Immunovant (IMVT) 10-K 1 Jun 21 2020 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Jun. 01, 2021	Sep. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-38906
Entity Registrant Name	IMMUNOVANT, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-2771572
Entity Address, Address Line One	320 West 37th Street
Entity Address, City or Town	New York,
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10018
City Area Code	917
Local Phone Number	580-3099
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	IMVT
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,460.5
Entity Common Stock, Shares Outstanding		97,976,695
Entity Central Index Key	0001764013
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Mar. 31, 2021	Mar. 31, 2020
Current assets:
Cash		$ 400,146	$ 100,571
Prepaid expenses		8,312	5,460
Income tax receivable		548	36
Value-added tax receivable		0	3,009
Total current assets		409,006	109,076
Operating lease right-of-use assets		3,282	0
Property and equipment, net		201	65
Deferred offering costs		0	246
Total assets		412,489	109,387
Current liabilities:
Accounts payable		2,432	1,190
Accrued expenses		15,160	10,938
Current portion of operating lease liabilities		1,179	0
Due to Roivant Sciences Ltd.		0	3,190
Total current liabilities		18,771	15,318
Operating lease liabilities, net of current portion		2,238	0
Total liabilities		21,009	15,318
Commitments and contingencies (Note 12)
Stockholders' equity:
Preferred stock value	[1]	0	0
Common stock, par value $0.0001 per share, 500,000,000 shares authorized, 97,971,243 shares issued and outstanding at March 31, 2021 and 500,000,000 shares authorized, 56,455,376 shares issued and 54,655,376 shares outstanding at March 31, 2020	[1]	10	5
Additional paid-in capital	[1]	590,425	185,306
Accumulated other comprehensive loss	[1]	(298)	(16)
Accumulated deficit	[1]	(198,657)	(91,226)
Total stockholders’ equity	[1]	391,480	94,069
Total liabilities and stockholders’ equity		412,489	109,387
Series A Preferred Stock
Stockholders' equity:
Preferred stock value	[1]	$ 0	$ 0
[1]	Retroactively restated for the reverse recapitalization as described in Note 1.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Mar. 31, 2020
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	500,000,000	500,000,000
Common stock, issued (in shares)	97,971,243	56,455,376
Common share, outstanding (in shares)	97,971,243	54,655,376
Series A Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	10,000	10,000
Preferred stock, issued (in shares)	10,000	10,000
Preferred stock, outstanding (in shares)	10,000	10,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Operating expenses:
Research and development (includes $7,033 and $3,130 of stock-based compensation expense for the years ended March 31, 2021 and 2020, respectively)	[1]	$ 68,604	$ 47,927
General and administrative (includes $11,789 and $3,833 of stock-based compensation expense for the years ended March 31, 2021 and 2020, respectively)	[2]	39,513	18,151
Total operating expenses		108,117	66,078
Interest expense		0	625
Other income, net		(328)	(412)
Loss before (benefit) provision for income taxes		(107,789)	(66,291)
(Benefit) provision for income taxes		(358)	97
Net loss	[3]	$ (107,431)	$ (66,388)
Net loss per common share - basic and diluted	[3]	$ (1.22)	$ (1.54)
Weighted-average common shares outstanding – basic and diluted	[3]	87,756,513	43,199,191
[1]	Includes $340 and $159 of costs allocated from Roivant Sciences Ltd. for the years ended March 31, 2021 and 2020, respectively.
[2]	Includes $1,180 and $1,381 of costs allocated from Roivant Sciences Ltd. for the years ended March 31, 2021 and 2020, respectively.
[3]	Retroactively restated for the reverse recapitalization as described in Note 1.

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Research and Development Expense
Share-based compensation expense	$ 7,033	$ 3,130
General and Administrative Expense
Share-based compensation expense	11,789	3,833
Roivant Sciences Ltd. (RSL) | Research and Development Expense
Costs allocated from related party	340	159
Roivant Sciences Ltd. (RSL) | General and Administrative Expense
Costs allocated from related party	$ 1,180	$ 1,381

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net loss	[1]	$ (107,431)	$ (66,388)
Other comprehensive loss:
Foreign currency translation adjustments		(282)	(362)
Total other comprehensive loss		(282)	(362)
Comprehensive loss		$ (107,713)	$ (66,750)
[1]	Retroactively restated for the reverse recapitalization as described in Note 1.

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Underwritten Public Offering	Upon Achievement of Earnout Shares Milestone	Warrant Redemption	Roivant Sciences Ltd. (RSL)	Series A preferred stock	Series A preferred stockUpon Achievement of Earnout Shares Milestone	Common stock		Common stockUnderwritten Public Offering	Common stockUpon Achievement of Earnout Shares Milestone	Common stockWarrant Redemption	Common stock subscribed	Common stock subscribedUnderwritten Public Offering	Additional paid-in capital	Additional paid-in capitalUnderwritten Public Offering	Additional paid-in capitalUpon Achievement of Earnout Shares Milestone	Additional paid-in capitalWarrant Redemption	Additional paid-in capitalRoivant Sciences Ltd. (RSL)	Accumulated other comprehensive income (loss)	Accumulated deficit
Beginning balance (in shares) at Mar. 31, 2019	[1]								38,590,381
Beginning balance at Mar. 31, 2019	[1]	$ 7,339							$ 4					$ (3)		$ 31,830					$ 346	$ (24,838)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Settlement of common stock subscription	[1]	1												3		(2)
Issuance of preferred and common stock, net of deferred offering costs upon Business Combination and Recapitalization (in shares)	[1]						10,000		12,565,000
Issuance of preferred and common stock, net of deferred offering costs upon Business Combination and Recapitalization	[1]	109,772							$ 1							109,771
Conversion of convertible promissory notes, shares	[1]								3,499,995
Conversion of convertible promissory notes	[1]	35,587														35,587
Capital contribution – stock-based compensation	[1]	175														175
Capital contribution – expenses allocated from Roivant Sciences Ltd.	[1]					$ 1,157														$ 1,157
Stock-based compensation	[1]	6,788														6,788
Foreign currency translation adjustments	[1]	(362)																			(362)
Net loss	[1]	(66,388)																				(66,388)
Ending balance (in shares) at Mar. 31, 2020	[1]						10,000		54,655,376
Ending balance at Mar. 31, 2020	[1]	$ 94,069							$ 5					$ 0		185,306					(16)	(91,226)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)	[1]							0			15,673,971	20,000,000	5,719,145
Issuance of common stock	[1]		$ 318,547	$ 0	$ 65,752						$ 2	$ 2	$ 1		$ 0		$ 318,545	$ (2)	$ 65,751
Vesting of sponsor restricted shares (in shares)	[1]								1,800,000
Stock options exercised and vesting of restricted stock units (in shares)		114,084							122,751	[1]
Stock options exercised and vesting of restricted stock units	[1]	$ 907														907
Capital contribution – stock-based compensation	[1]	184														184
Capital contribution – expenses allocated from Roivant Sciences Ltd.	[1]					$ 1,096														$ 1,096
Stock-based compensation	[1]	18,638														18,638
Foreign currency translation adjustments	[1]	(282)																			(282)
Net loss	[1]	(107,431)																				(107,431)
Ending balance (in shares) at Mar. 31, 2021	[1]						10,000		97,971,243
Ending balance at Mar. 31, 2021	[1]	$ 391,480							$ 10							$ 590,425					$ (298)	$ (198,657)
[1]	Retroactively restated for the reverse recapitalization as described in Note 1.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities
Net loss	[1]	$ (107,431)	$ (66,388)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation		18,822	6,963
Depreciation on property and equipment		65	21
Foreign currency translation adjustments		(282)	(362)
Loss on disposal of property and equipment		0	13
Gain on extinguishment of convertible notes		0	(38)
Write-off of deferred offering costs		0	1,628
Non-cash lease expense		933	0
Changes in operating assets and liabilities:
Prepaid expenses		(2,852)	(2,824)
Income tax receivable		(512)	13
Value-added tax receivable		3,009	(96)
Accounts payable		1,251	967
Accrued expenses		4,468	6,502
Operating lease liabilities		(798)	0
Due to Roivant Sciences Ltd.		0	244
Net cash used in operating activities		(83,327)	(53,357)
Cash flows from investing activities
Purchases of property and equipment		(210)	(31)
Net cash used in investing activities		(210)	(31)
Cash flows from financing activities
Capital contributions		1,096	1,157
Proceeds from stock options exercised		907	0
Payment of deferred offering costs		(1,236)	(3,107)
Proceeds from convertible promissory notes		0	35,000
Repayment of convertible promissory notes		0	(2,500)
Settlement of common stock subscribed		0	1
Recapitalization transaction (See Note 3)		0	111,016
Net cash provided by financing activities		383,112	146,974
Net change in cash		299,575	93,586
Cash – beginning of period		100,571	6,985
Cash – end of period		400,146	100,571
Non-cash operating activity
Operating lease right-of-use assets obtained and exchanged for operating lease liabilities		4,215	0
Non-cash investing activity
Payable for purchase of property and equipment		0	9
Non-cash financing activity
Conversion of convertible promissory notes to common stock		0	35,000
Deferred offering costs in accrued expenses		0	246
Cancellation of interest on convertible promissory notes recorded in equity		0	587
Total non-cash financing activity		0	35,833
Supplemental disclosure of cash paid:
Income taxes		166	61
Underwritten Public Offering
Cash flows from financing activities
Proceeds from issuance of common stock		319,783	0
Warrant Redemption
Cash flows from financing activities
Proceeds from issuance of common stock		65,752	0
Roivant Sciences Ltd. (RSL)
Cash flows from financing activities
Proceeds from convertible promissory notes		0	7,907
Repayment of convertible promissory notes		$ (3,190)	$ (2,500)
[1]	Retroactively restated for the reverse recapitalization as described in Note 1.

