Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
Document and Entity Information - USD ($) $ in Thousands	Mar. 31, 2017	Jun. 12, 2017	Oct. 27, 2016
Document and Entity Information
Entity Registrant Name	Myovant Sciences Ltd.
Entity Central Index Key	0001679082
Document Type	10-K
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		60,280,189
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Entity Public Float			$ 192,270,000
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Current assets:
Cash	$ 180,838	$ 0
Prepaid expenses and other current assets	3,221	0
Income tax receivable	105	0
Total current assets	184,164	0
Deferred tax assets	208	0
Property and equipment, net	906	0
Other assets	0	0
Total assets	185,278	0
Current liabilities:
Accounts payable	3,329	0
Accrued expenses	11,978	223
Due to Roivant Sciences Ltd. and Roivant Sciences, Inc.	3,030	0
Total current liabilities	18,337	223
Warrant liability	52	0
Deferred rent	113	0
Total liabilities	18,502	223
Commitments and contingencies (Note 10)
Shareholders’ equity (deficit):
Common shares, par value $0.000017727 per share, 564,111,242 shares authorized, 60,275,757 and 37,231,342 issued and outstanding at March 31, 2017 and March 31, 2016, respectively	1	1
Common shares subscribed	(1)	(1)
Accumulated other comprehensive income	140	0
Additional paid-in capital	251,733	1,434
Accumulated deficit	(85,097)	(1,657)
Total shareholders’ equity (deficit)	166,776	(223)
Total liabilities and shareholders’ equity (deficit)	$ 185,278	$ 0

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2017	Mar. 31, 2016
Statement of Financial Position [Abstract]
Common shares par value (in USD per share)	$ 0.000017727	$ 0.000017727
Common shares authorized (in shares)	564,111,242	564,111,242
Common shares issued (in shares)	60,275,757	37,231,342
Common shares outstanding (in shares)	60,275,757	37,231,342

Consolidated Statements of Operations - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2017
Operating expenses:
Research and development (includes $3,893 and $0 of share-based compensation expense for the year ended March 31, 2017 and the period from February 2, 2016 (Date of Inception) to March 31, 2016, respectively)	$ 0	$ 43,500
General and administrative (includes $4,824 and $987 of share-based compensation expense for the year ended March 31, 2017 and the period from February 2, 2016 (Date of Inception) to March 31, 2016, respectively)	1,657	12,357
Total operating expenses	1,657	55,857
Other expense:
Changes in the fair value of the warrant liability	0	27,518
Other expense	0	139
Loss before provision for income tax	(1,657)	(83,514)
Income tax benefit	0	(74)
Net loss	$ (1,657)	$ (83,440)
Net loss per common share — basic and diluted (in USD per share)	$ (0.04)	$ (1.70)
Weighted average common shares outstanding — basic and diluted (in shares)	37,231,342	49,184,668

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2017
Research and development
Share-based compensation	$ 0	$ 3,893
General and administrative
Share-based compensation	$ 987	$ 4,824

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (1,657)	$ (83,440)
Other comprehensive income:
Foreign currency translation adjustment	0	140
Total other comprehensive income	0	140
Comprehensive loss	$ (1,657)	$ (83,300)

Consolidated Statements of Shareholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Shares	Common Shares Subscribed	Additional Paid in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning balance (in shares) at Feb. 02, 2016		37,231,342
Beginning balance at Feb. 02, 2016	$ 0	$ 1	$ (1)	$ 0	$ 0	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital contribution	1,434			1,434
Translation adjustment	0
Net loss	$ (1,657)					(1,657)
Ending balance (in shares) at Mar. 31, 2016	37,231,342	37,231,342
Ending balance at Mar. 31, 2016	$ (223)	$ 1	(1)	1,434	0	(1,657)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of common shares in initial public offering ($15.00 per share), net of underwriting discounts and commissions and offering expenses of $17,536 (in shares)		14,500,000
Sale of common shares in initial public offering ($15.00 per share), net of underwriting discounts and commissions and offering expenses of $17,536	199,964	$ 0		199,964
Shares issued to Takeda under the Takeda license agreement (in shares)		5,077,001
Shares issued to Takeda under the Takeda license agreement	$ 7,740	$ 0		7,740
Shares issued to settle the warrant liability to Takeda (in shares)	2,339,192	2,339,192
Shares issued to settle the warrant liability to Takeda	$ 32,843	$ 0		32,843
Share-based compensation expense (in shares)		1,128,222
Share-based compensation expense	3,775	$ 0		3,775
Capital contribution — share-based compensation	4,942			4,942
Capital contribution	1,035			1,035
Translation adjustment	140				140
Net loss	$ (83,440)					(83,440)
Ending balance (in shares) at Mar. 31, 2017	60,275,757	60,275,757
Ending balance at Mar. 31, 2017	$ 166,776	$ 1	$ (1)	$ 251,733	$ 140	$ (85,097)

Consolidated Statement of Cash Flows - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2017
Cash flows from operating activities:
Net loss	$ (1,657)	$ (83,440)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	1,434	8,717
Depreciation	0	61
Purchase of in-process research and development expense	0	13,117
Changes in the fair value of the warrant liability	0	27,518
Unrealized currency translation	0	140
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	0	(3,221)
Income tax receivable	0	(105)
Deferred tax assets	0	(208)
Accounts payable	0	3,329
Accrued expenses	223	11,755
Due to Roivant Sciences Ltd. and Roivant Sciences, Inc.	0	4,009
Deferred rent	0	113
Net cash used in operating activities	0	(18,215)
Cash flows from investing activities:
Purchase of furniture and equipment	0	(967)
Net cash used in investing activities	0	(967)
Cash flows from financing activities:
Cash proceeds from issuance of common shares in initial public offering, net of underwriting discount	0	202,275
Initial public offering costs paid	0	(2,311)
Cash capital contribution from Roivant Sciences Ltd.	0	1,035
Due to Roivant Sciences Ltd. and Roivant Sciences, Inc. for amounts paid on behalf of the Company	0	(979)
Net cash provided by financing activities	0	200,020
Net change in cash	0	180,838
Cash—beginning of period	0	0
Cash—end of period	0	180,838
Non-cash investing and financing activities:
Purchase of in-process research and development	0	13,117
Supplemental disclosure of cash paid:
Income taxes	$ 0	$ 240

Description of Business	12 Months Ended
Description of Business	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Myovant Sciences Ltd. (or together with its wholly-owned subsidiaries, the Company) is a clinical-stage biopharmaceutical company focused on developing and commercializing innovative therapies for women’s health and endocrine diseases. The Company is developing its lead product candidate, relugolix, for the treatment of heavy menstrual bleeding associated with uterine fibroids, endometriosis-associated pain and advanced prostate cancer, and its second product candidate, MVT-602 (formerly known as RVT-602), for the treatment of female infertility as part of assisted reproduction. The Company was founded on February 2, 2016 as a Bermuda Exempted Limited Company and a wholly-owned subsidiary of Roivant Sciences Ltd., or RSL, under the name Roivant Endocrinology Ltd. The Company changed its name to Myovant Sciences Ltd., or MSL in May 2016. In April 2016, Roivant Endocrinology Inc., or REI, a wholly-owned subsidiary of the Company was formed and based in the United States of America and subsequently changed its name to Myovant Sciences, Inc., or MSI. In August 2016, the Company incorporated as its wholly-owned subsidiaries Myovant Holdings Limited, or MHL, a private limited company incorporated under the laws of England and Wales, and Myovant Sciences GmbH, or MSG, a company with limited liability formed under the laws of Switzerland. In November 2016, the Company moved its principal executive office from Bermuda to the United Kingdom and became a U.K. tax resident, and the Company assigned all of its intellectual property rights to MSG. MSG is the Company’s principal operating subsidiary and the Company remains incorporated in Bermuda. The Company also has a wholly-owned subsidiary, Myovant Sciences Ireland Limited, a company with limited liability formed under the laws of Ireland. Since its inception, the Company has devoted substantially all of its efforts to organizing the Company, acquiring its drug development programs and preparing for 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 has two product candidates, relugolix and MVT-602, under development which were licensed from Takeda Pharmaceuticals International AG, or Takeda, on April 29, 2016 (See Note 3). The Company has incurred and expects to continue to incur significant and increasing operating losses at least for the next several years. The Company does not expect to generate revenue unless and until it successfully completes development and obtains regulatory approval for one of its products in development. The Company may be required to obtain further funding through other public or private offerings of its share capital, debt financing, collaboration and licensing arrangements or other sources. Adequate additional funding may not be available to the Company on acceptable terms, or at all.

