Sio Gene Therapies (SIOX) 10-K 14 Jun 22 2022 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Mar. 31, 2022	Jun. 10, 2022	Sep. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Mar. 31, 2022
Current Fiscal Year End Date	--03-31
Document Transition Report	false
Entity File Number	001-37418
Entity Registrant Name	Sio Gene Therapies Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-3863315
Entity Address, Address Line One	130 West 42nd St.
Entity Address, Address Line Two	26th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10036
City Area Code	877
Local Phone Number	746-4891
Title of 12(b) Security	Common Stock, par value $0.00001 per share
Trading Symbol	SIOX
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	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 117,355,327
Entity Common Stock, Shares Outstanding		73,739,378
Entity Central Index Key	0001636050
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY

Audit Information

Audit Information	12 Months Ended
	Mar. 31, 2022
Audit Information [Abstract]
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Iselin, New Jersey

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Current assets:
Cash and cash equivalents	$ 63,729	$ 118,986
Restricted cash	1,184	0
Receivable from sale of long-term investment	0	4,343
Prepaid expenses and other current assets	5,214	7,348
Income tax receivable	1,609	1,656
Total current assets	71,736	132,333
Long-term restricted cash	0	1,184
Operating lease right-of-use assets	2,444	1,152
Property and equipment, net	900	478
Total assets	75,080	135,147
Current liabilities:
Accounts payable	3,984	1,341
Accrued expenses	8,232	9,196
Current portion of operating lease liabilities	786	311
Total current liabilities	13,002	10,848
Operating lease liabilities, net of current portion	1,730	932
Total liabilities	14,732	11,780
Commitments and contingencies
Stockholders’ equity:
Common stock, par value $0.00001 per share, 1,000,000,000 shares authorized, 73,739,378 and 69,377,567 shares issued and outstanding at March 31, 2022 and March 31, 2021, respectively	1	1
Accumulated other comprehensive income	337	335
Additional paid-in capital	922,966	914,100
Accumulated deficit	(862,956)	(791,069)
Total stockholders’ equity	60,348	123,367
Total liabilities and stockholders’ equity	$ 75,080	$ 135,147

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2022	Mar. 31, 2021
Common stock
Common shares par value (in dollars per share)	$ 0.00001	$ 0.00001
Common shares authorized (in shares)	1,000,000,000	1,000,000,000
Common shares issued (in shares)	73,739,378	69,377,567
Common shares outstanding (in shares)	73,739,378	69,377,567

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses:
Research and development expenses	$ 53,399	$ 24,903
General and administrative expenses	18,163	17,294
Total operating expenses	71,562	42,197
Interest expense	27	799
Other expense (income)	39	(10,359)
Loss before income tax expense (benefit)	(71,628)	(32,637)
Income tax expense (benefit)	259	(212)
Net loss	$ (71,887)	$ (32,425)
Net loss per share of common stock — basic (in dollars per share)	$ (0.98)	$ (0.62)
Net loss per share of common stock — diluted (in dollars per share)	$ (0.98)	$ (0.62)
Weighted-average shares of common stock outstanding — basic (in shares)	73,211,565	52,181,398
Weighted-average shares of common stock outstanding — diluted (in shares)	73,211,565	52,181,398

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Research and Development Expense
Share-based compensation expense	$ 1,286	$ 1,583
General and Administrative Expense
Share-based compensation expense	$ 6,139	$ 2,909

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net loss	$ (71,887)	$ (32,425)
Other comprehensive income:
Foreign currency translation adjustment	2	390
Total other comprehensive income	2	390
Comprehensive loss	$ (71,885)	$ (32,035)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Mar. 31, 2020		39,526,299
Beginning balance at Mar. 31, 2020	$ 61,558	$ 0	$ 820,257	$ (758,644)	$ (55)
Increase (Decrease) in Shareholders' Equity (Deficit)
Shares issued upon settlement of restricted stock units (in shares)		187,741
Shares sold in connection with at-the-market offering, net of brokerage fees and offering expenses (in shares)		29,663,527
Shares sold in connection with at-the-market offering, net of brokerage fees and offering expenses	89,231	$ 1	89,230
Stock-based compensation expense	4,492		4,492
Capital contribution received from Roivant Sciences, Inc.	121		121
Foreign currency translation adjustment	390				390
Net loss	(32,425)			(32,425)
Ending balance (in shares) at Mar. 31, 2021		69,377,567
Ending balance at Mar. 31, 2021	123,367	$ 1	914,100	(791,069)	335
Increase (Decrease) in Shareholders' Equity (Deficit)
Shares issued upon settlement of restricted stock units (in shares)		320,368
Shares sold in connection with at-the-market offering, net of brokerage fees and offering expenses (in shares)		739,445
Shares sold in connection with at-the-market offering, net of brokerage fees and offering expenses	1,441		1,441
Stock-based compensation expense	7,425		7,425
Shares issued upon exercise of pre-funded warrants (in shares)		3,301,998
Foreign currency translation adjustment	2				2
Net loss	(71,887)			(71,887)
Ending balance (in shares) at Mar. 31, 2022		73,739,378
Ending balance at Mar. 31, 2022	$ 60,348	$ 1	$ 922,966	$ (862,956)	$ 337

Consolidated Statements of St_2

Consolidated Statements of Stockholders’ Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Stockholders' Equity [Abstract]
Brokerage fees and offering expenses	$ 0.2	$ 4

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (71,887)	$ (32,425)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of operating lease right-of-use assets	398	1,521
Stock-based compensation expense	7,425	4,492
Depreciation and non-cash amortization	268	945
Gains on long-term investment	0	(11,256)
Change in operating lease liabilities	(417)	(866)
Other	7	474
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	2,134	(4,377)
Income tax receivable	47	51
Other non-current assets	0	46
Accounts payable	2,643	(3,071)
Accrued expenses	(964)	(2,123)
Net cash used in operating activities	(60,346)	(46,589)
Cash flows from investing activities:
Cash proceeds from sale of long-term investment	4,343	12,784
Purchases of property and equipment	(695)	(398)
Net cash provided by investing activities	3,648	12,386
Cash flows from financing activities:
Payments on long-term debt	0	(15,731)
Capital contribution received from affiliate	0	121
Cash proceeds from issuance of shares of common stock and pre-funded warrants, net of issuance costs	1,441	89,231
Net cash provided by financing activities	1,441	73,621
Net change in cash and cash equivalents, restricted cash and long-term restricted cash	(55,257)	39,418
Total cash and cash equivalents, restricted cash and long-term restricted cash—beginning of year	120,170	80,752
Total cash and cash equivalents, restricted cash and long-term restricted cash—end of year	64,913	120,170
Cash and cash equivalents—beginning of year	118,986	80,752
Restricted cash included in long-term assets—beginning of year	1,184	0
Cash and cash equivalents—end of year	63,729	118,986
Restricted cash included in current assets—end of year	1,184	0
Non-cash operating activities:
Operating lease right-of-use assets and liabilities recognized	1,690	1,141
Supplemental disclosure of cash paid:
Income taxes	5	40
Interest	$ 27	$ 465

