Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 29, 2014	Dec. 28, 2013
Current assets:
Cash and cash equivalents	$ 38,833	$ 44,765
Marketable securities	49,204	48,097
Accounts receivable, net of allowances of $293 and $293, respectively	32,417	31,436
Inventories	37,855	34,520
Inventories-delivered systems	2,249	6,901
Prepaid expenses and other	8,972	10,519
Deferred income tax assets	14,008	14,516
Total current assets	183,538	190,754
Property, plant and equipment, net	47,131	47,439
Goodwill	11,865	11,743
Intangible assets, net	7,139	7,864
Deferred income tax assets	4,345	4,338
Other assets	699	696
Total assets	254,717	262,834
Current liabilities:
Accounts payable	7,409	10,604
Accrued payroll and related expenses	8,200	7,853
Deferred revenue	11,542	21,749
Other current liabilities	8,185	7,993
Income taxes payable	557	758
Total current liabilities	35,893	48,957
Deferred revenue	3,310	3,718
Income taxes payable	599	1,171
Other long-term liabilities	1,645	1,615
Total liabilities	41,447	55,461
Commitments and contingencies (Note 16)
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; 23,876,666 and 23,537,275, respectively, issued and outstanding	24	24
Additional paid-in capital	248,824	244,733
Accumulated deficit	(36,401)	(37,996)
Accumulated other comprehensive income	823	612
Total stockholders’ equity	213,270	207,373
Total liabilities and stockholders’ equity	$ 254,717	$ 262,834