Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 98,038	$ 94,964
Short-term investments	235,299	212,526
Accounts receivable, net of allowances for doubtful accounts of $925 at March 31, 2012 and $725 at December 31, 2011	61,425	55,351
Inventories	34,295	34,778
Deferred income taxes	4,941	11,563
Prepaid expenses and other current assets	47,527	43,867
Total current assets	481,525	453,049
Long-term investments	17,729	17,477
Property and equipment, net	24,008	25,141
Goodwill	115,489	115,489
Other intangible assets, net	57,725	60,005
Other assets, net	36,334	34,830
Total assets	732,810	705,991
Current liabilities:
Accounts payable	29,965	26,354
Accrued expenses	30,810	30,857
Deferred income on shipments to distributors	28,269	24,962
Income taxes	1,302	665
Total current liabilities	90,346	82,838
Long-term obligations and other liabilities	19,053	24,214
Total liabilities	109,399	107,052
Commitments and contingencies
Stockholders' equity:
Preferred stock--$0.0001 par value; 10,000 shares authorized; no shares issued and outstanding
Common stock--$0.0001 par value; 250,000 shares authorized; 42,835 and 42,068 shares issued and outstanding at March 31, 2012 and December 31, 2011, respectively	4	4
Additional paid-in capital	24,251	14,749
Retained earnings	600,973	586,653
Accumulated other comprehensive loss	(1,817)	(2,467)
Total stockholders' equity	623,411	598,939
Total liabilities and stockholders' equity	$ 732,810	$ 705,991