Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2019	Mar. 30, 2018
Cash flows from operating activities:
Net income	$ 22,712	$ 20,340
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization of property, equipment and leasehold improvements	1,590	1,555
Amortization of premiums and accretion of discounts on short-term investments	(132)	0
Deferred rent	0	(74)
Provision for contract losses and doubtful accounts	788	561
Stock-based compensation	5,731	6,289
Deferred income tax provision	161	(815)
Changes in operating assets and liabilities:
Accounts receivable	(13,838)	(7,700)
Prepaid expenses and other current assets	(10,431)	(5,520)
Change in operating leases	(425)	0
Accounts payable and accrued liabilities	(333)	1,829
Accrued payroll and employee benefits	(16,477)	(12,383)
Deferred revenues	(1,599)	(390)
Net cash (used in) provided by operating activities	(12,253)	3,692
Cash flows from investing activities:
Capital expenditures	(5,670)	(6,810)
Purchase of short-term investments	(23,848)	(11,934)
Maturity of short-term investments	13,000	8,000
Net cash used in investing activities	(16,518)	(10,744)
Cash flows from financing activities:
Payroll taxes for restricted stock units	(11,194)	(8,637)
Exercise of stock-based payment awards	372	310
Dividends and dividend equivalents rights	(8,593)	(6,959)
Net cash used in financing activities	(19,415)	(15,286)
Effect of foreign currency exchange rates on cash and cash equivalents	207	696
Net decrease in cash and cash equivalents	(47,979)	(21,642)
Cash and cash equivalents at beginning of period	127,059	124,794
Cash and cash equivalents at end of period	$ 79,080	$ 103,152