Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 28, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net income	$ 28,753	$ 24,964
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and leasehold improvements	3,459	3,257
Amortization of premiums on short-term investments	428	199
Deferred rent	(296)	(392)
Provision for doubtful accounts	1,304	1,224
Stock-based compensation	9,932	8,208
Deferred income tax provision	(2,780)	(3,614)
Tax benefit for stock plans	(2,762)	(2,216)
Changes in operating assets and liabilities:
Accounts receivable	(16,594)	(1,761)
Prepaid expenses and other assets	(4,849)	(2,017)
Accounts payable and accrued liabilities	6,574	(1,220)
Accrued payroll and employee benefits	(925)	130
Deferred revenues	(610)	(1,347)
Net cash provided by operating activities	21,634	25,415
Cash flows from investing activities:
Capital expenditures	(3,425)	(2,638)
Purchase of short-term investments	(515)	(26,599)
Maturity of short-term investments	2,735
Sale of short-term investments	518	1,080
Net cash used in investing activities	(687)	(28,157)
Cash flows from financing activities:
Tax benefit for stock plans	2,762	2,216
Payroll taxes for restricted stock units	(3,531)	(3,473)
Repurchase of common stock	(19,437)	(38,551)
Exercise of share-based payment awards	2,071	1,148
Net cash used in financing activities	(18,135)	(38,660)
Effect of foreign currency exchange rates on cash and cash equivalents	402	98
Net increase (decrease) in cash and cash equivalents	3,214	(41,304)
Cash and cash equivalents at beginning of period	84,439	106,549
Cash and cash equivalents at end of period	$ 87,653	$ 65,245