Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013
Cash flows from operating activities:
Net income (loss)	$ 2,183	$ (10,148)
Reconciliation of net income (loss) to net cash used in operating activities:
Depreciation and amortization	4,814	4,268
Stock-based compensation	3,410	3,208
Excess tax benefit from equity awards	0	367
Loss on disposal of fixed assets	28	10
Inventory write-down	1,527	2,764
Deferred income taxes	490	(6,657)
Changes in fair value of contingent consideration	66	1,000
Changes in assets and liabilities:
Accounts receivable	(1,909)	(11,095)
Inventories	(3,830)	(4,121)
Inventories-delivered systems	6,543	(170)
Prepaid expenses and other	1,251	(109)
Accounts payable, accrued and other liabilities	(2,961)	1,566
Deferred revenue	(14,978)	2,548
Income taxes payable	(1,203)	(389)
Net cash used in operating activities	(4,569)	(16,958)
Cash flows from investing activities:
Maturities of marketable securities	17,620	22,788
Purchases of marketable securities	(19,479)	(23,454)
Purchases of property, plant and equipment	(3,813)	(1,970)
Net cash used in investing activities	(5,672)	(2,636)
Cash flows from financing activities:
Payments of contingent consideration	(261)	(216)
Repayments of debt obligations	0	(456)
Proceeds from sale of shares under employee stock option and purchase plans	4,201	2,858
Excess tax benefit from equity awards	0	(367)
Taxes paid on net issuance of stock awards	(664)	(86)
Repurchases of common stock	0	(5,000)
Net cash provided by (used in) financing activities	3,276	(3,267)
Effect of exchange rate changes on cash and cash equivalents	187	(952)
Net decrease in cash and cash equivalents	(6,778)	(23,813)
Cash and cash equivalents, beginning of period	44,765	62,915
Cash and cash equivalents, end of period	$ 37,987	$ 39,102