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2017
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. The accompanying consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles, or U.S. GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. The consolidated financial statements include the accounts of the Company and MSI, MSL and MSG, its wholly-owned subsidiaries. The Company has no unconsolidated subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. (B) Use of Estimates: The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company regularly evaluates estimates and assumptions related to assets, liabilities, costs, and expenses, including compensation expense allocated to the Company under its services agreements with Roivant Sciences, Inc., or RSI, and Roivant Sciences GmbH, or RSG, each a wholly-owned subsidiary of RSL, as well as share-based compensation and research and development costs. 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. (C) Risks and Uncertainties: The Company is subject to risks common to companies in the pharmaceutical industry including, but not limited to, uncertainties related to commercialization of products, regulatory approvals, dependence on key products, third-party service providers such as contract research organizations and protection of intellectual property rights. (D) Concentrations of Credit Risk: Financial instruments that potentially subject the Company to concentration of credit risk include cash. At March 31, 2017, substantially all of the cash balances are deposited in two banking institutions and are all in excess of insured levels. (E) Property and Equipment: Property and equipment, consisting of computers, equipment, furniture and fixtures, leasehold improvements, and software, is recorded at cost. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred. Upon disposal, retirement or sale, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation will be recorded for property and equipment using the straight-line method over the estimated useful lives of three to seven years, once the asset is installed and placed in service. The Company reviews the recoverability of all long-lived assets, including the related useful lives, whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset might not be recoverable. Recoverability is measured by comparison of the book values of the assets to future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceed their fair value, which is measured based on the projected discounted future net cash flows arising from the assets. (F) Contingencies: The Company may be, from time to time, a party to various disputes and claims arising from normal business activities. The Company continually assesses litigation to determine if an unfavorable outcome would lead to a probable loss or reasonably possible loss which could be estimated. In accordance with the guidance of the FASB on accounting for contingencies, the Company accrues for all contingencies at the earliest date at which the Company deems it probable that a liability has been incurred and the amount of such liability can be reasonably estimated. If the estimate of a probable loss is a range and no amount within the range is more likely than another, the Company accrues the minimum of the range. In the cases where the Company believes that a reasonably possible loss exists, the Company discloses the facts and circumstances of the litigation, including an estimable range, if possible. (G) Deferred Offering Costs: Deferred offering costs, which consisted of direct costs related to the Company’s initial public offering, or IPO, of its common shares, were capitalized in other assets until the consummation of the IPO. These offering costs were reclassified to additional paid-in capital upon the closing of the IPO on November 1, 2016. (H) Research and Development Expense: Research and development costs are expensed as incurred. Clinical study costs are accrued over the service periods specified in the contracts and adjusted as necessary based on an ongoing review of the level of effort and costs actually incurred. Payments for a product license prior to regulatory approval of the product and payments for milestones achieved prior to regulatory approval of the product are expensed in the period incurred as research and development. Milestone payments made in connection with regulatory approvals are capitalized and amortized to cost of revenue over the remaining useful life of the asset. Research and development expenses primarily consist of the intellectual property and research and development materials acquired, certain costs charged by RSI under its services agreement with the Company, and expenses from third parties who conduct research and development activities on behalf of the Company. The Company expenses in-process research and development projects acquired as asset acquisitions which have not reached technological feasibility and which have no alternative future use. Clinical study costs are accrued over the service periods specified in the contracts and adjusted as necessary based upon an ongoing review of the level of effort and costs actually incurred. For the year ended March 31, 2017, the Company recorded $43.5 million of research and development expense, of which $3.9 million was attributable to share-based compensation expense. For the period from February 2, 2015 (date of inception) to March 31, 2016, the Company did not incur any research and development expense. (I) Warrant Liability: The Company records the warrant liability at its estimated fair value as a liability in the consolidated balance sheets. The Company remeasures the estimated fair value of the warrant liability each reporting period and records the changes in the fair value in the consolidated statements of operations as other (expense) income (See Note 9). (J) Income Taxes: Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and the respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is recorded when, after consideration of all positive and negative evidence, it is not more likely than not that the Company’s deferred tax assets will be realizable. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. (K) Share-Based Compensation: Share-based awards to employees and directors are valued at fair value on the date of the grant and that fair value is recognized as share-based compensation expense on a straight-line basis over the requisite service period of the entire award. The Company values its stock options using the Black-Scholes option pricing model. Certain assumptions need to be made with respect to utilizing the Black-Scholes option pricing model, including the expected life of the award, volatility of the underlying shares, the risk-free interest rate, the fair value of the Company’s common shares and anticipated forfeiture of the share-based awards. Since the Company has limited option exercise history, it has generally elected to estimate the expected life of an award based upon the Securities and Exchange Commission-approved “simplified method” noted under the provisions of Staff Accounting Bulletin No. 107 with the continued use of this method extended under the provisions of Staff Accounting Bulletin No. 110. The risk-free interest rate is based on the rates paid on securities issued by the United States Treasury with a term approximating the expected life of the equity award. The expected share price volatility for the Company’s common shares is estimated by taking the average historical price volatility for industry peers. Estimates of pre-vesting award forfeitures are based on the Company’s expectations of future employee turnover. The Company will adjust its estimate of forfeitures over the requisite service period based on the extent to which actual forfeitures differ, or are expected to differ, from such estimates. Changes in estimated forfeitures will be recognized through a cumulative catch-up adjustment in the period of change and will also impact the amount of compensation expense to be recognized in future periods. The Company accounts for share-based payments to non-employees issued in exchange for services based upon the fair value of the equity instruments issued. Compensation expense for stock options issued to non-employees is calculated using the Black-Scholes option pricing model and is recorded over the service performance period. Options subject to vesting are required to be periodically remeasured over their service performance period, which is generally the same as the vesting period. (L) Net Loss per Common Share: Basic net loss per common share is computed by dividing 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. For the year ended March 31, 2017, 1,128,222 restricted share awards and 1,525,857 options to purchase common shares were not included in the calculation of diluted weighted-average common shares outstanding because they were anti-dilutive. (M) Recently Issued Accounting Pronouncements: In August 2014, the FASB issued ASU No. 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 310-40): Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern," which provides guidance on determining when and how to disclose going-concern uncertainties in the financial statements. This new ASU requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures if “conditions or events raise substantial doubt about the entity’s ability to continue as a going concern.” The ASU is effective for annual periods ending after December 15, 2016, and interim periods thereafter, with early adoption permitted. This guidance has been adopted as of March 31, 2017 and it did not have a material impact on the consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” (ASU No. 2016-02), which is a comprehensive new lease standard that amends various aspects of existing accounting guidance for leases. The core principle of ASU No. 2016-02 will require lessees to present the assets and liabilities that arise from leases on their balance sheets. ASU No. 2016-02 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. The Company is currently evaluating the new standard and its impact on the Company’s consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU No. 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” (ASU No. 2016-09). This ASU makes several modifications to Topic 718 related to the accounting for forfeitures, employer tax withholding on share-based compensation, and the financial statement presentation of excess tax benefits or deficiencies. ASU No. 2016-09 also clarifies the statement of cash flows presentation for certain components of share-based awards. The standard is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods, with early adoption permitted. The Company expects to adopt this guidance when effective and is currently evaluating the effect that the updated standard will have on its consolidated financial statements and related disclosures. (N) Foreign Currency: The Company has operations in the United States, the United Kingdom and Switzerland. The results of its non-U.S. dollar based functional currency operations are translated to U.S. dollars at the average exchange rates during the period. The Company’s assets and liabilities are translated using the current exchange rate as of the balance sheet date and shareholders’ equity is translated using historical rates. Adjustments resulting from the translation of the financial statements of the Company’s foreign subsidiaries into U.S. dollars are excluded from the determination of net loss and are accumulated in a separate component of shareholders’ equity. Foreign exchange transaction gains and losses are included in other income (loss) in the Company’s results of operations.

License Agreement

12 Months Ended

Mar. 31, 2017

Other Liabilities Disclosure [Abstract]

License Agreement

On April 29, 2016, the Company entered into a license agreement pursuant to which Takeda granted to the Company an exclusive, royalty-bearing license under certain patents and other intellectual property controlled by Takeda to develop and commercialize relugolix and MVT-602, in exchange for the following:


•	The Company issued and delivered 5,077,001 common shares upon entry into the license agreement.

