Note 11 - Employee Equity Incentive Plans - Allocated Share-based Compensation Expense (Details) - USD ($) $ in Thousands		3 Months Ended
		Jun. 30, 2015	Jun. 30, 2014
Cost of Sales [Member]
Stock-based Compensation Effect in Income before Taxes		$ 122	$ 108
Research and Development Expense [Member]
Stock-based Compensation Effect in Income before Taxes	[1]	460	189
Selling, General and Administrative Expenses [Member]
Stock-based Compensation Effect in Income before Taxes		406	384
Stock-based Compensation Effect in Income before Taxes		988	681
Provision for income taxes (2)	[2]	346	238
Net stock-based compensation effects in net income		$ 642	$ 443

[1] Includes acquisition related compensation expenses of $249,000 during the quarter ended June 30, 2015, settled in cash.

[2] Calculated at the U.S. statutory federal income tax rate of 35% in fiscal 2016 and 2015.