Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands		3 Months Ended				6 Months Ended		12 Months Ended
	May 08, 2019 shares	Sep. 30, 2020 USD ($) shares	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($) shares	Jun. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) shares	Sep. 30, 2019 USD ($) shares	Mar. 31, 2020 USD ($) shares	Feb. 29, 2020 shares	Apr. 01, 2019 USD ($)	Mar. 31, 2019 shares
Net Loss per Common Share
Common shares issued (in shares) | shares		47,249,729				47,249,729		47,249,729			22,800,000
Common shares outstanding (in shares) | shares		39,526,299				39,526,299		39,526,299			22,800,000
Reverse share split ratio	0.125
Cash and cash equivalents		$ 63,171				$ 63,171		$ 80,752
Accumulated deficit		(777,222)				(777,222)		(758,644)
Net loss		(9,984)	$ (8,594)	$ (13,884)	$ (28,057)	(18,578)	$ (41,941)	(72,600)
Number of options outstanding (in shares) | shares											1,900,000
Operating lease right-of-use assets		663				663		$ 1,532
Lease liability		$ 89				$ 89
Shares outstanding before split (in shares) | shares	182,200,000
Public Offering
Net Loss per Common Share
Number of securities called by warrants (in shares) | shares									3,301,998
Restricted Stock Units (RSUs)
Net Loss per Common Share
RSUs outstanding (in shares) | shares		900,000		300,000		900,000	300,000
Stock Options | 2015 Equity Incentive Plan
Net Loss per Common Share
Number of options outstanding (in shares) | shares		2,200,000		2,700,000		2,200,000	2,700,000
Accounting Standards Update 2016-02
Net Loss per Common Share
Operating lease right-of-use assets										$ 3,000
Lease liability										2,400
Prepaid rent										$ 600
Money Market Funds
Net Loss per Common Share
Money market funds		$ 40,450				$ 40,450
Money Market Funds | Fair Value, Inputs, Level 1
Net Loss per Common Share
Money market funds		$ 40,450				$ 40,450