Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 27, 2019	Dec. 28, 2018
Current assets:
Cash and cash equivalents	$ 132,843	$ 127,059
Short-term investments	77,125	81,495
Accounts receivable, net of allowance for contract losses and doubtful accounts of $5,218 and $4,066 at September 27, 2019 and December 28, 2018, respectively	128,333	105,814
Prepaid expenses and other current assets	13,231	12,244
Total current assets	351,532	326,612
Property, equipment and leasehold improvements, net	59,318	46,103
Operating lease right-of-use assets	23,715
Goodwill	8,607	8,607
Deferred income taxes	35,639	34,090
Deferred compensation plan assets	64,841	52,286
Other assets	839	1,238
Total assets	544,491	468,936
Current liabilities:
Accounts payable and accrued liabilities	16,526	12,283
Accrued payroll and employee benefits	69,552	76,855
Deferred revenues	8,900	9,166
Operating lease liabilities	6,056
Total current liabilities	101,034	98,304
Other liabilities	2,793	2,548
Deferred compensation plan liabilities	64,808	52,708
Deferred rent		1,467
Operating lease liabilities	18,577
Total liabilities	187,212	155,027
Stockholders’ equity:
Common stock, $0.001 par value; 120,000 shares authorized; 65,707 shares issued at September 27, 2019 and December 28, 2018	66	66
Additional paid-in capital	242,756	227,283
Accumulated other comprehensive income (loss)
Investment securities, available-for-sale	328	(45)
Foreign currency translation adjustments	(3,465)	(2,808)
Accumulated other comprehensive income (loss)	(3,137)	(2,853)
Retained earnings	374,033	342,024
Treasury stock, at cost; 13,682 and 14,208 shares held at September 27, 2019 and December 28, 2018, respectively	(256,439)	(252,611)
Total stockholders’ equity	357,279	313,909
Total liabilities and stockholders’ equity	$ 544,491	$ 468,936