Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
CURRENT ASSETS:
Cash and cash equivalents	$ 54,673	$ 60,610
Short-term investments	82,632	77,265
Accounts receivable, less allowances: 2012, $1,220; 2011, $1,294	26,351	25,385
Inventories	35,839	36,286
Income taxes receivable	4,171	6,881
Prepaid expenses and other	2,178	2,883
Deferred income taxes	22,070	22,854
Total current assets	227,914	232,164
LONG-TERM INVESTMENTS	6,850	6,857
PROPERTY, PLANT AND EQUIPMENT, NET	60,119	60,884
DEFERRED INCOME TAXES	9,365	8,657
OTHER ASSETS	2,481	1,413
TOTAL	306,729	309,975
CURRENT LIABILITIES:
Accounts payable	15,525	17,096
Deferred income on shipments to distributors	28,336	30,671
Other current liabilities	9,649	9,329
Total current liabilities	53,510	57,096
LONG-TERM INCOME TAXES PAYABLE	6,967	6,450
Total liabilities	60,477	63,546
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: 2012 - 60,624,655 shares; 2011 - 61,038,507 shares	0	206
Accumulated other comprehensive loss	(850)	(887)
Retained earnings	247,102	247,110
Total shareholders' equity	246,252	246,429
TOTAL	$ 306,729	$ 309,975