Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Jul. 27, 2013	Jul. 28, 2012
Revenue:
Product sales	$ 27,174	$ 28,690
Contract services	16,943	29,987
Total revenue	44,117	58,677
Cost of sales:
Product sales	20,555	20,559
Contract services	11,017	18,613
Total cost of sales	31,572	39,172
Gross margin	12,545	19,505
Selling, general and administrative	12,459	13,621
Research and development	7,190	8,136
Loss from operations	(7,104)	(2,252)
Other income (expense):
Interest income	205	172
Other expense	(3,394)
Loss before income taxes	(10,293)	(2,080)
Benefit for income taxes	(3,083)	(694)
Net loss	$ (7,210)	$ (1,386)
Loss per share data:
Basic (in dollars per share)	$ (0.32)	$ (0.06)
Diluted (in dollars per share)	$ (0.32)	$ (0.06)
Weighted average shares outstanding:
Basic (in shares)	22,238,363	21,929,455
Diluted (in shares)	22,238,363	21,929,455