Description of Business

Description of Business	12 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Historically, Sio Gene Therapies Inc. ("Sio"), together with its wholly owned subsidiaries (the "Company"), was a clinical-stage company focused on developing gene therapies to radically transform the lives of patients with neurodegenerative diseases (see Note 3 and Note 14). Sio is a Delaware corporation, which was originally an exempted limited company incorporated under the laws of Bermuda in October 2014 and was named Axovant Gene Therapies Ltd. ("AGT") from March 2019 until November 2020. During November 2020, the Company completed a corporate transformation, changing its jurisdiction of incorporation from Bermuda to the State of Delaware, changing its name to Sio Gene Therapies Inc., and changing its ticker symbol on The Nasdaq Global Select Market (“Nasdaq”) to “SIOX” (collectively, these events comprise the “Domestication”). The Company continues to be subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, and applicable rules of Nasdaq. Since its initial public offering in 2015, the Company has devoted substantially all of its efforts to raising capital, acquiring product candidates and advancing its product candidates into clinical development. The Company has determined that it has one operating and reporting segment as it allocates resources and assesses financial performance on a consolidated basis.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Mar. 31, 2022
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 fiscal quarters end on June 30, September 30, and December 31. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted 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 as amended by Accounting Standards Updates ("ASU") issued by the Financial Accounting Standards Board ("FASB"). These consolidated financial statements and accompanying notes 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. Certain prior period balances have been reclassified to conform to the current period presentation. During November 2020, the historical financial statements and subsidiaries of AGT became the historical financial statements and subsidiaries of Sio upon consummation of the Domestication. As a result, these consolidated financial statements and accompanying notes reflect (i) the historical operating results of AGT and its subsidiaries prior to the Domestication; (ii) the operating results of the Company following the Domestication; and (iii) the Company’s equity structure for all periods presented. (B) Going Concern and Management's Plans: The Company assesses and determines its ability to continue as a going concern in accordance with the provisions of ASC Subtopic 205-40, " Presentation of Financial Statements—Going Concern ", which requires the Company to evaluate whether there are conditions or events that raise substantial doubt about its ability to continue as a going concern within one year after the date that its annual and interim consolidated financial statements and accompanying notes are issued. Certain additional financial statement disclosures are required if such conditions or events are identified. If and when an entity’s liquidation becomes imminent, financial statements should be prepared under the liquidation basis of accounting. Determining the extent, if any, to which conditions or events raise substantial doubt about the Company’s ability to continue as a going concern, or the extent to which mitigating plans sufficiently alleviate any such substantial doubt, as well as whether or not liquidation is imminent, requires judgment by management. The Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the consolidated financial statements and accompanying notes are issued. The Company is currently a development stage company, and thus, has not yet achieved profitability. The Company expects to continue to incur significant operating and net losses, as well as negative cash flows from operations, for the foreseeable future. The Company has not generated any revenue to date. For the years ended March 31, 2022 and March 31, 2021, the Company incurred net losses of $71.9 million and $32.4 million, respectively. As of March 31, 2022, the Company's cash and cash equivalents totaled $63.7 million and its accumulated deficit was $863.0 million. The Company estimates that its current cash and cash equivalents balance is sufficient to support operations beyond the twelve-month period following the date that these consolidated financial statements and footnotes were issued. These estimates are based on assumptions that may prove to be wrong, and the Company could use its available capital resources sooner than it currently expects. The Company's future funding requirements, both near and long-term, will depend on many factors, including, but not limited to the timing and outcome of its exploration of, and execution upon any, potential strategic alternatives, the cost of obtaining necessary intellectual property and defending potential intellectual property disputes, realization of the anticipated benefits of the Company's headcount reduction, and the costs of operating as a public company. (C) Use of Estimates: The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company regularly evaluates estimates and assumptions related to certain assets and liabilities, including its research and development accruals, as well as assumptions used to estimate the fair value of its stock option awards, estimate its income tax expense and estimate its ability to continue as a going concern. Specifically, the Company’s assessment of the completeness of the information for research and development accruals is subject to variability and uncertainty. In addition, in certain circumstances, the determination of the nature and amount of research and development services that have been received during the reporting period requires judgment as the timing and pattern of vendor invoicing does not correspond to the level of services provided. The Company estimates the grant date fair value of stock option awards with only time-based vesting requirements using a Black-Scholes valuation model and uses a Monte Carlo Simulation method under the income approach to estimate the grant date fair value of stock option awards with market-based performance conditions. 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, 2022 and through the date of issuance of these audited consolidated financial statements and accompanying notes. 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. (D) Risks and Uncertainties: The Company is subject to risks common to companies in the pharmaceutical industry including, but not limited to, uncertainties related to commercialization of products, regulatory approvals, dependence on key products, dependence on key customers and suppliers, and protection of intellectual property rights. (E) Concentrations of Credit Risk: Financial instruments that potentially subject the Company to concentration of credit risk include cash and cash equivalents. At March 31, 2022, substantially all of the Company's cash balances are deposited in 1 banking institution in excess of insured levels. (F) Cash and Cash Equivalents: The Company considers all highly liquid investments purchased with original maturities of 90 days or less at acquisition to be cash equivalents. Cash and cash equivalents include cash held in banks and amounts held in money market funds. (G) Property and Equipment: Property and equipment, consisting of leasehold improvements, furniture and fixtures, computers, software and other office and laboratory equipment, 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. 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 results of operations. Depreciation is recorded for property and equipment using the straight-line method over the estimated useful lives of the respective assets, generally three The Company reviews the recoverability of all long-lived assets, including the related useful lives, whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset might not be recoverable. Recoverability is measured by comparison of the book values of the assets to future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceed their fair value, which is measured based on the projected discounted future net cash flows arising from the assets. (H) Debt Issuance Costs and Debt Discount: Debt issuance costs related to a recognized debt liability are presented on the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts, and are amortized to interest expense over the term of the related debt using the effective interest method. Further, debt discounts created as a result of the allocation of proceeds received from a debt issuance to warrants issued in conjunction with the debt issuance are amortized to interest expense under the effective interest method over the life of the recognized debt liability. (I) Research and Development Expense: Research and development costs are expensed as incurred. Clinical study costs are accrued over the service periods specified in the contracts and adjusted as necessary based upon an ongoing review of the level of effort and costs actually 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 final regulatory approvals are capitalized and amortized to cost of revenue over the remaining useful life of the asset. Research and development costs primarily consist of intellectual property and research and development materials acquired under license and license and collaboration agreements (see Note 3) and expenses from third parties who conduct research and development activities on behalf of the Company. The Company expenses in-process research and development projects acquired as asset acquisitions which have not reached technological feasibility, and which have no alternative future use. (J) Income Taxes: Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and the respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is recorded when, after consideration of all positive and negative evidence, it is not more likely than not that the Company's deferred tax assets will be realizable. 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. When and if the Company were to recognize interest and penalties related to unrecognized tax benefits, they would be reported in tax expense in the consolidated statement of operations. (K) Stock-Based Compensation: Stock-based awards to employees and directors with only time-based vesting requirements are valued at fair value on the date of grant and that fair value is recognized on a straight-line basis over the requisite service period of the entire award and is included in research and development expense and general and administrative expense in the Company's consolidated statements of operations. The Company values such time-based stock options using the Black-Scholes option pricing model. Certain assumptions are made with respect to utilizing the Black-Scholes option pricing model, including the expected life of the award, the volatility of the underlying shares and the risk-free interest rate. The expected life of such time-based stock options is calculated using the simplified method (based on the mid-point between the vesting date and the end of the contractual term), and 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. The expected share price volatility for such time-based stock option awards was estimated partially using weighted average measures of implied volatility and using the average historical price volatility for industry peers. The Company estimates the grant date fair value of stock option awards to employees with market-based performance conditions using a Monte Carlo Simulation method under the income approach. Certain assumptions are made with respect to utilizing the Monte Carlo Simulation method, including the volatility of the underlying shares and the drift rate, or estimated cost of equity. The expected share price volatility for such market-based performance stock option awards was estimated by taking the median historical price volatility for industry peers over the contractual term of the options. The drift rate, or estimated cost of equity, for such market-based performance stock option awards is based on various financial and risk-associated metrics of industry peers, as well as estimated factors specific to us. The Company accounts for stock-based payments to nonemployees issued in exchange for services in accordance with ASU No. 2018-07, " Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting " based upon the fair value of the equity instruments issued. Compensation expense for stock options issued to nonemployees is calculated using the Black-Scholes option pricing model on the grant date and is recorded over the service performance period. The Company recognizes forfeitures of awards when they occur. (L) Net Loss per Share of Common Stock: Basic net loss per share of common stock is computed by dividing the net loss applicable to holders of common stock by the weighted-average number of shares of common stock and 3,301,998 pre-funded warrants (see Note 9(B)) outstanding during the period, without further consideration for potentially dilutive securities. The pre-funded warrants were fully exercised in July 2021 (see Note 9(B)). In accordance with ASC Topic 260, Earnings Per Share , the pre-funded warrants were included in the computation of basic net loss per share because the exercise price was negligible and they were fully vested and exercisable at any time after the original issuance date. Diluted net loss per share of common stock is computed by dividing the net loss applicable to holders of common stock by the diluted weighted-average number of shares of common stock outstanding during the period calculated in accordance with the treasury stock method. In periods in which the Company reports a net loss, all common stock equivalents are deemed anti-dilutive such that basic net loss per share of common stock and diluted net loss per share of common stock are equivalent. Potentially dilutive shares of common stock have been excluded from the diluted net loss per share of common stock computations in all periods presented because such securities have an anti-dilutive effect on net loss per share of common stock due to the Company’s net loss. Restricted Stock Units ("RSUs") and stock options outstanding for totals of 5.0 million and 3.1 million shares of common stock were not included in the calculation of diluted weighted-average shares of common stock outstanding for the years ended March 31, 2022 and 2021, respectively, because they were anti-dilutive given the net loss of the Company. (M) Financial Instruments and Fair Value Measurement: The Company utilizes fair value measurement guidance prescribed by accounting standards to value its financial instruments. The guidance establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company's own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company's assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. Fair value is defined as the exchange price, or exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, the guidance establishes a three-tier fair value hierarchy that distinguishes among the following: • Level 1-Valuations are based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. • Level 2-Valuations are based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active and models for which all significant inputs are observable, either directly or indirectly. • Level 3-Valuations are based on inputs that are unobservable (supported by little or no market activity) and significant to the overall fair value measurement. 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 greatest 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 include cash and cash equivalents and restricted cash. Cash consists of non-interest-bearing deposits denominated in the U.S. dollar, Swiss franc and Euro, while cash equivalents consists of interest-bearing money market fund deposits denominated in the U.S. dollar, which are invested in debt securities issued or guaranteed by the U.S. government and repurchase agreements fully collateralized by U.S. Treasury and U.S. government securities, and restricted cash consists of interest-bearing deposits denominated in the U.S. dollar. Cash and restricted cash are stated at their historical carrying amounts, which approximate fair value due to their short-term nature. The carrying values of the Company's money market fund included in cash and cash equivalents of $61.0 million and $114.0 million at March 31, 2022 and 2021, respectively, approximated their fair values, which are based on quoted prices in active markets for identical securities. The following table summarizes the fair value of the Company's money market fund included in cash equivalents based on the inputs used at March 31, 2022 and 2021 in determining such values (in thousands): As of March 31, 2022 As of March 31, 2021 Fair Value Price Quotations (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value Price Quotations (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market fund $ 61,000 $ 61,000 $ — $ — $ 114,000 $ 114,000 $ — $ — (N) Recent Accounting Pronouncements: In June 2016, the FASB issued ASU No. 2016-13, “ Financial Instruments — Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments " ("ASU No. 2016-13"). ASU 2016-13 requires that financial assets measured at amortized cost, such as loans, accounts and trade receivables and investments, be represented net of expected credit losses, which may be estimated based on relevant information such as historical experience, current conditions, and future expectation for each pool of similar financial asset. ASU No. 2016-13 requires enhanced disclosures related to trade receivables and associated credit losses. In May 2019, the FASB issued ASU No. 2019-05, “ Financial Instruments — Credit Losses (Topic 326): Targeted Transition Relief ", which allows for a transition election on certain instruments and is effective for smaller reporting companies for fiscal years beginning after December 15, 2022 and interim periods in those fiscal years. In November 2019, the FASB issued ASU No. 2019-11, " Codification Improvements to Topic 326, Financial Instruments — Credit Losses ", which amends certain aspects of ASU No. 2016-13, including transition relief for trouble debt restructuring ("TDR"), among other topics. In March 2022, the FASB issued ASU No. 2022-02, " Financial Instruments — Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures " ("ASU No. 2022-02"), which eliminates the accounting guidance on TDRs for creditors in ASC Subtopic 310-40 and amends the guidance on “vintage disclosures” to require disclosure of current-period gross write-offs by year of origination. ASU No. 2022-02 also updates the requirements related to accounting for credit losses under ASC Topic 326 and adds enhanced disclosures for creditors with respect to loan refinancings and restructurings for borrowers experiencing financial difficulty. While the Company does not expect the adoption of this guidance to materially impact the Company's consolidated financial statements and related disclosures because it does not currently have any investments or trade receivables, the impact on the Company's consolidated financial statements and disclosures will depend on the facts and circumstances of any specific future transactions or circumstances. In August 2020, the FASB issued ASU No. 2020-06, " Debt — Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging — Contracts in Entity's Own Equity (Subtopic 815-40) " ("ASU No. 2020-06"). ASU No. 2020-06 simplifies the accounting for convertible debt instruments by removing the beneficial conversion and cash conversion separation models for convertible instruments. Under ASU No. 2020-06, the embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives or that do not result in substantial premiums accounted for as paid-in capital. ASU No. 2020-06 also amends the accounting for certain contracts in an entity’s own equity that are currently accounted for as derivatives because of specific settlement provisions. In addition, the new guidance modifies how particular convertible instruments and certain contracts that may be settled in cash or shares impact the computation of diluted earnings or loss per share. The provisions of ASU No. 2020-06 are effective for fiscal years beginning after December 15, 2021, and interim periods within those fiscal years, with early adoption permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The Company's adoption of ASU No. 2020-06 on April 1, 2022 did not impact the Company's consolidated financial statements and related disclosures because it did not maintain any debt instruments accounted for in accordance with ASC Subtopic 470-20, " Debt — Debt with Conversion and Other Options " or instruments accounted for as derivatives in accordance with ASC Subtopic 815-40, " Derivatives and Hedging — Contracts in Entity's Own Equity ", and the Company had also included outstanding pre-funded warrants in the computation of basic net loss per share (see Note 2(L)). In May 2021, the FASB issued ASU No. 2021-04, " Earnings Per Share (Topic 260), Debt — Modifications and Extinguishments (Subtopic 470-50), Compensation — Stock Compensation (Topic 718), and Derivatives and Hedging — Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options " ("ASU No. 2021-04"). ASU No. 2021-04 provides a principles-based framework for issuers to account for a modification or exchange of freestanding equity-classified written call options. To the extent applicable, issuers first reference other U.S. GAAP to account for the effect of the modification. In the absence of other U.S. GAAP, ASU No. 2021-04 clarifies whether to account for the effect as an adjustment to equity, and the related EPS implications, or as an expense, and if so the manner and pattern of recognition. The provisions of ASU No. 2021-04 are effective for annual periods beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted. The Company's adoption of ASU No. 2021-04 on April 1, 2022 did not impact the Company's consolidated financial statements and related disclosures because it did not modify outstanding equity-classified written call options upon adoption. In March 2022, the FASB issued ASU No. 2022-01, " Derivatives and Hedging (Topic 815) — Fair Value Hedging — Portfolio Layer Method " ("ASU No. 2022-01"). ASU No. 2022-01 clarifies the guidance in ASC Topic 815 on fair value hedge accounting of interest rate risk for portfolios of financial assets, and amends the guidance in ASU 2017-12, " Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities ", that, among other things, established the “last-of-layer” method for making the fair value hedge accounting for these portfolios more accessible. ASU 2022-01 renames that method the “portfolio layer” method. The provisions of ASU No. 2022-01 are effective for annual periods beginning after December 15, 2022, including interim periods within those fiscal years. Early adoption is permitted. While the Company does not expect the adoption of this guidance to materially impact the Company's consolidated financial statements and related disclosures because it does not currently have any financial instruments designated as fair value hedges, the impact on the Company's consolidated financial statements and disclosures will depend on the facts and circumstances of any specific future transactions or circumstances. Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force), the American Institute of Certified Public Accountants, and the SEC did not, or are not believed by management to, have a material impact on the Company’s present or future consolidated financial position, results of operations or cash flows. (O) Foreign Currency: The Company has operations in the United States, the United Kingdom, Ireland 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 year. The Company’s assets and liabilities are translated using the current exchange rate as of the balance sheet date and stockholders’ equity is translated using historical rates. Adjustments resulting from the translation of the financial statements of the Company’s foreign functional currency subsidiaries into U.S. dollars are excluded from the determination of net loss and are accumulated in a separate component of stockholders’ equity. Foreign exchange transaction gains and losses are included in other (income) expense in the Company’s results of operations.

