Sio Gene Therapies (SIOX) 10-Q 10 Feb 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Dec. 31, 2019	Feb. 06, 2020
Document And Entity Information [Abstract]
Entity Registrant Name	Axovant Gene Therapies Ltd.
Entity Central Index Key	0001636050
Document Type	10-Q
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		22,791,669
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Emerging Growth Company	true
Entity Small Business	true
Entity Ex Transition Period	true
Entity Shell Company	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019
Current assets:
Cash and cash equivalents	$ 27,812	$ 106,999
Prepaid expenses and other current assets	3,621	5,859
Income tax receivable	1,988	1,726
Total current assets	33,421	114,584
Long-term investment	5,871	5,871
Other non-current assets	46	973
Operating lease right-of-use assets	1,946
Property and equipment, net	980	1,278
Total assets	42,264	122,706
Current liabilities:
Accounts payable	347	1,698
Accrued expenses	20,334	20,619
Current portion of operating lease liabilities	1,156
Current portion of long-term debt	8,851	21,182
Total current liabilities	30,688	43,499
Operating lease liabilities, net of current portion	77
Long-term debt	6,452	22,994
Total liabilities	37,217	66,493
Commitments and contingencies (Note 11)
Shareholders’ equity:
Common shares, par value $0.00001 per share, 1,000,000,000 shares authorized, 22,791,669 and 22,779,891 issued and outstanding at December 31, 2019 and March 31, 2019, respectively	0	0
Additional paid-in capital	746,845	741,318
Accumulated deficit	(741,996)	(686,016)
Accumulated other comprehensive income	198	911
Total shareholders’ equity	5,047	56,213
Total liabilities and shareholders’ equity	$ 42,264	$ 122,706

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	May 08, 2019	May 07, 2019	Mar. 31, 2019
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)	22,791,669	22,800,000	182,200,000	22,779,891
Common shares outstanding (in shares)	22,791,669	22,800,000	182,200,000	22,779,891

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Operating expenses:
Research and development expenses	[1]	$ 8,267	$ 21,483	$ 36,190	$ 80,403
General and administrative expenses	[2]	5,409	10,933	16,928	33,309
Total operating expenses		13,676	32,416	53,118	113,712
Other (income) expenses:
Interest expense		1,066	1,906	3,937	5,808
Other (income) expense		(694)	(78)	(1,231)	275
Loss before income tax expense		(14,048)	(34,244)	(55,824)	(119,795)
Income tax expense (benefit)		(9)	52	156	224
Net loss		$ (14,039)	$ (34,296)	$ (55,980)	$ (120,019)
Net loss per common share — basic and diluted (in dollars per share)		$ (0.62)	$ (2.13)	$ (2.46)	$ (8.06)
Weighted-average common shares outstanding - basic and diluted (in shares)		22,791,669	16,096,488	22,785,006	14,897,890
Research and development expenses
Costs allocated		$ 0	$ 0	$ 0	$ (450)
General and administrative expenses
Costs allocated		$ 27	$ 698	$ 103	$ 2,772
[1]	Includes total costs (benefit) allocated from certain wholly owned subsidiaries of our parent company, Roivant Sciences Ltd., of $0 and $(450) for the nine months ended December 31, 2019 and 2018, respectively.
[2]	Includes total costs allocated from certain wholly owned subsidiaries of our parent company, Roivant Sciences Ltd., of $27 and $698 for the three months ended December 31, 2019 and 2018, respectively, and $103 and $2,772 for the nine months ended December 31, 2019 and 2018, respectively.

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Research and development expenses
Share-based compensation expense	$ 876	$ 1,910	$ 2,006	$ 3,299
General and administrative expenses
Share-based compensation expense	$ 1,436	$ 2,648	$ 3,332	$ 9,575

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (14,039)	$ (34,296)	$ (55,980)	$ (120,019)
Other comprehensive (loss) income:
Foreign currency translation adjustment	(293)	92	(713)	538
Total other comprehensive (loss) income	(293)	92	(713)	538
Comprehensive loss	$ (14,332)	$ (34,204)	$ (56,693)	$ (119,481)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Shares	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Private Placement	Private PlacementCommon Shares	Private PlacementAdditional Paid-in Capital	Public Offering	Public OfferingCommon Shares	Public OfferingAdditional Paid-in Capital	Share Sale Agreement	Share Sale AgreementCommon Shares	Share Sale AgreementAdditional Paid-in Capital
Beginning balance (in shares) at Mar. 31, 2018		13,473,512
Beginning balance at Mar. 31, 2018	$ 71,286	$ 0	$ 628,111	$ (556,951)	$ 126
Increase (Decrease) in Shareholders' Equity (Deficit)
Issuance of shares upon exercise of stock options (in shares)		875
Issuance of shares upon exercise of stock options	10		10
Share-based compensation expense	5,369		5,369
Capital contribution — share-based compensation expense	490		490
Foreign currency translation adjustment	559				559
Net loss	(51,888)			(51,888)
Ending balance (in shares) at Jun. 30, 2018		13,474,387
Ending balance at Jun. 30, 2018	25,826	$ 0	633,980	(608,839)	685
Beginning balance (in shares) at Mar. 31, 2018		13,473,512
Beginning balance at Mar. 31, 2018	71,286	$ 0	628,111	(556,951)	126
Increase (Decrease) in Shareholders' Equity (Deficit)
Foreign currency translation adjustment	538
Net loss	(120,019)
Ending balance (in shares) at Dec. 31, 2018		19,440,965
Ending balance at Dec. 31, 2018	22,760	$ 0	699,066	(676,970)	664
Beginning balance (in shares) at Mar. 31, 2018		13,473,512
Beginning balance at Mar. 31, 2018	71,286	$ 0	628,111	(556,951)	126
Increase (Decrease) in Shareholders' Equity (Deficit)
Net loss	(129,100)
Ending balance (in shares) at Mar. 31, 2019		22,779,891
Ending balance at Mar. 31, 2019	56,213	$ 0	741,318	(686,016)	911
Beginning balance (in shares) at Jun. 30, 2018		13,474,387
Beginning balance at Jun. 30, 2018	25,826	$ 0	633,980	(608,839)	685
Increase (Decrease) in Shareholders' Equity (Deficit)
Issuance of shares upon exercise of stock options (in shares)		11,090
Issuance of shares upon exercise of stock options	108		108
Shares issued/sold (in shares)							1,785,714						743
Shares issued/sold						$ 25,000		$ 25,000				$ 14		$ 14
Share-based compensation expense	5,635		5,635
Capital contribution — share-based compensation expense	(3,178)		(3,178)
Non-cash capital contribution received from Roivant Sciences, Inc.	422		422
Foreign currency translation adjustment	(113)				(113)
Net loss	(33,835)			(33,835)
Ending balance (in shares) at Sep. 30, 2018		15,271,934
Ending balance at Sep. 30, 2018	19,879	$ 0	661,981	(642,674)	572
Increase (Decrease) in Shareholders' Equity (Deficit)
Issuance of shares upon exercise of stock options (in shares)		21,572
Issuance of shares upon exercise of stock options	175		175
Shares issued/sold (in shares)										4,145,115			2,344
Shares issued/sold									$ 31,634		$ 31,634	$ 47		$ 47
Share-based compensation expense	4,530		4,530
Capital contribution — share-based compensation expense	28		28
Non-cash capital contribution received from Roivant Sciences, Inc.	671		671
Foreign currency translation adjustment	92				92
Net loss	(34,296)			(34,296)
Ending balance (in shares) at Dec. 31, 2018		19,440,965
Ending balance at Dec. 31, 2018	22,760	$ 0	699,066	(676,970)	664
Beginning balance (in shares) at Mar. 31, 2019		22,779,891
Beginning balance at Mar. 31, 2019	56,213	$ 0	741,318	(686,016)	911
Increase (Decrease) in Shareholders' Equity (Deficit)
Issuance of shares upon exercise of stock options (in shares)		781
Issuance of shares upon exercise of stock options	5		5
Share-based compensation expense	2,135		2,135
Non-cash capital contribution received from Roivant Sciences, Inc.	28		28
Foreign currency translation adjustment	(972)				(972)
Net loss	(28,057)			(28,057)
Ending balance (in shares) at Jun. 30, 2019		22,780,672
Ending balance at Jun. 30, 2019	29,352	$ 0	743,486	(714,073)	(61)
Beginning balance (in shares) at Mar. 31, 2019		22,779,891
Beginning balance at Mar. 31, 2019	56,213	$ 0	741,318	(686,016)	911
Increase (Decrease) in Shareholders' Equity (Deficit)
Foreign currency translation adjustment	(713)
Net loss	(55,980)
Ending balance (in shares) at Dec. 31, 2019		22,791,669
Ending balance at Dec. 31, 2019	5,047	$ 0	746,845	(741,996)	198
Beginning balance (in shares) at Jun. 30, 2019		22,780,672
Beginning balance at Jun. 30, 2019	29,352	$ 0	743,486	(714,073)	(61)
Increase (Decrease) in Shareholders' Equity (Deficit)
Issuance of shares upon exercise of stock options (in shares)		10,997
Issuance of shares upon exercise of stock options	81		81
Share-based compensation expense	891		891
Non-cash capital contribution received from Roivant Sciences, Inc.	48		48
Foreign currency translation adjustment	552				552
Net loss	(13,884)			(13,884)
Ending balance (in shares) at Sep. 30, 2019		22,791,669
Ending balance at Sep. 30, 2019	17,040	$ 0	744,506	(727,957)	491
Increase (Decrease) in Shareholders' Equity (Deficit)
Share-based compensation expense	2,312		2,312
Non-cash capital contribution received from Roivant Sciences, Inc.	27		27
Foreign currency translation adjustment	(293)				(293)
Net loss	(14,039)			(14,039)
Ending balance (in shares) at Dec. 31, 2019		22,791,669
Ending balance at Dec. 31, 2019	$ 5,047	$ 0	$ 746,845	$ (741,996)	$ 198

