Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 29, 2023	Dec. 30, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income	$ 100,339,000	$ 102,330,000	$ 101,202,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and leasehold improvements	8,916,000	7,079,000	6,487,000
Amortization of premiums and accretion of discounts on short-term investments			(11,000)
Provision for contract losses and doubtful accounts	3,225,000	3,081,000	1,958,000
Stock-based compensation	20,357,000	20,364,000	19,263,000
Deferred income tax provision	85,000	(7,363,000)	(6,005,000)
Changes in operating assets and liabilities:
Accounts receivable	(471,000)	(33,334,000)	(30,254,000)
Prepaid expenses and other current assets	(6,669,000)	(6,124,000)	(4,407,000)
Change in operating leases	(152,000)	(7,000)	(406,000)
Accounts payable and accrued liabilities	(5,055,000)	2,215,000	8,443,000
Accrued payroll and employee benefits	3,902,000	6,494,000	20,336,000
Deferred revenues	2,875,000	(928,000)	7,962,000
Net cash provided by operating activities	127,352,000	93,807,000	124,568,000
Cash flows from investing activities:
Capital expenditures	(16,356,000)	(12,043,000)	(6,826,000)
Purchase of short-term investments			(34,994,000)
Maturity of short-term investments			79,998,000
Net cash (used in) / provided by investing activities	(16,356,000)	(12,043,000)	38,178,000
Cash flows from financing activities:
Payroll taxes for restricted stock units	(9,942,000)	(12,904,000)	(15,666,000)
Repurchase of common stock	(24,208,000)	(155,856,000)	(7,000,000)
Exercise of stock-based payment awards	2,184,000	2,020,000	3,111,000
Dividends and dividend equivalent rights	(54,043,000)	(49,237,000)	(43,198,000)
Net cash used in financing activities	(86,009,000)	(215,977,000)	(62,753,000)
Effect of foreign currency exchange rates on cash and cash equivalents	705,000	(2,016,000)	169,000
Net increase in cash and cash equivalents	25,692,000	(136,229,000)	100,162,000
Cash and cash equivalents at beginning of year	161,458,000	297,687,000	197,525,000
Cash and cash equivalents at end of year	$ 187,150,000	$ 161,458,000	$ 297,687,000