Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income (loss)	$ (5,582)	$ 1,703
Reconciliation of net income (loss) to net cash used in operating activities:
Depreciation and amortization	2,108	1,790
Stock-based compensation	1,457	1,461
Excess tax benefit from equity awards	367	(645)
Loss on disposal of fixed assets	12	118
Inventory write down	1,321	806
Deferred income taxes	(4,065)	2,468
Changes in fair value of contingent consideration	389	8
Changes in assets and liabilities:
Accounts receivable	1,268	(9,617)
Inventories	(5,631)	(713)
Inventories-delivered systems	750	(61)
Prepaid expenses and other	592	(2,337)
Accounts payable, accrued and other liabilities	(351)	(1,166)
Deferred revenue	(796)	2,731
Income taxes payable	(360)	518
Net cash used in operating activities	(8,521)	(2,936)
Cash flows from investing activities:
Maturities of marketable securities	10,111	0
Purchases of marketable securities	(11,292)	0
Purchases of property, plant and equipment	(997)	(867)
Net cash used in investing activities	(2,178)	(867)
Cash flows from financing activities:
Payments of contingent consideration	(133)	(107)
Repayments of debt obligations	(227)	(186)
Proceeds from sale of shares under employee stock option plans and purchase plan	1,598	1,214
Excess tax benefit from equity awards	(367)	645
Taxes paid on net issuance of stock awards	(86)	(16)
Repurchases of common stock	(5,000)	0
Net cash provided by (used in) financing activities	(4,215)	1,550
Effect of exchange rate changes on cash and cash equivalents	(656)	32
Net decrease in cash and cash equivalents	(15,570)	(2,221)
Cash and cash equivalents, beginning of period	62,915	97,699
Cash and cash equivalents, end of period	$ 47,345	$ 95,478