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Shareholders’ Equity Condensed Consolidated Statements of Shareholders' Equity (Parenthetical) $ in Millions	3 Months Ended
	Dec. 31, 2018USD ($)
Statement of Stockholders' Equity [Abstract]
Underwriting discounts and commissions and offering expenses	$ 1.6

Condensed Consolidated Statem_6

Condensed Consolidated Statement of Cash Flows - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (14,039)	$ (28,057)	$ (34,296)	$ (51,888)	$ (55,980)	$ (120,019)	$ (129,100)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on disposal of fixed assets					17	10
Unrealized foreign currency translation adjustment					(713)	538
Amortization of operating lease right-of-use assets					1,203
Share-based compensation expense					5,338	12,874
Depreciation and non-cash amortization					1,175	2,123
Change in operating lease liabilities					(1,318)	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets					2,376	(2,709)
Income tax receivable					(262)	171
Other non-current assets					341	(3,449)
Accounts payable					(1,351)	(2,931)
Due to/from Roivant Sciences Ltd. and certain of its wholly owned subsidiaries					(138)	(281)
Accrued expenses					(251)	(8,951)
Net cash used in operating activities					(49,563)	(122,624)
Cash flows from investing activities:
Purchases of property and equipment					(250)	(74)
Net cash used in investing activities					(250)	(74)
Cash flows from financing activities:
Payments on long-term debt					(29,563)	(4,780)
Capital contribution received from Roivant Sciences, Inc.					103	1,093
Cash proceeds from stock option exercises					86	293
Cash proceeds from issuance of common shares, net of costs					0	56,694
Net cash (used in) provided by financing activities					(29,374)	53,300
Net change in cash and cash equivalents					(79,187)	(69,398)
Cash and cash equivalents—beginning of period		$ 106,999		$ 154,337	106,999	154,337	154,337
Cash and cash equivalents—end of period	$ 27,812		$ 84,939		27,812	84,939	$ 106,999
Non-cash operating activities:
Operating lease right-of-use assets recognized upon and since the adoption of ASC 842, Leases, on April 1, 2019					3,103	$ 0
Operating lease liabilities recognized upon and since the adoption of ASC 842, Leases, on April 1, 2019					2,517
Amounts reclassified from other non-current assets to operating lease right-of-use assets upon the adoption of ASC 842, Leases, on April 1, 2019					$ 586

Description of Business

Description of Business	9 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Axovant Gene Therapies Ltd. ("AGT"), together with its wholly owned subsidiaries (the "Company"), is a clinical-stage company focused on gene therapy for neurological diseases. The Company is developing a pipeline of innovative product candidates for the treatment of these debilitating diseases, including Parkinson's disease, GM1 gangliosidosis and GM2 gangliosidosis (including Tay-Sachs disease and Sandhoff disease). The Company is dedicated to realizing the potential of gene therapies to offer transformative patient outcomes in areas of high unmet medical need. AGT is an exempted limited company incorporated under the laws of Bermuda, which was originally formed under the name Roivant Neurosciences Ltd. in October 2014 and changed its name to Axovant Sciences Ltd. in March 2015 and to Axovant Gene Therapies Ltd. in March 2019. AGT has seven wholly owned subsidiaries: • Axovant Holdings Limited ("AHL"); • Axovant Sciences, Inc. ("ASI"); • Axovant Sciences GmbH ("ASG"); • Axovant Sciences America, Inc. ("ASA"); • Axovant Treasury Holdings, Inc. ("ATH"); • Axovant Treasury, Inc. ("ATI"); and • Axovant Sciences Europe Limited. Since its inception, the Company has devoted substantially all of its efforts to organizing and staffing the Company, 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. The Company does not expect to generate revenue unless and until it successfully completes development and obtains regulatory approval for one of its product candidates.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Dec. 31, 2019
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 unaudited condensed consolidated financial statements and accompanying notes have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. These unaudited condensed consolidated financial statements and accompanying notes should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended March 31, 2019 (the "Annual Report"), filed with the Securities and Exchange Commission ("SEC") on June 11, 2019. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary to present fairly the financial position of the Company and its results of operations and cash flows for the periods presented have been included. Operating results for the three and nine-months ended December 31, 2019 are not necessarily indicative of the results that may be expected for the year ending March 31, 2020, for any other interim period, or for any other future year. 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 unaudited condensed 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. These unaudited condensed consolidated financial statements and accompanying notes have been prepared on the basis that the Company will continue as a going concern, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern (see Note 2(B)). A 1-for-8 reverse share split of the Company's outstanding common stock was effected on May 8, 2019 as approved by the Company's Board of Directors and a majority of its shareholders, which reduced the number of common shares issued and outstanding from approximately 182.2 million to 22.8 million as of May 8, 2019. As such, all references to share and per share amounts in these unaudited condensed consolidated financial statements and accompanying notes have been retroactively restated to reflect the 1-for-8 reverse share split, except for the authorized number of shares of the Company's common stock and the par value per share, which were not affected. There have been no significant changes in the Company’s accounting policies from those disclosed in its Annual Report, except for the Company's adoption of Topic 842, " Leases (Topic 842) " ("Topic 842") (see Note 2(F) and Note 5). (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 Topic 205-40, " Presentation of Financial Statements—Going Concern " ("ASC Topic 205-40"), 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 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 significant 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 are issued. As of December 31, 2019 , the Company’s cash and cash equivalents totaled $27.8 million and its accumulated deficit was $742.0 million . For the nine months ended December 31, 2019 and the fiscal year ended March 31, 2019, the Company incurred net losses of $56.0 million and $129.1 million , respectively. As of December 31, 2019 , the Company had aggregate net interest-bearing indebtedness of $15.3 million , of which $8.9 million was due within one year. The Company expects to continue to incur significant operating and net losses, as well as negative cash flows from operations, for the foreseeable future as it continues to develop its gene therapy product candidates and prepares for potential future regulatory approvals and commercialization of its products, if approved. The Company has not generated any revenue to date and does not expect to generate product revenue unless and until it successfully completes development and obtains regulatory approval for at least one of its product candidates, and its current cash and cash equivalents balance will not be sufficient to complete all necessary development activities and commercially launch its products. The Company anticipates that its current cash and cash equivalents balance will not be sufficient to sustain operations beyond three months following the date that these unaudited condensed consolidated financial statements and notes were issued, which raises substantial doubt about the Company's ability to continue as a going concern. To continue as a going concern, the Company will need, among other things, to raise additional capital in the near term. The Company continually assesses multiple options to obtain additional funding to support its operations, including proceeds from offerings of the Company’s equity securities or debt, cash received from the exercise of outstanding common stock options, or transactions involving product development, technology licensing or collaboration arrangements, or other sources of capital to complete its currently planned development programs. Management can provide no assurances that it can raise a sufficient amount of financing for the Company on favorable terms, if at all. Although the Company has successfully obtained financing in the past, and management believes that it will continue to do so in the future, ASC Subtopic 205-40 does not permit future financing activities that are not probable of being implemented and probable of alleviating the conditions that raise substantial doubt to be included in the Company's assessment of its liquidity. Due to these uncertainties, there is substantial doubt about the Company’s ability to continue as going concern. These unaudited condensed consolidated financial statements and accompanying notes have been prepared on the basis that the Company will continue as a going concern, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern. (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, including which costs are charged to research and development and general and administrative expense, as well as assumptions used to estimate its ability to continue as a going concern and estimate the fair value of its stock option awards. Specifically, 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. (D) Net Loss per Common Share: Basic net loss per common share is computed by dividing the net loss applicable to common shareholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per common share is computed by dividing the net loss applicable to common shareholders by the diluted weighted-average number of common shares outstanding during the period calculated in accordance with the treasury stock method. In periods in which the Company reports a net loss, all common share equivalents are deemed anti-dilutive such that basic net loss per common share and diluted net loss per common share are equivalent. Potentially dilutive common shares have been excluded from the diluted net loss per common share computations in all periods presented because such securities have an anti-dilutive effect on net loss per common share due to the Company’s net loss. There are no reconciling items used to calculate the weighted-average number of total common shares outstanding for basic and diluted net loss per common share data. Stock options and Restricted Stock Units ("RSUs") to purchase approximately 2.9 million common shares were not included in the calculation of diluted weighted-average common shares outstanding for the three and nine -months ended December 31, 2019 because they were anti-dilutive given the net loss of the Company. Stock options to purchase approximately 2.1 million common shares were not included in the calculation of diluted weighted-average common shares outstanding for the three and nine -months ended December 31, 2018 because they were anti-dilutive given the net loss of the Company. (E) 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, a long-term investment, accounts payable and long-term debt. Cash consists of non-interest-bearing deposits denominated in the U.S. dollar and Swiss franc, 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. Cash and accounts payable are stated at their respective historical carrying amounts, which approximate fair value due to their short-term nature. The carrying value of the Company's money market fund included in cash and cash equivalents of $10.6 million at December 31, 2019 approximated fair value, which is based on quoted prices in active markets for identical securities. At December 31, 2019 , the Company held a long-term investment in nonredeemable convertible preferred stock, which is accounted for in accordance with the provisions of ASC 321, " Investments - Equity Securities " whereby the Company elected to use the measurement alternative therein (see Note 4). The following table summarizes the fair value of the Company's money market fund included in cash equivalents based on the inputs used at December 31, 2019 in determining such values (in thousands): Fair Value Price Quotations (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market fund $ 10,555 $ 10,555 $ — $ — The carrying value of the Company’s debt of $15.3 million at December 31, 2019 approximated fair value, which was based on current interest rates for similar types of borrowings and is in Level 2 of the fair value hierarchy. (F) Recent Accounting Pronouncements: In February 2016, the FASB issued Topic 842, which requires lessees to recognize on their consolidated balance sheets a liability to make lease payments and a right-of-use asset representing their right to use the underlying asset for the lease term for both finance and operating leases with lease terms greater than twelve months. Topic 842 is effective for annual periods beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2018. Early adoption is permitted. A modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial application. Topic 842 allows entities to choose to use either (i) the effective date or (ii) the beginning of the earliest comparative period presented in the financial statements as the date of initial application. Topic 842 provides a number of optional practical expedients in transition. The Company adopted Topic 842 on April 1, 2019 using the optional modified retrospective transition method. Comparative periods were not restated. For leases that commenced prior to April 1, 2019, the Company elected the following package of practical expedients when assessing the transition impact: (1) not to reassess whether any expired or existing contracts are or contain leases; (2) not to reassess the lease classification for any expired or existing leases; and (3) not to reassess initial direct costs for any existing leases. The Company also elected to: (1) use the total lease term in its initial incremental borrowing rate calculation; (2) combine its lease and non-lease components and account for them as a single lease component; and (3) 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. Upon adoption, the Company recorded corresponding aggregate operating lease right-of-use assets and operating lease liabilities of $3.0 million and $2.4 million , respectively, including $0.6 million of prepaid rent previously classified within other non-current assets in the Company’s consolidated balance sheet that was reclassified to operating lease right-of-use assets. The adoption of the new standard did not materially impact the Company’s consolidated results of operations and cash flows and did not have an impact on the Company’s beginning accumulated deficit balance. For additional information regarding the Company’s leases, see Note 5 for further information regarding the impact of the Company's adoption of Topic 842. In February 2018, the FASB issued ASU No. 2018-02, " Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income " ("ASU No. 2018-02"). On December 22, 2017, an Act to provide for reconciliation pursuant to titles II and V of the concurrent resolution on the budget for fiscal year 2018 (commonly known as the "Tax Cuts and Jobs Act") was enacted in the United States, which introduced a comprehensive set of tax reforms. ASU No. 2018-02 allows companies to reclassify stranded tax effects resulting from the Tax Cuts and Jobs Act, from accumulated other comprehensive (loss) income to retained earnings. ASU No. 2018-02 is effective for interim and annual reporting periods beginning after December 15, 2018, and early adoption is permitted. The Company adopted the provisions of ASU No. 2018-02 for the fiscal year beginning April 1, 2019, which did not have a material impact on its consolidated financial statements and related disclosures. In June 2018, the FASB issued ASU No. 2018-07, " Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting " ("ASU No. 2018-07") . ASU No. 2018-07 requires equity-classified share-based payment awards issued to nonemployees to be measured on the grant date, rather than remeasuring the awards through the performance completion date as previously required. Additionally, for nonemployee awards with performance conditions, compensation cost associated with the award is to be recognized when achievement of the performance condition is probable, rather than upon achievement of the performance condition. Further, the requirement to reassess the liability or equity classification for nonemployee awards upon vesting is eliminated, except for awards in the form of convertible instruments. ASU No. 2018-07 is effective for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year, with early adoption permitted after the adoption of ASU No. 2014-09. The Company adopted the provisions of ASU No. 2018-07 for the fiscal year beginning April 1, 2019, which did not have a material impact on its consolidated financial statements and related disclosures. In December 2019, the FASB issued ASU No. 2019-12, " Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes " ("ASU No. 2019-12"). ASU No. 2019-12 simplifies the accounting for income taxes, eliminates certain exceptions within Income Taxes (Topic 740) , and clarifies certain aspects of the current guidance to promote consistency among reporting entities, and is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. Most amendments within ASU No. 2019-12 are required to be applied on a prospective basis, while certain amendments must be applied on a retrospective or modified retrospective basis. The Company is currently in the process of evaluating the effects of ASU No. 2019-12 on its consolidated financial statements, including potential early adoption. 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.

