Note 3 - Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2016

Notes Tables

Schedule of Inventory, Current [Table Text Block]

	March 31,		December 31,
	2016		2015
Raw materials	$	12,147	$	14,907
Work in process		20,373		21,177
Finished goods		29,798		27,125
Total	$	62,318	$	63,209

Schedule of Other Assets, Noncurrent [Table Text Block]

	March 31,		December 31,
	2016		2015
Deferred compensation plan assets	$	15,317	$	13,985
Prepaid expense		1,395		1,257
Other		1,182		1,099
Total	$	17,894	$	16,341

Schedule of Accrued Liabilities [Table Text Block]

	March 31,		December 31,
	2016		2015
Dividends and dividend equivalents	$	9,053	$	8,675
Deferred revenue and customer prepayments		4,806		5,236
Stock rotation reserve		3,011		2,372
Commissions		865		763
Warranty		336		289
Income tax payable		280		465
Sales rebate		188		268
Other		1,501		1,916
Total	$	20,040	$	19,984

Schedule of Product Warranty Liability [Table Text Block]

	Three Months Ended March 31,
	2016			2015
Balance at beginning of period	$	289		$	240
Warranty provision for product sales		85			74
Unused warranty provision		(38	)		(18	)
Balance at end of period	$	336		$	296

Other Noncurrent Liabilities [Table Text Block]

	March 31,		December 31,
	2016		2015
Deferred compensation plan liabilities	$	14,383	$	14,147
Dividend equivalents		2,167		2,019
Other		139		379
Total	$	16,689	$	16,545