Organization and Nature of Busi

Organization and Nature of Business	12 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Nature of Business	Organization and Nature of Business [A] Description of Business Immunovant, Inc. together with its wholly owned subsidiaries (the “Company” or “Immunovant”) (formerly known as Health Sciences Acquisitions Corporation) is a clinical-stage biopharmaceutical company focused on enabling normal lives for people with autoimmune diseases. The Company is developing a novel, fully human monoclonal antibody, IMVT-1401 (formerly referred to as "RVT-1401"), that selectively binds to and inhibits the neonatal fragment crystallizable receptor. The Company intends to develop IMVT-1401 for indications in which there is robust evidence that pathogenic immunoglobulin G antibodies drive disease manifestation and for which reduction of these antibodies should lead to clinical benefit for patients with autoimmune diseases. The Company has determined that it has one operating and reporting segment. Reverse Recapitalization On December 18, 2019, Health Sciences Acquisitions Corporation (“HSAC”) completed the acquisition of Immunovant Sciences Ltd. (“ISL”) pursuant to the share exchange agreement dated as of September 29, 2019 (the “Share Exchange Agreement”), by and among HSAC, ISL, the stockholders of ISL (the “Sellers”), and Roivant Sciences Ltd. (“RSL”), as representative of the Sellers (the “Business Combination”). As of immediately prior to the closing of the Business Combination, the Sellers owned 100% of the issued and outstanding common shares of ISL (“ISL Shares”). At the closing of the Business Combination, HSAC acquired 100% of the issued and outstanding ISL Shares, in exchange for 42,080,376 shares of HSAC’s common stock issued to the Sellers and 10,000 shares of HSAC Series A preferred stock issued to RSL. Upon the closing of the Business Combination, ISL became a wholly owned subsidiary of HSAC and HSAC was renamed “Immunovant, Inc.” The Business Combination was accounted for as a reverse recapitalization and HSAC was treated as the “acquired” company for accounting purposes. The Business Combination was accounted as the equivalent of ISL issuing stock for the net assets of HSAC, accompanied by a recapitalization. Accordingly, all historical financial information presented in these consolidated financial statements represents the accounts of ISL and its wholly owned subsidiaries “as if” ISL is the predecessor to the Company. The shares prior to the Business Combination have been retroactively restated as shares reflecting the exchange ratio established in the Business Combination (0.48906624 Immunovant, Inc. shares for 1 ISL Share). ISL was founded on July 6, 2018 as a Bermuda exempted limited company and a wholly owned subsidiary of RSL. In July and August 2018, ISL incorporated its wholly owned subsidiaries, Immunovant Sciences Holdings Ltd. (“ISHL”), a private limited company incorporated in the United Kingdom under the laws of England and Wales, IMVT Corporation (formerly, Immunovant, Inc.), a Delaware corporation based in the United States of America, and Immunovant Sciences GmbH (“ISG”), a limited liability company formed under the laws of Switzerland. ISG holds all of the Company’s intellectual property rights. HSAC was incorporated in Delaware on December 6, 2018 and was formed as a blank check company for the purpose of effecting a merger, share exchange, asset acquisition, stock purchase, recapitalization, reorganization or similar business combination with one or more businesses. References herein to “date of formation” or “date of inception” refer to the founding of ISL. One of the primary purposes of the Business Combination was to provide a platform for ISL to gain access to the U.S. capital markets. See Note 3 – Business Combination and Recapitalization for additional details on the Business Combination. [B] Liquidity The Company has incurred significant losses and negative cash flows from operations since its inception. As of March 31, 2021, the Company’s cash totaled $400.1 million and its accumulated deficit was $198.7 million. The Company has not generated any revenues to date and does not anticipate generating any revenues unless and until it successfully completes development and obtains regulatory approval for IMVT-1401 or any future product candidate. Management expects to incur additional losses in the future to fund its operations and conduct product research and development and recognizes the need to raise additional capital to fully implement its business plan.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies [A] Basis of Presentation The Company’s fiscal year ends on March 31, and its first three fiscal quarters end on June 30, September 30, and December 31. The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. The Company has no unconsolidated subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. [B] Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company regularly evaluates estimates and assumptions related to assets, liabilities, stock-based compensation, litigation accruals, clinical trial accruals, operating leases, research and development costs and income taxes. The Company bases its estimates and assumptions on historical experience and on various other factors that it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates. Additionally, the Company assessed the impact that the COVID-19 pandemic has had on its operations and financial results as of March 31, 2021 and through the issuance of this report. The Company’s analysis was informed by the facts and circumstances as they were known to the Company. This assessment considered the impact COVID-19 may have on financial estimates and assumptions that affect the reported amounts of assets and liabilities and expenses. [C] Risks and Uncertainties The Company is subject to risks common to early-stage companies in the biopharmaceutical industry including, but not limited to, uncertainties related to commercialization of products, regulatory approvals, dependence on key products, key personnel and third-party service providers such as contract research organizations, protection of intellectual property rights and the ability to make milestone, royalty or other payments due under any license, collaboration or supply agreements. [D] Concentration of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk include cash. At March 31, 2021, the cash balance is kept in one banking institution that the Company believes is of high credit quality and is in excess of federally insured levels. The Company maintains its cash with an accredited financial institution and accordingly, such funds are subject to minimal credit risk. The Company has not experienced any losses on its cash. [E] Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents. At March 31, 2021, cash consisted of cash held at a financial institution. There were no cash equivalents as of March 31, 2021 and 2020. [F] Property and Equipment Property and equipment, consisting of computers, is recorded at cost. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred. Depreciation is recorded using the straight-line method over the estimated useful life of three years. Upon disposal, retirement or sale, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the consolidated statements of operations. [G] Impairment of Long-lived Assets Long-lived assets, such as right-of-use assets due to operating leases, property and equipment, are evaluated for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset to be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by an asset to the carrying value of the asset. If the carrying value of the long-lived asset is not recoverable on an undiscounted cash flow basis, impairment is recognized to the extent that the carrying value exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary. [H] Contingencies The Company, from time to time, may be a party to various disputes and claims arising from normal business activities. The Company continually assesses litigation to determine if an unfavorable outcome would lead to a probable loss or reasonably possible loss which could be estimated. The Company accrues for all contingencies at the earliest date at which the Company deems it probable that a liability has been incurred and the amount of such liability can be reasonably estimated. If the estimate of a probable loss is a range and no amount within the range is more likely than another, the Company accrues the minimum of the range. In the cases where the Company believes that a reasonably possible loss exists, the Company discloses the facts and circumstances of the litigation, including an estimable range, if possible. Legal defense costs associated with loss contingencies are expensed in the period incurred. Additionally, the Company records a receivable for rights to insurance recoveries, limited to the extent of incurred or probable losses, when such recoveries have been agreed to with third-party insurers and when receipt is deemed probable. This includes instances when the third-party insurers have agreed to pay, on the Company's behalf, certain legal defense costs and settlement amounts directly to applicable law firms and settlement funds. [I] Research and Development Expenses Research and development costs with no alternative future use are expensed as incurred. Payments for a product license prior to regulatory approval of the product and payments for milestones achieved prior to regulatory approval of the product are expensed in the period incurred as research and development. Milestone payments made in connection with regulatory approvals are capitalized and amortized to cost of product sales over the remaining useful life of the asset. Research and development expenses primarily consist of employee-related costs, milestone payments under the HanAll Agreement and expenses from third parties who conduct research and development activities (including manufacturing) on behalf of the Company. The Company accrues costs for clinical trial activities based upon estimates of the services received and related expenses incurred that have yet to be invoiced by contract research organizations. In making these estimates, the Company considers various factors, including status and timing of services performed, the number of patients enrolled and the rate of patient enrollment. The Company accrues costs for non-clinical studies and contract manufacturing activities over the service periods specified in the contracts and are adjusted as necessary based upon an ongoing review of the level of effort and costs actually incurred. The estimate of the work completed is developed through discussions with internal personnel and external services providers as to the progress toward completion of the services and the agreed-upon fee to be paid for such services. As actual costs become known, the accrued estimates are adjusted. Such estimates are not expected to be materially different from amounts actually incurred. [J] Leases The Company's operating leases primarily relate to its three subleased premises, two in New York and one in North Carolina. Operating lease right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset during the lease term, and operating lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and lease liabilities are initially recognized based on the present value of the future fixed lease payments over the expected lease term at commencement date calculated using the Company’s incremental borrowing rate applicable to the lease asset, unless the implicit rate is readily determinable. Operating lease ROU assets also include any lease payments made at or before lease commencement, adjusted by any initial direct costs and exclude any lease incentives received. The Company determines the lease term as the non-cancelable period of the lease and may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Leases with a term of 12 months or less are not recognized on the consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Variable lease costs such as common area costs and other operating costs are expensed as incurred. The Company accounts for lease and non-lease components as a single lease component for all its facilities leases. [K] Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between amounts in the consolidated financial statements and the tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income tax (benefit) expense in the accompanying consolidated statements of operations in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that it believes these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of its net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company has not recognized U.S. income taxes and foreign withholding taxes on undistributed earnings of foreign subsidiaries which the Company has determined to be indefinitely reinvested. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company’s policy is to recognize interest and/or penalties related to income tax matters in provision for income taxes. [L] Stock-based Compensation Stock-based awards to employees and directors are valued at fair value on the date of the grant and that fair value is recognized as stock-based compensation expense over the requisite service period. The grant date fair value of the stock-based awards with graded vesting is recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the respective awards. The Company values its stock options that only have service vesting requirements or performance-based awards without market conditions using the Black-Scholes option pricing model. For performance-based awards with market conditions, the Company determines the fair value of awards as of the grant date using a Monte Carlo simulation model. Stock-based compensation related to restricted stock awards is based on the fair value of the Company's common stock on the grant date. Certain assumptions need to be made with respect to utilizing the Black-Scholes option pricing model, including the expected life of the award, volatility of the underlying shares, the risk-free interest rate, expected dividend yield and the fair value of the Company’s common stock. Since the Company has limited option exercise history, it has generally elected to estimate the expected life of an award based upon the “simplified method” with the continued use of this method extended until such time the Company has sufficient exercise history. The expected share price volatility for the Company’s common stock is estimated by taking the average historical price volatility for the Company's peers. The risk-free interest rate is based on the rates paid on securities issued by the U.S. Treasury with a term approximating the expected life of the equity award. As the Company has never paid and does not anticipate paying cash dividends on its common stock, the expected dividend yield is assumed to be zero. The Company accounts for pre-vesting award forfeitures when they occur. As part of the valuation of stock-based compensation under the Black-Scholes option pricing model, it is necessary for the Company to estimate the fair value of its common stock. Prior to the closing of the Business Combination, the fair value of the Company’s common stock was estimated on each grant date by the Company’s board of directors. Given the absence of a public trading market, and in accordance with the American Institute of Certified Public Accountants’ Practice Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation , the Company exercised reasonable judgment and considered numerous objective and subjective factors to determine its best estimate of the fair value of its common stock. The estimation of the fair value of the common stock considered factors including the following: the estimated present value of the Company’s future cash flows; the Company’s business, financial condition and results of operations; the Company’s forecasted operating performance; the illiquid nature of the Company’s common stock; industry information such as market size and growth; market capitalization of comparable companies and the estimated value of transactions such companies have engaged in; and macroeconomic conditions. After the closing of the Business Combination, the Company’s board of directors determined the fair value of each share of common stock underlying stock-based awards based on the closing price of the Company’s common stock as reported by Nasdaq on the date of grant. Determining the appropriate amount to expense for performance-based awards based on the achievement of stated goals requires judgment. The estimate of expense is revised periodically based on the probability of achieving the required performance targets and adjustments are made as appropriate. The cumulative impact of any revisions is reflected in the period of change. If any applicable financial performance goals are not met, no compensation expense is recognized, and any previously recognized compensation cost is reversed. [M] Fair Value of Financial Instruments The Company applies a fair value framework in order to measure and disclose its financial assets and liabilities. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires an entity to maximize the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value: • Level 1 — Quoted prices in active markets for identical assets or liabilities. • Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Fair values are determined by utilizing quoted prices for similar assets and liabilities in active markets or other market observable inputs such as interest rates and yield curves. • Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is gr eatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company’s financial instruments consist of cash, accounts payable, accrued expenses and amounts due to RSL. These financial instruments are stated at their respective historical carrying amounts, which approximate fair value due to their short-term nature. There were no Level 2 or Level 3 financial instruments as of March 31, 2021 or 2020. [N] Foreign Currency The Company has operations in the United States, the United Kingdom, Bermuda, and Switzerland. The results of its non-U.S. dollar based functional currency operations are translated to U.S. dollars at the average exchange rates during the period. The Company’s assets and liabilities are translated using the current exchange rate as of the consolidated balance sheet date and equity is translated using historical rates. Adjustments resulting from the translation of the consolidated financial statements of the Company’s foreign functional currency subsidiaries into U.S. dollars are excluded from the determination of net loss and are recognized in accumulated other comprehensive loss. Foreign exchange transaction gains and losses are included in other income, net in the consolidated statements of operations. [O] Net Loss per Common Share Basic net loss per common share is computed by dividing net loss applicable to common stockholders by the weighted-average number of common stock outstanding during the period. Diluted net loss per common share is computed by dividing the net loss applicable to common stockholders by the diluted weighted-average number of common stock outstanding during the period. In periods in which the Company reports a net loss, all common stock equivalents are deemed anti-dilutive such that basic net loss per common share and diluted net loss per common share are equivalent. Potentially dilutive common stock has been excluded from the diluted net loss per common share computations in all periods presented because such securities have an anti-dilutive effect on net loss per common share due to the Company’s net loss. There are no reconciling items used to calculate the weighted-average number of total common stock outstanding for basic and diluted net loss per common share data. The following potentially dilutive securities have been excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect: Years Ended March 31, 2021 2020 Preferred stock as converted 10,000 10,000 Restricted stock (unvested) 1,095,676 1,800,000 Stock options 7,988,999 3,873,888 Warrants (See Note 9) — 5,750,000 Earnout shares (See Note 3) — 20,000,000 Total 9,094,675 31,433,888 In addition, the convertible promissory notes issued during the year ended March 31, 2020 were not included in the calculation of diluted weighted-average number of common shares outstanding because they were anti-dilutive given the net loss of the Company. [P] Deferred Offering Costs Legal, accounting and other costs directly attributable to the issuance of the Company’s equity are capitalized within deferred offering costs on the consolidated balance sheets and reclassified to equity upon issuance of the shares. Offering costs comprised of legal and accounting fees and other costs incurred through June 30, 2019 were directly related to ISL’s proposed initial public offering (“IPO”). In August 2019, ISL’s board of directors determined to suspend ISL’s IPO registration process. Accordingly, the Company has written off deferred offering costs previously capitalized to general and administrative expenses within the accompanying consolidated statement of operations for the year ended March 31, 2020. Deferred offering costs as of March 31, 2020 represented financing costs deferred for the follow-on underwritten public offering in April 2020. [Q] Common Stock Warrants The Company accounts for the issuance of common stock warrants based on the terms of the contract and whether there are any requirements for the Company to net cash settle the contract under any terms or conditions. Warrants for the purchase of 5,750,000 shares of common stock were issued by HSAC as part of the units sold in its IPO in May 2019. Each unit was comprised of one share of common stock and a warrant to purchase one half of one share of common stock upon the consummation of a business combination by HSAC. The warrants were classified as equity. None of the terms of the warrants were modified as a result of the Business Combination. During the year, the Company redeemed 11,438,290 warrants by issuing 5,719,145 shares of the Company’s common stock and the remaining 61,710 warrants were cancelled. No warrants remain outstanding as of March 31, 2021. See Note 9 – Stockholders’ Equity for additional details about common stock warrants. [R] Recently Adopted Accounting Pronouncements In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). ASU 2018-13 removes, modifies, and adds certain recurring and nonrecurring fair value measurement disclosures, including removing disclosures around the amount(s) of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, the policy for timing of transfers between levels, and the valuation process for Level 3 fair value measurements, among other things. ASU 2018-13 adds disclosure requirements around changes in unrealized gains and losses included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and a narrative description of measurement uncertainty. The amendments in ASU 2018-13 are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The Company has adopted ASU 2018-13 as of April 1, 2020, with no impact to the Company’s consolidated financial statements from the adoption of this new standard. In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model that requires the use of forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses on available-for-sale debt securities to be recorded through an allowance for credit losses instead of as a reduction in the amortized cost basis of the securities. ASU 2016-13 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted, including adoption in any interim period. The Company has adopted ASU 2016-13 as of April 1, 2020, with no impact to the Company’s consolidated financial statements from the adoption of this new standard. Recent authoritative guidance issued by the FASB (including technical corrections to the Accounting Standards Codification), the American Institute of Certified Public Accountants, and the Securities and Exchange Commission (“SEC”) did not, or are not expected to, have a material impact on the Company’s consolidated financial statements and related disclosures.