License and Collaboration Agree

License and Collaboration Agreements	9 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Collaboration Agreements	License and Collaboration Agreements (A) Oxford BioMedica License Agreement On June 5, 2018, the Company, through its wholly owned subsidiary, ASG, entered into an exclusive license 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 (the "Oxford Agreement"). In June 2018, as consideration for the license, the Company made an upfront nonrefundable payment to Oxford of $30.0 million , $5.0 million of which was applied as a credit against the process development work and clinical supply that Oxford is obligated to provide to the Company over the term of the Oxford Agreement. Under the terms of the Oxford Agreement, the Company could be obligated to make payments to Oxford totaling up to $55.0 million upon the achievement of specified development milestones and $757.5 million upon the achievement of specified regulatory and sales milestones. In April 2019, certain development milestones were achieved resulting in a $13.0 million net payment due to Oxford. The Company will also be obligated to pay Oxford a tiered royalty from 7% to 10% , based on yearly aggregate net sales of the underlying gene therapy products, subject to specified reductions upon the occurrence of certain events as set forth in the Oxford Agreement. These royalties are required to be paid, on a product-by-product and country-by-country basis, until the latest to occur of the expiration of the last to expire valid claim of a licensed patent covering such product in such country, the expiration of regulatory exclusivity for such product in such country, or 10 years after the first commercial sale of such product in such country. The Company is solely responsible, at its expense, for all activities related to the development and commercialization of the gene therapy products underlying the Oxford Agreement. Pursuant to the Oxford Agreement, the Company is required to use commercially reasonable efforts to develop, obtain regulatory approval of, and commercialize a gene therapy product underlying the Oxford Agreement in the United States and at least one major market country in Europe. In addition, the Company is required to meet certain diligence milestones and to include at least one U.S.-based clinical trial site in a pivotal study of a gene therapy product underlying the Oxford Agreement. If the Company fails to meet any of these specified development milestones, it may cure such failure by paying Oxford certain fees, which range from $0.5 million to $1.0 million . The Company evaluated the Oxford Agreement and determined that the acquired set of assets and activities did not meet the definition of a business and thus the transaction was not considered a business combination. The Company determined that the in-process research and development ("IPR&D") had not reached technological feasibility, and therefore, has no alternative future use. Accordingly, $25.0 million of the $30.0 million upfront nonrefundable payment to Oxford under the Oxford Agreement was recorded as research and development expense in the Company's condensed consolidated statements of operations during the three months ended June 30, 2018 . As the remaining $5.0 million of the upfront payment under the licensing agreement represents a nonrefundable payment for process development work and clinical supply that Oxford is obligated to provide over the term of the Oxford Agreement, the Company fully capitalized this portion of the payment upon execution, with $1.8 million remaining capitalized within prepaid expenses and other current assets in its unaudited condensed consolidated balance sheet as of December 31, 2019 , which will be recorded to research and development expense as the process development work and clinical supply are provided by Oxford. The Company has 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, or for a specified period of advance written notice after the first commercial sale of a product. Either party may terminate the Oxford Agreement for the other party's uncured material breach or with respect to a failure to make a required payment. Additionally, excluding the upfront nonrefundable payment and development milestones achieved, the Company incurred $2.4 million and $6.5 million of AXO-Lenti-PD program-specific costs within research and development expenses in its unaudited condensed consolidated statements of operations during the three and nine-months ended December 31, 2019 , respectively, and $1.9 million and $3.2 million during the three and nine-months ended December 31, 2018 , respectively. The Company paid Oxford a total of $1.7 million and $8.2 million during the three and nine-months ended December 31, 2019 , respectively, and $0.8 million and $30.9 million during the three and nine-months ended December 31, 2018 , respectively, including the upfront nonrefundable payment and payments made on development milestones achieved. (B) Benitec Biopharma License and Collaboration Agreement In July 2018, the Company, through its wholly owned subsidiary, ASG, entered into a license and collaboration agreement (the "Benitec Agreement") with Benitec Biopharma Limited ("Benitec"), pursuant to which the Company made an upfront payment of $10.0 million and received a worldwide, exclusive, royalty-bearing, sub-licensable license under certain patents and other intellectual property controlled by Benitec to develop and commercialize investigational gene therapy AXO-AAV-OPMD and related gene therapy products (collectively, the "AXO-AAV-OPMD Program") for all diseases and conditions. The Company terminated the Benitec Agreement in its entirety, effective September 3, 2019. The Company evaluated the Benitec Agreement and determined that the acquired set of assets and activities did not meet the definition of a business and thus the transaction was not considered a business combination. The Company determined that the IPR&D had not reached technological feasibility, and therefore, has no alternative future use. Accordingly, the $10.0 million upfront nonrefundable payment was recorded as research and development expense in the Company's unaudited condensed consolidated statement of operations during the three months ended September 30, 2018. The Company also incurred $(0.3) million and $1.8 million of AXO-AAV-OPMD program-specific costs within research and development expenses in its unaudited condensed consolidated statement of operations during the three and nine-months ended December 31, 2019 , respectively, and $1.9 million and $3.6 million during the three and nine-months ended December 31, 2018 , respectively, excluding the upfront nonrefundable payment. The Company paid Benitec a total of $0.4 million and $2.8 million during the three and nine-months ended December 31, 2019 , respectively, and $1.4 million and $11.4 million during the three and nine-months ended December 31, 2018 , respectively, including the upfront nonrefundable payment. (C) The University of Massachusetts Medical School Exclusive License Agreement In December 2018, the Company, through its wholly owned subsidiary, ASG, 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. This license is exclusive with respect to patents and biological materials and non-exclusive with respect to know-how and is subject to UMMS' retained rights for academic research, teaching and non-commercial patient care purposes, as well as to certain pre-existing rights of the U.S. government. 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 will reimburse UMMS for payments made by UMMS for the manufacture of clinical trial materials for the Company, up to a specified amount. The Company is obligated to use diligent efforts to develop and commercialize the licensed gene therapy product candidates and is required to achieve certain development and commercial milestones in accordance with the timeline set forth in the agreement. The Company evaluated the UMMS Agreement and determined that the acquired set of assets and activities did not meet the definition of a business and thus the transaction was not considered a business combination. The Company determined that the IPR&D had not reached technological feasibility, and therefore, has no alternative future use. Accordingly, the upfront payment of $ 10.0 million made from the Company to UMMS was recorded as research and development expense in the Company's unaudited condensed consolidated statement of operations during the three months ended December 31, 2018. In addition, the Company could be obligated to make payments to UMMS totaling up to $ 24.5 million upon the achievement of specified development and regulatory milestones and $ 39.8 million upon the achievement of specified commercial milestones. In February 2019, certain development and regulatory milestones were achieved resulting in a $1.0 million payment due to UMMS, and in October 2019, further development and regulatory milestones were achieved resulting in an additional $1.0 million payment due to UMMS. The Company is also obligated to pay UMMS tiered mid-single digit royalties based on yearly net sales of the licensed products, subject to a specified annual minimum amount. Additionally, the Company will pay UMMS a percentage of any revenues it receives from any third-party sublicenses to licensed products at rates ranging in the mid-single digits to mid-teens. The UMMS Agreement will expire upon the expiration of the Company's obligations to make royalty payments to UMMS, which continues until the later of the expiration of licensed patents and any applicable orphan designation exclusivity and 10 years after the first commercial sale of the licensed products. Upon such expiration, the licenses granted to the Company by UMMS will automatically convert to perpetual, irrevocable, worldwide royalty-free licenses. The Company has the right to terminate the UMMS Agreement at any time upon 90 days' advance written notice to UMMS. Either party may terminate the UMMS Agreement for the other party's uncured material breach upon 60 days' advance written notice, including in the event that UMMS reasonably determines the Company has not fulfilled its diligence obligations. During the three and nine-months ended December 31, 2019 , the Company incurred $1.8 million and $4.5 million , respectively, of program-specific costs excluding development and regulatory milestones achieved related to AXO-AAV-GM1 and AXO-AAV-GM2 within research and development expenses in its unaudited condensed consolidated statement of operations. Including the upfront payment and regulatory and development milestones achieved, the Company paid a total of $1.1 million and $2.9 million to UMMS during the three and nine-months ended December 31, 2019 , respectively, and a total of $10.0 million during the three and nine-months ended December 31, 2018.