•

The Company will pay Takeda a fixed, high single-digit royalty on net sales of relugolix and MVT-602 products in the Company’s territory, subject to certain agreed reductions. Takeda will pay the Company a royalty at the same rate as the Company’s on net sales of relugolix products for prostate cancer in Japan and certain other Asian countries, subject to certain agreed reductions. Royalties are required to be paid, on a product-by-product and country-by-country basis, until the latest 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. Under this license agreement, there are no payments upon the achievement of clinical development or marketing approval milestones.


•	The Company issued a warrant to Takeda to purchase an indeterminate number of capital shares. The warrant entitles Takeda, together with its affiliates, to maintain a 12% ownership interest in the Company, as determined after such exercise, through the later of (i) April 30, 2017 or (ii) the final closing of our IPO, unless earlier terminated upon a change in control.

For the consideration above, the Company also received a small quantity of relugolix and MVT-602, and certain historical research and development records. The Company did not hire, or receive, any Takeda workforce or employees working on relugolix and MVT-602, or any research, clinical or manufacturing equipment. The Company did not assume any contracts, licenses or agreements between Takeda and any third party with respect to relugolix and MVT-602. The Company will need to independently develop all clinical processes and procedures for its clinical trials through the use of internal and external resources once appropriate and acceptable resources have been identified and obtained. If the license agreement is terminated in its entirety or with respect to relugolix for prostate cancer, other than for safety reasons or by the Company for Takeda’s uncured material breach, prior to receipt of the first regulatory approval of relugolix for prostate cancer in Japan, then the Company must either reimburse Takeda for its out of pocket costs and expenses directly incurred in connection with Takeda’s completion of the relugolix development for prostate cancer, up to an agreed cap, or complete by itself the conduct of any clinical trials of relugolix for prostate cancer that are ongoing as of the effective date of such termination, at its cost and expense.

As the intellectual property and inventory acquired had no alternative future use, the Company recorded $13.1 million as research and development expense at the closing date of the acquisition of the rights, April 29, 2016, which consisted of $7.7 million for the estimated fair value of the 5,077,001 common shares issued and $5.4 million for the estimated fair value of warrant liability.

The estimation of the fair value of the common shares considered factors including the following: the estimated present value of the Company’s future cash flows; industry information such as market size and growth; market capitalization of comparable companies and the estimated value of transactions such companies have engaged in; and macroeconomic conditions.

The estimation of the fair value of the warrant liability was determined based on a Monte Carlo simulation model which requires various highly subjective unobservable inputs (See Note 9).

- Definition

The entire disclosure for research, development, and computer software activities, including contracts and arrangements to be performed for others and with federal government. Includes costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility and in-process research and development acquired in a business combination consummated during the period.

+ References + Details

Related Party Transactions	12 Months Ended
Related Party Transactions	Mar. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions (A) Services Agreements: In July 2016, the Company entered into a formal services agreement with RSI (the “Services Agreement”) effective April 29, 2016, under which RSI agreed to provide certain administrative and research and development services to the Company. Under the Services Agreement, the Company pays or reimburses RSI for any expenses it, or third parties acting on its behalf, incurs for the Company. For any general and administrative and research and development activities performed by RSI employees, RSI charges back the employee compensation expense plus a pre-determined mark-up. RSI also provided such services prior to the formalization of the Services Agreement, and such costs have been recognized by the Company in the period in which the services were rendered. Employee compensation expense, inclusive of base salary and fringe benefits, is determined based upon the relative percentage of time utilized on Company matters, which the Company believes is reasonable. All other costs are billed back at cost. The accompanying consolidated financial statements include third-party expenses that have been paid by RSI and RSL. During the year ended March 31, 2017, RSL and RSI provided certain administrative services on behalf of the Company during the formative period of the Company. Total compensation expense, inclusive of base salary, fringe benefits and share-based compensation, is proportionately allocated to the Company based upon the relative percentage of time utilized on the Company’s matters. Under the Services Agreement, for the year ended March 31, 2017 and the period from February 2, 2016 (Date of Inception) to March 31, 2016, the Company incurred expenses of $9.2 million and $0.4 million, respectively, inclusive of the mark-up. In February 2017, in connection with the contribution and assignment of all of the Company's intellectual property rights to MSG, the Company and MSI amended and restated the Services Agreement, effective as of November 11, 2016, to include MSG as a recipient of from MSI. In addition, in February 2017, MSG entered into a separate services agreement with RSG, a wholly-owned subsidiary of RSL, effective as of November 11, 2016, for the provisioning of services by RSG to MSG in relation to the identification of potential product candidates and project management of clinical trials, as well as other services related to clinical development, administrative and financial activities. Under the terms of both services agreements, the Company is obligated to pay or reimburse RSI and RSG for the costs they, or third parties acting on their behalf, incur in providing services to us, including administrative and support services, as well as research and development services. In addition, the Company is obligated to pay to RSI and RSG a pre-determined mark-up on the costs incurred directly by RSI and RSG in connection with any general and administrative and research and development services. (B) Option Agreement: In June 2016, the Company entered into an option agreement with RSL pursuant to which RSL granted to the Company an option to acquire the rights to products to which RSL or any nonpublic affiliate of RSL acquires the rights (other than a relugolix product or a competing product) for uterine fibroids or endometriosis, or for which the primary target indication is advanced prostate cancer. The Company’s option is exercisable at any time during the period commencing upon the completion of its IPO and ending two years following the date of first commercial sale of a relugolix product in a major market country. If the Company elects to exercise its option for a product, it will be required to reimburse RSL for 110% of any payments made by RSL or its affiliate for such product, and will receive an assignment of the agreement through which RSL or its affiliate acquired the rights to such product. (C) Information Sharing and Cooperation Agreement: In July 2016, the Company entered into an information sharing and cooperation agreement, or the Cooperation Agreement, with RSL. The Cooperation Agreement, among other things: (1) obligates the Company to deliver periodic financial statements and other financial information to RSL and to comply with other specified financial reporting requirements; and (2) requires the Company to supply certain material information to RSL to assist it in preparing any future SEC filings. Subject to specified exceptions, the Cooperation Agreement will terminate upon the earlier of the mutual written consent of the parties or when RSL is no longer required by U.S. GAAP to consolidate the Company’s results of operations and financial position, account for its investment in the Company under the equity method of accounting or, by any rule of the SEC, include the Company’s separate financial statements in any filings it may make with the SEC. (D) Manufacture and Supply Agreement: In June 2016, the Company and Takeda’s affiliate, Takeda Pharmaceutical Company Limited, or Takeda Limited, entered into an agreement for the manufacture and supply of relugolix. Under this agreement, Takeda Limited will supply the Company, and the Company will obtain from Takeda Limited, all of its requirements for relugolix drug substance and drug product to be used under its development plans for all indications. If the Company requests, Takeda Limited will assist it with a technical transfer of the manufacturing process for relugolix to it or its designee and the Company will pay the expenses related to such transfer.

Shareholders' Equity	12 Months Ended
Shareholders' Equity	Mar. 31, 2017
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity (A) Overview: The Company’s Memorandum of Association, filed on February 2, 2016 in Bermuda, authorized the creation of one class of shares. As of March 31, 2017, the Company had 564,111,242 shares authorized with a par value of $0.000017727 per share. (B) Restricted Share Award and Options Granted: During the year ended March 31, 2017, the Company granted a restricted share award for 1,128,222 common shares to the Company’s Principal Executive Officer under the 2016 Equity Incentive Plan. During the year ended March 31, 2017, the Company granted options to its employees, consultants and directors to purchase 1,525,857 of its common shares. (C) Initial Public Offering and Reverse Stock Split: On October 18, 2016, the Company's board of directors approved a 1-for-1.7727 reverse stock split of the Company's outstanding common shares. The reverse split became effective on October 18, 2016. These consolidated financial statements give retroactive effect to the reverse stock split for all periods presented. On November 1, 2016, the Company completed its IPO of common shares. The Company sold 14,500,000 shares at a price of $15.00 per share, for gross proceeds of $217.5 million. The Company received net proceeds of $200.0 million, after deducting $15.2 million in underwriting discounts and commissions and $2.3 million in offering expenses. The cash proceeds from the IPO are currently deposited with one banking institution and are substantially in excess of federally insured levels. (D) Warrant Liability: During the year ended March 31, 2017, the Company issued 2,339,192 common shares to Takeda upon the automatic exercise of the warrant, which was due to the issuance of 153,846 common shares initiated by the grant of a restricted share award for 1,128,222 common shares, issuance of 208,077 common shares initiated by the grant of options to its employees, consultants and directors to purchase 1,525,857 common shares and the issuance of an additional 1,977,269 common shares to Takeda, upon the closing of its IPO, based upon the sale and issuance of 14,500,000 common shares to investors in the IPO. The warrant expired on April 30, 2017.

