preferred stock warrants
Loss from change in fair value of the warrant liability	$ 0	$ 5,450

Stock Based Compensation (Details) - shares			3 Months Ended
Stock Based Compensation (Details) - shares	Apr. 01, 2019	Jul. 09, 2018	Jun. 30, 2019
2017 Plan
Share based payments
Total number of common shares authorized to issue			2,659,885
Number of shares available for grant			0
2017 Plan \| Maximum
Share based payments
Number of shares available for grant		2,520,247
2018 Plan
Share based payments
Total number of common shares authorized to issue		3,617,968
Number of shares available for grant	1,266,370	131,850	2,442,339
Common stock reserved for issuance		3,486,118
ESPP
Share based payments
Common stock reserved for issuance		348,612
Share based payment award percentage of outstanding shares		1.00%
Additional number of common shares authorized to issue	316,569	697,224
Stock options
Share based payments
Exercise price for persons holding ten percent of voting power (as a percent)			100.00%
Exercise price for persons holding more than ten percent of voting power (as a percent)			110.00%
Share based payment award expiration period			10 years
Share based payment award vesting period			4 years
Stock options \| Minimum
Share based payments
Expiration period for persons holding more than ten percent of voting power			10 years
Stock options \| Maximum
Share based payments
Expiration period for persons holding ten percent of voting power			5 years

Stock Based Compensation - Assumptions to determine grant-date fair value of stock options (Details)	3 Months Ended
	Jun. 30, 2019
Stock-Based Compensation
Risk-free interest rate	2.34%
Expected term (in years)	6 years
Expected volatility	71.00%
Expected dividend yield	0.00%

Stock Based Compensation - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Number of Shares
Outstanding at beginning of the period (in shares)	3,721,784
Granted (in shares)	1,130,035
Exercised (in shares)	(6,751)
Outstanding at end of the period (in shares)	4,845,068		3,721,784
Options exercisable (in shares)	1,417,945		1,278,330
Weighted Average Exercise Price
Outstanding at beginning of the period (in dollars per share)	$ 7.14
Granted (in dollars per share)	15.42
Exercised (in dollars per share)	2.64
Outstanding at end of the period (in dollars per share)	9.08		$ 7.14
Options exercisable (in dollars per share)	$ 2.54		$ 2.51
Weighted Average Contractual Term (Years)
Outstanding (years)	8 years 6 months 29 days		8 years 7 months 10 days
Granted (years)	9 years 9 months 7 days
Options exercisable (years)	7 years 6 months 11 days		7 years 9 months
Aggregate Intrinsic Value
Outstanding at beginning of the period	$ 30,150
Outstanding at end of the period	28,488		$ 30,150
Options exercisable	17,895		$ 16,249
Total fair value of options vested	$ 211	$ 45
Outstanding unvested service-based stock options	0

Stock Based Compensation - Classification of expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Share-Based Compensation
Allocated Share-based Compensation Expense, Total	$ 1,810	$ 225
Total unrecognized compensation cost	$ 21,265
Expenses expected to be recognized over a weighted average remaining period	2 years 5 months 1 day
Research and development expenses
Share-Based Compensation
Allocated Share-based Compensation Expense, Total	$ 841	126
General and administrative expenses
Share-Based Compensation
Allocated Share-based Compensation Expense, Total	$ 969	$ 99

Net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net loss attributable to common stockholders	$ (9,508)	$ (10,044)
Denominator:
Weighted average common shares outstanding basic and diluted	31,661,430	4,981,227
Net loss per share attributable to common stockholders, basic and diluted	$ (0.30)	$ (2.02)

Net loss per share - Computation of diluted net loss per share attributable to common stockholders (Details) - shares	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Diluted net loss per share attributable to common stockholders
Antidilutive securities excluded from computation of diluted weighted average shares outstanding	5,342,412	22,157,234
Options to purchase common stock
Diluted net loss per share attributable to common stockholders
Antidilutive securities excluded from computation of diluted weighted average shares outstanding	4,845,068	2,502,530
Convertible preferred stock
Diluted net loss per share attributable to common stockholders
Antidilutive securities excluded from computation of diluted weighted average shares outstanding		19,157,360
Warrants to purchase convertible preferred stock (as converted to common stock)
Diluted net loss per share attributable to common stockholders
Antidilutive securities excluded from computation of diluted weighted average shares outstanding	497,344	497,344

