Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Oct. 01, 2011	Oct. 02, 2010
Cash flows from operating activities:
Net income	$ 29,553	$ 18,514
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,237	5,673
Loss on disposal of property and equipment	476	117
Stock-based compensation	6,386	6,032
Deferred income taxes, net	447	(3,867)
Non-cash director deferred compensation	126	99
Changes in operating assets and liabilities - (use) source
Accounts receivable	(7,344)	7,377
Unbilled revenue	(3,887)	(703)
Inventory	(4,829)	(1,563)
Other assets	(6,572)	1,010
Accounts payable	1,833	5,118
Accrued expenses	(530)	(315)
Accrued compensation	(2,782)	(408)
Deferred revenue	(1,176)	(1,885)
Long term liabilities	143	(322)
Net cash provided by operating activities	19,081	34,877
Cash flows from investing activities:
Additions of property and equipment	(10,357)	(7,537)
Purchases of investments	(5,000)	(30,461)
Sales of investments	5,000	19,000
Net cash used in investing activities	(10,357)	(18,998)
Cash flows from financing activities:
Proceeds from stock option exercises	9,398	2,297
Income tax withholding payment associated with restricted stock vesting	(845)	(284)
Tax benefit of excess stock-based compensation deductions	6,002	855
Net cash provided by financing activities	14,555	2,868
Net increase in cash and cash equivalents	23,279	18,747
Cash and cash equivalents, at beginning of period	108,383	71,856
Cash and cash equivalents, at end of period	131,662	90,603
Supplemental disclosure of cash flow information:
Cash paid for income taxes	7,946	12,198
Supplemental disclosure of noncash investing and financing activities:
Transfer of inventory to fixed assets	$ 847	$ 1,945