CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net revenues	$ 43,343	$ 51,486	$ 42,643
Cost of revenues	18,000	19,858	20,217
Gross profit	25,343	31,628	22,426
Operating expenses:
Research and development	25,223	21,355	16,998
Selling, general and administrative	10,922	10,455	9,899
Total operating expenses	36,145	31,810	26,897
Loss from operations	(10,802)	(182)	(4,471)
Interest income, net	783	671	421
Other expense, net	(71)	(221)	(12)
Income (loss) before income taxes	(10,090)	268	(4,062)
Provision for income taxes	247	105	453
Net income (loss)	$ (10,337)	$ 163	$ (4,515)
Net income (loss) per share:
Basic	$ (0.45)	$ 0.01	$ (0.21)
Diluted	$ (0.45)	$ 0.01	$ (0.21)
Weighted average shares used in per share calculations:
Basic	22,968	21,889	21,085
Diluted	22,968	23,349	21,085