Business Combination and Recapi

Business Combination and Recapitalization	12 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Business Combination and Recapitalization	Business Combination and Recapitalization As discussed in Note 1, on December 18, 2019, HSAC completed the acquisition of ISL and acquired 100% of the ISL Shares in exchange for 42,080,376 shares of HSAC common stock issued to the Sellers and 10,000 shares of HSAC Series A preferred stock issued to RSL. The Business Combination was accounted for as a reverse recapitalization whereby HSAC was treated as the “acquired” company for accounting purposes. This determination was primarily based on the fact that subsequent to the Business Combination, the Sellers have a majority of the voting power of the combined company, ISL will comprise all of the ongoing operations of the combined entity, a majority of the governing body of the combined company, and ISL’s senior management will comprise all of the senior management of the combined company. The Business Combination was accounted as the equivalent of ISL issuing stock for the net assets of HSAC, accompanied by a recapitalization. The net assets of HSAC were stated at historical cost with no goodwill or other intangible assets recorded. Reported amounts from operations included herein prior to the Business Combination are those of ISL. The shares, options and net loss per share available to holders of the Company’s common stock, prior to the Business Combination, have been retroactively restated as shares reflecting the exchange ratio established in the Business Combination (0.48906624 Immunovant, Inc. shares for 1 ISL Share). The aggregate value of the consideration paid by HSAC in the Business Combination was $420.9 million, consisting of 42,080,376 shares of HSAC’s common stock and 10,000 shares of HSAC’s Series A preferred stock, in each case, valued at $10.00 per share (the deemed value of the shares issued pursuant to the Share Exchange Agreement). The closing price per share on the date of the closing of the Business Combination on December 18, 2019 was $13.88. As the Business Combination was accounted for as a reverse recapitalization, the $10.00 per share value is disclosed for informational purposes only in order to indicate the fair value of shares transferred. In addition, pursuant to the Share Exchange Agreement, all vested or unvested outstanding options to purchase common shares of ISL under its 2018 Equity Incentive Plan were automatically assumed by the Company and converted into options to purchase 4,408,287 shares of the Company’s common stock with no changes to the terms of the awards. In connection with the Business Combination and Recapitalization, the Company incurred direct and incremental costs of $2.8 million, consisting of legal, accounting, financial advisory and other professional fees, which are included in additional paid-in capital in the consolidated balance sheet as of March 31, 2020. The Company incurred additional financial advisory fees related to the Business Combination of $2.3 million, which are included in accumulated deficit within the consolidated balance sheet as of March 31, 2020. Earnout Shares Pursuant to the Share Exchange Agreement, the Sellers were entitled to receive up to an aggregate of 20,000,000 additional shares of the Company’s common stock (the “Earnout Shares”) if the volume-weighted average price of the Company’s shares equals or exceeds the following prices for any 20 trading days within any 30 trading-day period (the “Trading Period”) following December 18, 2019, the date of the closing of the Business Combination: (i) during any Trading Period prior to March 31, 2023, 10,000,000 Earnout Shares upon the achievement of a volume-weighted average price of at least $17.50 per share (the “First Earnout Milestone”); and (ii) during any Trading Period prior to March 31, 2025, 10,000,000 Earnout Shares upon the achievement of a volume-weighted average price of at least $31.50 per share (the “Second Earnout Milestone”). On May 12 and September 17, 2020, the Company achieved the First Earnout Milestone and the Second Earnout Milestone, respectively. Accordingly, the Company issued all of the 20,000,000 Earnout Shares to the Sellers (including 17,547,938 Earnout Shares issued to RSL) during the year ended March 31, 2021. Sponsor Restricted Stock Agreement In accordance with that certain restricted stock agreement, dated September 29, 2019, by and between HSAC and Health Sciences Holdings, LLC (the “Sponsor”), the Sponsor subjected 1,800,000 shares of its common stock (“Sponsor Restricted Shares”) to potential forfeiture, with 900,000 shares to vest and be released from potential forfeiture upon achievement of each of the First Earnout Milestone and the Second Earnout Milestone (as defined above), respectively. On May 12 and September 17, 2020, the Company achieved the First Earnout Milestone and the Second Earnout Milestone, respectively, and, as a result, all of the 1,800,000 Sponsor Restricted Shares vested and are no longer subject to forfeiture. Registration Rights In May 2019, HSAC entered into a registration rights agreement with the Sponsor, pursuant to which the Sponsor was granted certain rights relating to the registration of securities of HSAC held by the Sponsor. In September 2019, concurrent with the execution of the Share Exchange Agreement, HSAC, the Sponsor and the Sellers entered into an amended and restated registration rights agreement (the “Registration Rights Agreement”), which became effective as of the closing of the Business Combination. Under the Registration Rights Agreement, the Sponsor and the Sellers hold registration rights that obligate the Company to register for resale under the Securities Act of 1933, as amended (the “Securities Act”) all or any portion of the Registrable Securities (as defined in the Registration Rights Agreement) held by the Sponsor and the Sellers. Each of the Sponsor, RSL and stockholders holding a majority-in-interest of all such Registrable Securities will be entitled to make a written demand for registration under the Securities Act of all or part of their Registrable Securities, so long as such shares are not then restricted under certain lock-up agreements. Subject to certain exceptions, if the Company proposes to file a registration statement under the Securities Act with respect to the Company’s securities, under the Registration Rights Agreement, the Company will give notice to the Sponsor and the Sellers as to the proposed filing and offer such stockholders an opportunity to register the resale of such number of their Registrable Securities as they request in writing, subject to certain exceptions. In addition, subject to certain exceptions, such stockholders will be entitled under the Registration Rights Agreement to request in writing that the Company register the resale of any or all of their Registrable Securities on Form S-3 or any other registration statement that may be available at such time. The Registration Rights do not meet the definition of a registration payment arrangement as there are no terms that require the Company to transfer consideration to the various security holders if a registration statement is not declared effective or effectiveness is not maintained. See Note 9 – Stockholders’ Equity for details of the Company’s capital stock prior to and subsequent to the Business Combination and Recapitalization transaction.

Material Agreements

Material Agreements	12 Months Ended
	Mar. 31, 2021
Material Agreements [Abstract]
Material Agreements	Material Agreements License Agreement On December 19, 2017, Roivant Sciences GmbH (“RSG”), a wholly owned subsidiary of RSL, entered into a license agreement (the “HanAll Agreement”) with HanAll Biopharma Co., Ltd. (“HanAll"). Under the HanAll Agreement, RSG received (1) the non-exclusive right to manufacture and (2) the exclusive, royalty-bearing right to develop, import, use and commercialize the antibody referred to as IMVT-1401 and certain back-up and next-generation antibodies, and products containing such antibodies, in the United States, Canada, Mexico, the European Union, the United Kingdom, Switzerland, the Middle East, North Africa and Latin America (the “Licensed Territory”). In exchange for this license, RSG provided or agreed to provide the following consideration: • Upfront, non-refundable payment of $30.0 million; • Up to $20.0 million in shared (50%) research, development, and out-of-pocket costs incurred by HanAll; • Up to an aggregate of $442.5 million (after a $10 million milestone payment) upon the achievement of certain additional development, regulatory and sales milestones; and • Tiered royalties ranging from the mid-single digits to mid-teens on net product sales subject to reduction on a product-by-product and country-by-country basis, until the later of (1) expiration of patent and regulatory exclusivity or (2) the 11th anniversary of the first commercial sale of such product in such country. Since the acquisition of IMVT-1401, RSL and the Company have performed all the development associated with IMVT-1401 and no amounts were incurred by HanAll and reported to the Company, to research or develop the technology for the years ended March 31, 2021 and 2020. On August 18, 2018, RSG entered into a sublicense agreement (the “Sublicense Agreement”) with ISG to sublicense this technology, as well as RSG’s knowhow and patents necessary for the development, manufacture or commercialization of any compound or product that pertains to immunology. On December 7, 2018, RSG issued a notice to terminate the Sublicense Agreement with ISG and entered into an assignment and assumption agreement to assign to ISG all the rights, title, interest, and future obligations under the HanAll Agreement from RSG, including all rights to IMVT-1401 from RSG in the Licensed Territory, for an aggregate purchase price of $37.8 million. As a result of the assignment of IMVT-1401 by RSG to ISG, the Company recorded a Swiss value-added tax receivable of $3.0 million, which was a reflected as a capital contribution from RSL as of March 31, 2020. In April 2020, the Company received the payment related to this receivable. In May 2019, the Company achieved its first development and regulatory milestone under the HanAll Agreement which resulted in a $10.0 million milestone payment that the Company subsequently paid in August 2019. The milestone payment was recorded as a research and development expense in the accompanying consolidated statement of operations in the period incurred.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses consist of the following (in thousands): March 31, 2021 2020 Research and development expenses $ 10,147 $ 8,332 Legal and professional fees 1,196 1,231 Accrued bonuses 3,138 859 Other expenses 679 516 Total accrued expenses $ 15,160 $ 10,938

Related Party Transactions

Related Party Transactions	12 Months Ended
	Mar. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Roivant Sciences Inc. ("RSI") and RSG Services Agreements In addition to the agreements discussed in Note 4, in August 2018, the Company entered into services agreements (the “Services Agreements”) with RSI and RSG, under which RSI and RSG agreed to provide services related to development, administrative and financial activities to the Company during its formative period. Under each Services Agreement, the Company will pay or reimburse RSI or RSG, as applicable, for any expenses it, or third parties acting on its behalf, incurs for the Company. For any general and administrative and research and development activities performed by RSI or RSG employees, RSI or RSG, as applicable, will charge back the employee compensation expense plus a pre-determined mark-up. RSI and RSG also provided such services prior to the formalization of the Services Agreements, and such costs have been recognized by the Company in the period in which the services were rendered. Employee compensation expense, inclusive of base salary and fringe benefits, is determined based upon the relative percentage of time utilized on Company matters. All other costs will be billed back at cost. The term of the Services Agreements will continue until terminated by the Company, RSI or RSG, as applicable, upon 90 days’ written notice. The consolidated financial statements also include third-party expenses that have been paid by RSI, RSG and RSL since the inception of the Company. Total expense, inclusive of salary, fringe benefits and stock-based compensation, is proportionately allocated to the Company based upon the relative percentage of time utilized on the Company’s matters. For the year ended March 31, 2021, the Company was charged $1.3 million by RSI, RSG and RSL which were treated as capital contribution s in the accompanying consolidated financial statements. For the year ended March 31, 2020, the Company was charged $1.4 million by RSI, RSG and RSL of which $1.2 million and $0.2 million were treated as capital contributions and amounts due to RSL, respectively, in the accompanying consolidated financial statements. RSL Promissory Note In June 2019, the Company entered into an interest-free promissory note payable to RSL in the amount of $5.0 million (the “June Promissory Note”). The June Promissory Note was due and payable at the earlier of December 12, 2019 or upon demand by RSL. Subsequently, in August 2019, the Company cancelled the June Promissory Note and entered into a convertible promissory note with RSL in the amount of $5.0 million (the “RSL Convertible Promissory Note”) under the same terms as other convertible promissory notes entered into with RTW Master Fund, Ltd. and RTW Innovation Master Fund, Ltd. (the “RTW Entities”). In September 2019, the Company repaid $2.5 million aggregate principal amount of the RSL Convertible Promissory Note, and accrued interest on such amount was forgiven. The remaining aggregate principal balance of the RSL Convertible Note of $2.5 million automatically converted immediately prior to the closing of the Business Combination into shares of ISL exchangeable for an aggregate of 250,000 shares of the Company’s common stock upon the closing of the Business Combination. All interest under the RSL Convertible Promissory Note was waived and cancelled immediately prior to the closing of the Business Combination. In July 2019, the Company entered into an interest-free promissory note payable to RSL in the amount of $2.9 million (the “July Promissory Note”). The July Promissory Note had a 180-day term and was payable on demand upon the expiration of the term. In May 2020, the Company paid and settled the July Promissory Note. RSL Information Sharing and Cooperation Agreement In December 2018, the Company entered into an amended and restated information sharing and cooperation agreement (the “Cooperation Agreement”) with RSL. The Cooperation Agreement, among other things: (1) obligates the Company to deliver to RSL periodic financial statements and other information upon reasonable request and to comply with other specified financial reporting requirements; (2) requires the Company to supply certain material information to RSL to assist it in preparing any future SEC filings; and (3) requires the Company to implement and observe certain policies and procedures related to applicable laws and regulations. The Company has agreed to indemnify RSL and its affiliates and their respective officers, employees and directors against all losses arising out of, due to or in connection with RSL’s status as a stockholder under the Cooperation Agreement and the operations of or services provided by RSL or its affiliates or their respective officers, employees or directors to the Company or any of its subsidiaries, subject to certain limitations set forth in the Cooperation Agreement. No amounts have been paid or received under this agreement; however, the Company believes this agreement is material to its business and operations. Subject to specified exceptions, the Cooperation Agreement will terminate upon the earlier of (1) the mutual written consent of the parties or (2) the later of when RSL no longer (a) is required by U.S. GAAP to consolidate the Company’s results of operations and financial position, account for its investment in the Company under the equity method of accounting or, by any rule of the SEC, include the Company’s separate financial statements in any filings it may make with the SEC and (b) has the right to elect directors constituting a majority of the Company’s board of directors. RSI Subleases See Note 11 - Leases for a discussion of the subleases the Company has entered into with RSI.

