Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents	$ 28,371	$ 21,183
Restricted cash	45	44
Short-term investments	65,697	65,428
Accounts receivable, less allowances: 2015, $1,084; 2014, $1,058	28,427	30,523
Inventories	41,294	44,136
Prepaid taxes	5,910	5,633
Prepaid expenses and other	2,149	1,612
Deferred income taxes	21,508	22,356
Total current assets	193,401	190,915
LONG-TERM INVESTMENTS	1,436	1,436
PROPERTY, PLANT AND EQUIPMENT, NET	58,550	60,453
LONG-TERM PREPAID TAXES	955	1,711
GOODWILL	8,655	8,655
INTANGIBLE ASSETS, NET	9,424	9,792
DEFERRED INCOME TAXES	2,887	2,707
OTHER ASSETS	1,425	1,511
TOTAL ASSETS	276,733	277,180
CURRENT LIABILITIES:
Accounts payable	12,212	17,376
Accrued liabilities	12,044	12,869
Deferred income on shipments to distributors	23,436	22,947
Total current liabilities	47,692	53,192
LONG-TERM INCOME TAXES PAYABLE	3,592	3,511
LONG-TERM DEFERRED INCOME TAXES	868	807
OTHER LONG-TERM LIABILITIES	160	162
Total liabilities	52,312	57,672
COMMITMENTS AND CONTINGENCIES (Note 12)
SHAREHOLDERS' EQUITY:
Preferred stock, no par value - authorized: 5,000,000 shares; issued and outstanding: none	0	0
Common stock, no par value - authorized: 250,000,000 shares; issued and outstanding: 2015 - 56,865,368 shares; 2014 - 56,435,555 shares	4,995	0
Accumulated other comprehensive loss	(61)	(83)
Retained earnings	219,487	219,591
Total shareholders' equity	224,421	219,508
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 276,733	$ 277,180