Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Current assets:
Cash and cash equivalents	$ 96,103	$ 34,899
Marketable securities	76,835	82,130
Accounts receivable, net of allowances of $58 and $126, respectively	50,349	62,457
Inventories	58,884	52,860
Inventories-delivered systems	1,858	1,534
Prepaid expenses and other	7,070	6,234
Total current assets	291,099	240,114
Property, plant and equipment, net	43,135	44,810
Goodwill	10,611	10,232
Intangible assets, net	4,101	2,206
Deferred income tax assets	7,050	11,924
Other assets	456	413
Total assets	356,452	309,699
Current liabilities:
Accounts payable	20,870	13,857
Accrued payroll and related expenses	14,895	12,901
Deferred revenue	11,698	7,408
Other current liabilities	8,470	7,249
Income taxes payable	3,183	2,680
Total current liabilities	59,116	44,095
Deferred revenue	1,575	1,661
Income taxes payable	1,003	860
Deferred tax liability	172	179
Other long-term liabilities	511	521
Total liabilities	62,377	47,316
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.001 par value; 3,000,000 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.001 par value, 47,000,000 shares authorized: 24,215,562 and 24,628,722, respectively, issued and outstanding	24	26
Additional paid-in capital	241,318	255,368
Retained earnings	55,380	9,113
Accumulated other comprehensive loss	(2,647)	(2,124)
Total stockholders’ equity	294,075	262,383
Total liabilities and stockholders’ equity	$ 356,452	$ 309,699