Income Taxes

Income Taxes	12 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The loss before income taxes and the related tax (benefit) provision are as follows (in thousands): Years Ended March 31, 2021 2020 (Loss) income before income taxes United States $ (24,589) $ (9,245) Switzerland (82,739) (53,413) Bermuda (98) (3,661) United Kingdom 1 10 Other (364) 18 Total loss before income taxes $ (107,789) $ (66,291) Current taxes United States – Federal $ (346) $ 61 United States – State (12) 34 Other — 2 Total current tax (benefit) expense (358) 97 Deferred tax expense — — Total (benefit) provision for income taxes $ (358) $ 97 A reconciliation of the (benefit) provision for income taxes computed at the U.S. statutory rate of 21% for the years ended March 31, 2021 and 2020 to the (benefit) provision for income taxes reflected in the consolidated statements of operations is as follows (in thousands): Years Ended March 31, 2021 2020 Income tax benefit at statutory rate $ (22,636) $ (13,921) Foreign rate differential 6,662 4,255 Net operating loss carryback (363) — Research and development credits (1,303) (1,093) Valuation allowance 15,427 9,988 Non-deductible expense 1,581 951 Excess tax benefits from stock-based compensation (439) — Other 713 (83) Total (benefit) provision for income taxes $ (358) $ 97 The Company’s effective tax rate was 0.33% and (0.15)% for the years ended March 31, 2021 and March 31, 2020, respectively, primarily driven by the Company’s jurisdictional earnings by location, certain non-deductible expenditures, research and development credits, and a valuation allowance that eliminates the Company’s global net deferred tax assets. For the year ended March 31, 2021, the effective tax rate was also impacted by a tax benefit of approximately $0.4 million related to net operating loss carrybacks. Deferred taxes reflect the tax effects of the differences between the amounts recorded as assets and liabilities for financial reporting purposes and the comparable amounts recorded for income tax purposes. Significant components of the deferred tax assets (liabilities) at March 31, 2021 and 2020 are as follows (in thousands): March 31, 2021 2020 Deferred tax assets Intangible assets $ 6,597 $ 6,445 Net operating losses 21,865 9,443 Stock-based compensation 3,623 1,610 Research and development credits 2,790 1,487 Lease liability 698 — Accrued bonuses — 187 Others 214 — Total deferred tax assets 35,787 19,172 Valuation allowance (34,953) (19,129) Deferred tax assets, net of valuation allowance $ 834 $ 43 Deferred tax liabilities Depreciation $ (42) $ (13) Right-of-use assets (691) — Others (101) (30) Total deferred tax liabilities (834) (43) Total net deferred taxes $ — $ — As of March 31, 2021, the Company has net operating loss carryforwards in the following jurisdictions: Switzerland of approximately $150.6 million, which will begin to expire as of March 31, 2027, the United Kingdom of approximately $0.6 million, which can be carried forward indefinitely with an annual usage limitation, and the United States of approximately $10.0 million, which can be carried forward indefinitely with utilization limited to 80% of future taxable income for tax years beginning on or after January 1, 2021. The Company has research and development credit carryforwards in the United States of approximately $2.8 million which will begin to expire in the fiscal year ending March 31, 2039, and approximately $2.2 million is subject to an annual usage limitation. The Company assesses the realizability of the net deferred tax assets at each balance sheet date based on available positive and negative evidence in order to determine the amount which is more likely than not to be realized and record a valuation allowance as necessary. Due to the Company’s cumulative loss position which provides significant negative evidence difficult to overcome, the Company has recorded a valuation allowance of $35.0 million and $19.1 million for the years ended March 31, 2021 and 2020, respectively, representing the portion of the net deferred tax assets that is not expected to be realized. The amount of the net deferred tax assets considered realizable could be adjusted for future factors that would impact the assessment of the objective and subjective evidence of the Company. The Company will continue to assess the realizability of net deferred tax assets at each balance sheet date in order to determine the proper amount, if any, required for a valuation allowance. As of March 31, 2021, the Company does not have undistributed earnings from foreign subsidiaries. The Company regularly evaluates whether foreign earnings are expected to be indefinitely reinvested. This evaluation requires judgment about the future operating and liquidity needs of the Company. Changes in economic and business conditions, foreign or U.S. tax laws, or the Company’s financial situation could result in a change to the Company’s position. The Company is subject to tax and files income tax returns in the United Kingdom, Switzerland, and United States federal, state, and local jurisdictions. The Company’s March 31, 2021, 2020 and 2019 tax returns remain open for tax examinations in all applicable income tax jurisdictions. Tax audits and examinations can involve complex issues, interpretations and judgments. The resolution of matters may span multiple years particularly if subject to litigation or negotiation. The Company believes it has appropriately recorded its tax position using reasonable estimates and assumptions, however the potential tax benefits may impact the consolidated results of operations or cash flows in the period of resolution, settlement or when the statutes of limitations expire. There are no unrecognized tax benefits recorded as of March 31, 2021 and 2020.

Convertible Notes Payable

Convertible Notes Payable	12 Months Ended
	Mar. 31, 2021
Convertible Promissory Note [Abstract]
Convertible Notes Payable	Convertible Notes Payable On August 1, 2019, the Company issued two convertible promissory notes for an aggregate principal amount of $25.0 million (the “RTW Convertible Promissory Notes”) payable to the RTW Entities, investors of the Company. The RTW Convertible Promissory Notes accrued interest at 5% per annum and had a maturity date of March 31, 2020, the date upon which all unpaid interest and principal would have been due and payable. Prepayment of the RTW Convertible Promissory Notes prior to the maturity date was not permitted without the consent of the note holders of at least a majority of the outstanding principal amount of the convertible promissory notes issued by the Company. On September 26, 2019, such consent was obtained and $2.5 million aggregate principal amount of the RTW Convertible Promissory Notes was prepaid and the accrued interest on such principal amount was forgiven, bringing the aggregate principal balance of the RTW Convertible Promissory Notes to $22.5 million. On September 26, 2019, the Company issued four convertible promissory notes for an aggregate principal amount of $10.0 million (the “BVF Convertible Promissory Notes”) payable to entities affiliated with Biotechnology Value Fund, L.P. (“BVF”) under the same terms as the RTW Convertible Promissory Notes. The RSL Convertible Promissory Note (see Note 6), RTW Convertible Promissory Notes and BVF Convertible Promissory Notes (together, the “Convertible Promissory Notes”) included various conversion and redemption rights upon merger, certain financing events, change in control or maturity. Immediately prior to the closing of the Business Combination, the $35.0 million of Convertible Promissory Notes were automatically converted into an aggregate of 7,156,495 ISL Shares, which were then exchanged for an aggregate of 3,499,995 shares of the Company’s common stock upon the closing of the Business Combination. Accrued interest of $0.6 million on the Convertible Promissory Notes was waived and cancelled immediately prior to the closing of the Business Combination in accordance with the terms of the Convertible Promissory Notes and was recorded within additional paid-in capital on the accompanying consolidated statement of stockholders’ equity upon conversion of the underlying notes.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Series A Preferred Stock In connection with the closing of the Business Combination, the Company designated and issued 10,000 shares of Series A preferred stock, par value $0.0001 per share, to RSL, all of which shares are outstanding as of March 31, 2021. The holder(s) of the Series A preferred stock are entitled to cast the number of votes equal to the number of whole shares of common stock into which the shares of Series A preferred stock held by such holder are convertible as of the record date for determining stockholders entitled to vote on such matter, and do not have cumulative voting rights. The holder(s) of a majority of outstanding shares of Series A preferred stock, exclusively and as a separate class, are entitled to elect: (i) four Series A preferred directors, as long as the holder(s) of Series A preferred stock hold 50% or more of the voting power of all then-outstanding shares of capital stock entitled to vote generally at an election of directors, (ii) three Series A preferred directors, as long as the holder(s) of Series A preferred stock hold 40% or more but less than 50% of the voting power of all then-outstanding shares of capital stock entitled to vote generally at an election of directors, and (iii) two Series A preferred directors, as long as the holder(s) of Series A preferred stock hold 25% or more but less than 40% of the voting power of all then-outstanding shares of capital stock entitled to vote generally at an election of directors. Any Series A preferred director so elected may be removed without cause by, and only by, the affirmative vote of the holder(s) of Series A preferred stock given either at a special meeting of the holder(s) of Series A preferred stock duly called for that purpose or pursuant to a written consent of the holder(s) of Series A preferred stock. Each share of Series A preferred stock is convertible at any time at the option of the holder into one share of common stock. On any transfer of shares of Series A preferred stock, whether or not for value, each such transferred share will automatically convert into one share of common stock, except for certain transfers described in the amended and restated certificate of incorporation. Each share of Series A preferred stock will automatically convert into one share of common stock at such time as the holder(s) of Series A preferred stock hold less than 25% of the total voting power of the Company’s outstanding shares. The Company shall not, without the consent of the holder(s) of at least a majority of Series A preferred stock, alter or repeal any provisions of the Company’s amended and restated certificate of incorporation or bylaws that adversely affect the powers, preferences or rights of the Series A preferred stock. In the event of the Company’s liquidation, dissolution, or winding up, the holder(s) of the Series A preferred stock will receive first an amount per share equal to $0.01 and then will be entitled to share ratably in the assets legally available for distribution to all stockholders. Preferred Stock In connection with the closing of the Business Combination, the Company authorized 10,010,000 shares of preferred stock par value $0.0001 per share. The board of directors has the authority, without further action by the stockholders to issue such shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, and to fix the dividend, voting, and other rights, preferences and privileges of the shares. Other than the 10,000 shares of preferred stock designated as Series A preferred stock, there were no issued and outstanding shares of preferred stock as of March 31, 2021. Common Stock In connection with the closing of the Business Combination, the Company authorized 500,000,000 shares of common stock, par value $0.0001 per share. Each share of common stock has the right to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding having priority rights as to dividends. No dividends have been declared by the board of directors since the Company’s inception. Immediately after giving effect to the Business Combination, there were 56,455,376 shares of common stock issued and 54,655,376 shares of common stock outstanding. In April 2020, the Company completed an underwritten public offering of 9,613,365 shares of its common stock (including 1,034,483 shares of common stock purchased by RSL and the full exercise of the underwriters’ option to purchase 1,253,917 additional shares of common stock) at a price to the public of $14.50 per share, for net proceeds to the Company of approximately $131.0 million, after deducting underwriting discounts and commissions and offering expenses. On May 12 and September 17, 2020, the Company achieved the First Earnout Milestone and the Second Earnout Milestone, respectively, under the Share Exchange Agreement (See Note 3). As a result, the Company issued all of the 20,000,000 Earnout Shares to the Sellers, (including 17,547,938 Earnout Shares issued to RSL) in the six months ended September 30, 2020. In addition, upon the achievement of the First Earnout Milestone and the Second Earnout Milestone and pursuant to the Sponsor Restricted Stock Agreement, all of the 1,800,000 Sponsor Restricted Shares vested and are no longer subject to forfeiture. In September 2020, the Company completed an underwritten public offering of 6,060,606 shares of its common stock (including 380,000 shares of common stock purchased by RSL and the full exercise of the underwriters’ option to purchase 790,513 additional shares of common stock) at a price to the public of $33.00 per share, for net proceeds to the Company of approximately $188.1 million after deducting underwriting discounts and commissions and offering expenses. In January 2021, the Company filed a shelf registration statement on Form S-3 with the SEC which permits the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $900 million of its common stock, of which $150 million may be issued and sold pursuant to an at-the-market (ATM) offering program for sales of the Company's common stock under a sales agreement with SVB Leerink LLC, subject to certain conditions as specified in the sales agreement. The Company agreed to pay SVB Leerink up to 3% of the gross proceeds sold through the sale agreement. The Company's common stock would be sold at prevailing market prices at the time of the sale and, as a result, prices may vary. The Company has not issued or sold any securities pursuant to the shelf registration statement or ATM offering program. As of March 31, 2021, the Company had 97,971,243 shares of common stock outstanding, which include the above share issuances during the year, the issuance of shares of common stock against the redemption of warrants as described below and the issuance of shares of common stock from the exercise of stock options and vesting of restricted stock units. See Note 10 — Stock-Based Compensation for additional details about stock options and restricted stock units. The Company has reserved the following shares of common stock for issuance: March 31, 2021 2020 Conversion of Series A preferred stock 10,000 10,000 Stock options outstanding 7,988,999 3,873,888 Restricted stock units outstanding 1,095,676 — Equity awards available for future grants 1,781,043 5,283,520 Common stock warrants — 5,750,000 Earnout shares — 20,000,000 Total 10,875,718 34,917,408 Common Stock Warrants In connection with HSAC’s initial public offering in May 2019, HSAC issued 11,500,000 warrants for the purchase of one-half of one share of common stock (an aggregate of 5,750,000 shares) at a price of $11.50 per whole share, subject to adjustment. The warrants were classified as equity. All of the warrants remained outstanding as of and were exercisable commencing on May 14, 2020. The warrants were set to expire in December 2024 or earlier upon redemption or liquidation. The warrants were redeemable, at the Company’s option, in whole and not in part, at a price of $0.01 per warrant, upon a minimum of 30 days’ prior written notice of redemption, and if, and only if, the last sale price of the Company’s common stock equaled or exceeded $16.50 per share for any 20 trading days within a 30-trading day period ending on the third trading day prior to the date on which the Company sends a notice of redemption to the warrant holders. In May 2020, the Company delivered a notice of the redemption to the warrant holders, and an aggregate of 11,438,290 outstanding warrants were subsequently exercised for an aggregate of 5,719,145 shares of the Company’s common stock at a price of $11.50 per share, for net proceeds of approximately $65.8 million. The remaining 61,710 warrants were cancelled, and the holders thereof paid $0.01 per cancelled warrant. No warrants remain outstanding as of March 31, 2021. In May 2019, the Sponsor purchased from HSAC an aggregate of 10,000,000 warrants (the “private warrants”) at $0.50 per private warrant (for a total purchase price of $5.0 million), with each warrant exercisable for one-half share of common stock at an exercise price of $11.50 per share simultaneously with the closing of HSAC’s IPO in May 2019. Pursuant to the Share Exchange Agreement, all of the private warrants were cancelled upon the closing of the Business Combination. The Company did not recognize any expense on the cancellation of the private warrants.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation 2019 Equity Incentive Plan In December 2019, in connection with the Business Combination, the Company’s stockholders approved the 2019 Equity Incentive Plan (the “2019 Plan”) and reserved 5,500,000 shares of common stock for issuance thereunder. The 2019 Plan became effective immediately upon the closing of the Business Combination. The number of shares of common stock reserved for issuance under the 2019 Plan will automatically increase on April 1 of each year, beginning on April 1, 2020 and continuing through April 1, 2029, by 4.0% of the total number of shares of common stock outstanding on the last day of the preceding month, or a lesser number of shares as may be determined by the board of directors. The maximum number of shares of common stock that may be issued pursuant to the exercise of incentive options under the 2019 Plan is 16,500,000. The Company’s employees, directors and consultants are eligible to receive non-qualified and incentive stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, other stock awards, and performance awards under the plan. Generally, each option will have an exercise price equal to the fair market value of the Company’s common stock on the date of grant and a ten five 2018 Equity Incentive Plan In September 2018, ISL adopted its 2018 Equity Incentive Plan (the “2018 Plan”), under which 3,667,997 shares of common stock were reserved for grant. In July 2019, the 2018 Plan was amended and restated to increase the number of shares of common stock reserved for grant to 4,768,396. As discussed in Note 3, upon the closing of the Business Combination, the Company assumed all outstanding options, whether or not vested, under the 2018 Plan, with such options henceforth representing the right to purchase a number of shares of the Company’s common stock equal to approximately 0.48906624 multiplied by the number of shares of ISL common stock previously represented by such options. For accounting purposes, however, the Company is deemed to have assumed the 2018 Plan. The exchange of the stock options did not result in any incremental compensation expense, since there were no changes to the vesting terms of the awards. As of the effective date of the 2019 Plan, no further stock awards have been or will be made under 2018 Plan. As of March 31, 2021, 3,211,152 stock options were outstanding under the 2018 Plan. Stock Option Activity A summary of the stock option activity under the Company’s equity incentive plans is as follows: Number of Weighted- Weighted average Aggregate Balance – March 31, 2020 3,873,888 $ 8.33 9.37 $ 28,029 Granted 4,840,668 23.28 Exercised (114,084) 8.57 Forfeited (384,407) 17.14 Cancelled (226,233) 7.86 Expired (833) 24.41 Balance – March 31, 2021 7,988,999 $ 16.97 9.04 $ 25,958 Exercisable – March 31, 2021 1,626,473 $ 8.86 8.33 $ 11,977 The aggregate intrinsic value is calculated as the difference between the exercise price of all outstanding and exercisable stock options and the fair value of the Company’s common stock at March 31, 2021. The intrinsic value of stock options exercised for the year ended March 31, 2021 was $3.7 million. There were no stock options exercised during the year ended March 31, 2020. The stock options granted during the years ended March 31, 2021 and March 31, 2020 had a weighted-average fair value of $16.17 and $5.54 per share, respectively at the grant date. The Company estimated the fair value of each stock option on the date of grant using the Black-Scholes option pricing model applying the weighted-average assumptions in the following table: Years Ended March 31, 2021 2020 Risk-free interest rate 0.30% – 1.14% 0.51% – 2.25% Expected term, in years 5.50 – 6.11 5.75 – 6.11 Expected volatility 78.16% – 84.12% 74.69% – 77.93% Expected dividend yield —% —% Restricted Stock Unit Awards A summary of RSUs activity under the Company’s equity incentive plans is as follows: Number of RSUs Weighted- Average Grant Date Fair Value Unvested as of March 31, 2020 — $ — Issued 1,106,626 20.67 Vested (10,000) 44.60 Forfeited (950) 48.85 Outstanding, non-vested as of March 31, 2021 1,095,676 $ 20.43 Stock-based Compensation Expense For the years ended March 31, 2021 and 2020, stock-based compensation expense under the Company’s equity incentive plans was as follows (in thousands): Years Ended March 31, 2021 2020 Research and development expenses $ 6,866 $ 3,125 General and administrative expenses 11,772 3,663 Total stock-based compensation $ 18,638 $ 6,788 As of March 31, 2021, total unrecognized compensation expense related to non-vested stock options and RSUs was $76.1 million and $20.9 million, respectively, which is expected to be recognized over the remaining weighted-average service period of 3.1 years and 2.9 years, respectively. Stock-based Compensation Allocated to the Company by RSL In relation to the RSL common share awards and options issued by RSL to employees of RSL, RSI, RSG and the Company, stock-based compensation expense of $0.2 million and $0.2 million was recorded for years ended March 31, 2021 and 2020, respectively, in the accompanying consolidated statements of operations. The RSL common share awards are valued at fair value on the date of grant and that fair value is recognized over the requisite service period. Significant judgment and estimates were used to estimate the fair value of these awards, as they are not publicly traded. RSL common share awards are subject to specified vesting schedules and requirements (a mix of time-based and performance-based events). The fair value of each RSL common share award is based on various corporate event-based considerations, including targets for RSL’s post-IPO market capitalization and future financing events. The fair value of each RSL option on the date of grant is estimated using the Black-Scholes option-pricing model. Stock-based compensation expense is allocated to the Company over the required service period over which these RSL common share awards and RSL options would vest and is based upon the relative percentage of time utilized by RSL, RSI, and RSG employees on Company matters. RSL RSUs The Company’s Principal Executive Officer was granted 25,000 RSUs of RSL during the year ended March 31, 2021. These RSUs have a requisite service period of eight As of March 31, 2021, the liquidity event condition had not been met and was deemed not probable of being met. For the year ended March 31, 2021, the Company recorded no stock-based compensation expense related to these RSUs. At March 31, 2021, there was $1.0 million of unrecognized compensation expense related to unvested RSL RSUs. The Company will recognize this stock-based compensation expense upon achievement of the service requirement and liquidity event requirement through the requisite service period.

