Note 6 - Balance Sheet Details - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Property, plant and equipment, gross	$ 176,364	$ 175,912
Accumulated depreciation	(134,124)	(133,289)
Property, plant and equipment, net	42,240	42,623	$ 42,545
Building and Building Improvements [Member]
Property, plant and equipment, gross	38,195	35,290
Equipment [Member]
Property, plant and equipment, gross	137,105	139,318
Leasehold Improvements [Member]
Property, plant and equipment, gross	$ 1,064	$ 1,304