Condensed Consolidated Statement of Cash Flows (Unaudited) (USD $) In Thousands	6 Months Ended
	Sep. 30, 2011	Sep. 24, 2010
Condensed Consolidated Statement of Cash Flows (Unaudited) [Abstract]
Cash and cash equivalents at beginning of period	$ 2,367	$ 4,953
Cash flows from operating activities:
Net loss	(15,955)	(11,604)
Adjustments required to reconcile net loss to net cash used in operating activities:
Depreciation, amortization, and accretion	1,092	1,406
Stock-based compensation expense	1,740	2,913
Loss on disposition of property and equipment	0	19
Provision for deferred income taxes	202	222
Other	0	(1)
Changes in assets and liabilities:
Accounts receivable	(2,306)	(99)
Inventories	(523)	460
Prepaid expenses and other assets	65	2,049
Accounts payable	1,767	(71)
Accrued liabilities	(1,136)	(2,495)
Net cash used in operating activities	(15,054)	(7,201)
Cash flows from investing activities:
Purchase of short-term investments	(15,376)	(20,365)
Proceeds from sales and maturities of short-term investments	32,356	29,858
Purchases of property and equipment	(403)	(846)
Change in restricted cash	250	(1,637)
Net cash provided by investing activities	16,827	7,010
Cash flows from financing activities:
Issuance of common stock	1	42
Repurchase of common stock	(191)	(561)
Payments under capital lease and note payable obligations	(67)	(29)
Net cash used in financing activities	(257)	(548)
Effect of exchange rate changes on cash	(178)	(254)
Net increase (decrease) in cash and cash equivalents	1,338	(993)
Cash and cash equivalents at end of period	3,705	3,960
Cash paid during the period for:
Interest	1,063	1,056
Non-cash investing activities:
Net unrealized gain (loss) on available-for-sale securities	(130)	7
Assets acquired under capital lease	$ 0	$ 47