Leases

Leases	12 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases	LeasesIn June 2020, the Company entered into two sublease agreements with RSI, for two floors of the building the Company currently occupies as its headquarters in New York. The subleases will expire on February 27, 2024 and April 29, 2024, respectively, and have scheduled rent increases each year. In April 2020, the Company entered into a sublease agreement with an unrelated party for one floor of a building in North Carolina. The sublease will expire on February 28, 2022 and has no scheduled rent increases. These leases are classified as operating leases. Operating lease ROU assets of $4.2 million and lease liabilities of $4.2 million, were recognized based on the present value of remaining fixed lease payments over the expected lease term using an incremental borrowing rate of 3.9%. As the Company’s operating leases do not provide an implicit rate, estimated incremental borrowing rates based on the information available at the time of execution of sublease agreement were used in determining the present value of lease payments. The aggregate weighted-average remaining lease term was 3.0 years as of March 31, 2021. Variable lease costs such as common area costs and other operating costs are expensed as incurred and were minimal for the year ended March 31, 2021. During the year ended March 31, 2021, the Company incurred $1.1 million in rent expense and paid $0.9 million in cash related to contractual rent obligations under the operating leases. The following table provides a reconciliation of the Company’s remaining undiscounted contractual rent obligations due within each respective fiscal year ending March 31 to the operating lease liabilities recognized as of March 31, 2021 (in thousands): Years Ending March 31, Operating Leases 2022 $ 1,290 2023 1,152 2024 1,130 2025 47 Total undiscounted payments 3,619 Less: present value adjustment (202) Present value of future payments 3,417 Less: current portion of operating lease liabilities (1,179) Operating lease liabilities, net of current portion $ 2,238

