Note 15 - Segment and Geographic Information - Segment and Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Net Revenues	$ 79,484	$ 75,133	$ 238,751	$ 237,437
UNITED STATES
Net Revenues	20,605	18,334	60,291	57,784
FRANCE
Net Revenues	1,901	2,382	7,472	6,724
GERMANY
Net Revenues	9,253	7,201	26,812	24,123
RUSSIAN FEDERATION
Net Revenues	353	2,196	941	2,914
NETHERLANDS
Net Revenues	1,241	761	3,322	2,298
UNITED KINGDOM
Net Revenues	3,565	3,686	10,401	10,400
Other Europe and the Middle East Regions [Member]
Net Revenues	6,646	6,217	19,431	21,281
CHINA
Net Revenues	20,690	19,090	64,548	60,378
JAPAN
Net Revenues	1,663	1,451	5,089	7,175
KOREA, REPUBLIC OF
Net Revenues	4,268	5,360	13,316	17,585
MALAYSIA [Member]
Net Revenues	1,300	689	3,392	3,253
SINGAPORE
Net Revenues	3,751	3,112	10,335	9,249
Other Asia Pacific Regions [Member]
Net Revenues	2,020	2,527	7,021	7,655
INDIA
Net Revenues	1,209	1,095	3,316	3,136
Other Rest of the World [Member]
Net Revenues	$ 1,019	$ 1,032	$ 3,064	$ 3,482