Shareholders' Equity (Details) $ / shares in Units, $ in Thousands					1 Months Ended		2 Months Ended	11 Months Ended	12 Months Ended
	May 08, 2019 shares	Dec. 18, 2018 USD ($) $ / shares shares	Jul. 09, 2018 USD ($)	Jun. 05, 2018 $ / shares shares	Feb. 29, 2020 USD ($) $ / shares shares	Mar. 31, 2019 USD ($) $ / shares shares	Jun. 09, 2020 USD ($) shares	Mar. 31, 2020 USD ($) $ / shares shares	Mar. 31, 2020 USD ($) $ / shares shares	Mar. 31, 2019 USD ($) $ / shares shares	Apr. 30, 2020 USD ($)	Jun. 22, 2018 USD ($)	Mar. 31, 2018 shares
Class of Stock [Line Items]
Common shares authorized (in shares) | shares						1,000,000,000		1,000,000,000	1,000,000,000	1,000,000,000
Common shares par value (in dollars per share) | $ / shares						$ 0.00001		$ 0.00001	$ 0.00001	$ 0.00001
Stock split ratio	0.125							0.125
Capital contribution | $									$ 148	$ 1,894
Public Offering
Class of Stock [Line Items]
Common stock issued during period (in shares) | shares		4,145,115			16,631,336	3,333,333
Common stock issued (in dollars per share) | $ / shares		$ 8				$ 12		$ 3.75	$ 3.75	$ 12
Net proceeds from common stock issued | $		$ 31,600			$ 70,800	$ 37,900
Gross proceeds from common stock issued | $		$ 33,200				$ 40,000
Warrants issued (in shares) | shares					3,301,998
Warrants issued (in dollars per share) | $ / shares					$ 3.74999
Percent ownership threshold to no longer exercise					9.99%
Underwriter's Option
Class of Stock [Line Items]
Common stock issued during period (in shares) | shares		395,115			2,600,000
Roivant Sciences, Ltd. | Public Offering
Class of Stock [Line Items]
Common stock issued during period (in shares) | shares		1,250,000			5,333,333	833,333
Roivant Sciences, Ltd. | Private Placement
Class of Stock [Line Items]
Common stock issued during period (in shares) | shares				1,785,714
Common stock issued (in dollars per share) | $ / shares				$ 14
Net proceeds from common stock issued | $			$ 25,000
Cowen and Company, LLC | Private Placement
Class of Stock [Line Items]
Amount available for issuance under equity offering program | $								$ 100	$ 100
Maximum offering under equity offering program | $												$ 75,000
RSL
Class of Stock [Line Items]
Capital contribution | $									$ 100	$ 1,900
Common Shares
Class of Stock [Line Items]
Shares outstanding before split (in shares) | shares	182,200,000
Shares outstanding (in shares) | shares						22,779,891		39,526,299	39,526,299	22,779,891			13,473,512
Subsequent Event | SVB Leerink LLC | Private Placement
Class of Stock [Line Items]
Common stock issued during period (in shares) | shares							900,000
Net proceeds from common stock issued | $							$ 2,700
Maximum offering under equity offering program | $											$ 25,000
Percentage of gross proceeds from common stock issuance paid for services											3.00%