Long-term Investment

Long-term Investment	9 Months Ended
	Dec. 31, 2019
Investments, All Other Investments [Abstract]
Long-term Investment	Long-term Investment On February 13, 2019 , ASG 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 ASG to Arvelle. The first closing under the Subscription Agreement occurred on February 25, 2019 with ASG 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 the Company's consolidated statement of operations. ASG 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. The Company accounts 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 investment will be remeasured upon future observable price change(s) in orderly transaction(s) or upon impairment, if any. On February 13, 2019, ASI and ASG entered into a transition services agreement with two wholly owned subsidiaries of Arvelle, whereby ASI and ASG received reimbursement for any expenses they, or third parties acting on their behalf, incurred on behalf of Arvelle or its subsidiaries (the "Transition Services Agreement"). For any general and administrative and research and development activities performed by its employees, ASI billed the employee compensation expense plus a predetermined mark-up, whereby the Company recorded $0.2 million to other income in its unaudited condensed consolidated statement of operations during the nine-months ended December 31, 2019 for such costs, inclusive of the mark-up. The Company billed Arvelle for all other charges at cost under the terms of the Transition Services Agreement. The Transition Services Agreement ended in September 2019.

Leases

Leases	9 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Leases The Company adopted the provisions of Topic 842 on April 1, 2019 using the effective date as its date of initial application and applied the optional modified retrospective transition method. Comparative periods were not restated. For leases that commenced prior to April 1, 2019, the Company elected the following package of practical expedients when assessing the transition impact: (1) not to reassess whether any expired or existing contracts are or contain leases; (2) not to reassess the lease classification for any expired or existing leases; and (3) not to reassess initial direct costs for any existing leases. The Company also elected to: (1) use the total lease term in its initial incremental borrowing rate calculation; (2) combine its lease and non-lease components and account for them as a single lease component; and (3) 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. Upon adoption, the Company recorded corresponding aggregate operating lease right-of-use assets and operating lease liabilities of $3.0 million and $2.4 million , respectively, including $0.6 million of prepaid rent previously classified within other non-current assets in the Company’s consolidated balance sheet that was reclassified to operating lease right-of-use assets. Operating right-of-use assets and obligations were recognized based on the present value of remaining lease payments over the lease term using an incremental borrowing rate of 12.9% . As the Company’s operating leases do not provide an implicit rate, estimated incremental borrowing rates were used based on the information available at the adoption date in determining the present value of lease payments. 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 unaudited condensed balance sheet. In addition, the Company reviews agreements at inception to determine if they include a lease, and when they do, uses its incremental borrowing rate or implicit interest rate to determine the present value of the future lease payments. The Company leases office facilities in New York, New York, Durham, North Carolina, and Princeton, New Jersey, with corresponding lease terms ending in January 2021, November 2022, and October 2020, respectively, whereby the last payment under the lease agreement for the office facility in New York, New York is due in September 2020. These leases are classified as operating leases in accordance with the provisions of Topic 842. The aggregate weighted-average remaining lease term and aggregate weighted-average discount rate were 1.2 years and 12.9% , respectively, for the Company's contractual rent obligations for operating leases as of December 31, 2019 . In each of the three- and nine-month periods ended December 31, 2019 and 2018, the Company incurred $ 0.4 million and $1.3 million , respectively, in rent expense associated with contractual rent obligations for its operating leases. During the nine months ended December 31, 2019 , the Company paid $1.5 million related to its contractual rent obligations associated with operating lease right-of-use assets. 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 December 31, 2019 (in thousands): Fiscal Year Ending March 31, Amount 2020 $ 306 2021 943 2022 46 2023 31 2024 — Thereafter — Total undiscounted payments 1,326 Less: Present value adjustment (93 ) Present value of future payments $ 1,233

Accrued Expenses

Accrued Expenses	9 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses As of December 31, 2019 , and March 31, 2019, accrued expenses consisted of the following (in thousands): December 31, 2019 March 31, 2019 Research and development expenses $ 17,348 $ 13,416 Salaries, bonuses, and other compensation expenses 1,816 3,899 Legal expenses 363 1,319 Other expenses 807 1,985 Total accrued expenses $ 20,334 $ 20,619

Long Term Debt

Long Term Debt	9 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Long Term Debt	Long-term Debt On February 2, 2017, AGT and its subsidiaries, AHL, ASG and ASI, entered into a loan and security agreement (as amended on May 24, 2017, September 22, 2017 and November 27, 2019) (the "Loan Agreement") with Hercules, under which AGT, AHL and ASG (the "Borrowers") borrowed an aggregate of $55.0 million (the "Term Loan"). Subsequently, ASA was added as a Borrower in July 2017, ATH and ATI were added as Borrowers in April 2018 and RSL was added as a guarantor in November 2019. Pursuant to the Loan Agreement, ASI and RSL have issued guarantees of the Borrowers’ obligations under the Loan Agreement, and the Borrowers and ASI have granted Hercules a first position lien on substantially all of their respective assets, excluding intellectual property. 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 Term Loan has a scheduled maturity date of March 1, 2021. The Borrowers were initially obligated to make monthly payments of accrued interest under the Loan Agreement until September 1, 2018, followed by monthly installments of principal and interest beginning October 1, 2018, through March 1, 2021. Subsequent to the November 2019 amendment of the Loan Agreement, the Borrowers are obligated to make monthly payments of accrued interest from December 1, 2019 until August 1, 2020, followed by monthly installments of principal and interest from September 1, 2020 through March 1, 2021. Prepayment of the Term Loan is subject to penalty. The Loan Agreement with Hercules initially required a covenant that the Borrowers maintain an aggregate minimum cash balance equal to the lesser of $30.0 million or the outstanding amount due under the Term Loan, which was removed as a result of the November 2019 amendment of the Loan Agreement. The Borrowers 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. The Loan Agreement also includes customary events of default. Upon the occurrence of an event of default, a default interest rate of an additional 5.0% may be applied to the outstanding principal balance, and Hercules may declare all outstanding obligations immediately due and payable and take such other actions as set forth in the Loan Agreement. At no time have the Borrowers been in default under the provisions of the Loan Agreement. In addition, for so long as the Term Loan remains outstanding, the Borrowers shall be required to use their commercially reasonable efforts to afford Hercules the opportunity to participate in future underwritten equity offerings of the Company's common shares up to a total of $3.0 million . In connection with the Loan Agreement, the Company issued a warrant to Hercules, exercisable for an aggregate of 34,260 of the Company's common shares at an exercise price of $96.32 per share (the "Warrant"). In August 2017, Hercules exercised the Warrant on a cashless basis and received a net issuance of 16,228 of the Company's common shares. The Warrant was accounted for as an equity instrument since it was indexed to the Company’s common shares and met the criteria for classification in shareholders’ equity. The relative fair value of the Warrant on the date of issuance of approximately $2.3 million was estimated using the Black-Scholes model. In addition, at the closing of the Term Loan, the Company paid transaction costs of $1.5 million . These amounts were recorded as a discount on the debt and are amortized to interest expense using the effective interest method over the life of the Term Loan, which is a period of 48 months. Outstanding debt obligations were as follows (in thousands): December 31, 2019 March 31, 2019 Principal amount $ 15,733 $ 45,295 Less: unamortized discount and debt issuance costs (430 ) (1,119 ) Loan payable less unamortized discount and debt issuance costs 15,303 44,176 Less: current portion of long-term debt (8,851 ) (21,182 ) Long-term loan payable, net of current maturities $ 6,452 $ 22,994 Annual maturities of debt outstanding as of December 31, 2019 are as follows (in thousands): Fiscal year ending March 31, 2020 $ — 2021 15,733 Thereafter — Total $ 15,733

