Nature of Business - Additional Information (Detail) - USD ($)			1 Months Ended		12 Months Ended
	Feb. 08, 2021	Jan. 07, 2020	Jun. 30, 2021	Apr. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Oct. 18, 2019
Nature Of Business [Line Items]
Proceeds from issuance of common stock and warrants					$ 99,547,283	$ 32,555,738
Net cash used in operating activities					(23,564,478)	(19,560,311)
Net loss					(28,978,763)	(22,000,556)
Non-cash expenses related to change in fair value of warrant liability					3,915,393	(3,644,601)
Non-cash equity compensation					3,456,895	6,085,673
Non-cash gain on warrant exchange					2,228,697
Working capital					104,000,000
Registered Direct Offering [Member]
Nature Of Business [Line Items]
Proceeds from issuance of common stock	$ 100,000,000
Related cost offset the proceeds	$ 6,200,000
Securities Purchase Agreement [Member] | Eagle Pharmaceuticals, Inc [Member]
Nature Of Business [Line Items]
Share price (in dollars per share)		$ 2.00
Underwritten Registered Offering [Member]
Nature Of Business [Line Items]
Proceeds from issuance of common stock and warrants				$ 11,300,000
Sale Agreement [Member] | Jefferies [Member]
Nature Of Business [Line Items]
Proceeds from issuance of common stock					6,100,000	1,700,000
Offering expense					300,000	$ 200,000
Available for offering					$ 22,200,000
Common Stock [Member] | Registered Direct Offering [Member]
Nature Of Business [Line Items]
Number of shares issued upon new issue	40,000,000
Share price (in dollars per share)	$ 2.50
Common Stock [Member] | Securities Purchase Agreement [Member]
Nature Of Business [Line Items]
Number of shares issued upon new issue					40,000,000	10,000,000
Common Stock [Member] | Securities Purchase Agreement [Member] | Eagle Pharmaceuticals, Inc [Member]
Nature Of Business [Line Items]
Number of shares issued upon new issue		10,000,000
Share price (in dollars per share)		$ 2.00
Proceeds from issuance of common stock		$ 20,000,000
Common Stock [Member] | Underwritten Registered Offering [Member]
Nature Of Business [Line Items]
Number of shares issued upon new issue						8,000,000
Share price (in dollars per share)				$ 1.50
Minimum [Member] | Scenario Forecast [Member]
Nature Of Business [Line Items]
Anticipated close out trial costs			$ 2,000,000
Maximum [Member] | Sale Agreement [Member] | Jefferies [Member]
Nature Of Business [Line Items]
Aggregate offering							$ 30,000,000
Maximum [Member] | Scenario Forecast [Member]
Nature Of Business [Line Items]
Anticipated close out trial costs			$ 3,000,000