CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Sep. 29, 2012	Oct. 01, 2011
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 4,267	$ 14,450
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	4,598	5,411
Amortization of acquired intangible assets	1,155	894
Share-based compensation expense	4,650	7,153
Provision for doubtful accounts		50
Gain on sale of previously impaired auction rate securities		(2,729)
Loss on disposal of property, plant and equipment		2
Deferred income taxes	2,665	2,286
Changes in operating accounts:
(Increase) decrease in trade receivables, net	(25,254)	14,545
Increase in inventories	(11,859)	(9,704)
Decrease in shipped systems pending acceptance	1,098	3,950
Decrease in other current assets	130	2,598
Increase (decrease) in accounts payable and accrued liabilities	20,107	(16,680)
Decrease in deferred revenue	(1,407)	(6,690)
Net cash provided by operating activities	150	15,536
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of investments	(559,927)	(436,281)
Proceeds from sales and maturities of investments	577,733	394,023
Proceeds from sale of auction rate securities		6,450
Increase in restricted cash		(11,500)
Purchase of property, plant and equipment	(2,511)	(3,445)
Cash paid for acquisition of Eolite Systems, net of cash acquired	(9,466)
(Increase) decrease in other assets	(63)	217
Net cash provided by (used in) investing activities	5,766	(50,536)
CASH FLOWS FROM FINANCING ACTIVITIES
Cash dividends paid to shareholders	(4,673)
Stock plan activity, net	(478)	1,686
Excess tax benefit of share-based compensation	54	519
Net cash (used in) provided by financing activities	(5,097)	2,205
Effect of exchange rate changes on cash	357	526
NET CHANGE IN CASH AND CASH EQUIVALENTS	1,176	(32,269)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	69,780	116,412
CASH AND CASH EQUIVALENTS AT END OF PERIOD	70,956	84,143
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for income taxes	(550)	(2,383)
Income tax refunds received	$ 650	$ 120