Related Party Transactions

Related Party Transactions	9 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions (A) Services Agreements: In October 2014, AGT and ASI entered into a services agreement with Roivant Sciences, Inc. ("RSI"), a wholly owned subsidiary of RSL, under which RSI agreed to provide certain administrative and research and development services to AGT and ASI (the "RSI Services Agreement"). AGT and ASI amended and restated the RSI Services Agreement with RSI on October 13, 2015, effective for the fiscal year commencing April 1, 2015. Under the RSI Services Agreement, as amended and restated, AGT and ASI pay or reimburse RSI for any expenses it, or third parties acting on its behalf, incurs for AGT and ASI. For any general and administrative and research and development activities performed by RSI employees, RSI charges back the employee compensation expense plus a predetermined mark-up. Employee compensation expense, inclusive of base salary and fringe benefits, is determined based upon the relative percentage of time utilized on AGT and ASI matters. All other costs are billed back at cost. In February 2017, AGT and ASI amended and restated the RSI Services Agreement, effective as of December 13, 2016, to add ASG as a services recipient. In addition, in February 2017, ASG entered into a separate services agreement with Roivant Sciences GmbH ("RSG"), a wholly owned subsidiary of RSL, effective as of December 13, 2016 (the "RSG Services Agreement"), for the provision of services by RSG to ASG in relation to the identification of potential product candidates and project management of clinical trials, as well as other services related to development, administrative and financial activities. In June 2019, both the RSI Services Agreement and the RSG Services Agreement were amended, whereby RSI and RSG, respectively, as service providers, have agreed to indemnify AGT, ASI and ASG and each of their 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 applicable services agreement, subject to certain limitations set forth in the applicable services agreement. In addition, AGT, ASI and ASG have agreed to indemnify RSI and RSG, respectively, 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 applicable services agreement, subject to certain limitations set forth in the applicable services agreement. Such indemnification obligations will not exceed the payments made by AGT, ASI and ASG under the applicable services agreement 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. Under the RSI Services Agreement, expenses of $27 thousand and $103 thousand were incurred during the three and nine-months ended December 31, 2019 , respectively, inclusive of the mark-up. Under the RSI Services Agreement and the RSG Services Agreement, expenses of $0.7 million and $5.0 million were incurred during the three and nine-months ended December 31, 2018 , respectively, inclusive of the mark-up. (B) Information Sharing and Cooperation Agreement: In March 2015, the Company entered into an information sharing and cooperation agreement (the "Cooperation Agreement") with RSL. The Cooperation Agreement, among other things, grants the Company a right of first review on any potential dementia-related product or investment opportunity that RSL may consider pursuing and obligates the Company to deliver periodic financial statements and other financial information to RSL and comply with other specified financial reporting requirements. On June 5, 2018, in connection with a share purchase placement agreement with RSL (the “Private Placement”), the Company entered into an amended and restated information sharing and cooperation agreement (the "Restated Cooperation Agreement") with RSL, which became effective as of July 9, 2018, the closing date of the Private Placement. The Restated Cooperation Agreement, among other things: (1) obligates the Company to deliver to RSL periodic financial statements and other information upon reasonable request and to comply with other specified financial reporting requirements; (2) requires the Company to supply certain material information to RSL to assist it in preparing any future SEC filings; and (3) requires the Company to implement and observe certain policies and procedures related to applicable laws and regulations. The Company 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 shareholder 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. Subject to specified exceptions, the Restated Cooperation Agreement will terminate at such time as RSL is no longer required (a) under U.S. GAAP to consolidate the Company's results of operations and financial position, (b) under U.S. GAAP to account for its investment in the Company under the equity method of accounting, or (c) otherwise to include separate financial statements of the Company in its filings with the SEC pursuant to any SEC rule. In addition, the Cooperation Agreement may be terminated upon mutual written consent of the parties or upon written notice from RSL to the Company in the event of the Company's bankruptcy, liquidation, dissolution or winding-up. (C) RSL Financings: In July 2018, the Company received $25.0 million of net proceeds from RSL in exchange for the issuance and sale of 1,785,714 of the Company's common shares to RSL at a purchase price of $14.00 per common share, which was the closing price per share of the Company's common shares on the Nasdaq Global Select Market on June 5, 2018, the date of the share purchase agreement (see Note 9(B)). In December 2018, the Company issued and sold 4,145,115 common shares in a follow-on public offering, including 395,115 common shares sold pursuant to the exercise of the underwriters' option to purchase additional shares, at an offering price of $8.00 per common share for gross proceeds of $33.2 million , including 1,250,000 shares issued and sold to RSL. The aggregate net proceeds to the Company were approximately $31.6 million , after deducting underwriting discounts and commissions and offering expenses incurred (see Note 9(B)). In March 2019, the Company issued and sold 3,333,333 common shares at an offering price of $12.00 per common share for gross proceeds of $40.0 million , including 833,333 shares issued and sold to RSL. The aggregate net proceeds to the Company were approximately $37.9 million , after deducting underwriting discounts and commissions and offering expenses incurred (see Note 9(B)).

