Note 15 - Segment and Geographic Information - Segment and Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Net Revenues	$ 83,372	$ 79,484	$ 78,629	$ 80,638	$ 79,772	$ 75,133	$ 80,257	$ 82,047	$ 322,123	$ 317,209	$ 338,767
UNITED STATES
Net Revenues									81,499	75,994	85,314
Austria [Member]
Net Revenues									2,313	1,836	2,290
FINLAND
Net Revenues									2,178	1,899	1,669
FRANCE
Net Revenues									9,553	9,076	7,917
GERMANY
Net Revenues									37,919	33,215	32,866
HUNGARY
Net Revenues									1,942	2,082	2,571
ITALY
Net Revenues									4,091	4,328	4,645
NETHERLANDS
Net Revenues									4,488	3,608	2,315
RUSSIAN FEDERATION
Net Revenues									1,263	4,773	5,051
SWEDEN
Net Revenues									1,694	2,155	4,460
SWITZERLAND
Net Revenues									2,311	2,789	2,569
TURKEY
Net Revenues									1,929	2,376	2,658
UNITED KINGDOM
Net Revenues									14,042	13,502	19,832
Other Europe and the Middle East Regions [Member]
Net Revenues									10,097	10,700	11,259
CHINA
Net Revenues									84,447	79,575	83,597
INDONESIA
Net Revenues									2,160	2,128	3,224
JAPAN
Net Revenues									6,995	9,271	8,469
MALAYSIA [Member]
Net Revenues									4,692	4,662	5,580
SINGAPORE
Net Revenues									13,509	12,353	11,694
KOREA, REPUBLIC OF
Net Revenues									19,282	23,215	22,371
TAIWAN, PROVINCE OF CHINA
Net Revenues									2,051	3,151	2,688
THAILAND
Net Revenues									3,547	3,904	4,300
Other Asia Pacific Regions [Member]
Net Revenues									1,557	1,929	1,148
INDIA
Net Revenues									4,315	4,293	5,163
Other Rest of the World [Member]
Net Revenues									$ 4,249	$ 4,395	$ 5,117