License and Collaboration Agree

License and Collaboration Agreements	12 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Collaboration Agreements	License and Collaboration Agreements (A) The University of Massachusetts Medical School Exclusive License Agreement: In December 2018, the Company entered into an exclusive license agreement (the "UMMS Agreement"), with the University of Massachusetts Medical School ("UMMS") pursuant to which the Company received a worldwide, royalty-bearing, sub-licensable license under certain patent applications and any patents issuing therefrom, biological materials and know-how controlled by UMMS to develop and commercialize gene therapy product candidates, including AXO-AAV-GM1 and AXO-AAV-GM2, for the treatment of GM1 gangliosidosis and GM2 gangliosidosis (including Tay-Sachs disease and Sandhoff disease), respectively. In April 2022, the Company provided notice of termination to UMMS of the UMMS Agreement, which termination is expected to become effective by June 30, 2022 (see Note 14). Under the UMMS Agreement, the Company is solely responsible, at its expense, for the research, development and commercialization of the licensed gene therapy product candidates. The Company reimburses UMMS for payments made by UMMS for the manufacture of clinical trial materials for the Company, up to a specified amount. The Company incurred totals of $27.7 million and $6.9 million of program-specific costs related to its AXO-AAV-GM1 and AXO-AAV-GM2 programs within research and development expenses in its consolidated statements of operations during the years ended March 31, 2022 and March 31, 2021, respectively, including a total of $3.0 million for license fee milestones due under the terms of the UMMS Agreement during the year ended March 31, 2022. The Company paid totals of $5.3 million and $29 thousand to UMMS during the years ended March 31, 2022 and March 31, 2021, respectively. (B) Oxford Biomedica License Agreement: In June 2018, the Company entered into a license agreement (the "Oxford Agreement") with Oxford Biomedica (UK) Ltd. ("Oxford"), pursuant to which the Company received a worldwide, exclusive, royalty-bearing, sub-licensable license under certain patents and other intellectual property controlled by Oxford to develop and commercialize AXO-Lenti-PD and related gene therapy products for all diseases and conditions. In February 2022, the Company provided notice of termination to Oxford of the Oxford Agreement, which termination is expected to become effective by June 30, 2022. The Company incurred $10.6 million and $5.7 million of AXO-Lenti-PD program-specific costs within research and development expenses in its consolidated statements of operations during the years ended March 31, 2022 and March 31, 2021, respectively, including a $2.0 million nonrecurring development milestone achieved during the year ended March 31, 2022. The Company paid totals of $7.2 million and $3.5 million to Oxford during the years ended March 31, 2022 and March 31, 2021, respectively, including the payment for the nonrecurring development milestone achieved.

Investment in Arvelle Therapeut

Investment in Arvelle Therapeutics B.V.	12 Months Ended
	Mar. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Investment in Arvelle Therapeutics B.V.	Investment in Arvelle Therapeutics B.V. On February 13, 2019, the Company entered into a share subscription agreement (the "Subscription Agreement") to purchase up to approximately 8.1 million shares of nonredeemable convertible preferred stock of Arvelle Therapeutics B.V. ("Arvelle") in exchange for €0.00001 per share paid in cash, as well as certain goods and services provided by the Company to Arvelle. The Company accounted for its investment in Arvelle in accordance with the provisions of ASC 321, " Investments - Equity Securities ", and elected to use the measurement alternative therein. The first closing under the Subscription Agreement occurred on February 25, 2019 with the Company purchasing approximately 5.9 million nonredeemable convertible preferred shares of Arvelle, which was initially recorded at a fair value of $5.9 million and was capitalized as a long-term investment in the Company's consolidated balance sheet and recorded to other non-operating income in its consolidated statement of operations. The Company also received the right to purchase up to approximately 2.2 million additional nonredeemable convertible preferred shares of Arvelle at a price of €0.00001 per share upon a potential future second closing under the Subscription Agreement. In May 2020, the Company fully exercised this right and purchased the approximately 2.2 million additional nonredeemable convertible preferred shares upon the closing of the second financing under the Subscription Agreement, which was recorded at a fair value of $2.2 million and was capitalized as a long-term investment in the Company's consolidated balance sheet and recorded to other non-operating income in the Company's consolidated statement of operations. In February 2021, the Company sold its investment in Arvelle to a third party as part of that third party's cash acquisition of all of the outstanding equity of Arvelle. In exchange, the Company received an upfront payment of approximately $11.6 million, in addition to a future payment to be received of approximately $1.2 million that is being held in escrow and that is recorded as restricted cash in the Company's consolidated balance sheet at March 31, 2022, as well as the right to receive up to an additional total of $7.0 million in potential future regulatory and sales milestone payments (collectively, the "Arvelle Sale"). The Company recorded a net gain of approximately $4.7 million to other non-operating income in the Company's consolidated statement of operations upon the closing of the Arvelle Sale in February 2021, as well as a gain of approximately $4.3 million recorded to other non-operating income in the Company's consolidated statement of operations and to receivable from sale of long-term investment in its consolidated balance sheet upon the achievement of a regulatory milestone in March 2021 that was collected during the year ended March 31, 2022.

Leases

Leases	12 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Leases	Leases Under the provisions of ASC Topic 842, " Leases " ("Topic 842"), the Company has elected the practical expedients to: (i) use the total lease term in its initial incremental borrowing rate calculation; (ii) combine its lease and non-lease components and account for them as a single lease component; and (iii) not apply the use of hindsight in determining the lease term when considering lessee options to extend or terminate the lease and to purchase the underlying asset. The Company reviews agreements at inception to determine if they include a lease, and when they do, uses an implicit interest rate or its estimated incremental borrowing rate to determine the present value of the future fixed lease payments. As the Company’s operating leases have not provided an implicit rate, estimated incremental borrowing rates were used based on the information available at the adoption date with operating right-of-use assets and obligations recognized based on the present value of remaining lease payments over the lease term using such estimated incremental borrowing rates. Operating lease expense 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. Leases with an initial term of 12 months or less are not recorded within the Company's balance sheet. In November 2021, the Company entered into a lease agreement for a research and development facility and related office space in Durham, North Carolina with an initial term expiring in December 2024. Upon commencement of this lease, the Company recorded operating lease right-of-use assets and operating lease liabilities of approximately $1.7 million based on the present value of payments over the lease term using an incremental borrowing rate of approximately 8.4%. In August 2020, the Company entered into a lease agreement for an office facility in New York, New York that commenced in December 2020 and ends in June 2026. Upon commencement of this lease, the Company recorded operating lease right-of-use assets and operating lease liabilities of approximately $1.1 million, net of expected abatement, based on the present value of payments over the lease term using an incremental borrowing rate of approximately 8.9%. The Company also leases an office facility in Durham, North Carolina with a lease term ending in November 2022, and the Company had leased other office facilities in New York, New York and Princeton, New Jersey with lease terms that ended in January 2021 and October 2020, respectively. The aggregate weighted-average remaining payment term, aggregate weighted-average remaining lease term and aggregate weighted-average discount rate were 3.2 years, 3.3 years and 8.7%, respectively, for the Company's contractual rent obligations for its operating leases as of March 31, 2022. During the years ended March 31, 2022 and March 31, 2021, the Company incurred $0.6 million and $1.6 million, respectively, of rent expense associated with contractual rent obligations for its operating leases. During the years ended March 31, 2022 and March 31, 2021, the Company paid $0.6 million and $0.9 million, respectively, related to its 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, 2022 (in thousands): Year Ending March 31, Amount 2022 $ 828 2023 936 2024 799 2025 310 2026 53 Thereafter — Total undiscounted payments 2,926 Less: present value adjustment (410) Present value of future payments $ 2,516

Accrued Expenses

Accrued Expenses	12 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses As of March 31, 2022 and 2021, accrued expenses consisted of the following (in thousands): March 31, 2022 March 31, 2021 Research and development expenses $ 4,392 $ 6,091 Bonuses and other compensation expenses 2,113 2,331 Other expenses 1,727 774 Total accrued expenses $ 8,232 $ 9,196

