Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 30, 2017
Current assets:
Cash and cash equivalents	$ 86,201	$ 34,899
Marketable securities	62,501	82,130
Accounts receivable, net of allowances of $52 and $126, respectively	54,623	62,457
Inventories	54,238	52,860
Inventories-delivered systems	1,855	1,534
Prepaid expenses and other	9,851	6,234
Total current assets	269,269	240,114
Property, plant and equipment, net	43,050	44,810
Goodwill	10,611	10,232
Intangible assets, net	4,136	2,206
Deferred income tax assets	7,405	11,924
Other assets	332	413
Total assets	334,803	309,699
Current liabilities:
Accounts payable	18,976	13,857
Accrued payroll and related expenses	13,457	12,901
Deferred revenue	8,962	7,408
Other current liabilities	8,508	7,249
Income taxes payable	3,133	2,680
Total current liabilities	53,036	44,095
Deferred revenue	1,649	1,661
Income taxes payable	943	860
Deferred tax liability	179	179
Other long-term liabilities	512	521
Total liabilities	56,319	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: 24,066,368 and 24,628,722, respectively, issued and outstanding	24	26
Additional paid-in capital	237,378	255,368
Retained earnings	43,811	9,113
Accumulated other comprehensive loss	(2,729)	(2,124)
Total stockholders’ equity	278,484	262,383
Total liabilities and stockholders’ equity	$ 334,803	$ 309,699