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Indemnification Agreements The Company is a party to a number of agreements entered into in the ordinary course of business that contain typical provisions that obligate the Company to indemnify the other parties to such agreements upon the occurrence of certain events. The aggregate maximum potential future liability of the Company under such indemnification provisions is uncertain. The Company also indemnifies each of its directors and officers for certain events or occurrences, subject to certain limits. The maximum amount of potential future indemnification is unlimited; however, the Company currently holds director and officer liability insurance. Litigation The Company is involved in various lawsuits, claims and other legal matters from time to time that arise in the ordinary course of conducting business. The Company records a liability when a particular contingency is probable and estimable. In February 2021, a putative securities class action complaint was filed against the Company and certain of its current and former officers in the United States District Court for the Eastern District of New York on behalf of a class consisting of those who acquired the Company’s securities from October 2, 2019 and February 1, 2021. The complaint alleges that the Company and certain of its officers violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, by making false and misleading statements regarding the safety of IMVT-1401 and seeks unspecified monetary damages on behalf of the putative class and an award of costs and expenses, including reasonable attorneys’ fees. On April 20, 2021, three movants filed motions for appointment as lead plaintiff, one of which was subsequently withdrawn on April 23, 2021. No hearing date has been set for the lead plaintiff motions. Following appointment of lead plaintiff, defendants, including the Company, expect the lead plaintiff to file an amended complaint and defendants, including the Company, to file a motion to dismiss the amended complaint. The Company intends to defend the case vigorously and has not recorded a liability related to this lawsuit because, at this time, the Company is unable to reasonably estimate possible losses or determine whether an unfavorable outcome is either probable or remote. Commitments As of March 31, 2021, the Company did not have any ongoing material contractual obligations for which cash flows are fixed and determinable. The Company expects to enter into other commitments as the business further develops. In the normal course of business, the Company enters into agreements with contract service providers to assist in the performance of its research and development activities. Subject to required notice periods and the Company’s obligations under binding purchase orders, the Company can elect to discontinue the work under these agreements at any time. The Company expects to enter into additional collaborative research, contract research, manufacturing, and supplier agreements in the future, which may require upfront payments and long-term commitments of capital resources. Contingencies In March 2020, COVID-19 disease was declared a pandemic by the World Health Organization. The COVID-19 pandemic is disrupting supply chains and affecting production and sales across a range of industries. Currently, the Company has not suffered significant adverse consequences as a result of the COVID-19 pandemic, but the extent of the impact of COVID-19 on the Company’s future operational and financial performance will depend on certain developments, including the duration and spread of the outbreak, impact on employees and vendors all of which are uncertain and cannot be predicted. At this point, the extent to which COVID-19 may impact the Company’s future financial condition or results of operations is uncertain.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	[A] Basis of Presentation The Company’s fiscal year ends on March 31, and its first three fiscal quarters end on June 30, September 30, and December 31. The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. The Company has no unconsolidated subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	[B] Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company regularly evaluates estimates and assumptions related to assets, liabilities, stock-based compensation, litigation accruals, clinical trial accruals, operating leases, research and development costs and income taxes. The Company bases its estimates and assumptions on historical experience and on various other factors that it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates. Additionally, the Company assessed the impact that the COVID-19 pandemic has had on its operations and financial results as of March 31, 2021 and through the issuance of this report. The Company’s analysis was informed by the facts and circumstances as they were known to the Company. This assessment considered the impact COVID-19 may have on financial estimates and assumptions that affect the reported amounts of assets and liabilities and expenses.
Risks and Uncertainties	[C] Risks and Uncertainties The Company is subject to risks common to early-stage companies in the biopharmaceutical industry including, but not limited to, uncertainties related to commercialization of products, regulatory approvals, dependence on key products, key personnel and third-party service providers such as contract research organizations, protection of intellectual property rights and the ability to make milestone, royalty or other payments due under any license, collaboration or supply agreements.
Concentrations of Credit Risk	[D] Concentration of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk include cash. At March 31, 2021, the cash balance is kept in one banking institution that the Company believes is of high credit quality and is in excess of federally insured levels. The Company maintains its cash with an accredited financial institution and accordingly, such funds are subject to minimal credit risk. The Company has not experienced any losses on its cash.
Cash and Cash Equivalents	[E] Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents. At March 31, 2021, cash consisted of cash held at a financial institution. There were no cash equivalents as of March 31, 2021 and 2020.
Property and Equipment	[F] Property and Equipment Property and equipment, consisting of computers, is recorded at cost. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred. Depreciation is recorded using the straight-line method over the estimated useful life of three years. Upon disposal, retirement or sale, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the consolidated statements of operations.
Impairment of Long-lived Assets	[G] Impairment of Long-lived Assets Long-lived assets, such as right-of-use assets due to operating leases, property and equipment, are evaluated for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset to be tested for possible impairment, the Company first compares undiscounted cash flows expected to be generated by an asset to the carrying value of the asset. If the carrying value of the long-lived asset is not recoverable on an undiscounted cash flow basis, impairment is recognized to the extent that the carrying value exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary.
Contingencies	[H] ContingenciesThe Company, from time to time, may be a party to various disputes and claims arising from normal business activities. The Company continually assesses litigation to determine if an unfavorable outcome would lead to a probable loss or reasonably possible loss which could be estimated. The Company accrues for all contingencies at the earliest date at which the Company deems it probable that a liability has been incurred and the amount of such liability can be reasonably estimated. If the estimate of a probable loss is a range and no amount within the range is more likely than another, the Company accrues the minimum of the range. In the cases where the Company believes that a reasonably possible loss exists, the Company discloses the facts and circumstances of the litigation, including an estimable range, if possible. Legal defense costs associated with loss contingencies are expensed in the period incurred. Additionally, the Company records a receivable for rights to insurance recoveries, limited to the extent of incurred or probable losses, when such recoveries have been agreed to with third-party insurers and when receipt is deemed probable. This includes instances when the third-party insurers have agreed to pay, on the Company's behalf, certain legal defense costs and settlement amounts directly to applicable law firms and settlement funds.
Research and Development Expenses	[I] Research and Development Expenses Research and development costs with no alternative future use are expensed as incurred. Payments for a product license prior to regulatory approval of the product and payments for milestones achieved prior to regulatory approval of the product are expensed in the period incurred as research and development. Milestone payments made in connection with regulatory approvals are capitalized and amortized to cost of product sales over the remaining useful life of the asset. Research and development expenses primarily consist of employee-related costs, milestone payments under the HanAll Agreement and expenses from third parties who conduct research and development activities (including manufacturing) on behalf of the Company. The Company accrues costs for clinical trial activities based upon estimates of the services received and related expenses incurred that have yet to be invoiced by contract research organizations. In making these estimates, the Company considers various factors, including status and timing of services performed, the number of patients enrolled and the rate of patient enrollment. The Company accrues costs for non-clinical studies and contract manufacturing activities over the service periods specified in the contracts and are adjusted as necessary based upon an ongoing review of the level of effort and costs actually incurred. The estimate of the work completed is developed through discussions with internal personnel and external services providers as to the progress toward completion of the services and the agreed-upon fee to be paid for such services. As actual costs become known, the accrued estimates are adjusted. Such estimates are not expected to be materially different from amounts actually incurred.
Leases	[J] Leases The Company's operating leases primarily relate to its three subleased premises, two in New York and one in North Carolina. Operating lease right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset during the lease term, and operating lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and lease liabilities are initially recognized based on the present value of the future fixed lease payments over the expected lease term at commencement date calculated using the Company’s incremental borrowing rate applicable to the lease asset, unless the implicit rate is readily determinable. Operating lease ROU assets also include any lease payments made at or before lease commencement, adjusted by any initial direct costs and exclude any lease incentives received. The Company determines the lease term as the non-cancelable period of the lease and may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Leases with a term of 12 months or less are not recognized on the consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Variable lease costs such as common area costs and other operating costs are expensed as incurred. The Company accounts for lease and non-lease components as a single lease component for all its facilities leases.
Income Taxes	[K] Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between amounts in the consolidated financial statements and the tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income tax (benefit) expense in the accompanying consolidated statements of operations in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that it believes these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of its net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company has not recognized U.S. income taxes and foreign withholding taxes on undistributed earnings of foreign subsidiaries which the Company has determined to be indefinitely reinvested. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company’s policy is to recognize interest and/or penalties related to income tax matters in provision for income taxes.
Share-based Compensation	[L] Stock-based Compensation Stock-based awards to employees and directors are valued at fair value on the date of the grant and that fair value is recognized as stock-based compensation expense over the requisite service period. The grant date fair value of the stock-based awards with graded vesting is recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the respective awards. The Company values its stock options that only have service vesting requirements or performance-based awards without market conditions using the Black-Scholes option pricing model. For performance-based awards with market conditions, the Company determines the fair value of awards as of the grant date using a Monte Carlo simulation model. Stock-based compensation related to restricted stock awards is based on the fair value of the Company's common stock on the grant date. Certain assumptions need to be made with respect to utilizing the Black-Scholes option pricing model, including the expected life of the award, volatility of the underlying shares, the risk-free interest rate, expected dividend yield and the fair value of the Company’s common stock. Since the Company has limited option exercise history, it has generally elected to estimate the expected life of an award based upon the “simplified method” with the continued use of this method extended until such time the Company has sufficient exercise history. The expected share price volatility for the Company’s common stock is estimated by taking the average historical price volatility for the Company's peers. The risk-free interest rate is based on the rates paid on securities issued by the U.S. Treasury with a term approximating the expected life of the equity award. As the Company has never paid and does not anticipate paying cash dividends on its common stock, the expected dividend yield is assumed to be zero. The Company accounts for pre-vesting award forfeitures when they occur. As part of the valuation of stock-based compensation under the Black-Scholes option pricing model, it is necessary for the Company to estimate the fair value of its common stock. Prior to the closing of the Business Combination, the fair value of the Company’s common stock was estimated on each grant date by the Company’s board of directors. Given the absence of a public trading market, and in accordance with the American Institute of Certified Public Accountants’ Practice Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation , the Company exercised reasonable judgment and considered numerous objective and subjective factors to determine its best estimate of the fair value of its common stock. The estimation of the fair value of the common stock considered factors including the following: the estimated present value of the Company’s future cash flows; the Company’s business, financial condition and results of operations; the Company’s forecasted operating performance; the illiquid nature of the Company’s common stock; industry information such as market size and growth; market capitalization of comparable companies and the estimated value of transactions such companies have engaged in; and macroeconomic conditions. After the closing of the Business Combination, the Company’s board of directors determined the fair value of each share of common stock underlying stock-based awards based on the closing price of the Company’s common stock as reported by Nasdaq on the date of grant. Determining the appropriate amount to expense for performance-based awards based on the achievement of stated goals requires judgment. The estimate of expense is revised periodically based on the probability of achieving the required performance targets and adjustments are made as appropriate. The cumulative impact of any revisions is reflected in the period of change. If any applicable financial performance goals are not met, no compensation expense is recognized, and any previously recognized compensation cost is reversed.
Fair Value of Financial Instruments	[M] Fair Value of Financial Instruments The Company applies a fair value framework in order to measure and disclose its financial assets and liabilities. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires an entity to maximize the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value: • Level 1 — Quoted prices in active markets for identical assets or liabilities. • Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Fair values are determined by utilizing quoted prices for similar assets and liabilities in active markets or other market observable inputs such as interest rates and yield curves. • Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is gr eatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company’s financial instruments consist of cash, accounts payable, accrued expenses and amounts due to RSL. These financial instruments are stated at their respective historical carrying amounts, which approximate fair value due to their short-term nature. There were no Level 2 or Level 3 financial instruments as of March 31, 2021 or 2020.
Foreign Currency	[N] Foreign Currency The Company has operations in the United States, the United Kingdom, Bermuda, and Switzerland. The results of its non-U.S. dollar based functional currency operations are translated to U.S. dollars at the average exchange rates during the period. The Company’s assets and liabilities are translated using the current exchange rate as of the consolidated balance sheet date and equity is translated using historical rates. Adjustments resulting from the translation of the consolidated financial statements of the Company’s foreign functional currency subsidiaries into U.S. dollars are excluded from the determination of net loss and are recognized in accumulated other comprehensive loss. Foreign exchange transaction gains and losses are included in other income, net in the consolidated statements of operations.
Net Loss per Common Share	[O] Net Loss per Common Share Basic net loss per common share is computed by dividing net loss applicable to common stockholders by the weighted-average number of common stock outstanding during the period. Diluted net loss per common share is computed by dividing the net loss applicable to common stockholders by the diluted weighted-average number of common stock outstanding during the period. In periods in which the Company reports a net loss, all common stock equivalents are deemed anti-dilutive such that basic net loss per common share and diluted net loss per common share are equivalent. Potentially dilutive common stock has been excluded from the diluted net loss per common share computations in all periods presented because such securities have an anti-dilutive effect on net loss per common share due to the Company’s net loss. There are no reconciling items used to calculate the weighted-average number of total common stock outstanding for basic and diluted net loss per common share data. The following potentially dilutive securities have been excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect: Years Ended March 31, 2021 2020 Preferred stock as converted 10,000 10,000 Restricted stock (unvested) 1,095,676 1,800,000 Stock options 7,988,999 3,873,888 Warrants (See Note 9) — 5,750,000 Earnout shares (See Note 3) — 20,000,000 Total 9,094,675 31,433,888
Deferred Offering Costs	[P] Deferred Offering Costs Legal, accounting and other costs directly attributable to the issuance of the Company’s equity are capitalized within deferred offering costs on the consolidated balance sheets and reclassified to equity upon issuance of the shares. Offering costs comprised of legal and accounting fees and other costs incurred through June 30, 2019 were directly related to ISL’s proposed initial public offering (“IPO”). In August 2019, ISL’s board of directors determined to suspend ISL’s IPO registration process. Accordingly, the Company has written off deferred offering costs previously capitalized to general and administrative expenses within the accompanying consolidated statement of operations for the year ended March 31, 2020. Deferred offering costs as of March 31, 2020 represented financing costs deferred for the follow-on underwritten public offering in April 2020.
Common Stock Warrants	[Q] Common Stock Warrants The Company accounts for the issuance of common stock warrants based on the terms of the contract and whether there are any requirements for the Company to net cash settle the contract under any terms or conditions. Warrants for the purchase of 5,750,000 shares of common stock were issued by HSAC as part of the units sold in its IPO in May 2019. Each unit was comprised of one share of common stock and a warrant to purchase one half of one share of common stock upon the consummation of a business combination by HSAC. The warrants were classified as equity. None of the terms of the warrants were modified as a result of the Business Combination. During the year, the Company redeemed 11,438,290 warrants by issuing 5,719,145 shares of the Company’s common stock and the remaining 61,710 warrants were cancelled. No warrants remain outstanding as of March 31, 2021. See Note 9 – Stockholders’ Equity for additional details about common stock warrants.
Recently Adopted Accounting Pronouncements	[R] Recently Adopted Accounting Pronouncements In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). ASU 2018-13 removes, modifies, and adds certain recurring and nonrecurring fair value measurement disclosures, including removing disclosures around the amount(s) of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, the policy for timing of transfers between levels, and the valuation process for Level 3 fair value measurements, among other things. ASU 2018-13 adds disclosure requirements around changes in unrealized gains and losses included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and a narrative description of measurement uncertainty. The amendments in ASU 2018-13 are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The Company has adopted ASU 2018-13 as of April 1, 2020, with no impact to the Company’s consolidated financial statements from the adoption of this new standard. In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model that requires the use of forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses on available-for-sale debt securities to be recorded through an allowance for credit losses instead of as a reduction in the amortized cost basis of the securities. ASU 2016-13 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted, including adoption in any interim period. The Company has adopted ASU 2016-13 as of April 1, 2020, with no impact to the Company’s consolidated financial statements from the adoption of this new standard.
Recently Issued Accounting Pronouncements	Recent authoritative guidance issued by the FASB (including technical corrections to the Accounting Standards Codification), the American Institute of Certified Public Accountants, and the Securities and Exchange Commission (“SEC”) did not, or are not expected to, have a material impact on the Company’s consolidated financial statements and related disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of dilutive securities have been excluded from the calculation of diluted net loss per share due to their anti-dilutive effect	The following potentially dilutive securities have been excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect: Years Ended March 31, 2021 2020 Preferred stock as converted 10,000 10,000 Restricted stock (unvested) 1,095,676 1,800,000 Stock options 7,988,999 3,873,888 Warrants (See Note 9) — 5,750,000 Earnout shares (See Note 3) — 20,000,000 Total 9,094,675 31,433,888

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following (in thousands): March 31, 2021 2020 Research and development expenses $ 10,147 $ 8,332 Legal and professional fees 1,196 1,231 Accrued bonuses 3,138 859 Other expenses 679 516 Total accrued expenses $ 15,160 $ 10,938

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The loss before income taxes and the related tax (benefit) provision are as follows (in thousands): Years Ended March 31, 2021 2020 (Loss) income before income taxes United States $ (24,589) $ (9,245) Switzerland (82,739) (53,413) Bermuda (98) (3,661) United Kingdom 1 10 Other (364) 18 Total loss before income taxes $ (107,789) $ (66,291) Current taxes United States – Federal $ (346) $ 61 United States – State (12) 34 Other — 2 Total current tax (benefit) expense (358) 97 Deferred tax expense — — Total (benefit) provision for income taxes $ (358) $ 97
Schedule of Reconciliation of Income Tax Provision	A reconciliation of the (benefit) provision for income taxes computed at the U.S. statutory rate of 21% for the years ended March 31, 2021 and 2020 to the (benefit) provision for income taxes reflected in the consolidated statements of operations is as follows (in thousands): Years Ended March 31, 2021 2020 Income tax benefit at statutory rate $ (22,636) $ (13,921) Foreign rate differential 6,662 4,255 Net operating loss carryback (363) — Research and development credits (1,303) (1,093) Valuation allowance 15,427 9,988 Non-deductible expense 1,581 951 Excess tax benefits from stock-based compensation (439) — Other 713 (83) Total (benefit) provision for income taxes $ (358) $ 97
Components of Deferred Tax Assets and Liabilities	Significant components of the deferred tax assets (liabilities) at March 31, 2021 and 2020 are as follows (in thousands): March 31, 2021 2020 Deferred tax assets Intangible assets $ 6,597 $ 6,445 Net operating losses 21,865 9,443 Stock-based compensation 3,623 1,610 Research and development credits 2,790 1,487 Lease liability 698 — Accrued bonuses — 187 Others 214 — Total deferred tax assets 35,787 19,172 Valuation allowance (34,953) (19,129) Deferred tax assets, net of valuation allowance $ 834 $ 43 Deferred tax liabilities Depreciation $ (42) $ (13) Right-of-use assets (691) — Others (101) (30) Total deferred tax liabilities (834) (43) Total net deferred taxes $ — $ —