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders' Equity (A) Overview: The Company’s Memorandum of Association, filed on October 31, 2014 in Bermuda, authorized the issuance of one class of shares. The total number of shares authorized was 1,000,000,000 with a par value per share of $0.00001 at December 31, 2019 . A 1-for-8 reverse share split of the Company's outstanding common stock was effected on May 8, 2019 as approved by the Company's Board of Directors and a majority of its shareholders, which reduced the number of common shares issued and outstanding from approximately 182.2 million to 22.8 million as of May 8, 2019. As such, all references to share and per share amounts in these unaudited condensed consolidated financial statements and accompanying notes have been retroactively restated to reflect the 1-for-8 reverse share split, except for the authorized number of shares of the Company's common stock and the par value per share, which were not affected. (B) Transactions: During the nine months ended December 31, 2019 , expenses of $103 thousand were incurred by RSI on behalf of the Company that were treated as capital contributions (see Note 8(A)). On June 5, 2018, the Company entered into a share purchase agreement with RSL, its majority shareholder, pursuant to which the Company agreed to issue and sell to RSL 1,785,714 of its common shares at a purchase price of $14.00 per share, which was the closing price per share of the Company's common shares on the Nasdaq Global Select Market on June 5, 2018. On July 9, 2018, the Company received $25.0 million of net proceeds from RSL upon the closing of this private placement (see Note 8 (C)). On June 22, 2018, the Company entered into a sales agreement with Cowen and Company, LLC ("Cowen") to sell the Company's common shares having an aggregate offering price of up to $75.0 million from time to time through an at-the-market equity offering program under which Cowen is acting as the Company's agent. Cowen is entitled to compensation for its services in an amount up to 3% of the gross proceeds of any of the Company's common shares sold under the sales agreement. As of December 31, 2019 , approximately $74.9 million of the Company's common shares remained available for sale under the sales agreement. On December 18, 2018 , the Company issued and sold 4,145,115 common shares in a follow-on public offering, including 395,115 common shares sold pursuant to the exercise of the underwriters’ option to purchase additional shares, at an offering price of $8.00 per common share for gross proceeds of $33.2 million , including 1,250,000 shares issued and sold to RSL (see Note 8(C)). The aggregate net proceeds to the Company were approximately $31.6 million , after deducting underwriting discounts and commissions and offering expenses incurred. In March 2019, the Company issued and sold 3,333,333 common shares, including 833,333 shares issued and sold to RSL, at an offering price of $12.00 per common share for gross proceeds of $40.0 million . The aggregate net proceeds to the Company were approximately $37.9 million , after deducting underwriting discounts and commissions and offering expenses incurred.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation In March 2015, the Company adopted its 2015 Equity Incentive Plan, which was amended and restated in June 2017 by its Board of Directors and became effective upon shareholder approval in August 2017 (the "2015 Plan"). A 1-for-8 reverse share split of the Company's outstanding common stock was effected on May 8, 2019 as approved by the Company's Board of Directors and a majority of its shareholders. As such, all references to share and per share amounts in these unaudited condensed consolidated financial statements and accompanying notes have been retroactively restated to reflect the 1-for-8 reverse share split, except for the authorized number of shares of the Company's common stock and the par value per share, which were not affected. In April 2019, the number of common shares authorized for issuance under the 2015 Plan increased automatically to approximately 4.0 million common shares in accordance with the terms of the 2015 Plan. Under the 2015 Plan at December 31, 2019 , a total of 1.0 million common shares were available for future grant, RSUs underlying approximately 0.3 million common shares were outstanding, and options to purchase approximately 2.5 million common shares were outstanding with a weighted-average exercise price of $16.53 per share. (A) Equity Awards: During the nine months ended December 31, 2019 and 2018 , the Company granted options to purchase a total of 1.5 million and 0.6 million of its common shares, respectively, with weighted-average exercise prices of $8.12 and $16.54 , respectively, and estimated grant date fair values of $7.6 million and $6.2 million , respectively, under the 2015 Plan. The stock options granted to employees during the nine months ended December 31, 2019 and 2018 include options with market-based performance conditions to purchase 0.4 million and 0.1 million common shares, respectively, with weighted-average exercise prices of $8.07 and $20.49 per share, respectively, and corresponding estimated grant date fair values of $1.2 million and $1.5 million , respectively, which were estimated using Monte Carlo Simulation methods under the income approach. As of December 31, 2019 , options with market-based performance conditions to purchase 0.4 million common shares at a weighted-average exercise price of $10.77 per share were outstanding. The market-based performance options vest based on the trading price for the Company’s common shares exceeding certain closing price thresholds. As of December 31, 2019 , stock options with market-based performance conditions to purchase approximately 27 thousand common shares with a weighted-average exercise price of $11.68 per share were outstanding and vested. During the nine months ended December 31, 2019 , the Company granted RSUs underlying a total of 0.4 million common shares with an aggregate grant date fair value of $2.7 million to its employees under the 2015 Plan, with one-half of the RSUs granted vesting on January 31, 2020 and the remainder vesting on July 31, 2020 . The Company recorded total share-based compensation expense of $2.2 million and $4.2 million for the three months ended December 31, 2019 and 2018 , respectively, and $5.3 million and $14.4 million for the nine months ended December 31, 2019 and 2018 , respectively, related to options and RSUs granted to its employees, directors and consultants. The share-based compensation expense was recorded as research and development and general and administrative expenses in the Company's unaudited condensed consolidated statements of operations. At December 31, 2019 , total unrecognized compensation expense related to non-vested outstanding equity awards related to options and RSUs granted to its employees, directors and consultants was $11.1 million , which is expected to be recognized over the remaining weighted-average service period of 2.34 years . (B) Share-Based Compensation for Related Parties: (1) Share-Based Compensation Allocated to the Company by RSL: The Company has incurred share-based compensation expense for RSL common share awards and RSL options issued by RSL to RSL, RSG and RSI employees. Share-based compensation expense has been allocated to the Company by RSL based upon the relative percentage of time utilized by RSL, RSG and RSI employees on Company matters. The Company recorded no share-based compensation expense for the three and nine -months ended December 31, 2019 and share-based compensation expense (benefit) of $27 thousand and $(2.7) million for the three and nine -months ended December 31, 2018 , respectively, in relation to the RSL common share awards and options issued by RSL to RSL, RSG and RSI employees. (2) RSL Common Share Awards and Options: Certain employees of the Company have been granted RSL common share awards and options. The Company recorded share-based compensation expense of $0.1 million and $0.3 million for the three months ended December 31, 2019 and 2018 , respectively, and $16 thousand and $1.1 million for the nine months ended December 31, 2019 and 2018 , respectively, related to these awards.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies As of December 31, 2019 , the Company had entered into commitments under the Oxford Agreement (see Note 3), the UMMS Agreement (see Note 3), the Loan Agreement (see Note 7), the services agreements with RSI and RSG (see Note 8(A)), and agreements to rent office space. In addition, the Company has entered into services agreements with third parties for pharmaceutical manufacturing and research activities. See Note 5 for information regarding rent expense incurred, and remaining contractual rent obligations due, in connection with the Company's outstanding contractual rent obligations. In June 2019, the Company entered into a manufacturing services agreement with a third-party for the manufacture of cGMP grade viral vector, which can be terminated without cause by the Company with six months written notice. Under the terms of this agreement, the Company is committed to pay a minimum of approximately $1.5 million for manufacturing services through December 2020, which remains outstanding at December 31, 2019 . The Company has 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, or for a specified period of advance written notice after the first commercial sale of a product. Either party may terminate the Oxford Agreement for the other party's uncured material breach or with respect to a failure to make a required payment. The Company has the right to terminate the UMMS Agreement at any time upon 90 days' advance written notice to UMMS. Either party may terminate the UMMS Agreement for the other party's uncured material breach upon 60 days' advance written notice, including in the event that UMMS reasonably determines the Company has not fulfilled its diligence obligations.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Dec. 31, 2019
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 unaudited condensed consolidated financial statements and accompanying notes have been prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. These unaudited condensed consolidated financial statements and accompanying notes should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended March 31, 2019 (the "Annual Report"), filed with the Securities and Exchange Commission ("SEC") on June 11, 2019. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary to present fairly the financial position of the Company and its results of operations and cash flows for the periods presented have been included. Operating results for the three and nine-months ended December 31, 2019 are not necessarily indicative of the results that may be expected for the year ending March 31, 2020, for any other interim period, or for any other future year. 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 unaudited condensed 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. These unaudited condensed consolidated financial statements and accompanying notes have been prepared on the basis that the Company will continue as a going concern, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern (see Note 2(B)). A 1-for-8 reverse share split of the Company's outstanding common stock was effected on May 8, 2019 as approved by the Company's Board of Directors and a majority of its shareholders, which reduced the number of common shares issued and outstanding from approximately 182.2 million to 22.8 million as of May 8, 2019. As such, all references to share and per share amounts in these unaudited condensed consolidated financial statements and accompanying notes have been retroactively restated to reflect the 1-for-8 reverse share split, except for the authorized number of shares of the Company's common stock and the par value per share, which were not affected. There have been no significant changes in the Company’s accounting policies from those disclosed in its Annual Report, except for the Company's adoption of Topic 842, " Leases (Topic 842) " ("Topic 842") (see Note 2(F) and Note 5).
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 Topic 205-40, " Presentation of Financial Statements—Going Concern " ("ASC Topic 205-40"), 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 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 significant 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 are issued. As of December 31, 2019 , the Company’s cash and cash equivalents totaled $27.8 million and its accumulated deficit was $742.0 million . For the nine months ended December 31, 2019 and the fiscal year ended March 31, 2019, the Company incurred net losses of $56.0 million and $129.1 million , respectively. As of December 31, 2019 , the Company had aggregate net interest-bearing indebtedness of $15.3 million , of which $8.9 million was due within one year. The Company expects to continue to incur significant operating and net losses, as well as negative cash flows from operations, for the foreseeable future as it continues to develop its gene therapy product candidates and prepares for potential future regulatory approvals and commercialization of its products, if approved. The Company has not generated any revenue to date and does not expect to generate product revenue unless and until it successfully completes development and obtains regulatory approval for at least one of its product candidates, and its current cash and cash equivalents balance will not be sufficient to complete all necessary development activities and commercially launch its products. The Company anticipates that its current cash and cash equivalents balance will not be sufficient to sustain operations beyond three months following the date that these unaudited condensed consolidated financial statements and notes were issued, which raises substantial doubt about the Company's ability to continue as a going concern. To continue as a going concern, the Company will need, among other things, to raise additional capital in the near term. The Company continually assesses multiple options to obtain additional funding to support its operations, including proceeds from offerings of the Company’s equity securities or debt, cash received from the exercise of outstanding common stock options, or transactions involving product development, technology licensing or collaboration arrangements, or other sources of capital to complete its currently planned development programs. Management can provide no assurances that it can raise a sufficient amount of financing for the Company on favorable terms, if at all. Although the Company has successfully obtained financing in the past, and management believes that it will continue to do so in the future, ASC Subtopic 205-40 does not permit future financing activities that are not probable of being implemented and probable of alleviating the conditions that raise substantial doubt to be included in the Company's assessment of its liquidity. Due to these uncertainties, there is substantial doubt about the Company’s ability to continue as going concern. These unaudited condensed consolidated financial statements and accompanying notes have been prepared on the basis that the Company will continue as a going concern, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern.
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, including which costs are charged to research and development and general and administrative expense, as well as assumptions used to estimate its ability to continue as a going concern and estimate the fair value of its stock option awards. Specifically, 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.
Net Loss per Common Share	Net Loss per Common Share: Basic net loss per common share is computed by dividing the net loss applicable to common shareholders by the weighted-average number of common shares outstanding during the period. Diluted net loss per common share is computed by dividing the net loss applicable to common shareholders by the diluted weighted-average number of common shares outstanding during the period calculated in accordance with the treasury stock method. In periods in which the Company reports a net loss, all common share equivalents are deemed anti-dilutive such that basic net loss per common share and diluted net loss per common share are equivalent. Potentially dilutive common shares have been excluded from the diluted net loss per common share computations in all periods presented because such securities have an anti-dilutive effect on net loss per common share due to the Company’s net loss.
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. 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, a long-term investment, accounts payable and long-term debt. Cash consists of non-interest-bearing deposits denominated in the U.S. dollar and Swiss franc, 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. Cash and accounts payable are stated at their respective historical carrying amounts, which approximate fair value due to their short-term nature.
Recent Accounting Pronouncements	Recent Accounting Pronouncements: In February 2016, the FASB issued Topic 842, which requires lessees to recognize on their consolidated balance sheets a liability to make lease payments and a right-of-use asset representing their right to use the underlying asset for the lease term for both finance and operating leases with lease terms greater than twelve months. Topic 842 is effective for annual periods beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2018. Early adoption is permitted. A modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial application. Topic 842 allows entities to choose to use either (i) the effective date or (ii) the beginning of the earliest comparative period presented in the financial statements as the date of initial application. Topic 842 provides a number of optional practical expedients in transition. The Company adopted Topic 842 on April 1, 2019 using the optional modified retrospective transition method. Comparative periods were not restated. For leases that commenced prior to April 1, 2019, the Company elected the following package of practical expedients when assessing the transition impact: (1) not to reassess whether any expired or existing contracts are or contain leases; (2) not to reassess the lease classification for any expired or existing leases; and (3) not to reassess initial direct costs for any existing leases. The Company also elected to: (1) use the total lease term in its initial incremental borrowing rate calculation; (2) combine its lease and non-lease components and account for them as a single lease component; and (3) 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. Upon adoption, the Company recorded corresponding aggregate operating lease right-of-use assets and operating lease liabilities of $3.0 million and $2.4 million , respectively, including $0.6 million of prepaid rent previously classified within other non-current assets in the Company’s consolidated balance sheet that was reclassified to operating lease right-of-use assets. The adoption of the new standard did not materially impact the Company’s consolidated results of operations and cash flows and did not have an impact on the Company’s beginning accumulated deficit balance. For additional information regarding the Company’s leases, see Note 5 for further information regarding the impact of the Company's adoption of Topic 842. In February 2018, the FASB issued ASU No. 2018-02, " Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income " ("ASU No. 2018-02"). On December 22, 2017, an Act to provide for reconciliation pursuant to titles II and V of the concurrent resolution on the budget for fiscal year 2018 (commonly known as the "Tax Cuts and Jobs Act") was enacted in the United States, which introduced a comprehensive set of tax reforms. ASU No. 2018-02 allows companies to reclassify stranded tax effects resulting from the Tax Cuts and Jobs Act, from accumulated other comprehensive (loss) income to retained earnings. ASU No. 2018-02 is effective for interim and annual reporting periods beginning after December 15, 2018, and early adoption is permitted. The Company adopted the provisions of ASU No. 2018-02 for the fiscal year beginning April 1, 2019, which did not have a material impact on its consolidated financial statements and related disclosures. In June 2018, the FASB issued ASU No. 2018-07, " Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting " ("ASU No. 2018-07") . ASU No. 2018-07 requires equity-classified share-based payment awards issued to nonemployees to be measured on the grant date, rather than remeasuring the awards through the performance completion date as previously required. Additionally, for nonemployee awards with performance conditions, compensation cost associated with the award is to be recognized when achievement of the performance condition is probable, rather than upon achievement of the performance condition. Further, the requirement to reassess the liability or equity classification for nonemployee awards upon vesting is eliminated, except for awards in the form of convertible instruments. ASU No. 2018-07 is effective for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year, with early adoption permitted after the adoption of ASU No. 2014-09. The Company adopted the provisions of ASU No. 2018-07 for the fiscal year beginning April 1, 2019, which did not have a material impact on its consolidated financial statements and related disclosures. In December 2019, the FASB issued ASU No. 2019-12, " Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes " ("ASU No. 2019-12"). ASU No. 2019-12 simplifies the accounting for income taxes, eliminates certain exceptions within Income Taxes (Topic 740) , and clarifies certain aspects of the current guidance to promote consistency among reporting entities, and is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. Most amendments within ASU No. 2019-12 are required to be applied on a prospective basis, while certain amendments must be applied on a retrospective or modified retrospective basis. The Company is currently in the process of evaluating the effects of ASU No. 2019-12 on its consolidated financial statements, including potential early adoption. 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.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Money Market Fund	The following table summarizes the fair value of the Company's money market fund included in cash equivalents based on the inputs used at December 31, 2019 in determining such values (in thousands): Fair Value Price Quotations (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market fund $ 10,555 $ 10,555 $ — $ —