Significant agreements (Details) - USD ($) $ in Thousands	3 Months Ended
Significant agreements (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Significant agreements
Prepaid expenses and other current assets	$ 4,529		$ 3,696
Agreement with Regeneron Pharmaceuticals, Inc
Significant agreements
Payments received under the terms of the agreement	337	$ 0
Prepaid expenses and other current assets	$ 912		$ 337

Commitments and contingencies - Lease agreements (Details) $ in Thousands	1 Months Ended				3 Months Ended	9 Months Ended	30 Months Ended
	Jun. 30, 2019 USD ($) ft²	Jun. 30, 2018 USD ($) ft² Option	Apr. 30, 2016	Dec. 31, 2015 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2019 USD ($)	Apr. 01, 2019 USD ($)	Mar. 31, 2019 USD ($)
Lease agreements
Number of options to extend lease agreement (in years)				5 years
Monthly lease payments, inclusive of base rent and ancillary charges				$ 7
Prior notice period upon termination of lease			9 months
Base rent of monthly lease payments						$ 23	$ 31
Leased office space \| ft²	18,700	63,000
Lease rent commencement duration		8 months
Rentable office space \| ft²		106,000
Lease term		10 years
Number of options to renewal the lease \| Option		2
Renewal period of lease		5 years
Annual rental payment	$ 488	$ 2,373
Percentage of annual increase in lease rental expenses	1.60%	3.00%			1.60%		1.60%
Property, plant and equipment, net	$ 963				$ 963		$ 963		$ 12,159
Financing obligation									6,561
Long term prepaid rent	11,901				11,901		11,901
Operating lease, paid	730				730		730
Operating lease, remained payable					119
ASU 2016-02
Lease agreements
Property, plant and equipment, net								$ 645
Long term prepaid rent								$ 5,006
Operating lease, paid	$ 837				$ 837		$ 837
Build-to-suit lease asset
Lease agreements
Property, plant and equipment, net									$ 11,514

Commitments and contingencies - Components of lease expense (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2019 USD ($)
Commitments and contingencies
Lease cost	$ 114
Total lease cost	$ 114

Commitments and contingencies - Future lease payments under operating leases (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Commitments and contingencies
2020 (remaining nine months)	$ 353
2021	471
Total lease payments	824
Less: interest	(94)
Total lease liabilities	$ 730

Commitments and contingencies - Future annual minimum lease payment commitments (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Commitments and contingencies
2020	$ 2,062
2021	2,901
2022	2,493
2023	2,568
2024	2,645
2025	2,725
Thereafter	12,770
Total	$ 28,164

Commitments and contingencies - Additional information related to leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Leases
Right-to-use asset	$ 690
Long term prepaid rent	11,901
Lease liabilities, current	394
Lease liabilities, non-current	336
Total lease liabilities	730
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for amounts included in the measurement of lease liabilities	119
Right-to-use asset obtained in exchange for new operating lease liabilities	$ 789
Weighted-average remaining lease term - leases	1 year 9 months 18 days
Weighted-average discount rate - leases	15.00%
Rent expense	$ 114	$ 110

Geographic Information (Details) $ in Thousands	3 Months Ended
Geographic Information (Details) $ in Thousands	Jun. 30, 2019 USD ($) segment	Mar. 31, 2019 USD ($)
Geographic Information
Number of operating geographic regions \| segment	2
Long-lived assets	$ 963	$ 12,159
United States
Geographic Information
Long-lived assets	452	11,648
United Kingdom
Geographic Information
Long-lived assets	$ 511	$ 511

Subsequent Events (Details) - Subsequent events - USD ($) $ / shares in Units, $ in Thousands	Aug. 08, 2019	Aug. 07, 2019
ATM Program
Subsequent events
Share Price	$ 0.001
Percentage Of Commission	3.00%
Term Loan Agreement
Debt Securities
Maximum Borrowing Amount		$ 30,000
Facility charge		$ 225
Interest rate		8.75%
Loan agreement term		4 years
Percentage of prepayment charge payable within the first twelve months		3.00%
Percentage of prepayment charge payable after twelve months but prior to twenty four months		2.00%
Percentage of prepayment charge payable anytime thereafter		1.00%
Percentage of charge Payable on aggregate debt amount		4.95%
Term Loan Agreement \| Prime Rate
Debt Securities
Variable interest rate		2.75%
Term Loan Agreement Tranche
Debt Securities
Maximum Borrowing Amount		$ 10,000
Maximum \| ATM Program
Subsequent events
Aggregate amount	$ 75,000
Securities offered to the public during the period	$ 250,000

Commitments and contingencies - Manufacturing commitments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019
Commitments and contingencies
Minimum payments committed to manufacturing organization	$ 3,784	$ 4,694