Income Taxes

12 Months Ended

Mar. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

The loss before income taxes and the related tax benefit are as follows (in thousands):



	Year ended March 31, 2017			Period from February 2, 2016 (Date of Inception) to March 31, 2016
Loss before income taxes:
United States	$	(2,924	)	$	—
Switzerland	(29,745		)	—
Bermuda	(50,845		)	(1,657		)
Total loss before income taxes	$	(83,514	)	$	(1,657	)

Current taxes:
United States	$	134		$	—
Switzerland	—			—
Bermuda	—			—
Total current tax expense	134			—
Deferred taxes:
United States	(208		)	—
Switzerland	—			—
Bermuda	—			—
Total deferred tax benefit	(208		)	—
Total income tax benefit	$	(74	)	$	—

A reconciliation of income tax benefit computed at the Bermuda statutory rate to income tax benefit reflected in the financial statements is as follows:



	Year ended March 31, 2017					Period from February 2, 2016 (Date of Inception) to March 31, 2016
	in 000s			%		in 000s		%
Income tax benefit at Bermuda statutory rate	$	—		—	%	$	—	—	%
Foreign rate differential	(7,592		)	9.09		—		—
Valuation allowance	7,378			(8.83	)	—		—
Other	140			(0.17	)	—		—
Total income tax benefit	$	(74	)	0.09	%	$	—	—	%

The Company's provision for income taxes is based primarily on income taxes in the United States for federal, state and local income taxes. The Company's effective tax rate for the years ended March 31, 2017 and 2016 was 0.09% and 0.00%, respectively, primarily due to the organization of the Company as a Bermuda Exempted Limited Company, for which there is no current tax regime, due to United States permanent unfavorable differences, and a valuation allowance that effectively eliminates the Company's net deferred tax assets in the United States. As of March 31, 2017, the Company had an aggregate income tax receivable of $0.1 million from various federal, state, and local jurisdictions.

Deferred taxes reflect the tax effects of the differences between the amounts records as assets and liabilities for financial reporting purposes and the comparable amounts recorded for income tax purposes. Significant components of the deferred tax assets (liabilities) at March 31, 2017 are as follows (in thousands):



	March 31, 2017			March 31, 2016
Research tax credits	$	163		$	—
Other	300			—
Depreciation	(255		)	—
Swiss net operating loss	6,019			—
Share-based compensation	1,382			—
Subtotal	7,609			—
Valuation allowance	(7,401		)	—
Total deferred tax assets	$	208		$	—

The Company assesses the realizability of the deferred tax assets at each balance sheet date based on available positive and negative evidence in order to determine the amount which is more likely than not to be realized and record a valuation allowance as necessary. As a result of this assessment, a valuation allowance of $1.4 million related to share-based compensation and $6.0 million related to Swiss net operating loss carryforward has been recorded as of March 31, 2017. The Swiss net operating loss carryforward expires in year 2024. The Company believes that it is more likely than not, given the weight of available evidence, that all other deferred tax assets will be realized. The Company will continue to assess the realizability of deferred tax assets at each balance sheet date in order to determine the proper amount, if any, required for a valuation allowance.

The Company files income tax returns in the United States federal, state and local jurisdictions. MSI will file its initial United States federal, state and local income tax returns for the fiscal year ended March 31, 2017 in December 2017. The Company is subject to tax examinations for fiscal year 2016 and forward in all applicable income tax jurisdictions.

Share-Based Compensation

12 Months Ended

Mar. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-Based Compensation

Stock Options:

In June 2016, the Company adopted its 2016 Equity Incentive Plan (as amended, the “2016 Plan”), under which 4,512,889 common shares are reserved for grant. The Company’s employees, directors, officers and consultants are eligible to receive non-qualified and incentive stock options, stock appreciation rights, restricted share awards, restricted share unit awards, and other share awards under the plan. Each option will have an exercise price equal to the fair market value of the Company’s common shares on the date of grant. For grants of incentive stock options, if the grantee owns, or is deemed to own, 10% or more of the total voting power of the Company, then the exercise price shall be 110% of the fair market value of the Company’s common shares on the date of grant and the option will have a five-year contractual term. Options that are forfeited or expire are available for future grants.

Stock options granted under the 2016 Plan may provide option holders, if approved by the board of directors, the right to exercise their options prior to vesting. In the event that an option holder exercises the unvested portion of any option, such unvested portion will be subject to a repurchase option held by the Company at the lower of (1) the fair market value of its common shares on the date of repurchase and (2) the exercise price of the options. Any common shares underlying such unvested portion will continue to vest in accordance with the original vesting schedule of the option.

At March 31, 2017, a total of 1,858,810 common shares were available for future issuance under the 2016 Plan.

The Company estimated the fair value of each option on the date of grant using the Black-Scholes closed-form option-pricing model applying the weighted average assumptions in the following table.



	Year Ended March 31, 2017		Period from February 2, 2016 (Date of Inception) to March 31, 2016
Expected common share price volatility	75.5	%	—	%
Expected risk free interest rate	1.57	%	—	%
Expected term, in years	6.35		—
Expected dividend yield	—	%	—	%

The following table presents a summary of option activity and data under the Company's stock incentive plans through March 31, 2017:



	Number of Options	Weighted Average Exercise Price		Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value
Options outstanding at March 31, 2016	—	$	—	$	—	—	$	—
Granted	1,525,857	5.06		11.90		—	—
Options outstanding at March 31, 2017	1,525,857	5.06		11.90		9.52	10,255,341
Options vested and expected to vest at March 31, 2017	1,471,815	5.06		11.90		9.52	9,890,661
Options exercisable at March 31, 2017	200	11.19		9.56		9.88	110

At March 31, 2017, there were 200 vested options outstanding.

(A) Stock Options and Restricted Share Award Granted to Employees and Directors:

In June 2016, the Company granted a restricted share award for 1,128,222 common shares to the Company’s Principal Executive Officer under the 2016 Plan. In August 2016, the Company granted options to purchase 541,544 common shares to certain employees of the Company, with an exercise price of $2.38 under the 2016 Plan. In September 2016, the Company granted options to purchase 572,568 common shares to certain employees, officers and directors of the Company, with a weighted average exercise price of $4.00 under the 2016 Plan. During the year ended March 31, 2017, the Company granted options to purchase 1,464,458 common shares to certain employees and directors of the Company.

For the year ended March 31, 2017, share-based compensation expense related to the restricted share award was $1.2 million.

For the year ended March 31, 2017, the Company recorded share-based compensation expense related to stock options issued to employees, officers and directors of $2.2 million and share-based compensation expense related to stock options issued to non-employees of $0.4 million (Note 8(B)(1)). This share-based compensation expense is included in research and development and general and administrative expenses in the accompanying consolidated statements of operations.

There was no share-based compensation expense for the period from February 2, 2016 (date of inception) to March 31, 2016.

In connection with the IPO and after preliminary discussions with the underwriters, the Company reassessed the fair value of: (1) 1,128,222 restricted common shares issued to our Principal Executive Officer in June 2016 with an initial fair value of $1.52 per common share; (2) 602,743 common shares underlying stock options granted in August 2016 (including options to purchase 61,199 common shares granted to certain consultants as described below in Note 8(B)(1)) with an exercise price of $2.38 per common share; and (3) 572,568 common shares underlying stock options granted in September 2016 to the Company’s employees, officers and directors with a weighted-average exercise price of $4.00 per common share. As a result, the Company determined that the reassessed fair value of the restricted common shares was $5.10 per common share and the reassessed fair value of the common shares underlying the stock options granted in August and September 2016 was $15.00 per common share, which was the initial public offering price of the Company's common shares in the IPO. The use of this higher fair value per common share increased the weighted-average fair value of the stock options granted in August and September 2016 to $13.44 per common share and $12.78 per common share, respectively. Prior to the IPO, the fair value of the common shares underlying the Company’s stock options was estimated on each grant date by the board of directors. In order to determine the fair value of the Company’s common shares underlying granted stock options, the board of directors considered, among other things, timely valuations of the common shares prepared by an unrelated third-party valuation firm in accordance with the guidance provided by the American Institute of Certified Public Accountants Practice Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation. The use of this higher share price increased both recognized and unrecognized share-based compensation expense.

At March 31, 2017, total unrecognized compensation expense related to non-vested options for employees, officers and directors was $15.1 million and is expected to be recognized over the remaining weighted-average service period of 3.48 years.