Leases (Tables)

Leases (Tables)	9 Months Ended
	Dec. 31, 2019
Leases [Abstract]
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 December 31, 2019 (in thousands): Fiscal Year Ending March 31, Amount 2020 $ 306 2021 943 2022 46 2023 31 2024 — Thereafter — Total undiscounted payments 1,326 Less: Present value adjustment (93 ) Present value of future payments $ 1,233

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	As of December 31, 2019 , and March 31, 2019, accrued expenses consisted of the following (in thousands): December 31, 2019 March 31, 2019 Research and development expenses $ 17,348 $ 13,416 Salaries, bonuses, and other compensation expenses 1,816 3,899 Legal expenses 363 1,319 Other expenses 807 1,985 Total accrued expenses $ 20,334 $ 20,619

Long Term Debt (Tables)

Long Term Debt (Tables)	9 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Outstanding Debt Obligations	Outstanding debt obligations were as follows (in thousands): December 31, 2019 March 31, 2019 Principal amount $ 15,733 $ 45,295 Less: unamortized discount and debt issuance costs (430 ) (1,119 ) Loan payable less unamortized discount and debt issuance costs 15,303 44,176 Less: current portion of long-term debt (8,851 ) (21,182 ) Long-term loan payable, net of current maturities $ 6,452 $ 22,994
Annual Maturities of Debt Outstanding	Annual maturities of debt outstanding as of December 31, 2019 are as follows (in thousands): Fiscal year ending March 31, 2020 $ — 2021 15,733 Thereafter — Total $ 15,733

Description of Business (Detail

Description of Business (Details)	9 Months Ended
	Dec. 31, 2019segmentsubsidiary
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of subsidiaries | subsidiary	7
Number of operating segments	1
Number of reporting segments	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) $ in Thousands	May 08, 2019shares	Dec. 31, 2019USD ($)shares	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)shares	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares	Mar. 31, 2019USD ($)shares	Nov. 30, 2019USD ($)	May 07, 2019shares	Apr. 01, 2019USD ($)
Net Loss per Common Share
Common shares issued (in shares) | shares	22,800,000	22,791,669						22,791,669		22,779,891		182,200,000
Common shares outstanding (in shares) | shares	22,800,000	22,791,669						22,791,669		22,779,891		182,200,000
Reverse share split ratio	0.125
Cash and cash equivalents		$ 27,812						$ 27,812		$ 106,999
Accumulated deficit		(741,996)						(741,996)		(686,016)
Net loss		(14,039)	$ (13,884)	$ (28,057)	$ (34,296)	$ (33,835)	$ (51,888)	(55,980)	$ (120,019)	(129,100)
Net interest-bearing indebtedness		15,303						15,303		44,176
Net interest-bearing indebtedness, due within one year		8,851						8,851		$ 21,182
Operating lease right-of-use assets		1,946						1,946
Lease liability		$ 1,233						$ 1,233
Stock Options and RSUs
Net Loss per Common Share
Anti-dilutive securities not included in calculation of common shares outstanding (in shares) | shares		2,900,000						2,900,000
Stock Options
Net Loss per Common Share
Anti-dilutive securities not included in calculation of common shares outstanding (in shares) | shares					2,100,000				2,100,000
Loan and Security Agreement with Hercules Capital, Inc. | Secured Debt
Net Loss per Common Share
Minimum unrestricted cash											$ 30,000
Money Market Funds
Net Loss per Common Share
Money market funds		$ 10,555						$ 10,555
Money Market Funds | Fair Value, Inputs, Level 1
Net Loss per Common Share
Money market funds		10,555						10,555
Money Market Funds | Fair Value, Inputs, Level 2
Net Loss per Common Share
Money market funds		0						0
Money Market Funds | Fair Value, Inputs, Level 3
Net Loss per Common Share
Money market funds		$ 0						$ 0
Accounting Standards Update 2016-02
Net Loss per Common Share
Operating lease right-of-use assets													$ 3,000
Lease liability													2,400
Prepaid rent													$ 600

Summary of Significant Accoun_5

Summary of Significant Accounting Policies Money Market Fund (Details) - Money market fund $ in Thousands	Dec. 31, 2019USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value disclosure	$ 10,555
Price Quotations (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value disclosure	10,555
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value disclosure	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value disclosure	$ 0

License and Collaboration Agr_2

License and Collaboration Agreements License and Collaboration Agreements (Details) - USD ($)	Apr. 30, 2019	Dec. 07, 2018	Jun. 05, 2018	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Oct. 31, 2019	Mar. 31, 2019	Feb. 28, 2019
License Agreement [Line Items]
Payments for license agreement	$ 13,000,000
Capitalized costs, current					$ 17,348,000		$ 17,348,000			$ 13,416,000
Oxford BioMedica (UK) Ltd.
License Agreement [Line Items]
Payments for license agreement			$ 30,000,000		1,700,000	$ 800,000	8,200,000	$ 30,900,000
Payments for license agreement, developmental milestones			55,000,000
Payments for license agreement, regulatory and sales milestones			$ 757,500,000
License agreement term			10 years
License agreement costs					2,400,000	1,900,000	6,500,000	3,200,000
Benitec Biopharma Limited
License Agreement [Line Items]
Payments for license agreement					400,000	1,400,000	2,800,000	11,400,000
License agreement costs					(300,000)	1,900,000	1,800,000	3,600,000
The University of Massachusetts Medical School
License Agreement [Line Items]
Payments for license agreement		$ 10,000,000			1,100,000	$ 10,000,000	2,900,000	$ 10,000,000
License agreement term		10 years
License agreement costs					1,800,000		4,500,000
Payments for license and collaboration agreement, development and regulatory milestones, total		$ 24,500,000
Payments for license and collaboration agreement, sales milestones, total		$ 39,800,000
Additional payment due to UMMS									$ 1,000,000		$ 1,000,000
Termination notice term, other party's uncured material breach		60 days
Research and development expenses | Oxford BioMedica (UK) Ltd.
License Agreement [Line Items]
Payments for license agreement			$ 25,000,000
Research and development expenses | Benitec Biopharma Limited
License Agreement [Line Items]
License agreement costs				$ 10,000,000
Prepaid Expenses and Other Current Assets and Other Noncurrent Assets | Oxford BioMedica (UK) Ltd.
License Agreement [Line Items]
Payments for license agreement			$ 5,000,000
Prepaid Expenses and Other Current Assets | Oxford BioMedica (UK) Ltd.
License Agreement [Line Items]
Capitalized costs, current					$ 1,800,000		$ 1,800,000
Minimum | Oxford BioMedica (UK) Ltd.
License Agreement [Line Items]
Royalty percentage			7.00%
Fee if developmental milestones are not me			$ 500,000
Maximum | Oxford BioMedica (UK) Ltd.
License Agreement [Line Items]
Royalty percentage			10.00%
Fee if developmental milestones are not me			$ 1,000,000

Long-term Investment (Details)