Long-term Debt

Long-term Debt	12 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Long-term Debt	Long-term DebtIn February 2017, the Company and certain of its subsidiaries (the "Borrowers") entered into a loan and security agreement (as amended in May 2017, September 2017 and November 2019) with Hercules Capital, Inc. ("Hercules") (the "Loan Agreement"), under which the Borrowers borrowed an aggregate of $55.0 million (the "Term Loan"). The Term Loan had a scheduled maturity date of March 1, 2021. The Term Loan initially bore interest at a variable per annum rate calculated for any day as the greater of either (i) the prime rate plus 6.80%, and (ii) 10.55%, which was subsequently changed in connection with the November 2019 amendment of the Loan Agreement to a variable per annum rate calculated for any day as the greater of either (i) the prime rate plus 6.80%, and (ii) 11.55%. The Borrowers were initially obligated to make monthly payments of accrued interest under the Loan Agreement until September 2018, followed by monthly installments of principal and interest from October 2018 until March 2021. Subsequent to the November 2019 amendment of the Loan Agreement, the Borrowers were obligated to make monthly payments of accrued interest from December 2019 until August 2020, followed by monthly installments of principal and interest from September 2020 until March 2021. Prepayment of the Term Loan was subject to penalty. The Company prepaid 50%, or approximately $15.7 million, of outstanding principal due without penalty in connection with the November 2019 amendment of the Loan Agreement, which was accounted for as a modification of debt in accordance with applicable accounting guidance. In April 2020, the Company prepaid $15.7 million of outstanding principal, together with $0.3 million of accrued interest, fees and other amounts, due under the Loan Agreement with Hercules, which was accounted for as an extinguishment of debt with a corresponding loss of approximately $0.5 million recorded to interest expense during the year ended March 31, 2021. In connection with the prepayment, the credit facility and the Loan Agreement with Hercules were terminated, and all obligations, liens and security interests under the Loan Agreement were released, discharged and satisfied.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Mar. 31, 2022
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions (A) Services Agreements: The Company has entered into services agreements with Roivant Sciences, Inc. ("RSI") and Roivant Sciences GmbH (collectively, the "Service Providers"), each a wholly owned subsidiary of Roivant Sciences Ltd. ("RSL"), pursuant to which the Service Providers provide the Company with services in relation to the identification of potential product candidates and project management of clinical trials, as well as other services related to the Company's development, administrative and financial functions (the "Services Agreements"). Under the terms of the Services Agreements, the Company is obligated to pay or reimburse the Service Providers for the costs they, or third parties acting on their behalf, incur in providing services to the Company, including administrative and support services as well as research and development services. In addition, the Company is obligated to pay to the Service Providers at a predetermined mark-up on any general and administrative and research and development services incurred directly by the Service Providers. Under the terms of the Services Agreements, the Service Providers have agreed to indemnify the Company and its officers, employees and directors against all losses arising out of, due to or in connection with the provision of services (or the failure to provide services) under the Services Agreements, subject to certain limitations set forth in the Service Agreements. In addition, the Company has agreed to indemnify the Service Providers and their respective affiliates and officers, employees and directors against all losses arising out of, due to or in connection with the receipt of services under the Services Agreements, subject to certain limitations set forth in the Services Agreements. Such indemnification obligations will not exceed the payments made by the Company under the Services Agreements for the specific service that allegedly caused or was related to the losses during the period in which such alleged losses were incurred. The term of each of the services agreements will continue until terminated upon 90 days’ written notice by any party with respect to the services such party provides or receives thereunder. For the years ended March 31, 2022 and 2021, the Company incurred expenses of zero and $0.1 million, respectively, under the Services Agreements, inclusive of the mark-up, which have been treated as capital contributions. (B) Information Sharing and Cooperation Agreement: In March 2015, the Company entered into an information sharing and cooperation agreement with RSL, as amended and restated in June 2018 (the "Restated Cooperation Agreement") in connection with a share purchase placement agreement with RSL (the "Private Placement"), for which the amendments became effective in July 2018 upon the closing of the Private Placement. The Restated Cooperation Agreement, among other things, obligates the Company to deliver periodic financial statements and other financial information to RSL and comply with other specified financial reporting requirements, and requires the Company to implement and observe certain policies and procedures related to applicable laws and regulations. The Company 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 Restated 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 Restated Cooperation Agreement.

Stockholders_ Equity

Stockholders’ Equity	12 Months Ended
	Mar. 31, 2022
Stockholders' Equity Note [Abstract]
Stockholders’ Equity	Stockholders’ Equity (A) Overview: Sio's Certificate of Incorporation filed with the State of Delaware on November 12, 2020 authorizes the issuance of up to a total of 1,010,000,000 shares, of which 1,000,000,000 shares are common stock with a par value of $0.00001 per share and 10,000,000 shares are preferred stock with a par value of $0.00001 per share. (B) Transactions: In February 2020, as part of a follow-on public offering, the Company issued and sold pre-funded warrants to purchase up to 3,301,998 shares of common stock at an offering price of $3.74999 and an exercise price of $0.00001 per pre-funded warrant, which were fully exercised in July 2021. The pre-funded warrants were classified as equity and the fair value of the pre-funded warrants was recorded as a credit to additional paid-in capital and was not subject to remeasurement. The Company has engaged SVB Securities LLC as its agent to sell shares of the Company's common stock from time to time through an at-the-market equity offering program. SVB Securities LLC receives compensation for its services in an amount equal to 3% of the gross proceeds of any of the Company's common stock sold. During the year ended March 31, 2021, which was the inception of this program, the Company sold approximately 29.7 million shares of its common stock for total proceeds of approximately $90.5 million, net of brokerage fees. During the year ended March 31, 2022, the Company sold approximately 0.7 million shares of its common stock for total proceeds of approximately $1.5 million, net of brokerage fees, under this program. As of March 31, 2022, the Company sold a total of approximately 30.4 million shares of its common stock for aggregate proceeds of approximately $92.0 million, net of brokerage fees, under and since the inception of this program.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation (A) Amended and Restated 2015 Equity Incentive Plan: In March 2015, the Company adopted its 2015 Equity Incentive Plan, which was (i) amended and restated in June 2017 by its Board of Directors and became effective upon stockholder approval in August 2017, (ii) further amended and restated in October 2020 by its Board of Directors, and (iii) further amended and restated in August 2021 by its Board of Directors and became effective upon stockholder approval in September 2021 (the "2015 Plan"). In April 2021 and April 2020, the number of shares of common stock authorized for issuance under the 2015 Plan increased automatically by 2.8 million and 1.6 million, respectively, in accordance with the terms of the 2015 Plan. Upon amendment and restatement by the Company's board of directors and stockholder approval of the 2015 Plan in August 2021 and September 2021, respectively, the number of shares of common stock authorized for issuance under the 2015 Plan increased by 5.0 million. At March 31, 2022, totals of 13.4 million shares of common stock were authorized for issuance and 7.6 million shares of common stock were available for future issuance under the 2015 Plan. (B) Stock Options: Time-based stock options granted to the Company's employees vest over a period of either (i) four years with 25% of the shares of common stock underlying the option vesting on the first anniversary of the vesting commencement date and the remainder vesting in 12 equal quarterly installments thereafter for such stock options granted prior to April 2021, or (ii) three years with one-third of the shares of common stock underlying the stock option vesting on the first anniversary of the vesting commencement date and the remainder vesting in 8 equal quarterly installments thereafter for such stock options granted since April 2021, each subject to continuing service. Initial stock options granted to the Company's non-employee directors vest in equal installments on the first, second and third anniversaries of the vesting commencement date, and stock options subsequently granted annually to the Company's non-employee directors vest fully on the first anniversary of the vesting commencement date, each subject to continuous service. Options with market-based performance conditions vest based on the trading price for the Company's shares of common stock exceeding certain closing price thresholds. Stock options granted under the 2015 Plan provide option holders, if provided for by the terms of the option agreement or if approved by the Board of Directors, the right to exercise their options prior to vesting. In the event that an option holder exercises the unvested portion of any option, such unvested portion will be subject to a repurchase option held by the Company at the lower of (i) the fair market value of its common stock on the date of repurchase and (ii) the exercise price of the options. Any shares of common stock underlying such unvested portion will continue to vest in accordance with the original vesting schedule of the option. The Company did not grant any market-based performance stock options during the years ended March 31, 2022 and March 31, 2021. At March 31, 2022, options with market-based performance conditions to purchase 0.1 million shares of common stock at a weighted average exercise price of $6.42 per share were outstanding. The market-based performance options vest based on the trading price for the Company's shares of common stock exceeding certain closing price thresholds. The Company estimated the fair value of each time-based stock option on the date of grant using the Black-Scholes closed-form option-pricing model applying the weighted average assumptions during the years ended March 31, 2022 and March 31, 2021, as follows: Years Ended March 31, 2022 2021 Expected stock price volatility 112.9 % 109.5 % Expected risk free interest rate 1.01 % 0.43 % Expected term, in years 5.93 6.11 Expected dividend yield — % — % The following table presents a summary of stock option activity and data under the 2015 Plan: Number of Options Weighted Average Exercise Price Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value Options outstanding at March 31, 2020 2,008,735 $ 14.39 $ 13.87 8.33 $ — Granted 434,775 3.72 3.07 Exercised — — — — Forfeited (347,967) 13.92 15.84 Options outstanding at March 31, 2021 2,095,543 $ 12.26 $ 11.30 7.90 $ — Granted 1,594,400 2.47 2.06 Exercised — — — — Forfeited (1,979,933) 5.93 4.10 Options outstanding at March 31, 2022 1,710,010 $ 10.46 $ 10.84 7.38 $ — Options vested and expected to vest at March 31, 2022 1,710,010 $ 10.46 $ 10.84 7.38 $ — Options exercisable at March 31, 2022 1,174,102 $ 13.87 $ 14.68 6.72 $ — During the years ended March 31, 2022 and March 31, 2021, the total grant date fair values of options that vested under the 2015 Plan were $2.4 million and $3.5 million, respectively. At March 31, 2022 under the 2015 Plan, vested options to purchase a total of 1.0 million shares of common stock were outstanding, with no options with market-based performance conditions vested and outstanding. (C) Restricted Stock Units: RSUs granted during years ended March 31, 2022 and March 31, 2021 vest in three equal annual installments commencing on the first anniversary of the vesting commencement date, subject to continuing service. Of the total number of RSUs granted in September 2019 representing approximately 0.3 million shares of the Company's common stock, one-half vested on January 31, 2020 and the remaining one-half vested on July 31, 2020, subject to continuing service. The following table presents a summary of restricted stock unit activity and data under the 2015 Plan: Number of RSUs Weighted Average Grant Date Fair Value RSUs outstanding at March 31, 2020 247,863 $ 7.37 Granted 1,247,850 3.37 Vested and settled (187,741) 7.68 Forfeited (281,756) 3.95 RSUs outstanding at March 31, 2021 1,026,216 $ 3.39 Granted 3,407,270 1.48 Vested and settled (320,368) 3.38 Forfeited (821,627) 2.53 RSUs outstanding at March 31, 2022 3,291,491 $ 1.63 During the years ended March 31, 2022 and March 31, 2021, the total grant date fair values of RSUs that vested under the 2015 Plan were $1.1 million and $1.0 million, respectively. Approximately 3.3 million of the RSUs outstanding at March 31, 2022 were unvested, and all 1.0 million of the RSUs outstanding at March 31, 2021 were unvested. (D) Stock-based Compensation Expense: The Company recorded total stock-based compensation expense of $3.5 million and $4.4 million for the years ended March 31, 2022 and March 31, 2021, respectively, related to options and RSUs granted to its employees and directors, excluding stock-based compensation expense allocated to the Company from RSL (see Note 10(E)). This stock-based compensation expense was included in research and development and general and administrative expenses in the Company's consolidated statements of operations. At March 31, 2022, total unrecognized compensation expense for unvested outstanding option and RSU equity awards of the Company's common stock granted to its employees and directors under the 2015 Plan was $5.1 million, which is expected to be recognized over a remaining weighted-average service period of 2.11 years. (E) RSL Common Share Awards and Options: Certain employees of the Company were granted RSL equity instruments for which the Company recognized stock-based compensation expense of $4.0 million and $0.1 million during the years ended March 31, 2022 and March 31, 2021, respectively, and which is recorded to general and administrative expenses in the Company's consolidated statements of operations. Certain of these RSL equity instruments were granted to the Company's former CEO (the "RSL Equity Instruments"), who resigned as the Company's CEO in January 2022. The RSL Equity Instruments vest based on the satisfaction of time-based service and liquidity event requirements. The liquidity event vesting requirement was determined to be met upon the closing of RSL's business combination with Montes Archimedes Acquisition Corp., a special purpose acquisition company, on September 30, 2021. Accordingly, the Company commenced recognition of stock-based compensation expense for the RSL Equity Instruments on September 30, 2021.