(B) Share-Based Compensation for Related Parties:

(1) Stock Options Granted to Non-Employees:

During the year ended March 31, 2017, the Company granted options to purchase 61,399 common shares to certain consultants, who are also employees of RSI, with a weighted average exercise price of $2.41 under the 2016 Plan. As discussed above in Note 8(A), the use of the higher fair value per common share of $15.00, which was reassessed in conjunction with the IPO and after preliminary discussions with the underwriters, increased both recognized and unrecognized share-based compensation expense. For the year ended March 31, 2017, share-based compensation expense related to stock options granted to consultants was $0.4 million. At March 31, 2017, total unrecognized compensation expense related to stock options granted to consultants was $0.3 million, which is expected to be recognized over 0.94 years.

(2) Share-Based Compensation Allocated to the Company by RSL:

In relation to the RSL common share awards and options issued by RSL to RSL and RSI employees, the Company recorded

share-based compensation expense of $4.9 million and $1.0 million, respectively, for the year ended March 31, 2017 and the period from February 2, 2016 (Date of Inception) to March 31, 2016.

Share-based compensation expense is allocated to the Company by RSL based upon the relative percentage of time utilized by RSL and RSI employees on Company matters.

The RSL common share awards are valued at fair value on the date of grant and that fair value is recognized over the requisite service period. Significant judgment and estimates were used to estimate the fair value of these awards, as they are not publicly traded. RSL common share awards are subject to specified vesting schedules and requirements (a mix of time-based, performance-based and corporate event-based, including targets for RSL’s post-IPO market capitalization and future financing events). The Company estimated the fair value of each RSL option on the date of grant using the Black-Scholes closed-form option-pricing model.

Compensation expense will be allocated to the Company over the required service period over which these RSL common share awards and RSL options would vest and is based upon the relative percentage of time utilized by RSL and RSI employees on Company matters.

(3) RSL Restricted Stock Unit ("RSUs"):

Lynn Seely, M.D., our Principal Executive Officer, was granted 66,845 restricted stock units (“RSUs”) of RSL during the year ended March 31, 2017. The RSUs have a requisite service period of eight years and have no dividend rights. The RSUs will vest upon the achievement of both a performance and liquidity condition, if both are achieved within the requisite service period. As of March 31, 2017, the performance conditions had not been met and were deemed not probable of being met. For the year ended March 31, 2017, the Company recorded no share-based compensation expense related to the RSUs that were issued. At March 31, 2017, there was $0.6 million of unrecognized compensation expense related to non-vested RSUs. The Company will recognize the expense upon achievement of the performance and market conditions through the requisite service period.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Fair Value Measurements

12 Months Ended

Mar. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

The Company applies a fair value framework in order to measure and disclose its financial assets and liabilities. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires an entity to maximize the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value:

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

Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Fair values are determined by utilizing quoted prices for similar assets and liabilities in active markets or other market observable inputs such as interest rates and yield curves.

Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s Level 3 assets and liabilities consist of the warrant liability associated with the license agreement with Takeda. The fair value of the warrant liability was determined based on a Monte Carlo simulation model which requires various highly subjective unobservable inputs. The significant unobservable inputs used in the fair value measurement are the probability of a future financing event; the expected date or dates of a future financing event; the potential size of a future financing event; the enterprise value of the Company; and the expected volatility in the Company’s valuation.

Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis

Financial assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability.

The following table sets forth the Company’s assets and liabilities that are measured at fair value on a recurring basis as of March 31, 2017 and March 31, 2016, by level, within the fair value hierarchy:



	As of March 31, 2017								As of March 31, 2016
(in thousands)
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance as of March 31, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance as of March 31, 2016
Assets:
Total assets at fair value	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Liabilities:
Warrant liability	$	—	$	—	$	52	$	52	$	—	$	—	$	—	$	—
Total liabilities at fair value	$	—	$	—	$	52	$	52	$	—	$	—	$	—	$	—

There were no transfers of assets between Level 1 and Level 2 of the fair value measurement hierarchy that occurred during the year ended March 31, 2017.

Level 3 Disclosures

The Company measures the warrant liability at fair value based on significant inputs not observable in the market, which causes it to be classified as a Level 3 measurement within the fair value hierarchy. The valuation of the warrant liability uses assumptions and estimates the Company believes would be made by a market participant in making the same valuation. The Company assesses these assumptions and estimates on an ongoing basis as additional data impacting the assumptions and estimates are obtained. Changes in the fair value of the warrant liability related to updated assumptions and estimates are recognized as other (expense) income in the accompanying consolidated statements of operations.

The warrant liability may change significantly as additional data are obtained, impacting the Company’s assumptions regarding probabilities of successful financing events used to estimate the fair value of the liability. In evaluating this information, considerable judgment is required to interpret the data used to develop the assumptions and estimates. The estimates of fair value may not be indicative of the amounts that could be realized in a financing event. Accordingly, the use of different market assumptions and/or different valuation techniques may have a material effect on the estimated fair value amounts, and such changes could materially impact the Company’s results of operations in future periods.

The fair value of our warrant liability as of March 31, 2017 was calculated using the following significant unobservable inputs:



Input	Range or Point Estimate Used
Projected time frame to an equity financing	April 2017
Probability of a successful equity financing	2.0	%
Annualized equity volatility	73.4	%
Risk-free interest rate	0.74	%

The changes in fair value of the Company’s Level 3 warrant liability during the year ended March 31, 2017 were as follows (in thousands):



Balance at March 31, 2016	$	—
Fair value of the warrant liability issued	5,377
Changes in the fair value of the warrant liability, included in net loss	27,518
Settlements	(32,843		)
Balance at March 31, 2017	$	52

For the year ended March 31, 2017, changes in the carrying value of the warrant liability resulted from settlements related to the fair value of the warrant exercised, partially offset by changes in the fair value of the warrant liability primarily due to the changes in the estimated probabilities of future financing events, change in the enterprise value of the Company, automatic exercise of the warrant and the passage of time.

- Definition

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

+ References + Details

Commitments and Contingencies

12 Months Ended

Mar. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

The Company entered into certain commitments under the Takeda license agreement (See Note 3), amended its services agreement with RSI and entered into a separate service agreement with RSG (See Note 5(A)). As of March 31, 2016 and March 31, 2017, the Company did not have any ongoing material financial commitments. The Company expects to enter into other commitments as the business further develops.

The Company may be, from time to time, a party to various disputes and claims arising from normal business activities. The Company accrues for loss contingencies when available information indicates that it is probable that a liability has been incurred and the amount of such loss can be reasonably estimated. In the cases where the Company believes that a reasonably possible loss exists, the Company discloses the facts and circumstances of the litigation, including an estimable range, if possible.

Currently, the Company is party to a legal proceeding as described in Part I, Item 3, Legal Proceedings, of this Annual Report on Form 10-K. The Company believes that it is not probable that a liability has been incurred and that the amount of any such liability cannot be reasonably estimated. As a result, the Company has not recorded a loss contingency related to this legal proceeding. While it is not possible to determine the outcome of the matter, the Company believes the resolution of such matter will not have a material adverse effect on its business, financial condition or results of operations.

The following table provides information with respect to contractual obligations as of March 31, 2017:



Contractual Obligations (in thousands)	Total		Under 1 year		1-2 years		2-3 years		3-4 years		4-5 years		Over 5 years

Lease obligations	$	5,327	$	581	$	926	$	968	$	993	$	1,016	$	843
Total	$	5,327	$	581	$	926	$	968	$	993	$	1,016	$	843

Selected Quarterly Data (Unaudited)

12 Months Ended

Mar. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Data (Unaudited)

The following table presents selected quarterly financial data for the year ended March 31, 2017 and the period from February 2, 2016 (Date of Inception) to March 31, 2016.



	First Quarter Ended			Second Quarter Ended			Third Quarter Ended			Fourth Quarter Ended			Period from February 2, 2016 (Date of Inception) to
	June 30,			September 30,			December 31,			March 31,			March 31,
	2016 ⁽¹⁾			2016			2016			2017			2016
Total operating expenses	$	17,135		$	6,720		$	9,056		$	22,946		$	1,657
Net loss	(18,970		)	(34,712		)	(8,083		)	(21,675		)	(1,657		)
Net loss per share attributable to common shareholders - basic and diluted	(0.47		)	(0.82		)	(0.15		)	(0.37		)	(0.04		)

(1)

On April 29, 2016, the Company entered into a license agreement with Takeda. As a result of this transaction, the Company recorded $13.1 million as research and development expense at the closing date of the acquisition of the rights, which consisted of $7.7 million for the estimated fair value of the 5,077,001 common shares issued and $5.4 million for the estimated fair value of warrant liability. Please refer to Note 3 for further details.

