Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 30, 2017
Current assets:
Cash and cash equivalents	$ 65,912	$ 34,899
Marketable securities	57,975	82,130
Accounts receivable, net of allowances of $116 and $126, respectively	59,034	62,457
Inventories	53,110	52,860
Inventories-delivered systems	1,493	1,534
Prepaid expenses and other	6,905	6,234
Total current assets	244,429	240,114
Property, plant and equipment, net	43,795	44,810
Goodwill	10,611	10,232
Intangible assets, net	3,171	2,206
Deferred income tax assets	9,671	11,924
Other assets	345	413
Total assets	312,022	309,699
Current liabilities:
Accounts payable	18,492	13,857
Accrued payroll and related expenses	9,669	12,901
Deferred revenue	9,029	7,408
Other current liabilities	7,120	7,249
Income taxes payable	3,565	2,680
Total current liabilities	47,875	44,095
Deferred revenue	1,290	1,661
Income taxes payable	1,409	860
Deferred tax liability	186	179
Other long-term liabilities	535	521
Total liabilities	51,295	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: 23,890,563 and 24,628,722, respectively, issued and outstanding	24	26
Additional paid-in capital	234,793	255,368
Retained earnings	26,136	9,113
Accumulated other comprehensive loss	(226)	(2,124)
Total stockholders’ equity	260,727	262,383
Total liabilities and stockholders’ equity	$ 312,022	$ 309,699