Income Taxes

Income Taxes	12 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The loss before income taxes and the related tax expense (benefit) are as follows (in thousands): Year ended March 31, 2022 Year ended March 31, 2021 Loss before income taxes: Domestic $ (71,444) $ (17,382) Foreign (184) (15,255) Total loss before income taxes $ (71,628) $ (32,637) Current taxes: Domestic $ 259 $ (212) Foreign — — Total current tax expense (benefit) 259 (212) Deferred taxes: Domestic $ — $ — Foreign — — Total deferred tax expense — — Total income tax expense (benefit) $ 259 $ (212) A reconciliation of income tax benefit computed at the U.S/Bermuda statutory rate to income tax expense (benefit) reflected in the financial statements is as follows (in thousands): Year Ended Year Ended March 31, 2022 March 31, 2021 $ % $ % Income tax benefit at federal statutory rate $ (15,042) 21.00 % $ (6,854) 21.00 % Foreign rate differential (1) 13 (0.02) 1,118 (3.43) Nondeductible/nontaxable items 118 (0.16) (1,823) 5.59 Valuation allowance 15,129 (21.12) 10,749 (32.94) Research and development credit (300) 0.42 (914) 2.80 Research and development true-up (106) 0.15 (301) 0.92 Deferred adjustments (10) 0.01 2,139 (6.55) Restructuring — — (4,108) 12.59 Other 457 (0.64) (218) 0.67 Total income tax expense (benefit) $ 259 (0.36) % $ (212) 0.65 % (1) Primarily related to current tax on United States operations including permanent and temporary differences, Swiss net operating losses and United Kingdom taxation of the parent company. Until November 12, 2020, the Company was not subject to taxation under the laws of Bermuda since AGT was organized as a Bermuda Exempted Limited Company, for which there is no current tax regime. Since November 12, 2020, when Sio was incorporated in the State of Delaware in connection with the Domestication (see Note 1), the Company is subject to taxation under the laws of the United States of America. The Company's provision for income taxes is primarily federal, state and local taxes in the United States. The Company's effective tax rates of (0.36)% and 0.65% for the years ended March 31, 2022 and March 31, 2021, respectively, differ from the U.S. federal statutory rate of 21% and the Bermuda federal statutory rate of 0% primarily due to the U.S. permanent unfavorable tax differences, including stock compensation, and a valuation allowance that effectively eliminates the Company's net deferred tax assets. On March 27, 2020, the United States government enacted the Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act") which includes numerous modifications to income tax provisions, including a limitation on business interest expense and net operating loss provisions and the acceleration of alternative minimum tax credits. Given the Company's history of losses, the CARES Act is not expected to have a material impact on its income tax positions. As of March 31, 2022, the Company had an aggregate tax receivable of $1.6 million from various federal, state and local jurisdictions. 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, 2022 and 2021 are as follows (in thousands): March 31, 2022 March 31, 2021 Deferred tax assets: Net operating loss $ 172,292 $ 154,877 Research tax credits 12,205 11,798 Stock-based compensation 9,609 8,341 Intangibles 8,025 8,747 Lease liability 540 257 Other 10 51 Subtotal 202,681 184,071 Valuation allowance (201,976) (183,703) Deferred tax liabilities: Right of use assets (513) (250) Other (192) (118) Total net deferred tax assets $ — $ — The Company had net operating losses in the United States, Switzerland, the United Kingdom and Ireland in the amounts of $71.9 million, $1.21 billion, $167 thousand and $115 thousand, respectively, as of March 31, 2022. The United States federal net operating loss can be carried forward indefinitely with utilization limited to 80% of future taxable income for tax years beginning after January 1, 2021. The Switzerland net operating loss will begin to expire as of March 31, 2025. The United Kingdom net operating loss can be carried forward indefinitely with an annual limitation on utilization. As of March 31, 2022, the Company has federal research and development carryforwards of approximately $12.2 million. If not utilized, the research and development credit carryforwards will start to expire in 2038. The Company assesses the realizability of the 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 full valuation allowance of $202.0 million as of March 31, 2022, representing the portion of the deferred tax asset that is not more likely than not to be realized. The Company will continue to assess the realizability of 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, 2022, deferred tax liabilities for the foreign subsidiaries that are not indefinitely reinvested were not material to the Company’s consolidated financial statements. The potential tax implications of the repatriation of unremitted earnings are driven by the facts at the time of distribution; however, due to U.S. tax reform and the Company’s current accumulated earnings deficit, the incremental cost to repatriate earnings is not expected to be material. The Company is subject to tax and files income tax returns in the United Kingdom, Switzerland, Ireland and the United States federal and United States state and local jurisdictions. The Company is subject to tax examinations for tax years ended March 31, 2016 and forward 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 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, 2022.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies As of March 31, 2022, the Company had entered into commitments under the UMMS Agreement (see Note 3(A)) for which the Company provided notice of termination to UMMS of the UMMS Agreement in April 2022, which termination is expected to become effective by June 30, 2022 (see Note 14); the Services Agreements with certain of RSL's wholly owned subsidiaries (see Note 8(A)); and agreements to rent office and research and development laboratory spaces (see Note 5). In addition, the Company has entered into services agreements with third parties for pharmaceutical manufacturing and research activities in the normal course of business, which can generally be terminated by the Company with 30- to 60-days' written notice, unless otherwise indicated. Further, certain of the Company's manufacturing agreements could require early termination and wind-down payments due from the Company as a result of the recent termination of its clinical trials. The Company had the right to terminate the UMMS Agreement at any time upon 90 days' advance written notice to UMMS. The Company had the right to terminate the Oxford Agreement at any time upon two months' advance written notice prior to the first commercial sale of a product.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Mar. 31, 2022
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) The following table presents selected quarterly financial data for the years ended March 31, 2022 and March 31, 2021 (in thousands, except per share amounts): First Quarter Ended Second Quarter Ended Third Quarter Ended Fourth Quarter Ended First Quarter Ended Second Quarter Ended Third Quarter Ended Fourth Quarter Ended June 30, September 30, December 31, March 31, June 30, September 30, December 31, March 31, 2021 2021 2021 2022 2020 2020 2020 2021 Research and development expenses $ 8,058 $ 11,448 $ 21,287 $ 12,606 $ 5,194 $ 5,058 $ 6,407 $ 8,244 General and administrative expenses 3,859 9,748 4,086 470 4,640 4,491 4,198 3,965 Total operating expenses 11,917 21,196 25,373 13,076 9,834 9,549 10,605 12,209 Net loss (11,870) (21,237) (25,456) (13,324) (8,594) (9,984) (10,516) (3,331) Net loss per share attributable to stockholders of common stock - basic and diluted $ (0.16) $ (0.29) $ (0.35) $ (0.18) $ (0.20) $ (0.21) $ (0.20) $ (0.05)