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Schedule of common stock reserved for future issuance	The Company has reserved the following shares of common stock for issuance: March 31, 2021 2020 Conversion of Series A preferred stock 10,000 10,000 Stock options outstanding 7,988,999 3,873,888 Restricted stock units outstanding 1,095,676 — Equity awards available for future grants 1,781,043 5,283,520 Common stock warrants — 5,750,000 Earnout shares — 20,000,000 Total 10,875,718 34,917,408

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Summary of stock option activity	A summary of the stock option activity under the Company’s equity incentive plans is as follows: Number of Weighted- Weighted average Aggregate Balance – March 31, 2020 3,873,888 $ 8.33 9.37 $ 28,029 Granted 4,840,668 23.28 Exercised (114,084) 8.57 Forfeited (384,407) 17.14 Cancelled (226,233) 7.86 Expired (833) 24.41 Balance – March 31, 2021 7,988,999 $ 16.97 9.04 $ 25,958 Exercisable – March 31, 2021 1,626,473 $ 8.86 8.33 $ 11,977
Schedule of fair value assumptions	The Company estimated the fair value of each stock option on the date of grant using the Black-Scholes option pricing model applying the weighted-average assumptions in the following table: Years Ended March 31, 2021 2020 Risk-free interest rate 0.30% – 1.14% 0.51% – 2.25% Expected term, in years 5.50 – 6.11 5.75 – 6.11 Expected volatility 78.16% – 84.12% 74.69% – 77.93% Expected dividend yield —% —%
Schedule of Restricted Stock Unit Awards Activity	A summary of RSUs activity under the Company’s equity incentive plans is as follows: Number of RSUs Weighted- Average Grant Date Fair Value Unvested as of March 31, 2020 — $ — Issued 1,106,626 20.67 Vested (10,000) 44.60 Forfeited (950) 48.85 Outstanding, non-vested as of March 31, 2021 1,095,676 $ 20.43
Summary of stock-based compensation expense	For the years ended March 31, 2021 and 2020, stock-based compensation expense under the Company’s equity incentive plans was as follows (in thousands): Years Ended March 31, 2021 2020 Research and development expenses $ 6,866 $ 3,125 General and administrative expenses 11,772 3,663 Total stock-based compensation $ 18,638 $ 6,788

Leases (Tables)

Leases (Tables)	12 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Schedule of Remaining Undiscounted Contractual Rent Obligations	The following table provides a reconciliation of the Company’s remaining undiscounted contractual rent obligations due within each respective fiscal year ending March 31 to the operating lease liabilities recognized as of March 31, 2021 (in thousands): Years Ending March 31, Operating Leases 2022 $ 1,290 2023 1,152 2024 1,130 2025 47 Total undiscounted payments 3,619 Less: present value adjustment (202) Present value of future payments 3,417 Less: current portion of operating lease liabilities (1,179) Operating lease liabilities, net of current portion $ 2,238

Organization and Nature of Bu_2

Organization and Nature of Business - Additional Information (Detail) $ in Thousands		Dec. 18, 2019shares	Mar. 31, 2021USD ($)segment	Mar. 31, 2020USD ($)	Dec. 17, 2019
Business Acquisition [Line Items]
Number of operating segments | segment			1
Number of reportable segments | segment			1
Cash | $			$ 400,146	$ 100,571
Accumulated deficit | $	[1]		$ (198,657)	$ (91,226)
Series A Preferred Stock
Business Acquisition [Line Items]
Number of shares issued in business combination		10,000
Roivant Sciences Ltd. (RSL) | Series A Preferred Stock
Business Acquisition [Line Items]
Number of shares issued in business combination		10,000
Immunovant Sciences Ltd
Business Acquisition [Line Items]
Percentage of business acquisition		100.00%
Number of shares issued in business combination		42,080,376
Immunovant Sciences Ltd | Revision of Prior Period, Adjustment
Business Acquisition [Line Items]
Shares exchange ratio		48.90662%
Immunovant Sciences Ltd | Sellers
Business Acquisition [Line Items]
Ownership percentage					100.00%
[1]	Retroactively restated for the reverse recapitalization as described in Note 1.

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - Additional information (Detail) - subleaseAgreement	12 Months Ended
	Mar. 31, 2021	Jun. 30, 2020
Accounting Policies [Abstract]
Property, plant and equipment, useful life	3 years
Number of sublease agreements	3	2

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Details) - Warrants (Detail) - shares	Mar. 31, 2021	May 31, 2020	Mar. 31, 2020	May 31, 2019
Subsidiary, Sale of Stock [Line Items]
Number of securities called by warrants or rights	0		5,750,000
Warrants redeemed (in shares)		11,438,290
Option exercise price range, shares exercisable (in shares)		5,719,145
Warrant, cancelled (in shares)		61,710
IPO
Subsidiary, Sale of Stock [Line Items]
Number of securities called by each warrant or right (in shares)				0.5
Option exercise price range, shares exercisable (in shares)				5,750,000
Warrant | IPO
Subsidiary, Sale of Stock [Line Items]
Number of securities called by warrants or rights				5,750,000
Number of securities called by each warrant or right (in shares)				0.5

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of dilutive securities have been excluded from the calculation of diluted net loss per share due to their anti-dilutive effect (Detail) - shares	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	9,094,675	31,433,888
Preferred stock as converted
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	10,000	10,000
Restricted stock (unvested)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,095,676	1,800,000
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	7,988,999	3,873,888
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0	5,750,000
Earnout shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0	20,000,000

Business Combination and Reca_2

Business Combination and Recapitalization - Additional Information (Detail) $ / shares in Units, $ in Millions		Sep. 17, 2020shares	Dec. 18, 2019USD ($)tradingDay$ / sharesshares	Dec. 17, 2019shares	Sep. 29, 2019shares	Mar. 31, 2021shares	Mar. 31, 2020USD ($)shares	Mar. 31, 2025$ / sharesshares	Mar. 31, 2023$ / sharesshares	Sep. 30, 2020shares
Business Acquisition [Line Items]
Business combination consideration | $			$ 420.9
Preferred stock, outstanding (in shares)						0	0
Business acquisition price per share | $ / shares			$ 10
Closing of share price | $ / shares			13.88
Business combination per share disclosed in fair value | $ / shares			$ 10
Business combination costs | $							$ 2.8
Earnout shares (in shares)						0	20,000,000
Business combination, share price, threshold trading days | tradingDay			20
Business combination, share price, trading period | tradingDay			30
Common stock to potential forfeiture in the event that the milestones are not achieved (in shares)					1,800,000
Vesting of sponsor restricted shares (in shares)		1,800,000
Sponsor
Business Acquisition [Line Items]
Vesting of sponsor restricted shares (in shares)					900,000
General and Administrative Expense
Business Acquisition [Line Items]
Additional financial advisory fees | $							$ 2.3
Forecast | Milestone Achievement One
Business Acquisition [Line Items]
Volume-weighted average price (in dollars per share) | $ / shares								$ 31.50	$ 17.50
2018 Equity Incentive Plan
Business Acquisition [Line Items]
Options outstanding number (in shares)			4,408,287
Common stock
Business Acquisition [Line Items]
Number of shares issued in business combination			42,080,376	3,499,995
Earnout shares (in shares)			20,000,000
Vesting of sponsor restricted shares (in shares)	[1]					1,800,000
Common stock | Forecast | Milestone Achievement One
Business Acquisition [Line Items]
Earnout shares (in shares)								10,000,000	10,000,000
Immunovant Sciences Ltd
Business Acquisition [Line Items]
Percentage of business acquisition			100.00%
Number of shares issued in business combination			42,080,376
Immunovant Sciences Ltd | Revision of Prior Period, Adjustment
Business Acquisition [Line Items]
Shares exchange ratio			48.90662%
Immunovant Sciences Ltd | Common stock
Business Acquisition [Line Items]
Earnout shares for issuance ( in shares)						20,000,000				20,000,000
Roivant Sciences Ltd. (RSL) | Common stock
Business Acquisition [Line Items]
Earnout shares for issuance ( in shares)						17,547,938				17,547,938
Series A Preferred Stock
Business Acquisition [Line Items]
Number of shares issued in business combination			10,000
Preferred stock, outstanding (in shares)			10,000			10,000	10,000
Series A Preferred Stock | Roivant Sciences Ltd. (RSL)
Business Acquisition [Line Items]
Number of shares issued in business combination			10,000
Series A Preferred Stock | Roivant Sciences Ltd. (RSL)
Business Acquisition [Line Items]
Preferred stock, outstanding (in shares)						10,000
[1]	Retroactively restated for the reverse recapitalization as described in Note 1.

Material Agreements - Additiona

Material Agreements - Additional Information (Detail) - USD ($) $ in Millions	May 31, 2019	Dec. 07, 2018	Dec. 19, 2017	Mar. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront, non-refundable payment			$ 30
Research and development and out-of-pocket			50.00%
Milestone payments			$ 10
Purchase price		$ 37.8
Swiss value-added tax receivable				$ 3
Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Consideration paid			20
Maximum | Upon Achievement Of Development Regulatory And Sales Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent milestone payments			$ 442.5
Achievement of Development and Regulatory Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments	$ 10

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Payables and Accruals [Abstract]
Research and development expenses	$ 10,147	$ 8,332
Legal and professional fees	1,196	1,231
Accrued bonuses	3,138	859
Other expenses	679	516
Total accrued expenses	$ 15,160	$ 10,938

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands		Dec. 17, 2019	Sep. 30, 2019	Jul. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Aug. 31, 2019	Jun. 30, 2019
Related Party Transaction [Line Items]
Due to related parties					$ 0	$ 3,190
Roivant Sciences Ltd. (RSL)
Related Party Transaction [Line Items]
Capital contribution – expenses allocated from Roivant Sciences Ltd.	[1]				1,096	1,157
Due to related parties				$ 2,900			$ 5,000	$ 5,000
Repayments of notes payable		$ 2,500	$ 2,500
Business combination number of shares exchanged		250,000
Promissory note term				180 days
Service Agreements
Related Party Transaction [Line Items]
Related party transaction, amounts					$ 1,300	1,400
Service Agreements | Capital Contributions
Related Party Transaction [Line Items]
Capital contribution – expenses allocated from Roivant Sciences Ltd.						1,200
Service Agreements | Roivant Sciences Ltd. (RSL)
Related Party Transaction [Line Items]
Capital contribution – expenses allocated from Roivant Sciences Ltd.						$ 200
[1]	Retroactively restated for the reverse recapitalization as described in Note 1.

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
(Loss) income before income taxes
Total (loss) income before income taxes	$ (107,789)	$ (66,291)
Current taxes
Total current tax (benefit) expense	(358)	97
Deferred taxes
Deferred tax expense	0	0
Total (benefit) provision for income taxes	(358)	97
United States
(Loss) income before income taxes
Total (loss) income before income taxes	(24,589)	(9,245)
Current taxes
United States – Federal	(346)	61
United States – State	(12)	34
Switzerland
(Loss) income before income taxes
Total (loss) income before income taxes	(82,739)	(53,413)
Bermuda
(Loss) income before income taxes
Total (loss) income before income taxes	(98)	(3,661)
United Kingdom
(Loss) income before income taxes
Total (loss) income before income taxes	1	10
Other
(Loss) income before income taxes
Total (loss) income before income taxes	(364)	18
Current taxes
Other	$ 0	$ 2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Taxes [Line Items]
Effective income tax rate	0.33%	(0.15%)
(Benefit) provision for income taxes	$ 358	$ (97)
Research and development tax credit carry forwards	2,790	1,487
Valuation allowance	34,953	$ 19,129
Switzerland
Income Taxes [Line Items]
Net operating loss carry forwards	150,600
United Kingdom
Income Taxes [Line Items]
Net operating loss carry forwards	$ 600
United States
Income Taxes [Line Items]
Effective income tax rate	21.00%	21.00%
Net operating loss carry forwards	$ 10,000
Research and development tax credit carry forwards	2,800
United States | Research Tax Credit Carryforward
Income Taxes [Line Items]
Research and development tax credit carry forwards	$ 2,200

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Income Tax Provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Effective Income tax rate reconciliation, amount
Income tax benefit at statutory rate	$ (22,636)	$ (13,921)
Foreign rate differential	6,662	4,255
Net operating loss carryback	(363)	0
Research and development credits	(1,303)	(1,093)
Valuation allowance	15,427	9,988
Non-deductible expense	1,581	951
Excess tax benefits from stock-based compensation	(439)	0
Other	713	(83)
Total (benefit) provision for income taxes	$ (358)	$ 97

