CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Income Statement
Net revenues	$ 53,498us-gaap_SalesRevenueNet	$ 58,579us-gaap_SalesRevenueNet	$ 66,014us-gaap_SalesRevenueNet
Cost of revenues	28,375us-gaap_CostOfRevenue	32,469us-gaap_CostOfRevenue	37,426us-gaap_CostOfRevenue
Gross profit	25,123us-gaap_GrossProfit	26,110us-gaap_GrossProfit	28,588us-gaap_GrossProfit
Operating expenses:
Research and development	11,917us-gaap_ResearchAndDevelopmentExpense	13,110us-gaap_ResearchAndDevelopmentExpense	11,472us-gaap_ResearchAndDevelopmentExpense
Selling, general and administrative	19,247	18,814	13,696
Total operating expenses	31,164us-gaap_OperatingExpenses	31,924us-gaap_OperatingExpenses	25,168us-gaap_OperatingExpenses
Income (loss) from operations	(6,041)us-gaap_OperatingIncomeLoss	(5,814)us-gaap_OperatingIncomeLoss	3,420us-gaap_OperatingIncomeLoss
Interest income, net	324us-gaap_InvestmentIncomeNet	387us-gaap_InvestmentIncomeNet	455us-gaap_InvestmentIncomeNet
Other income (expense), net	64us-gaap_NonoperatingIncomeExpense	(49)us-gaap_NonoperatingIncomeExpense	9us-gaap_NonoperatingIncomeExpense
Income (loss) before income taxes	(5,653)	(5,476)	3,884
Provision (benefit) for income taxes	(675)us-gaap_IncomeTaxExpenseBenefit	713us-gaap_IncomeTaxExpenseBenefit	38us-gaap_IncomeTaxExpenseBenefit
Net income (loss)	$ (4,978)us-gaap_NetIncomeLoss	$ (6,189)us-gaap_NetIncomeLoss	$ 3,846us-gaap_NetIncomeLoss
Net income (loss) per share:
Basic	$ (0.20)us-gaap_EarningsPerShareBasic	$ (0.23)us-gaap_EarningsPerShareBasic	$ 0.14us-gaap_EarningsPerShareBasic
Diluted	$ (0.20)us-gaap_EarningsPerShareDiluted	$ (0.23)us-gaap_EarningsPerShareDiluted	$ 0.14us-gaap_EarningsPerShareDiluted
Weighted average shares used in per share calculations:
Basic	25,029	27,505	27,124
Diluted	25,029	27,505	28,077

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