Subsequent Events

Subsequent Events	12 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsIn April 2022, the Company provided notice of termination to UMMS of the UMMS Agreement, which termination is expected to become effective by June 30, 2022 (see Note 3(A) and Note 12). In connection with the termination of the UMMS Agreement, the Company implemented a significant reduction in its workforce subsequent to March 31, 2022. The Company expects to complete the workforce reduction, including the payment of any employee severance and benefits, by June 30, 2022. As a result of the workforce reduction, the Company estimates that it will incur aggregate costs ranging from approximately $0.9 million to $1.5 million for one-time severance and related costs, all of which are expected to result in cash expenditures during the fiscal quarter ending June 30, 2022.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation: The Company’s fiscal year ends on March 31, and its fiscal quarters end on June 30, September 30, and December 31. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted 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 as amended by Accounting Standards Updates ("ASU") issued by the Financial Accounting Standards Board ("FASB"). These consolidated financial statements and accompanying notes 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. Certain prior period balances have been reclassified to conform to the current period presentation. During November 2020, the historical financial statements and subsidiaries of AGT became the historical financial statements and subsidiaries of Sio upon consummation of the Domestication. As a result, these consolidated financial statements and accompanying notes reflect (i) the historical operating results of AGT and its subsidiaries prior to the Domestication; (ii) the operating results of the Company following the Domestication; and (iii) the Company’s equity structure for all periods presented.
Going Concern and Management's Plans	Going Concern and Management's Plans: The Company assesses and determines its ability to continue as a going concern in accordance with the provisions of ASC Subtopic 205-40, " Presentation of Financial Statements—Going Concern ", which requires the Company to evaluate whether there are conditions or events that raise substantial doubt about its ability to continue as a going concern within one year after the date that its annual and interim consolidated financial statements and accompanying notes are issued. Certain additional financial statement disclosures are required if such conditions or events are identified. If and when an entity’s liquidation becomes imminent, financial statements should be prepared under the liquidation basis of accounting. Determining the extent, if any, to which conditions or events raise substantial doubt about the Company’s ability to continue as a going concern, or the extent to which mitigating plans sufficiently alleviate any such substantial doubt, as well as whether or not liquidation is imminent, requires judgment by management. The Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the consolidated financial statements and accompanying notes are issued. The Company is currently a development stage company, and thus, has not yet achieved profitability. The Company expects to continue to incur significant operating and net losses, as well as negative cash flows from operations, for the foreseeable future. The Company has not generated any revenue to date. For the years ended March 31, 2022 and March 31, 2021, the Company incurred net losses of $71.9 million and $32.4 million, respectively. As of March 31, 2022, the Company's cash and cash equivalents totaled $63.7 million and its accumulated deficit was $863.0 million. The Company estimates that its current cash and cash equivalents balance is sufficient to support operations beyond the twelve-month period following the date that these consolidated financial statements and footnotes were issued. These estimates are based on assumptions that may prove to be wrong, and the Company could use its available capital resources sooner than it currently expects. The Company's future funding requirements, both near and long-term, will depend on many factors, including, but not limited to the timing and outcome of its exploration of, and execution upon any, potential strategic alternatives, the cost of obtaining necessary intellectual property and defending potential intellectual property disputes, realization of the anticipated benefits of the Company's headcount reduction, and the costs of operating as a public company.
Use of Estimates	Use of Estimates: The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company regularly evaluates estimates and assumptions related to certain assets and liabilities, including its research and development accruals, as well as assumptions used to estimate the fair value of its stock option awards, estimate its income tax expense and estimate its ability to continue as a going concern. Specifically, the Company’s assessment of the completeness of the information for research and development accruals is subject to variability and uncertainty. In addition, in certain circumstances, the determination of the nature and amount of research and development services that have been received during the reporting period requires judgment as the timing and pattern of vendor invoicing does not correspond to the level of services provided. The Company estimates the grant date fair value of stock option awards with only time-based vesting requirements using a Black-Scholes valuation model and uses a Monte Carlo Simulation method under the income approach to estimate the grant date fair value of stock option awards with market-based performance conditions. 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, 2022 and through the date of issuance of these audited consolidated financial statements and accompanying notes. 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	Risks and Uncertainties:The Company is subject to risks common to companies in the pharmaceutical industry including, but not limited to, uncertainties related to commercialization of products, regulatory approvals, dependence on key products, dependence on key customers and suppliers, and protection of intellectual property rights.
Concentrations of Credit Risk	Concentrations of Credit Risk:Financial instruments that potentially subject the Company to concentration of credit risk include cash and cash equivalents. At March 31, 2022, substantially all of the Company's cash balances are deposited in 1 banking institution in excess of insured levels.
Cash and Cash Equivalents	Cash and Cash Equivalents:The Company considers all highly liquid investments purchased with original maturities of 90 days or less at acquisition to be cash equivalents. Cash and cash equivalents include cash held in banks and amounts held in money market funds.
Property and Equipment	Property and Equipment:Property and equipment, consisting of leasehold improvements, furniture and fixtures, computers, software and other office and laboratory equipment, 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. 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 results of operations. Depreciation is recorded for property and equipment using the straight-line method over the estimated useful lives of the respective assets, generally three
Debt Issuance Costs and Debt Discount	Debt Issuance Costs and Debt Discount:Debt issuance costs related to a recognized debt liability are presented on the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts, and are amortized to interest expense over the term of the related debt using the effective interest method. Further, debt discounts created as a result of the allocation of proceeds received from a debt issuance to warrants issued in conjunction with the debt issuance are amortized to interest expense under the effective interest method over the life of the recognized debt liability.
Research and Development Expense	Research and Development Expense:Research and development costs are expensed as incurred. Clinical study costs are accrued over the service periods specified in the contracts and adjusted as necessary based upon an ongoing review of the level of effort and costs actually 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 final regulatory approvals are capitalized and amortized to cost of revenue over the remaining useful life of the asset. Research and development costs primarily consist of intellectual property and research and development materials acquired under license and license and collaboration agreements (see Note 3) and expenses from third parties who conduct research and development activities on behalf of the Company. The Company expenses in-process research and development projects acquired as asset acquisitions which have not reached technological feasibility, and which have no alternative future use.
Income Taxes	Income Taxes:Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and the respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is recorded when, after consideration of all positive and negative evidence, it is not more likely than not that the Company's deferred tax assets will be realizable. 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. When and if the Company were to recognize interest and penalties related to unrecognized tax benefits, they would be reported in tax expense in the consolidated statement of operations.
Stock-Based Compensation	Stock-Based Compensation:Stock-based awards to employees and directors with only time-based vesting requirements are valued at fair value on the date of grant and that fair value is recognized on a straight-line basis over the requisite service period of the entire award and is included in research and development expense and general and administrative expense in the Company's consolidated statements of operations. The Company values such time-based stock options using the Black-Scholes option pricing model. Certain assumptions are made with respect to utilizing the Black-Scholes option pricing model, including the expected life of the award, the volatility of the underlying shares and the risk-free interest rate. The expected life of such time-based stock options is calculated using the simplified method (based on the mid-point between the vesting date and the end of the contractual term), and 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. The expected share price volatility for such time-based stock option awards was estimated partially using weighted average measures of implied volatility and using the average historical price volatility for industry peers. The Company estimates the grant date fair value of stock option awards to employees with market-based performance conditions using a Monte Carlo Simulation method under the income approach. Certain assumptions are made with respect to utilizing the Monte Carlo Simulation method, including the volatility of the underlying shares and the drift rate, or estimated cost of equity. The expected share price volatility for such market-based performance stock option awards was estimated by taking the median historical price volatility for industry peers over the contractual term of the options. The drift rate, or estimated cost of equity, for such market-based performance stock option awards is based on various financial and risk-associated metrics of industry peers, as well as estimated factors specific to us. The Company accounts for stock-based payments to nonemployees issued in exchange for services in accordance with ASU No. 2018-07, " Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting " based upon the fair value of the equity instruments issued. Compensation expense for stock options issued to nonemployees is calculated using the Black-Scholes option pricing model on the grant date and is recorded over the service performance period.
Net Loss per Share of Common Stock	Net Loss per Share of Common Stock: Basic net loss per share of common stock is computed by dividing the net loss applicable to holders of common stock by the weighted-average number of shares of common stock and 3,301,998 pre-funded warrants (see Note 9(B)) outstanding during the period, without further consideration for potentially dilutive securities. The pre-funded warrants were fully exercised in July 2021 (see Note 9(B)). In accordance with ASC Topic 260, Earnings Per Share , the pre-funded warrants were included in the computation of basic net loss per share because the exercise price was negligible and they were fully vested and exercisable at any time after the original issuance date. Diluted net loss per share of common stock is computed by dividing the net loss applicable to holders of common stock by the diluted weighted-average number of shares of common stock outstanding during the period calculated in accordance with the treasury stock method. In periods in which the Company reports a net loss, all common stock equivalents are deemed anti-dilutive such that basic net loss per share of common stock and diluted net loss per share of common stock are equivalent. Potentially dilutive shares of common stock have been excluded from the diluted net loss per share of common stock computations in all periods presented because such securities have an anti-dilutive effect on net loss per share of common stock due to the Company’s net loss. Restricted Stock Units ("RSUs") and stock options outstanding for totals of 5.0 million and 3.1 million shares of common stock were not included in the calculation of diluted weighted-average shares of common stock outstanding for the years ended March 31, 2022 and 2021, respectively, because they were anti-dilutive given the net loss of the Company.
Financial Instruments and Fair Value Measurement	Financial Instruments and Fair Value Measurement: The Company utilizes fair value measurement guidance prescribed by accounting standards to value its financial instruments. The guidance establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company's own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company's assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. Fair value is defined as the exchange price, or exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, the guidance establishes a three-tier fair value hierarchy that distinguishes among the following: • Level 1-Valuations are based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. • Level 2-Valuations are based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active and models for which all significant inputs are observable, either directly or indirectly. • Level 3-Valuations are based on inputs that are unobservable (supported by little or no market activity) and significant to the overall fair value measurement.
Recently Accounting Pronouncements	Recent Accounting Pronouncements: In June 2016, the FASB issued ASU No. 2016-13, “ Financial Instruments — Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments " ("ASU No. 2016-13"). ASU 2016-13 requires that financial assets measured at amortized cost, such as loans, accounts and trade receivables and investments, be represented net of expected credit losses, which may be estimated based on relevant information such as historical experience, current conditions, and future expectation for each pool of similar financial asset. ASU No. 2016-13 requires enhanced disclosures related to trade receivables and associated credit losses. In May 2019, the FASB issued ASU No. 2019-05, “ Financial Instruments — Credit Losses (Topic 326): Targeted Transition Relief ", which allows for a transition election on certain instruments and is effective for smaller reporting companies for fiscal years beginning after December 15, 2022 and interim periods in those fiscal years. In November 2019, the FASB issued ASU No. 2019-11, " Codification Improvements to Topic 326, Financial Instruments — Credit Losses ", which amends certain aspects of ASU No. 2016-13, including transition relief for trouble debt restructuring ("TDR"), among other topics. In March 2022, the FASB issued ASU No. 2022-02, " Financial Instruments — Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures " ("ASU No. 2022-02"), which eliminates the accounting guidance on TDRs for creditors in ASC Subtopic 310-40 and amends the guidance on “vintage disclosures” to require disclosure of current-period gross write-offs by year of origination. ASU No. 2022-02 also updates the requirements related to accounting for credit losses under ASC Topic 326 and adds enhanced disclosures for creditors with respect to loan refinancings and restructurings for borrowers experiencing financial difficulty. While the Company does not expect the adoption of this guidance to materially impact the Company's consolidated financial statements and related disclosures because it does not currently have any investments or trade receivables, the impact on the Company's consolidated financial statements and disclosures will depend on the facts and circumstances of any specific future transactions or circumstances. In August 2020, the FASB issued ASU No. 2020-06, " Debt — Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging — Contracts in Entity's Own Equity (Subtopic 815-40) " ("ASU No. 2020-06"). ASU No. 2020-06 simplifies the accounting for convertible debt instruments by removing the beneficial conversion and cash conversion separation models for convertible instruments. Under ASU No. 2020-06, the embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives or that do not result in substantial premiums accounted for as paid-in capital. ASU No. 2020-06 also amends the accounting for certain contracts in an entity’s own equity that are currently accounted for as derivatives because of specific settlement provisions. In addition, the new guidance modifies how particular convertible instruments and certain contracts that may be settled in cash or shares impact the computation of diluted earnings or loss per share. The provisions of ASU No. 2020-06 are effective for fiscal years beginning after December 15, 2021, and interim periods within those fiscal years, with early adoption permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The Company's adoption of ASU No. 2020-06 on April 1, 2022 did not impact the Company's consolidated financial statements and related disclosures because it did not maintain any debt instruments accounted for in accordance with ASC Subtopic 470-20, " Debt — Debt with Conversion and Other Options " or instruments accounted for as derivatives in accordance with ASC Subtopic 815-40, " Derivatives and Hedging — Contracts in Entity's Own Equity ", and the Company had also included outstanding pre-funded warrants in the computation of basic net loss per share (see Note 2(L)). In May 2021, the FASB issued ASU No. 2021-04, " Earnings Per Share (Topic 260), Debt — Modifications and Extinguishments (Subtopic 470-50), Compensation — Stock Compensation (Topic 718), and Derivatives and Hedging — Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options " ("ASU No. 2021-04"). ASU No. 2021-04 provides a principles-based framework for issuers to account for a modification or exchange of freestanding equity-classified written call options. To the extent applicable, issuers first reference other U.S. GAAP to account for the effect of the modification. In the absence of other U.S. GAAP, ASU No. 2021-04 clarifies whether to account for the effect as an adjustment to equity, and the related EPS implications, or as an expense, and if so the manner and pattern of recognition. The provisions of ASU No. 2021-04 are effective for annual periods beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted. The Company's adoption of ASU No. 2021-04 on April 1, 2022 did not impact the Company's consolidated financial statements and related disclosures because it did not modify outstanding equity-classified written call options upon adoption. In March 2022, the FASB issued ASU No. 2022-01, " Derivatives and Hedging (Topic 815) — Fair Value Hedging — Portfolio Layer Method " ("ASU No. 2022-01"). ASU No. 2022-01 clarifies the guidance in ASC Topic 815 on fair value hedge accounting of interest rate risk for portfolios of financial assets, and amends the guidance in ASU 2017-12, " Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities ", that, among other things, established the “last-of-layer” method for making the fair value hedge accounting for these portfolios more accessible. ASU 2022-01 renames that method the “portfolio layer” method. The provisions of ASU No. 2022-01 are effective for annual periods beginning after December 15, 2022, including interim periods within those fiscal years. Early adoption is permitted. While the Company does not expect the adoption of this guidance to materially impact the Company's consolidated financial statements and related disclosures because it does not currently have any financial instruments designated as fair value hedges, the impact on the Company's consolidated financial statements and disclosures will depend on the facts and circumstances of any specific future transactions or circumstances. Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force), the American Institute of Certified Public Accountants, and the SEC did not, or are not believed by management to, have a material impact on the Company’s present or future consolidated financial position, results of operations or cash flows.
Foreign Currency	Foreign Currency:The Company has operations in the United States, the United Kingdom, Ireland 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 year. The Company’s assets and liabilities are translated using the current exchange rate as of the balance sheet date and stockholders’ equity is translated using historical rates. Adjustments resulting from the translation of the financial statements of the Company’s foreign functional currency subsidiaries into U.S. dollars are excluded from the determination of net loss and are accumulated in a separate component of stockholders’ equity. Foreign exchange transaction gains and losses are included in other (income) expense in the Company’s results of operations.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Fair Value of Cash Equivalents	The following table summarizes the fair value of the Company's money market fund included in cash equivalents based on the inputs used at March 31, 2022 and 2021 in determining such values (in thousands): As of March 31, 2022 As of March 31, 2021 Fair Value Price Quotations (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value Price Quotations (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market fund $ 61,000 $ 61,000 $ — $ — $ 114,000 $ 114,000 $ — $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Schedule of Leases Remaining 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, 2022 (in thousands): Year Ending March 31, Amount 2022 $ 828 2023 936 2024 799 2025 310 2026 53 Thereafter — Total undiscounted payments 2,926 Less: present value adjustment (410) Present value of future payments $ 2,516

