Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Oct. 02, 2020	Sep. 27, 2019
Cash flows from operating activities:
Net income	$ 60,712,000	$ 63,339,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and leasehold improvements	5,176,000	4,904,000
Amortization of premiums and accretion of discounts on short-term investments	(150,000)	(442,000)
Provision for contract losses and doubtful accounts	2,890,000	2,146,000
Stock-based compensation	13,326,000	13,585,000
Deferred income tax provision	(2,505,000)	(1,671,000)
Changes in operating assets and liabilities:
Accounts receivable	7,284,000	(24,665,000)
Prepaid expenses and other current assets	(8,439,000)	(5,604,000)
Change in operating leases	(331,000)	24,000
Accounts payable and accrued liabilities	311,000	3,102,000
Accrued payroll and employee benefits	(12,507,000)	(2,159,000)
Deferred revenues	(3,320,000)	(266,000)
Net cash provided by operating activities	62,447,000	52,293,000
Cash flows from investing activities:
Capital expenditures	(4,144,000)	(17,024,000)
Purchase of short-term investments		(38,693,000)
Maturity of short-term investments	35,000,000	44,000,000
Net cash provided by/(used in) investing activities	30,856,000	(11,717,000)
Cash flows from financing activities:
Payroll taxes for restricted stock units	(15,263,000)	(11,183,000)
Repurchase of common stock	(40,049,000)
Exercise of stock-based payment awards	3,013,000	1,969,000
Dividends and dividend equivalents rights	(29,936,000)	(25,223,000)
Net cash used in financing activities	(82,235,000)	(34,437,000)
Effect of foreign currency exchange rates on cash and cash equivalents	128,000	(355,000)
Net increase in cash and cash equivalents	11,196,000	5,784,000
Cash and cash equivalents at beginning of period	176,436,000	127,059,000
Cash and cash equivalents at end of period	$ 187,632,000	$ 132,843,000