Note 6 - Stock-Based Awards (Details) - Stock-based Compensation Expense (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated stock-based compensation expense	$ 195	$ (227)	$ 349	$ 328
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated stock-based compensation expense	22	12	38	42
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated stock-based compensation expense	166	(244)	289	265
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated stock-based compensation expense	$ 7	$ 5	$ 22	$ 21