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	As of March 31, 2022 and 2021, accrued expenses consisted of the following (in thousands): March 31, 2022 March 31, 2021 Research and development expenses $ 4,392 $ 6,091 Bonuses and other compensation expenses 2,113 2,331 Other expenses 1,727 774 Total accrued expenses $ 8,232 $ 9,196

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
Schedule of Weighted Average Assumptions Used for Estimating the Fair Value of Stock Options	The Company estimated the fair value of each time-based stock option on the date of grant using the Black-Scholes closed-form option-pricing model applying the weighted average assumptions during the years ended March 31, 2022 and March 31, 2021, as follows: Years Ended March 31, 2022 2021 Expected stock price volatility 112.9 % 109.5 % Expected risk free interest rate 1.01 % 0.43 % Expected term, in years 5.93 6.11 Expected dividend yield — % — %
Schedule of Stock Option Activity	The following table presents a summary of stock option activity and data under the 2015 Plan: Number of Options Weighted Average Exercise Price Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value Options outstanding at March 31, 2020 2,008,735 $ 14.39 $ 13.87 8.33 $ — Granted 434,775 3.72 3.07 Exercised — — — — Forfeited (347,967) 13.92 15.84 Options outstanding at March 31, 2021 2,095,543 $ 12.26 $ 11.30 7.90 $ — Granted 1,594,400 2.47 2.06 Exercised — — — — Forfeited (1,979,933) 5.93 4.10 Options outstanding at March 31, 2022 1,710,010 $ 10.46 $ 10.84 7.38 $ — Options vested and expected to vest at March 31, 2022 1,710,010 $ 10.46 $ 10.84 7.38 $ — Options exercisable at March 31, 2022 1,174,102 $ 13.87 $ 14.68 6.72 $ —
Schedule of Restricted Stock Unit Activity	The following table presents a summary of restricted stock unit activity and data under the 2015 Plan: Number of RSUs Weighted Average Grant Date Fair Value RSUs outstanding at March 31, 2020 247,863 $ 7.37 Granted 1,247,850 3.37 Vested and settled (187,741) 7.68 Forfeited (281,756) 3.95 RSUs outstanding at March 31, 2021 1,026,216 $ 3.39 Granted 3,407,270 1.48 Vested and settled (320,368) 3.38 Forfeited (821,627) 2.53 RSUs outstanding at March 31, 2022 3,291,491 $ 1.63

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The loss before income taxes and the related tax expense (benefit) are as follows (in thousands): Year ended March 31, 2022 Year ended March 31, 2021 Loss before income taxes: Domestic $ (71,444) $ (17,382) Foreign (184) (15,255) Total loss before income taxes $ (71,628) $ (32,637) Current taxes: Domestic $ 259 $ (212) Foreign — — Total current tax expense (benefit) 259 (212) Deferred taxes: Domestic $ — $ — Foreign — — Total deferred tax expense — — Total income tax expense (benefit) $ 259 $ (212)
Reconciliation of Income Tax Benefit to Statutory Rate	A reconciliation of income tax benefit computed at the U.S/Bermuda statutory rate to income tax expense (benefit) reflected in the financial statements is as follows (in thousands): Year Ended Year Ended March 31, 2022 March 31, 2021 $ % $ % Income tax benefit at federal statutory rate $ (15,042) 21.00 % $ (6,854) 21.00 % Foreign rate differential (1) 13 (0.02) 1,118 (3.43) Nondeductible/nontaxable items 118 (0.16) (1,823) 5.59 Valuation allowance 15,129 (21.12) 10,749 (32.94) Research and development credit (300) 0.42 (914) 2.80 Research and development true-up (106) 0.15 (301) 0.92 Deferred adjustments (10) 0.01 2,139 (6.55) Restructuring — — (4,108) 12.59 Other 457 (0.64) (218) 0.67 Total income tax expense (benefit) $ 259 (0.36) % $ (212) 0.65 %
Schedule of Deferred Tax Assets and Liabilities	Significant components of the deferred tax assets (liabilities) at March 31, 2022 and 2021 are as follows (in thousands): March 31, 2022 March 31, 2021 Deferred tax assets: Net operating loss $ 172,292 $ 154,877 Research tax credits 12,205 11,798 Stock-based compensation 9,609 8,341 Intangibles 8,025 8,747 Lease liability 540 257 Other 10 51 Subtotal 202,681 184,071 Valuation allowance (201,976) (183,703) Deferred tax liabilities: Right of use assets (513) (250) Other (192) (118) Total net deferred tax assets $ — $ —

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Mar. 31, 2022
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	The following table presents selected quarterly financial data for the years ended March 31, 2022 and March 31, 2021 (in thousands, except per share amounts): First Quarter Ended Second Quarter Ended Third Quarter Ended Fourth Quarter Ended First Quarter Ended Second Quarter Ended Third Quarter Ended Fourth Quarter Ended June 30, September 30, December 31, March 31, June 30, September 30, December 31, March 31, 2021 2021 2021 2022 2020 2020 2020 2021 Research and development expenses $ 8,058 $ 11,448 $ 21,287 $ 12,606 $ 5,194 $ 5,058 $ 6,407 $ 8,244 General and administrative expenses 3,859 9,748 4,086 470 4,640 4,491 4,198 3,965 Total operating expenses 11,917 21,196 25,373 13,076 9,834 9,549 10,605 12,209 Net loss (11,870) (21,237) (25,456) (13,324) (8,594) (9,984) (10,516) (3,331) Net loss per share attributable to stockholders of common stock - basic and diluted $ (0.16) $ (0.29) $ (0.35) $ (0.18) $ (0.20) $ (0.21) $ (0.20) $ (0.05)

Description of Business (Detail

Description of Business (Details)	12 Months Ended
	Mar. 31, 2022segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	1
Number of reporting segments	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Going Concern and Management's Plans (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Accounting Policies [Abstract]
Net loss	$ (13,324)	$ (25,456)	$ (21,237)	$ (11,870)	$ (3,331)	$ (10,516)	$ (9,984)	$ (8,594)	$ (71,887)	$ (32,425)
Cash and cash equivalents	63,729				118,986				63,729	118,986	$ 80,752
Accumulated deficit	$ (862,956)				$ (791,069)				$ (862,956)	$ (791,069)

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Concentration Risk (Details)	Mar. 31, 2022banking_institution
Credit Concentration Risk
Concentration Risk [Line Items]
Number of banking institutions	1

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Property and Equipment (Details)	12 Months Ended
	Mar. 31, 2022
Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Net Loss per Share of Common Stock (Details) - shares	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Jul. 31, 2021	Feb. 29, 2020
Stock options and RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in calculation of common shares outstanding (in shares)	5,000,000	3,100,000
Public Offering
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of securities called by warrants (in shares)			3,301,998	3,301,998

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Financial Instruments and Fair Value Measurement (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Accounting Policies [Abstract]
Money market fund	$ 61,000	$ 114,000

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Fair Value of Cash Equivalents (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund	$ 61,000	$ 114,000
Price Quotations (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund	61,000	114,000
Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund	$ 0	$ 0

License and Collaboration Agr_2

License and Collaboration Agreements (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021
License Agreement [Line Items]
Research and development expenses	$ 12,606	$ 21,287	$ 11,448	$ 8,058	$ 8,244	$ 6,407	$ 5,058	$ 5,194	$ 53,399	$ 24,903
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | The University of Massachusetts Medical School
License Agreement [Line Items]
Research and development expenses									27,700	6,900
Additional research and development expense									3,000	3,000
Payments for license agreement									5,300	29
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Oxford BioMedica (UK) Ltd.
License Agreement [Line Items]
Research and development expenses									10,600	5,700
Additional research and development expense									2,000	2,000
Payments for license agreement									$ 7,200	$ 3,500

Investment in Arvelle Therape_2

Investment in Arvelle Therapeutics B.V. (Details) $ / shares in Units, shares in Millions, $ in Millions	Feb. 25, 2019shares	Feb. 13, 2019€ / sharesshares	Mar. 31, 2021USD ($)	Feb. 28, 2021USD ($)	May 31, 2020USD ($)shares	Mar. 31, 2022USD ($)	Nov. 12, 2020$ / shares	Feb. 13, 2019USD ($)shares
Equity Securities without Readily Determinable Fair Value [Line Items]
Maximum shares to be purchased under subscription agreement (in shares) | shares								8.1
Par value (in EUR per share) | $ / shares							$ 0.00001
Number of shares acquired during period (in shares) | shares	5.9	2.2
Long-term investment								$ 5.9
Arvelle Therapeutics
Equity Securities without Readily Determinable Fair Value [Line Items]
Equity Securities (in shares) | shares					2.2
Capitalized as a long-term investment					$ 2.2
Proceeds from sale of equity method investments				$ 11.6
Received held in escrow				1.2
Contingent consideration expected to be received						$ 7
Realized gain (loss) on disposal			$ 4.3	$ 4.7
Long-term Investee
Equity Securities without Readily Determinable Fair Value [Line Items]
Par value (in EUR per share) | € / shares		€ 0.00001

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2021	Mar. 31, 2022	Mar. 31, 2021	Aug. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets and liabilities recognized	$ 1,700	$ 1,690	$ 1,141
Operating lease right-of-use assets		$ 2,444	1,152
Payment term		3 years 2 months 12 days
Operating lease, weighted average remaining lease term		3 years 3 months 18 days
Operating lease, weighted average discount rate, percent		8.70%
Rent expense		$ 600	1,600
Payments for contractual rent obligations		$ 600	$ 900
Office Lease Facility In New York New York
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lessee, operating lease, discount rate	8.40%			8.90%
Operating lease right-of-use assets				$ 1,100

Leases - Remaining Contractual

Leases - Remaining Contractual Rent Obligations (Details) $ in Thousands	Mar. 31, 2022USD ($)
Leases [Abstract]
2022	$ 828
2023	936
2024	799
2025	310
2026	53
Thereafter	0
Total undiscounted payments	2,926
Less: present value adjustment	(410)
Present value of future payments	$ 2,516

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Payables and Accruals [Abstract]
Research and development expenses	$ 4,392	$ 6,091
Bonuses and other compensation expenses	2,113	2,331
Other expenses	1,727	774
Total accrued expenses	$ 8,232	$ 9,196

Long-term Debt (Details)