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Accounting	The accompanying consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles, or U.S. GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. The consolidated financial statements include the accounts of the Company and MSI, MSL and MSG, its wholly-owned subsidiaries. The Company has no unconsolidated subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company regularly evaluates estimates and assumptions related to assets, liabilities, costs, and expenses, including compensation expense allocated to the Company under its services agreements with Roivant Sciences, Inc., or RSI, and Roivant Sciences GmbH, or RSG, each a wholly-owned subsidiary of RSL, as well as share-based compensation and research and development costs. 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.
Concentrations of Credit Risk	Financial instruments that potentially subject the Company to concentration of credit risk include cash. At March 31, 2017, substantially all of the cash balances are deposited in two banking institutions and are all in excess of insured levels.
Property and Equipment	Property and equipment, consisting of computers, equipment, furniture and fixtures, leasehold improvements, and software, is recorded at cost. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred. Upon disposal, retirement or sale, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation will be recorded for property and equipment using the straight-line method over the estimated useful lives of three to seven years, once the asset is installed and placed in service. The Company reviews the recoverability of all long-lived assets, including the related useful lives, whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset might not be recoverable. Recoverability is measured by comparison of the book values of the assets to future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceed their fair value, which is measured based on the projected discounted future net cash flows arising from the assets.
Contingencies	The Company may be, from time to time, a party to various disputes and claims arising from normal business activities. The Company continually assesses litigation to determine if an unfavorable outcome would lead to a probable loss or reasonably possible loss which could be estimated. In accordance with the guidance of the FASB on accounting for contingencies, the Company accrues for all contingencies at the earliest date at which the Company deems it probable that a liability has been incurred and the amount of such liability can be reasonably estimated. If the estimate of a probable loss is a range and no amount within the range is more likely than another, the Company accrues the minimum of the range. In the cases where the Company believes that a reasonably possible loss exists, the Company discloses the facts and circumstances of the litigation, including an estimable range, if possible.
Deferred Offering Costs	Deferred offering costs, which consisted of direct costs related to the Company’s initial public offering, or IPO, of its common shares, were capitalized in other assets until the consummation of the IPO. These offering costs were reclassified to additional paid-in capital upon the closing of the IPO on November 1, 2016.
Research and Development Expense	Research and development costs are expensed as incurred. Clinical study costs are accrued over the service periods specified in the contracts and adjusted as necessary based on an ongoing review of the level of effort and costs actually incurred. Payments for a product license prior to regulatory approval of the product and payments for milestones achieved prior to regulatory approval of the product are expensed in the period incurred as research and development. Milestone payments made in connection with regulatory approvals are capitalized and amortized to cost of revenue over the remaining useful life of the asset. Research and development expenses primarily consist of the intellectual property and research and development materials acquired, certain costs charged by RSI under its services agreement with the Company, and expenses from third parties who conduct research and development activities on behalf of the Company. The Company expenses in-process research and development projects acquired as asset acquisitions which have not reached technological feasibility and which have no alternative future use. Clinical study costs are accrued over the service periods specified in the contracts and adjusted as necessary based upon an ongoing review of the level of effort and costs actually incurred.
Warrant Liability	The Company records the warrant liability at its estimated fair value as a liability in the consolidated balance sheets. The Company remeasures the estimated fair value of the warrant liability each reporting period and records the changes in the fair value in the consolidated statements of operations as other (expense) income (See Note 9).
Income Taxes	Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and the respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is recorded when, after consideration of all positive and negative evidence, it is not more likely than not that the Company’s deferred tax assets will be realizable. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances.
Share-based Compensation	Share-based awards to employees and directors are valued at fair value on the date of the grant and that fair value is recognized as share-based compensation expense on a straight-line basis over the requisite service period of the entire award. The Company values its stock options using the Black-Scholes option pricing model. Certain assumptions need to be made with respect to utilizing the Black-Scholes option pricing model, including the expected life of the award, volatility of the underlying shares, the risk-free interest rate, the fair value of the Company’s common shares and anticipated forfeiture of the share-based awards. Since the Company has limited option exercise history, it has generally elected to estimate the expected life of an award based upon the Securities and Exchange Commission-approved “simplified method” noted under the provisions of Staff Accounting Bulletin No. 107 with the continued use of this method extended under the provisions of Staff Accounting Bulletin No. 110. The risk-free interest rate is based on the rates paid on securities issued by the United States Treasury with a term approximating the expected life of the equity award. The expected share price volatility for the Company’s common shares is estimated by taking the average historical price volatility for industry peers. Estimates of pre-vesting award forfeitures are based on the Company’s expectations of future employee turnover. The Company will adjust its estimate of forfeitures over the requisite service period based on the extent to which actual forfeitures differ, or are expected to differ, from such estimates. Changes in estimated forfeitures will be recognized through a cumulative catch-up adjustment in the period of change and will also impact the amount of compensation expense to be recognized in future periods. The Company accounts for share-based payments to non-employees issued in exchange for services based upon the fair value of the equity instruments issued. Compensation expense for stock options issued to non-employees is calculated using the Black-Scholes option pricing model and is recorded over the service performance period. Options subject to vesting are required to be periodically remeasured over their service performance period, which is generally the same as the vesting period.
Net Loss Per Common Share	Basic net loss per common share is computed by dividing 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.
Recently Issued Accounting Pronouncements	In August 2014, the FASB issued ASU No. 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 310-40): Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern," which provides guidance on determining when and how to disclose going-concern uncertainties in the financial statements. This new ASU requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures if “conditions or events raise substantial doubt about the entity’s ability to continue as a going concern.” The ASU is effective for annual periods ending after December 15, 2016, and interim periods thereafter, with early adoption permitted. This guidance has been adopted as of March 31, 2017 and it did not have a material impact on the consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” (ASU No. 2016-02), which is a comprehensive new lease standard that amends various aspects of existing accounting guidance for leases. The core principle of ASU No. 2016-02 will require lessees to present the assets and liabilities that arise from leases on their balance sheets. ASU No. 2016-02 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. The Company is currently evaluating the new standard and its impact on the Company’s consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU No. 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” (ASU No. 2016-09). This ASU makes several modifications to Topic 718 related to the accounting for forfeitures, employer tax withholding on share-based compensation, and the financial statement presentation of excess tax benefits or deficiencies. ASU No. 2016-09 also clarifies the statement of cash flows presentation for certain components of share-based awards. The standard is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods, with early adoption permitted. The Company expects to adopt this guidance when effective and is currently evaluating the effect that the updated standard will have on its consolidated financial statements and related disclosures.
Foreign Currency	The Company has operations in the United States, the United Kingdom and Switzerland. The results of its non-U.S. dollar based functional currency operations are translated to U.S. dollars at the average exchange rates during the period. The Company’s assets and liabilities are translated using the current exchange rate as of the balance sheet date and shareholders’ equity is translated using historical rates. Adjustments resulting from the translation of the financial statements of the Company’s foreign subsidiaries into U.S. dollars are excluded from the determination of net loss and are accumulated in a separate component of shareholders’ equity. Foreign exchange transaction gains and losses are included in other income (loss) in the Company’s results of operations.

Income Taxes (Tables)

12 Months Ended

Mar. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of Loss Before Income Taxes and Related Tax Benefit

The loss before income taxes and the related tax benefit are as follows (in thousands):



	Year ended March 31, 2017			Period from February 2, 2016 (Date of Inception) to March 31, 2016
Loss before income taxes:
United States	$	(2,924	)	$	—
Switzerland	(29,745		)	—
Bermuda	(50,845		)	(1,657		)
Total loss before income taxes	$	(83,514	)	$	(1,657	)

Current taxes:
United States	$	134		$	—
Switzerland	—			—
Bermuda	—			—
Total current tax expense	134			—
Deferred taxes:
United States	(208		)	—
Switzerland	—			—
Bermuda	—			—
Total deferred tax benefit	(208		)	—
Total income tax benefit	$	(74	)	$	—

Schedule of Effective Income Tax Reconciliation

A reconciliation of income tax benefit computed at the Bermuda statutory rate to income tax benefit reflected in the financial statements is as follows:



	Year ended March 31, 2017					Period from February 2, 2016 (Date of Inception) to March 31, 2016
	in 000s			%		in 000s		%
Income tax benefit at Bermuda statutory rate	$	—		—	%	$	—	—	%
Foreign rate differential	(7,592		)	9.09		—		—
Valuation allowance	7,378			(8.83	)	—		—
Other	140			(0.17	)	—		—
Total income tax benefit	$	(74	)	0.09	%	$	—	—	%

Schedule of Deferred Taxes

Significant components of the deferred tax assets (liabilities) at March 31, 2017 are as follows (in thousands):



	March 31, 2017			March 31, 2016
Research tax credits	$	163		$	—
Other	300			—
Depreciation	(255		)	—
Swiss net operating loss	6,019			—
Share-based compensation	1,382			—
Subtotal	7,609			—
Valuation allowance	(7,401		)	—
Total deferred tax assets	$	208		$	—

Share-Based Compensation (Tables)

12 Months Ended

Mar. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Weighted Average Fair Value Assumptions

The Company estimated the fair value of each option on the date of grant using the Black-Scholes closed-form option-pricing model applying the weighted average assumptions in the following table.



