Condensed Consolidated Statements of Cash Flows (USD $) In Thousands	6 Months Ended
	Jul. 02, 2011	Jul. 03, 2010
Cash flows from operating activities:
Net income	$ 21,597	$ 17,493
Reconciliation of net income to net cash provided by operating activities:
Depreciation and amortization	2,910	3,006
Asset impairment	0	388
Stock-based compensation	1,777	2,131
Excess tax benefit from equity awards	(1,519)	0
Loss (gain) on disposal of fixed assets	3	(206)
Inventory write down	728	804
Deferred income taxes	1,425	96
Unrealized foreign exchange transaction (gain) loss	0	(523)
Changes in fair value of contingent payments to Zygo Corporation	391	443
Changes in assets and liabilities:
Accounts receivable	1,092	(11,857)
Inventories	(5,502)	(3,796)
Inventories-delivered systems	(969)	1,167
Prepaid expenses and other assets	(3,200)	106
Accounts payable, accrued and other liabilities	2,010	5,490
Deferred revenue	2,607	(2,306)
Income taxes payable	2,315	949
Net cash provided by operations	25,665	13,385
Cash flows from investing activities:
Payments to Zygo Corporation related to acquisition	(191)	(3,446)
Purchases of property, plant and equipment	(1,746)	(691)
Proceeds from sale of property, plant and equipment	0	492
Net cash used in investing activities	(1,937)	(3,645)
Cash flows from financing activities:
Repayments of debt obligations	(282)	(200)
Proceeds from sale of shares under employee stock plans	3,539	1,834
Stock offering costs	0	(28)
Excess tax benefit from equity awards	1,519	0
Taxes paid on net issuance of stock awards	(46)	(166)
Repurchases of common stock	(4,257)	0
Net cash provided by financing activities	473	1,440
Effect of exchange rate changes on cash and cash equivalents	1,024	197
Net increase in cash and cash equivalents	25,225	11,377
Cash and cash equivalents, beginning of period	66,460	43,526
Cash and cash equivalents, end of period	$ 91,685	$ 54,903