CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 34,291	$ 49,464	$ 23,269
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	15,372	12,341	9,667
Amortization of intangibles	943	674	673
Gain on sale of property and equipment	(41)	(330)	(5)
Stock-based compensation expense	8,969	10,721	11,330
Amortization of premium on held-to-maturity investments	1,627	1,765	319
Deferred income taxes	1,577	1,124	658
Decrease in accounts receivable allowances	(61)	(27)	(4)
Excess tax benefit from stock options exercised	(796)	(1,309)	(562)
Tax benefit associated with employee stock plans	2,201	2,891	1,403
Change in operating assets and liabilities:
Accounts receivable	(3,621)	16,236	(8,709)
Inventories	10,037	(33,588)	2,136
Prepaid expenses and other assets	1,619	(8,515)	(10,110)
Accounts payable	(1,564)	(483)	6,838
Taxes payable and accrued liabilities	2,977	5,828	3,825
Deferred income on sales to distributors	(4,338)	3,180	4,243
Net cash provided by operating activities	69,192	59,972	44,971
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(23,223)	(30,567)	(14,356)
Proceeds from sale of property and equipment	2,249	1,415	0
Investment in third party	0	(1,831)	0
Other assets	(1,277)	0	0
Acquisitions (Note 11)	(6,914)	(8,598)	0
Increase in financing lease receivables	(8,116)	0	0
Collections of financing lease receivable	425	0	0
Notes to third parties	(3,000)	(6,750)	0
Collection of notes to third party	3,000	0	10,000
Purchases of held-to-maturity investments	(42,176)	(27,224)	(60,461)
Proceeds from sales and maturities of held-to-maturity investments	26,725	27,010	6,849
Net cash used in investing activities	(52,307)	(46,545)	(57,968)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of common stock under employee stock plans	22,210	26,263	20,353
Repurchase of common stock	(50,000)	(13,960)	(28,673)
Payment for tender offer	0	0	(9,048)
Retirement of shares for income tax withholding	0	(769)	0
Payments of dividends to stockholders	(5,722)	(5,577)	(2,695)
Excess tax benefit from stock options exercised	796	1,309	562
Net cash (used in) provided by financing activities	(32,716)	7,266	(19,501)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(15,831)	20,693	(32,498)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	155,667	134,974	167,472
CASH AND CASH EQUIVALENTS AT END OF PERIOD	139,836	155,667	134,974
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Unpaid property and equipment	3,497	5,369	785
Unpaid financing lease equipment	321	0	0
Conversion of notes receivable in connection with acquisition (Note 11)	0	1,752	0
Application of prepayment to acquisition (Note 11)	0	1,200	0
Conversion of notes receivable in connection with equity investment	0	5,169	0
Acquisition (Note 11)	0	6,955	0
Settlement of pre-existing arrangement in connection with acquisition	0	5,250	0
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	0	3	397
Cash paid for income taxes, net of refunds	$ 1,233	$ 3,018	$ 150