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Deferred tax assets
Intangible assets	$ 6,597	$ 6,445
Net operating losses	21,865	9,443
Stock-based compensation	3,623	1,610
Research and development credits	2,790	1,487
Lease liability	698	0
Accrued bonuses	0	187
Others	214	0
Total deferred tax assets	35,787	19,172
Valuation allowance	(34,953)	(19,129)
Deferred tax assets, net of valuation allowance	834	43
Deferred tax liabilities
Depreciation	(42)	(13)
Right-of-use assets	(691)	0
Others	(101)	(30)
Total deferred tax liabilities	(834)	(43)
Total net deferred taxes	$ 0	$ 0

Convertible Notes Payable - Add

Convertible Notes Payable - Additional Information (Detail) $ in Millions	Dec. 18, 2019shares	Dec. 17, 2019USD ($)shares	Sep. 26, 2019USD ($)promissoryNote	Aug. 01, 2019USD ($)promissoryNote
Accrued Interest
Convertible Notes Payable [Line Items]
Accrued interest waived		$ 0.6
Common stock
Convertible Notes Payable [Line Items]
Number of shares issued in business combination | shares	42,080,376	3,499,995
RTW Convertible Promissory Notes
Convertible Notes Payable [Line Items]
Number of promissory notes issued | promissoryNote				2
Debt face amount			$ 22.5	$ 25
Debt instrument, interest rate				5.00%
Prepayment			$ 2.5
BVF Convertible Promissory Notes
Convertible Notes Payable [Line Items]
Number of promissory notes issued | promissoryNote			4
Debt face amount			$ 10
Convertible Promissory Notes
Convertible Notes Payable [Line Items]
Debt face amount		$ 35
Conversion of convertible notes into common stock (in shares) | shares		7,156,495

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands		Sep. 17, 2020shares	May 14, 2020tradingDay$ / shares	May 31, 2019USD ($)$ / sharesshares	Jan. 31, 2021USD ($)	Sep. 30, 2020USD ($)$ / sharesshares	May 31, 2020USD ($)$ / sharesshares	Apr. 30, 2020USD ($)$ / sharesshares	Mar. 31, 2021USD ($)$ / sharesshares	Mar. 31, 2020USD ($)$ / sharesshares	Dec. 18, 2019$ / sharesshares
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, shares issued									0	0
Preferred stock, outstanding (in shares)									0	0
Preferred stock, par value (in dollars per share) | $ / shares									$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)									10,000,000	10,000,000
Common stock, authorized (in shares)									500,000,000	500,000,000
Common stock, issued (in shares)									97,971,243	56,455,376
Common share, outstanding (in shares)									97,971,243	54,655,376
Vesting of sponsor restricted shares (in shares)		1,800,000
Maximum offering price | $					$ 900,000
Percentage of proceeds owed through sales agreement					3.00%
Warrants outstanding (in shares)							11,438,290
Exercise price of warrant (in dollars per share) | $ / shares							$ 11.50
Option exercise price range, shares exercisable (in shares)							5,719,145
Proceeds from warrant exercises | $							$ 65,800
Warrant, cancelled (in shares)							61,710
IPO
Subsidiary or Equity Method Investee [Line Items]
Common stock, sale price (in dollars per share) | $ / shares			$ 16.50
Warrants outstanding (in shares)				11,500,000
Exercise price of warrant (in dollars per share) | $ / shares				$ 11.50
Redemption price per warrant (in dollars per share) | $ / shares			$ 0.01
Option exercise price range, shares exercisable (in shares)				5,750,000
Written notice of redemption period minimum days | tradingDay			30
Threshold trading days | tradingDay			20
Threshold consecutive trading days | tradingDay			30
Number of securities called by each warrant or right (in shares)				0.5
Private Placement
Subsidiary or Equity Method Investee [Line Items]
Exercise price of warrant (in dollars per share) | $ / shares				$ 11.50
Issuance of common stock (in shares)				10,000,000
Generating gross proceeds of private placement warrants | $				$ 5,000
Number of securities called by each warrant or right (in shares)				0.5
Underwritten Public Offering
Subsidiary or Equity Method Investee [Line Items]
Sale of stock, number of shares						6,060,606		9,613,365
Common stock, sale price (in dollars per share) | $ / shares						$ 33		$ 14.50
Proceeds from issuance of common stock | $						$ 188,100		$ 131,000	$ 319,783	$ 0
Maximum offering price | $					$ 150,000
Underwritten Public Offering | Roivant Sciences Ltd. (RSL)
Subsidiary or Equity Method Investee [Line Items]
Sale of stock, number of shares						380,000		1,034,483
Over-Allotment Option
Subsidiary or Equity Method Investee [Line Items]
Sale of stock, number of shares						790,513		1,253,917
Series A preferred stock
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares									$ 0.0001
Preferred stock, authorized (in shares)									10,010,000
Common stock
Subsidiary or Equity Method Investee [Line Items]
Common stock, authorized (in shares)											500,000,000
Common stock par value (in dollars per share) | $ / shares											$ 0.0001
Common stock, issued (in shares)											56,455,376
Common share, outstanding (in shares)											54,655,376
Vesting of sponsor restricted shares (in shares)	[1]								1,800,000
Common stock | Roivant Sciences Ltd. (RSL)
Subsidiary or Equity Method Investee [Line Items]
Earnout shares for issuance ( in shares)						17,547,938			17,547,938
Common stock | Immunovant Sciences Ltd
Subsidiary or Equity Method Investee [Line Items]
Earnout shares for issuance ( in shares)						20,000,000			20,000,000
Common stock | Underwritten Public Offering
Subsidiary or Equity Method Investee [Line Items]
Issuance of common stock (in shares)	[1]								15,673,971
Minimum | Private Placement
Subsidiary or Equity Method Investee [Line Items]
Common stock, sale price (in dollars per share) | $ / shares				$ 0.50
Series A Preferred Stock
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, shares issued									10,000	10,000
Preferred stock, outstanding (in shares)									10,000	10,000	10,000
Preferred stock, par value (in dollars per share) | $ / shares									$ 0.0001	$ 0.0001
Percentage of voting power of outstanding shares									25.00%
Liquidation amount (in dollars per share) | $ / shares									$ 0.01
Preferred stock, authorized (in shares)									10,000	10,000
Series A Preferred Stock | Roivant Sciences Ltd. (RSL)
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, shares issued									10,000
Preferred stock, outstanding (in shares)									10,000
Preferred stock, par value (in dollars per share) | $ / shares									$ 0.0001
Two Series A Preferred Stock | Minimum
Subsidiary or Equity Method Investee [Line Items]
Percentage of voting power of outstanding shares									25.00%
Two Series A Preferred Stock | Maximum
Subsidiary or Equity Method Investee [Line Items]
Percentage of voting power of outstanding shares									40.00%
Three Series A Preferred Stock | Minimum
Subsidiary or Equity Method Investee [Line Items]
Percentage of voting power of outstanding shares									40.00%
Three Series A Preferred Stock | Maximum
Subsidiary or Equity Method Investee [Line Items]
Percentage of voting power of outstanding shares									50.00%
Four Series A Preferred Stock Member
Subsidiary or Equity Method Investee [Line Items]
Percentage of voting power of outstanding shares									50.00%
[1]	Retroactively restated for the reverse recapitalization as described in Note 1.

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of common stock reserved for future issuance (Detail) - shares	Mar. 31, 2021	Apr. 01, 2020	Mar. 31, 2020
Schedule Of Common Stock Reserved For Future Issuance [Line Items]
Conversion of Series A preferred stock (in shares)	10,000		10,000
Stock options outstanding (in shares)	7,988,999		3,873,888
Equity awards available for future grants (in shares)	1,781,043		5,283,520
Common stock purchase warrants (in shares)	0		5,750,000
Earnout shares	0		20,000,000
Total (in shares)	10,875,718	2,186,215	34,917,408
Restricted stock units (unvested)
Schedule Of Common Stock Reserved For Future Issuance [Line Items]
Restricted stock units outstanding (in shares)	1,095,676		0

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Apr. 01, 2020	Dec. 18, 2019	Jul. 31, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares available for future issuance		10,875,718	34,917,408	2,186,215
Stock options outstanding (in shares)		7,988,999	3,873,888
Restricted stock units outstanding (in shares)		1,095,676	0
Common shares reserved for grant		1,781,043	5,283,520
Stock options exercised, intrinsic value		$ 11,977,000
Weighted average fair value at the grant date (in dollars per share)		$ 16.17	$ 5.54
Share based compensation expense		$ 18,638,000	$ 6,788,000
Awards granted in period (in shares)		1,106,626
Revision of Prior Period, Adjustment | Immunovant Sciences Ltd
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares exchange ratio					48.90662%
Incentive Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized equity-based compensation related to unvested stock options		$ 76,100,000
Remaining weighted average service period for recognition		3 years 1 month 6 days
Restricted stock units (unvested)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized equity-based compensation related to unvested stock options		$ 20,900,000
Remaining weighted average service period for recognition		2 years 10 months 24 days
Roivant Sciences Ltd. (RSL)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense		$ 200,000	200,000
Roivant Sciences Ltd. (RSL) | Restricted stock units (unvested)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized equity-based compensation related to unvested stock options		1,000,000
Share based compensation expense		$ 0
Awards granted in period (in shares)		25,000
Requisite service period (in years)		8 years
2018 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)		3,211,152
Common shares reserved for grant						4,768,396	3,667,997
2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares available for future issuance	5,500,000	1,781,043
Percentage of common stock outstanding	4.00%
Maximum number of shares issued	16,500,000
Share based compensation, contractual term	10 years
Stock options outstanding (in shares)		4,777,847
Stock options exercised, intrinsic value		$ 3,700,000	$ 0
2019 Equity Incentive Plan | Incentive Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation, contractual term	5 years
Share-based compensation, exercise price, percent	110.00%
2019 Equity Incentive Plan | Restricted stock units (unvested)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding (in shares)		1,095,676

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of stock option activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Number of options
Number of options, beginning balance (in shares)	3,873,888
Number of options, granted (in shares)	4,840,668
Number of options, exercised (in shares)	(114,084)
Number of options, forfeited (in shares)	(384,407)
Number of options, cancelled (in shares)	(226,233)
Number of options, expired (in shares)	(833)
Number of options, ending balance (in shares)	7,988,999	3,873,888
Weighted- average exercise price
Weighted average exercise price, beginning balance (in dollars per share)	$ 8.33
Weighted average exercise price, granted (in dollars per share)	23.28
Weighted average exercise price, exercised (in dollars per share)	8.57
Weighted average exercise price, forfeited (in dollars per share)	17.14
Weighted average exercise price, cancelled (in dollars per share)	7.86
Weighted average exercise price, expired (in dollars per share)	24.41
Weighted average exercise price, ending balance (in dollars per share)	$ 16.97	$ 8.33
Additional Disclosures
Remaining contractual term	9 years 14 days	9 years 4 months 13 days
Aggregate intrinsic value	$ 25,958	$ 28,029
Number of options, exercisable	1,626,473
Weighted average exercise price, exercisable	$ 8.86
Remaining contractual term, exercisable	8 years 3 months 29 days
Aggregate intrinsic value, exercisable	$ 11,977

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of fair value assumptions (Detail)	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.30%	0.51%
Expected term, in years	5 years 6 months	5 years 9 months
Expected volatility	78.16%	74.69%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.14%	2.25%
Expected term, in years	6 years 1 month 9 days	6 years 1 month 9 days
Expected volatility	84.12%	77.93%

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Restricted Stock Unit Awards (Details)	12 Months Ended
	Mar. 31, 2021$ / sharesshares
Unvested Restricted Stock Outstanding
Outstanding, beginning balance (in shares) | shares	0
Restricted stock units, issued in period (in shares) | shares	1,106,626
Restricted stock units, vested in period (in shares) | shares	(10,000)
Restricted stock units, forfeited in period (in shares) | shares	(950)
Outstanding, ending balance (in shares) | shares	1,095,676
Weighted- Average Grant Date Fair Value
Outstanding, weighted average grant date fair value, beginning balance (in dollars per share) | $ / shares	$ 0
Issued, weighted average grant date fair value (in dollars per share) | $ / shares	20.67
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	44.60
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	48.85
Outstanding, weighted average grant date fair value, ending balance (in dollars per share) | $ / shares	$ 20.43

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of share based compensation expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 18,638	$ 6,788
Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	6,866	3,125
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 11,772	$ 3,663

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2021USD ($)subleaseAgreement	Jun. 30, 2020USD ($)subleaseAgreement	Mar. 31, 2020USD ($)
Leases [Abstract]
Number of sublease agreements | subleaseAgreement	3	2
Operating lease right-of-use assets	$ 3,282	$ 4,200	$ 0
Present value of future payments	$ 3,417	$ 4,200
Incremental borrowing rate		3.90%
Operating lease, weighted average remaining lease term	3 years
Operating lease rent expense	$ 1,100
Operating lease payments	$ 900

Leases - Schedule of Remaining

Leases - Schedule of Remaining Undiscounted Contractual Rent Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Leases [Abstract]
2022	$ 1,290
2023	1,152
2024	1,130
2025	47
Total undiscounted payments	3,619
Less: present value adjustment	(202)
Present value of future payments	3,417	$ 4,200
Less: current portion of operating lease liabilities	(1,179)		$ 0
Operating lease liabilities, net of current portion	$ 2,238		$ 0