CONDENSED 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, 2018	21,407,247
Beginning Balance - Amount at Mar. 31, 2018	$ 21	$ 27,391	$ (142)	$ 59,545	$ 86,815
Issuance of common stock under employee stock option plans, shares	352,847
Issuance of common stock under employee stock option plans, amount	$ 1	1,502			1,503
Stock-based compensation expense		542			542
Comprehensive loss:
Net loss				(1,646)	(1,646)
Net unrealized gain (loss) on available-for-sale investments			(10)		(10)
Ending Balance, Shares at Jun. 30, 2018	21,760,094
Ending Balance, Amount at Jun. 30, 2018	$ 22	29,435	(152)	57,899	87,204
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	578,032
Issuance of common stock under employee stock option plans, amount	$ 1	2,349			2,350
Stock-based compensation expense		651			651
Comprehensive loss:
Net loss				(125)	(125)
Net unrealized gain (loss) on available-for-sale investments			51		51
Ending Balance, Shares at Jun. 30, 2019	22,898,188
Ending Balance, Amount at Jun. 30, 2019	$ 23	$ 36,462	$ 14	$ 59,583	$ 96,082