Long-term Investment (Details) $ in Thousands, shares in Millions	Feb. 25, 2019USD ($)shares	Dec. 31, 2019USD ($)	Mar. 31, 2019USD ($)	Feb. 13, 2019€ / sharesshares
Related Party Transaction [Line Items]
Maximum shares to be purchased under subscription agreement (in shares)				8.1
Par value (in EUR per share) | € / shares				€ 0.00001
Number of shares acquired during period (in shares)	5.9
Long-term investment | $	$ 5,900	$ 5,871	$ 5,871
Additional maximum shares to be purchased under subscription agreement (in shares)	2.2
Transition Services Agreement, Reimbursements, Employee Compensation Expense | Investee
Related Party Transaction [Line Items]
Reimbursements received | $		$ 200

Leases (Details)

Leases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Apr. 01, 2019
Lessor, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 1,946		$ 1,946
Lease liability	$ 1,233		$ 1,233
Incremental borrowing rate					12.90%
Aggregate weighted average remaining lease payment term	1 year 2 months 25 days		1 year 2 months 25 days
Aggregate weighted average discount rate	12.90%		12.90%
Rent expense	$ 400		$ 1,300
Operating leases, rent expense		$ 400		$ 1,300
Operating lease payments			$ 1,500
Accounting Standards Update 2016-02
Lessor, Lease, Description [Line Items]
Operating lease right-of-use assets					$ 3,000
Lease liability					2,400
Costs previously classified within other non-current assets					$ 600

Leases Remaining Contractual Re

Leases Remaining Contractual Rent Obligations (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 306
2021	943
2022	46
2023	31
2024	0
Thereafter	0
Total undiscounted payments	1,326
Less: Present value adjustment	(93)
Present value of future payments	$ 1,233

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019
Payables and Accruals [Abstract]
Research and development expenses	$ 17,348	$ 13,416
Salaries, bonuses, and other compensation expenses	1,816	3,899
Legal expenses	363	1,319
Other expenses	807	1,985
Total accrued expenses	$ 20,334	$ 20,619

Long Term Debt (Details)

Long Term Debt (Details) - USD ($)	Nov. 27, 2019	Feb. 02, 2017	Aug. 31, 2017	Nov. 30, 2019
Debt Instrument [Line Items]
Exercise of warrants (in shares)			16,228
Common Shares
Debt Instrument [Line Items]
Number of securities called by warrants (in shares)		34,260
Exercise price (in dollars per share)		$ 96.32
Fair value of warrants not settable in cash		$ 2,300,000
Loan and Security Agreement with Hercules Capital, Inc. | Secured Debt
Debt Instrument [Line Items]
Face amount		$ 55,000,000
Minimum unrestricted cash				$ 30,000,000
Prepayment of outstanding principal due (as a percent)	50.00%
Prepayment of outstanding principal due	$ 15,700,000
Default interest rate (as a percent)		5.00%
Maximum equity offering opportunity to be provided		$ 3,000,000
Transaction costs		$ 1,500,000
Loan term		48 months
Loan and Security Agreement with Hercules Capital, Inc. | Secured Debt | Minimum
Debt Instrument [Line Items]
Stated interest rate (as a percent)	11.55%	10.55%
Loan and Security Agreement with Hercules Capital, Inc. | Secured Debt | Prime Rate
Debt Instrument [Line Items]
Variable interest rate (as a percent)	6.80%	6.80%

Long Term Debt - Outstanding De

Long Term Debt - Outstanding Debt Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019
Debt Disclosure [Abstract]
Principal amount	$ 15,733	$ 45,295
Less: unamortized discount and debt issuance costs	(430)	(1,119)
Loan payable less unamortized discount and debt issuance costs	15,303	44,176
Current portion of long-term debt	(8,851)	(21,182)
Long-term loan payable, net of current maturities	$ 6,452	$ 22,994

Long Term Debt - Annual Maturit

Long Term Debt - Annual Maturities of Debt Outstanding (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019
Debt Disclosure [Abstract]
2020	$ 0
2021	15,733
Thereafter	0
Total	$ 15,733	$ 45,295

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 09, 2018	Jun. 05, 2018	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
RSI
Related Party Transaction [Line Items]
Expense under service agreement					$ 27	$ 700	$ 103	$ 5,000
Private Placement | RSL
Related Party Transaction [Line Items]
Net proceeds from common stock issued	$ 25,000
Shares sold in common stock issuance (in shares)		1,785,714	833,333
Price of shares sold in common stock issuance (in USD per share)		$ 14
Public Offering
Related Party Transaction [Line Items]
Net proceeds from common stock issued			$ 37,900	$ 31,600
Shares sold in common stock issuance (in shares)			3,333,333	4,145,115
Price of shares sold in common stock issuance (in USD per share)			$ 12	$ 8		$ 8		$ 8
Gross proceeds from common stock issued			$ 40,000	$ 33,200
Public Offering | RSL
Related Party Transaction [Line Items]
Shares sold in common stock issuance (in shares)				1,250,000
Underwriter's Option
Related Party Transaction [Line Items]
Shares sold in common stock issuance (in shares)				395,115

Shareholders' Equity (Details)

Shareholders' Equity (Details) $ / shares in Units, $ in Thousands	May 08, 2019shares	Jul. 09, 2018USD ($)	Jun. 05, 2018$ / sharesshares	Mar. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / shares	May 07, 2019shares	Jun. 22, 2018USD ($)
Shareholders' Equity
Common shares authorized (in shares) | shares				1,000,000,000		1,000,000,000
Common shares par value (in dollars per share) | $ / shares				$ 0.00001		$ 0.00001
Reverse share split ratio	0.125
Common shares issued (in shares) | shares	22,800,000			22,779,891		22,791,669		182,200,000
Capital contribution						$ 103	$ 1,093
Stock Offering
Shareholders' Equity
Shares sold in common stock issuance (in shares) | shares				3,333,333	4,145,115
Price of shares sold in common stock issuance (in USD per share) | $ / shares				$ 12	$ 8		$ 8
Net proceeds from common stock issued				$ 37,900	$ 31,600
Gross proceeds from common stock issued				$ 40,000	$ 33,200
Underwriter's Option
Shareholders' Equity
Shares sold in common stock issuance (in shares) | shares					395,115
RSI
Shareholders' Equity
Capital contribution						103
RSL | Stock Offering
Shareholders' Equity
Shares sold in common stock issuance (in shares) | shares					1,250,000
RSL | Private Placement
Shareholders' Equity
Shares sold in common stock issuance (in shares) | shares			1,785,714	833,333
Price of shares sold in common stock issuance (in USD per share) | $ / shares			$ 14
Net proceeds from common stock issued		$ 25,000
Cowen and Company, LLC | Private Placement
Shareholders' Equity
Maximum offering under equity offering program									$ 75,000
Percentage of gross proceeds from common stock issuance paid for services									3.00%
Amount available for issuance under equity offering program						$ 74,900

Share-Based Compensation (Detai

Share-Based Compensation (Details) $ / shares in Units, shares in Thousands	May 08, 2019	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Apr. 30, 2019shares
Share-Based Compensation
Reverse share split ratio	0.125
RSL
Share-Based Compensation
Share-based compensation expense | $		$ 0	$ 27,000	$ 0	$ (2,700,000)
Employees | RSL
Share-Based Compensation
Share-based compensation expense | $		$ 100,000	300,000	$ 16,000	1,100,000
Restricted Stock Units (RSUs)
Share-Based Compensation
RSUs outstanding (in shares)		300		300
RSUs granted (in shares)				400
Aggregate grant date fair value of RSUs | $				$ 2,700,000
Stock Options
Share-Based Compensation
Total unrecognized compensation expense, stock options | $		$ 11,100,000		$ 11,100,000
Remaining weighted-average service period				2 years 4 months 2 days
Stock Options | Grants To Directors And Employees
Share-Based Compensation
Share-based compensation expense | $		$ 2,200,000	$ 4,200,000	$ 5,300,000	$ 14,400,000
Market-Based Performance Stock Options
Share-Based Compensation
Number of options outstanding (in shares)		400		400
Weighted average exercise price of options outstanding (in dollars per share) | $ / shares		$ 10.77		$ 10.77
Number of options granted (in shares)				400	100
Exercise price of options granted (in USD per share) | $ / shares				$ 8.07	$ 20.49
Estimated grant date fair value of options granted | $				$ 1,200,000	$ 1,500,000
Number of options vested (in shares)				27
Exercise price of options vested (in USD per share) | $ / shares				$ 11.68
2015 Equity Incentive Plan
Share-Based Compensation
Number of shares reserved for grant (in shares)						4,000
Number of shares available for future grant (in shares)		1,000		1,000
2015 Equity Incentive Plan | Stock Options
Share-Based Compensation
Number of options outstanding (in shares)		2,500		2,500
Weighted average exercise price of options outstanding (in dollars per share) | $ / shares		$ 16.53		$ 16.53
Number of options granted (in shares)				1,500	600
Exercise price of options granted (in USD per share) | $ / shares				$ 8.12	$ 16.54
Estimated grant date fair value of options granted | $				$ 7,600,000	$ 6,200,000
Tranche One | Restricted Stock Units (RSUs)
Share-Based Compensation
RSUs vesting (as a percent)				50.00%
Tranche Two | Restricted Stock Units (RSUs)
Share-Based Compensation
RSUs vesting (as a percent)				50.00%

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	Dec. 07, 2018	Dec. 31, 2019	Jun. 30, 2019
cGMP Grade Viral Vector Production
Long-term Purchase Commitment [Line Items]
Minimum payment for manufacturing services			$ 1.5
Oxford BioMedica (UK) Ltd.
Long-term Purchase Commitment [Line Items]
Termination notice term, prior to first commercial sale of product		2 months
The University of Massachusetts Medical School
Long-term Purchase Commitment [Line Items]
Termination notice term	90 days
Termination notice term, other party's uncured material breach	60 days