	Year Ended March 31, 2017		Period from February 2, 2016 (Date of Inception) to March 31, 2016
Expected common share price volatility	75.5	%	—	%
Expected risk free interest rate	1.57	%	—	%
Expected term, in years	6.35		—
Expected dividend yield	—	%	—	%

Summary of Stock Option Activity

The following table presents a summary of option activity and data under the Company's stock incentive plans through March 31, 2017:



	Number of Options	Weighted Average Exercise Price		Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value
Options outstanding at March 31, 2016	—	$	—	$	—	—	$	—
Granted	1,525,857	5.06		11.90		—	—
Options outstanding at March 31, 2017	1,525,857	5.06		11.90		9.52	10,255,341
Options vested and expected to vest at March 31, 2017	1,471,815	5.06		11.90		9.52	9,890,661
Options exercisable at March 31, 2017	200	11.19		9.56		9.88	110

Fair Value Measurements (Tables)

12 Months Ended

Mar. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis



	As of March 31, 2017								As of March 31, 2016
(in thousands)
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance as of March 31, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance as of March 31, 2016
Assets:
Total assets at fair value	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Liabilities:
Warrant liability	$	—	$	—	$	52	$	52	$	—	$	—	$	—	$	—
Total liabilities at fair value	$	—	$	—	$	52	$	52	$	—	$	—	$	—	$	—

Schedule of Significant Unobservable Inputs

The fair value of our warrant liability as of March 31, 2017 was calculated using the following significant unobservable inputs:



Input	Range or Point Estimate Used
Projected time frame to an equity financing	April 2017
Probability of a successful equity financing	2.0	%
Annualized equity volatility	73.4	%
Risk-free interest rate	0.74	%

Schedule of Changes in Fair Value of Level 3 Warrant Liability

The changes in fair value of the Company’s Level 3 warrant liability during the year ended March 31, 2017 were as follows (in thousands):



Balance at March 31, 2016	$	—
Fair value of the warrant liability issued	5,377
Changes in the fair value of the warrant liability, included in net loss	27,518
Settlements	(32,843		)
Balance at March 31, 2017	$	52

Selected Quarterly Data (Unaudited) (Tables)

12 Months Ended

Mar. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Data

The following table presents selected quarterly financial data for the year ended March 31, 2017 and the period from February 2, 2016 (Date of Inception) to March 31, 2016.



	First Quarter Ended			Second Quarter Ended			Third Quarter Ended			Fourth Quarter Ended			Period from February 2, 2016 (Date of Inception) to
	June 30,			September 30,			December 31,			March 31,			March 31,
	2016 ⁽¹⁾			2016			2016			2017			2016
Total operating expenses	$	17,135		$	6,720		$	9,056		$	22,946		$	1,657
Net loss	(18,970		)	(34,712		)	(8,083		)	(21,675		)	(1,657		)
Net loss per share attributable to common shareholders - basic and diluted	(0.47		)	(0.82		)	(0.15		)	(0.37		)	(0.04		)

(1)

Description of Business - Narrative (Details)	12 Months Ended
Description of Business - Narrative (Details)	Mar. 31, 2017 segment product_candidate
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	1
Number of reporting segments	1
Number of product candidates \| product_candidate	2

Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2017 USD ($) bank shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Research and development expense \| $	$ 0	$ 43,500
Restricted Share Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted weighted-average common shares outstanding (in shares) \| shares		1,128,222
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted weighted-average common shares outstanding (in shares) \| shares		1,525,857
Research and development
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share-based compensation \| $	$ 0	$ 3,893
Minimum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Estimated useful lives of property and equipment		3 years
Maximum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Estimated useful lives of property and equipment		7 years
Credit Concentration Risk
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of banking institutions \| bank		2

License Agreement - Narrative (Details) - USD ($) $ in Thousands		2 Months Ended	12 Months Ended
	Apr. 29, 2016	Mar. 31, 2016	Mar. 31, 2017
Other Liabilities Disclosure [Abstract]
Shares issued to Takeda under the Takeda license agreement (in shares)	5,077,001
Period for which royalties are required to be paid after the first commercial sale of relugolix or MVT-602 products			10 years
Ownership percentage to which the warrants entitle Takeda			12.00%
Purchase of in-process research and development expense	$ 13,100	$ 0	$ 13,117
Research and development expense, fair value of shares issued	7,700		$ 7,740
Warrant liability	$ 5,400

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Payables and Accruals [Abstract]
Research and development expenses	$ 9,737	$ 0
Salaries, bonuses, and other compensation expenses	797	0
Legal expenses	481	164
Other expenses	963	59
Total accrued expenses	$ 11,978	$ 223

Related Party Transactions - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Mar. 31, 2017
RSL \| Option Agreement
Related Party Transaction [Line Items]
Option agreement, term	2 years
Option agreement, purchase price as a percent of payments made by RSL	110.00%
RSL and RSI \| RSL and RSI \| Services Agreement
Related Party Transaction [Line Items]
Base salary, fringe benefits, and share-based compensation		$ 0.4	$ 9.2

Shareholders' Equity - Narrative (Details) $ / shares in Units, $ in Thousands			1 Months Ended		2 Months Ended	12 Months Ended
	Nov. 01, 2016 USD ($) $ / shares shares	Oct. 18, 2016	Aug. 31, 2016 shares	Jun. 30, 2016 shares	Mar. 31, 2016 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) bank $ / shares shares	Feb. 02, 2016 class
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of classes of shares \| class							1
Common shares authorized (in shares)					564,111,242	564,111,242
Common shares par value (in USD per share) \| $ / shares					$ 0.000017727	$ 0.000017727
Options granted (in shares)						1,525,857
Reverse stock split ratio		0.5641
Shares sold, price (in USD per share) \| $ / shares						$ 15.00
Gross proceeds on sale of shares \| $						$ 199,964
Net proceeds on sale of shares \| $					$ 0	$ 202,275
Number of banking institutions \| bank						1
Shares issued to settle the warrant liability to Takeda (in shares)						2,339,192
Initial Public Offering
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares sold (in shares)	14,500,000
Shares sold, price (in USD per share) \| $ / shares	$ 15.00
Gross proceeds on sale of shares \| $	$ 217,500
Net proceeds on sale of shares \| $	200,000
Underwriting discounts and commissions \| $	15,200
Offering expenses \| $	$ 2,300
Shares issued to settle the warrant liability to Takeda (in shares)						1,977,269
Restricted Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted (in shares)				1,128,222		1,128,222
Shares issued to settle the warrant liability to Takeda (in shares)						153,846
Employee and Non-employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)			602,743			1,525,857
Shares issued to settle the warrant liability to Takeda (in shares)						208,077

Income Taxes - Loss Before Income Taxes and Related Tax Benefit (Details) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2017
Loss before income taxes:
Bermuda	$ (1,657)	$ (50,845)
Total loss before income taxes	(1,657)	(83,514)
Current taxes:
Bermuda	0	0
Total current tax expense	0	134
Deferred taxes:
Bermuda	0	0
Total deferred tax benefit	0	(208)
Total income tax benefit	0	(74)
United States
Loss before income taxes:
Foreign	0	(2,924)
Current taxes:
Foreign	0	134
Deferred taxes:
Foreign	0	(208)
Switzerland
Loss before income taxes:
Foreign	0	(29,745)
Current taxes:
Foreign	0	0
Deferred taxes:
Foreign	$ 0	$ 0

Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Effective Income Tax Rate Reconciliation, Amount
Income tax benefit at Bermuda statutory rate	$ 0	$ 0
Foreign rate differential	0	(7,592)
Valuation allowance	0	7,378
Other	0	140
Total income tax benefit	$ 0	$ (74)
Effective Income Tax Rate Reconciliation, Percent
Income tax benefit at Bermuda statutory rate	0.00%	0.00%
Foreign rate differential	0.00%	9.09%
Valuation allowance	0.00%	(8.83%)
Other	0.00%	(0.17%)
Total income tax benefit	0.00%	0.09%	0.00%

