Income Taxes - Summary of Reconciliation of Statutory Federal Rate and Effective Rate for Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Tax computed at federal statutory rate	$ (3,929)	$ (5,593)
State income tax, net of federal benefit	(714)	(884)
Executive compensation	0	0
Stock based compensation	893	871
Research credits	(421)	(1,033)
Change in tax rate	(193)	(380)
Removal of net operating losses and research development credits	5,091	4,171
Rate adjustment - tax law	0	14
Other	70	2,795
Valuation allowance	(797)	39
Provision (benefit) for income taxes	$ 0	$ 0
Tax computed at federal statutory rate	21.00%	21.00%
State income tax, net of federal benefit	3.80%	3.30%
Executive compensation	0.00%	0.00%
Stock based compensation	(4.80%)	(3.30%)
Research credits	2.20%	3.90%
Change in tax rate	1.00%	1.40%
Removal of net operating losses and research development credits	(27.20%)	(15.70%)
Rate adjustment - tax law	0.00%	(0.10%)
Other	(0.30%)	(10.50%)
Valuation allowance	4.20%	(0.10%)
Provision (benefit) for income taxes	0.00%	0.00%