CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Total
Beginning Balance - Shares at Mar. 31, 2019	22,320,156
Beginning Balance - Amount at Mar. 31, 2019	$ 22	$ 33,462	$ (37)	$ 59,708	$ 93,155
Issuance of common stock under employee stock option plans, shares	909,130
Issuance of common stock under employee stock option plans, amount	$ 1	4,148			4,149
Stock-based compensation expense		2,566			2,566
Comprehensive loss:
Net loss				(10,337)	(10,337)
Net unrealized gain (loss) on available-for-sale investments			108		108
Ending Balance, Shares at Mar. 31, 2020	23,229,286
Ending Balance, Amount at Mar. 31, 2020	$ 23	40,176	71	49,371	89,641
Issuance of common stock under employee stock option plans, shares	790,990
Issuance of common stock under employee stock option plans, amount	$ 1	4,692			4,693
Stock-based compensation expense		2,854			2,854
Comprehensive loss:
Net loss				(21,505)	(21,505)
Net unrealized gain (loss) on available-for-sale investments			(91)		(91)
Ending Balance, Shares at Mar. 31, 2021	24,020,276
Ending Balance, Amount at Mar. 31, 2021	$ 24	47,722	(20)	27,866	75,592
Issuance of common stock under employee stock option plans, shares	465,963
Issuance of common stock under employee stock option plans, amount		2,368			2,368
Stock-based compensation expense		2,993			2,993
Comprehensive loss:
Net loss				(16,368)	(16,368)
Net unrealized gain (loss) on available-for-sale investments			(134)		(134)
Ending Balance, Shares at Mar. 31, 2022	24,486,239
Ending Balance, Amount at Mar. 31, 2022	$ 24	$ 53,083	$ (154)	$ 11,498	$ 64,451