Income Taxes - Narrative (Details) - USD ($)	2 Months Ended	12 Months Ended
Income Taxes - Narrative (Details) - USD ($)	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	0.00%	0.09%	0.00%
Unrecognized tax benefits		$ 0
Income tax receivable	$ 0	105,000	$ 0
Valuation Allowance [Line Items]
Deferred tax assets valuation allowance	$ 0	7,401,000	$ 0
Share-Based Compensation
Valuation Allowance [Line Items]
Deferred tax assets valuation allowance		1,400,000
Swiss Operating Loss Carryforward
Valuation Allowance [Line Items]
Deferred tax assets valuation allowance		$ 6,000,000

Income Taxes - Deferred Taxes (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Research tax credits	$ 163	$ 0
Other	300	0
Depreciation	(255)	0
Swiss net operating loss	6,019	0
Share-based compensation	1,382	0
Subtotal	7,609	0
Valuation allowance	(7,401)	0
Total deferred tax assets	$ 208	$ 0

Share-Based Compensation - Narrative (Details) - USD ($)	1 Months Ended			2 Months Ended	12 Months Ended
	Sep. 30, 2016	Aug. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for grant (in shares)			4,512,889
Vested options outstanding (in shares)					200
Options granted (in shares)					1,525,857
Exercise price of options granted in period (in USD per share)					$ 5.06
Fair value of underlying common shares (in USD per share)	$ 15				15.00
Fair value of stock options granted (in USD per share)					$ 11.90
RSI Employees \| Share-Based Compensation Allocated to the Company by RSL
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation				$ 1,000,000	$ 4,900,000
2016 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for grant (in shares)					1,858,810
Employee and Non-employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)		602,743			1,525,857
Exercise price of options granted in period (in USD per share)		$ 2.38
Fair value of stock options granted (in USD per share)		$ 13.44
Employee and Non-employee Stock Option \| Stock Option Grantees Holding More Than 10% of the Total Voting Power of the Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Threshold percentage of total voting power of company					10.00%
Exercise price as a percentage of fair value					110.00%
Contractual term					5 years
Restricted Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted (in shares)			1,128,222		1,128,222
Share-based compensation					$ 1,200,000
Fair value of restricted stock granted (in USD per share)			$ 5.10
Restricted Share Awards \| Originally reported
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock granted (in USD per share)			$ 1.52
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	572,568	541,544			1,464,458
Exercise price of options granted in period (in USD per share)	$ 4.00	$ 2.38
Share-based compensation				$ 0	$ 2,200,000
Fair value of stock options granted (in USD per share)	$ 12.78
Unrecognized compensation expense related to options for employees, officers, and directors					$ 15,100,000
Unrecognized compensation expense, period for recognition, related to options for employees, officers, and directors					3 years 5 months 23 days
Non-employee Stock Option \| RSI Employees \| Stock Options Granted to Non-Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)		61,199			61,399
Exercise price of options granted in period (in USD per share)					$ 2.41
Share-based compensation					$ 400,000
Unrecognized compensation expense related to options for non-employees					$ 300,000
Unrecognized compensation expense, period for recognition, related to options for non-employees					11 months 9 days
Restricted Stock Units \| Principal Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted (in shares)					66,845
Share-based compensation					$ 0
Requisite service period					8 years
Unrecognized compensation cost related to restricted stock units					$ 600,000

Share-Based Compensation - Schedule of Fair Value Assumptions for Stock Options (Details)	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected common share price volatility	0.00%	75.50%
Expected risk free interest rate	0.00%	1.57%
Expected term, in years	0 years	6 years 4 months 5 days
Expected dividend yield	0.00%	0.00%

Share-Based Compensation - Summary of Option Activity (Details) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Number of Options
Beginning balance (in shares)	0
Granted (in shares)	1,525,857
Ending balance (in shares)	1,525,857	0
Weighted Average Exercise Price
Beginning balance (in USD per share)	$ 0.00
Granted (in USD per share)	5.06
Ending balance (in USD per share)	5.06	$ 0.00
Weighted Average Grant Date Fair Value
Beginning balance (in USD per share)	0.00
Granted (in USD per share)	11.90
Ending balance (in USD per share)	$ 11.90	$ 0.00
Options Vested and Expected to Vest
Number of Options (in shares)	1,471,815
Weighted Average Exercise Price (in USD per share)	$ 5.06
Weighted Average Grant Date Fair Value (in USD per share)	$ 11.90
Weighted Average Remaining Contractual Life	9 years 6 months 7 days
Aggregate Intrinsic Value	$ 9,890,661
Additional Information
Options outstanding, Weighted Average Remaining Contractual Life	9 years 6 months 7 days	0 years
Options outstanding, Aggregate Intrinsic Value	$ 10,255,341	$ 0
Options exercisable, Number of Options (in shares)	200
Options exercisable, Weighted Average Exercise Price (in USD per share)	$ 11.19
Options exercisable, Weighted Average Grant Date Fair Value (in USD per share)	$ 9.56
Options exercisable, Weighted Average Remaining Contractual Life	9 years 10 months 17 days
Options exercisable, Aggregate Intrinsic Value	$ 110

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Apr. 29, 2016	Mar. 31, 2016
Liabilities:
Warrant liability		$ 5,400
Fair Value, Measurements, Recurring
Assets:
Total assets at fair value	$ 0		$ 0
Liabilities:
Warrant liability	52		0
Total liabilities at fair value	52		0
Fair Value, Measurements, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets at fair value	0		0
Liabilities:
Warrant liability	0		0
Total liabilities at fair value	0		0
Fair Value, Measurements, Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Total assets at fair value	0		0
Liabilities:
Warrant liability	0		0
Total liabilities at fair value	0		0
Fair Value, Measurements, Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Total assets at fair value	0		0
Liabilities:
Warrant liability	52		0
Total liabilities at fair value	$ 52		$ 0

Fair Value Measurements - Schedule of Significant Unobservable Inputs (Details) - Fair Value, Measurements, Recurring - Warrant Liability - Significant Unobservable Inputs (Level 3)	12 Months Ended
	Mar. 31, 2017
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Probability of a successful equity financing	2.00%
Annualized equity volatility	73.40%
Risk-free interest rate	0.74%

Fair Value Measurements - Schedule of Changes in Fair Value of Liabilities (Details) - Warrant Liability $ in Thousands	12 Months Ended
	Mar. 31, 2017 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at March 31, 2016	$ 0
Fair value of the warrant liability issued	5,377
Changes in the fair value of the warrant liability, included in net loss	27,518
Settlements	(32,843)
Balance at March 31, 2017	$ 52

Commitments and Contingencies - Contractual Obligations (Details) $ in Thousands	Mar. 31, 2017 USD ($)
Lease obligations
Total	$ 5,327
Under 1 year	581
1-2 years	926
2-3 years	968
3-4 years	993
4-5 years	1,016
Over 5 years	843
Total
Total	5,327
Under 1 year	581
1-2 years	926
2-3 years	968
3-4 years	993
4-5 years	1,016
Over 5 years	$ 843

Selected Quarterly Data (Unaudited) - Schedule of Quarterly Data (Details) - USD ($) $ / shares in Units, $ in Thousands		2 Months Ended	3 Months Ended				12 Months Ended
	Apr. 29, 2016	Mar. 31, 2016	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total operating expenses		$ 1,657	$ 22,946	$ 9,056	$ 6,720	$ 17,135	$ 55,857
Net loss		$ (1,657)	$ (21,675)	$ (8,083)	$ (34,712)	$ (18,970)	$ (83,440)
Net loss per share attributable to common shareholders - basic and diluted (in USD per share)		$ (0.04)	$ (0.37)	$ (0.15)	$ (0.82)	$ (0.47)	$ (1.70)
Purchase of in-process research and development expense	$ 13,100	$ 0					$ 13,117
Research and development expense, fair value of shares issued	$ 7,700						$ 7,740
Shares issued to Takeda under the Takeda license agreement (in shares)	5,077,001
Warrant liability	$ 5,400

Consolidated Statements of Shareholders' Equity (Deficit) (Parenthetical) $ in Thousands	12 Months Ended
	Mar. 31, 2017 USD ($) $ / shares
Statement of Stockholders' Equity [Abstract]
Shares sold, price (in USD per share) \| $ / shares	$ 15.00
Underwriting discounts and commissions and offering expenses \| $	$ 17,536