CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 39,147	$ 59,544	$ 57,266
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	16,464	15,884	16,088
Amortization of intangibles	7,039	6,072	7,404
Loss (gain) on disposal of property and equipment	361	250	(131)
Gain on sale of asset held for sale	0	0	(497)
Stock-based compensation expense	14,767	14,282	16,485
Amortization of premium on marketable securities	1,063	1,694	789
Deferred income taxes	(5,416)	157	(2,781)
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)	127	70	(127)
Excess tax benefit from employee stock plans	0	(437)	(734)
Tax (Shortfall) Benefit Associated With Employee Stock Plans	(189)	815	1,284
Change in operating assets and liabilities:
Accounts receivable	4,131	2,133	(4,936)
Inventories	13,500	(21,703)	2,375
Prepaid expenses and other assets	3,391	8,211	(1,523)
Accounts payable	(2,000)	2,337	2,467
Taxes payable and accrued liabilities	(76)	(3,242)	1,065
Deferred income on sales to distributors	(122)	(505)	4,177
Net cash provided by operating activities	92,187	85,562	98,671
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(11,359)	(23,071)	(13,960)
Proceeds from sale of property and equipment	0	0	36
Proceeds from sale of assets held for sale	0	0	959
Other assets	0	(1,261)	0
Payment for purchase of building (Note 11)	(10,389)	0	0
Payment for acquisition, net of cash acquired (Note 11)	(15,549)	0	0
Collections of financing lease receivables and other receivables	0	0	433
Loans to third parties (Notes 11)	0	(6,600)	0
Purchases of marketable securities	(29,748)	(45,269)	(109,482)
Proceeds from sales and maturities of marketable securities	59,309	38,052	31,350
Net cash used in investing activities	(7,736)	(38,149)	(90,664)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of common stock under employee stock plans	12,580	13,855	30,239
Repurchase of common stock	(53,731)	(80,760)	0
Payments of dividends to stockholders	(13,916)	(13,165)	(9,446)
Excess tax benefit from employee stock plans	0	437	734
Net cash (used in) provided by financing activities	(55,067)	(79,633)	21,527
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	29,384	(32,220)	29,534
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	60,708	92,928	63,394
CASH AND CASH EQUIVALENTS AT END OF PERIOD	90,092	60,708	92,928
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Unpaid property and equipment	1,472	1,733	2,862
Loan applied to CamSemi purchase price (Note 11)	6,600	0	0
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid (refund) for income taxes, net of refunds (Note 8)	$ 473	$ (3,121)	$ (4,137)