Long-term Debt (Details) - Term Loan - Loan and Security Agreement with Hercules Capital, Inc. - USD ($) $ in Millions	Nov. 27, 2019	Feb. 02, 2017	Apr. 30, 2020	Mar. 31, 2022
Debt Instrument [Line Items]
Amount borrowed	$ 55
Debt instrument, redemption price, percentage of principal amount redeemed	50.00%
Prepayment of outstanding principal due	$ 15.7		$ 15.7
Accrued interest, fees and other amounts			$ 0.3
Extinguishment of debt, amount				$ 0.5
Minimum
Debt Instrument [Line Items]
Fixed interest rate	11.55%	10.55%
Prime Rate
Debt Instrument [Line Items]
Variable interest rate	6.80%	6.80%

Related Party Transactions (Det

Related Party Transactions (Details) - RSI - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Related Party Transaction [Line Items]
Termination notice period	90 days
Expense under service agreement	$ 0	$ 0.1

Stockholders_ Equity (Details)

Stockholders’ Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		26 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Jul. 31, 2021	Nov. 12, 2020	Feb. 29, 2020
Class of Stock [Line Items]
Common shares authorized (in shares)	1,000,000,000	1,000,000,000	1,000,000,000		1,010,000,000
Common stock issued (in shares)	73,739,378	69,377,567	73,739,378		1,000,000,000
Common shares par value (in dollars per share)	$ 0.00001	$ 0.00001	$ 0.00001		$ 0.00001
Preferred stock authorized (in dollars per share)					10,000,000
Preferred Stock shares par value (in dollars per share)					$ 0.00001
Public Offering
Class of Stock [Line Items]
Number of securities called by warrants (in shares)				3,301,998		3,301,998
Warrants issued (in dollars per share)						$ 3.74999
Exercise price of warrants (in dollars per share)						$ 0.00001
Private Placement
Class of Stock [Line Items]
Percentage of gross proceeds from common stock issuance paid for services						3.00%
SVB Leerink LLC | Private Placement
Class of Stock [Line Items]
Common stock issued during period (in shares)	700,000	29,700,000	30,400,000
Net proceeds from common stock issued	$ 1.5	$ 90.5	$ 92

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2019shares	Mar. 31, 2022USD ($)installment$ / sharesshares	Mar. 31, 2021USD ($)installment$ / sharesshares	Apr. 30, 2021shares	Apr. 30, 2020shares	Mar. 31, 2020$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)		1,710,010	2,095,543			2,008,735
Exercise price of options (in dollars per share) | $ / shares		$ 10.46	$ 12.26			$ 14.39
Fair value of options vested | $		$ 2.4	$ 3.5
Grants To Directors And Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $		3.5	4.4
Unrecognized compensation expense related to options | $		$ 5.1
Remaining weighted-average service period		2 years 1 month 9 days
Employees | RSL
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $		$ 4	$ 0.1
Time-Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options vested (in shares)		1,000,000
Time-Based Stock Options | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
Vesting percentage		25.00%
Number of installments | installment		12
Time-Based Stock Options | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Vesting percentage		33.33%
Number of installments | installment		8
Market-Based Performance Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)		100,000
Exercise price of options (in dollars per share) | $ / shares		$ 6.42
Number of options vested (in shares)		0
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		33.33%
Number of installments | installment		3	3
Number of shares from vesting (in shares)	300,000
Fair value of awards vested | $		$ 1.1	$ 1
Outstanding unvested (in shares)		3,291,491	1,026,216			247,863
Restricted Stock Units (RSUs) | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		50.00%
Restricted Stock Units (RSUs) | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		50.00%
2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares)		13,400,000		2,800,000	1,600,000
Share-based compensation , increase in the number of shares authorized (in shares)		5,000,000
Number of shares available for future issuance (in shares)		7,600,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option, Fair Value Assumptions (Details) - Time-Based Stock Options	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected stock price volatility	112.90%	109.50%
Expected risk free interest rate	1.01%	0.43%
Expected term, in years	5 years 11 months 4 days	6 years 1 month 9 days
Expected dividend yield	0.00%	0.00%

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock Option Activity (Details) - USD ($)	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Number of Options
Beginning balance (in shares)	2,095,543	2,008,735
Granted (in shares)	1,594,400	434,775
Exercised (in shares)	0	0
Forfeited (in shares)	(1,979,933)	(347,967)
Ending balance (in shares)	1,710,010	2,095,543	2,008,735
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 12.26	$ 14.39
Granted (in dollars per share)	2.47	3.72
Exercised (in dollars per share)	0	0
Forfeited (in dollars per share)	5.93	13.92
Ending balance (in dollars per share)	10.46	12.26	$ 14.39
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)	11.30	13.87
Granted (in dollars per share)	2.06	3.07
Exercised (in dollars per share)	0	0
Forfeited (in dollars per share)	4.10	15.84
Ending balance (in dollars per share)	$ 10.84	$ 11.30	$ 13.87
Additional Disclosures
Options outstanding, weighted average contractual term	7 years 4 months 17 days	7 years 10 months 24 days	8 years 3 months 29 days
Options outstanding, aggregate intrinsic value	$ 0	$ 0	$ 0
Options granted, aggregate intrinsic value	$ 0	$ 0
Options exercisable, number of options (in shares)	1,174,102
Options exercisable, weighted average exercise price (in dollars per share)	$ 13.87
Options exercisable, weighted average grant date fair value (in dollars per share)	$ 14.68
Options exercisable, weighted average contractual term	6 years 8 months 19 days
Options exercisable, aggregate intrinsic value	$ 0
Options Vested and Expected to Vest
Number of options (in shares)	1,710,010
Weighted average exercise price (in dollars per share)	$ 10.46
Weighted average grant date fair value (in dollars per share)	$ 10.84
Weighted Average Remaining Contractual Life (in years)	7 years 4 months 17 days
Aggregate Intrinsic Value	$ 0

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) - $ / shares	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Number of RSUs
Beginning balance (in shares)	1,026,216	247,863
Granted (in shares)	3,407,270	1,247,850
Vested and settled (in shares)	(320,368)	(187,741)
Forfeited (in shares)	(821,627)	(281,756)
Ending balance (in shares)	3,291,491	1,026,216
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 3.39	$ 7.37
Granted (in dollars per share)	1.48	3.37
Vested and settled (in dollars per share)	3.38	7.68
Forfeited (in dollars per share)	2.53	3.95
Ending balance (in dollars per share)	$ 1.63	$ 3.39

Income Taxes- Summary of Income

Income Taxes- Summary of Income Tax Expense by Jurisdiction (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Loss before income taxes:
Domestic	$ (71,444)	$ (17,382)
Foreign	(184)	(15,255)
Total loss before income taxes	(71,628)	(32,637)
Current taxes:
Domestic	259	(212)
Foreign	0	0
Total current tax expense (benefit)	259	(212)
Deferred taxes:
Domestic	0	0
Foreign	0	0
Total deferred tax expense	0	0
Total income tax expense (benefit)	$ 259	$ (212)

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Benefit to Statutory Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
$
Income tax benefit at federal statutory rate	$ (15,042)	$ (6,854)
Foreign rate differential	13	1,118
Nondeductible/nontaxable items	118	(1,823)
Valuation allowance	15,129	10,749
Research and development credit	(300)	(914)
Research and development true-up	(106)	(301)
Deferred adjustments	(10)	2,139
Restructuring	0	(4,108)
Other	457	(218)
Total income tax expense (benefit)	$ 259	$ (212)
%
Income tax benefit at federal statutory rate	21.00%	21.00%
Foreign rate differential	(0.02%)	(3.43%)
Nondeductible/nontaxable items	(0.16%)	5.59%
Valuation allowance	(21.12%)	(32.94%)
Research and development credit	0.42%	2.80%
Research and development true-up	0.15%	0.92%
Deferred adjustments	0.01%	(6.55%)
Restructuring	0.00%	12.59%
Other	(0.64%)	0.67%
Total income tax expense (benefit)	(0.36%)	0.65%

Income Taxes- Narrative (Detail

Income Taxes- Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Loss Carryforwards [Line Items]
Effective income tax rate	(0.36%)	0.65%
Income tax receivable	$ 1,609	$ 1,656
Valuation allowance on deferred tax assets	201,976	$ 183,703
Unrecognized tax benefits	0
Research and Development Tax Credit
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ 12,200
Bermuda
Operating Loss Carryforwards [Line Items]
Effective income tax rate	(0.36%)	0.65%
United States
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 71,900
Switzerland
Operating Loss Carryforwards [Line Items]
Net operating losses	1,210,000
United Kingdom
Operating Loss Carryforwards [Line Items]
Net operating losses	167
Ireland
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 115

Income Taxes- Schedule of Defer

Income Taxes- Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Deferred tax assets:
Net operating loss	$ 172,292	$ 154,877
Research tax credits	12,205	11,798
Stock-based compensation	9,609	8,341
Intangibles	8,025	8,747
Lease liability	540	257
Other	10	51
Subtotal	202,681	184,071
Valuation allowance	(201,976)	(183,703)
Deferred tax liabilities:
Right of use assets	(513)	(250)
Other	(192)	(118)
Total net deferred tax assets	$ 0	$ 0

Commitments and Contingencies (

Commitments and Contingencies (Details)	12 Months Ended
	Mar. 31, 2022
Third Parties for Pharmaceutical Manufacturing and Research Activities | Minimum
Other Commitments [Line Items]
Termination notice term	30 days
Third Parties for Pharmaceutical Manufacturing and Research Activities | Maximum
Other Commitments [Line Items]
Termination notice term	60 days
The University of Massachusetts Medical School
Other Commitments [Line Items]
Termination notice term	90 days
Oxford BioMedica (UK) Ltd.
Other Commitments [Line Items]
License agreement, termination notice prior term	2 months

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Research and development expenses	$ 12,606	$ 21,287	$ 11,448	$ 8,058	$ 8,244	$ 6,407	$ 5,058	$ 5,194	$ 53,399	$ 24,903
General and administrative expenses	470	4,086	9,748	3,859	3,965	4,198	4,491	4,640	18,163	17,294
Total operating expenses	13,076	25,373	21,196	11,917	12,209	10,605	9,549	9,834	71,562	42,197
Net loss	$ (13,324)	$ (25,456)	$ (21,237)	$ (11,870)	$ (3,331)	$ (10,516)	$ (9,984)	$ (8,594)	$ (71,887)	$ (32,425)
Net loss per share attributable to stockholders of common stock — basic (in dollars per share)	$ (0.18)	$ (0.35)	$ (0.29)	$ (0.16)	$ (0.05)	$ (0.20)	$ (0.21)	$ (0.20)	$ (0.98)	$ (0.62)
Net loss per share attributable to stockholders of common stock — diluted (in dollars per share)	$ (0.18)	$ (0.35)	$ (0.29)	$ (0.16)	$ (0.05)	$ (0.20)	$ (0.21)	$ (0.20)	$ (0.98)	$ (0.62)

Subsequent Events (Details)

Subsequent Events (Details) - Forecast - Termination Of UMMS Agreement $ in Millions	3 Months Ended
	Jun. 30, 2022USD ($)
Minimum
Subsequent Event [Line Items]
One-time severance and related costs	$ 0.9
Maximum
Subsequent Event [Line Items]
One-time severance and related costs	$ 1.5