Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 26, 2013	Oct. 27, 2012	Oct. 26, 2013	Oct. 27, 2012
Revenue:
Product sales	$ 51,537	$ 52,415	$ 78,711	$ 81,105
Contract services	13,330	27,863	30,273	57,850
Total revenue	64,867	80,278	108,984	138,955
Cost of sales:
Product sales	32,143	28,215	52,698	48,774
Contract services	8,846	16,427	19,863	35,040
Total cost of sales	40,989	44,642	72,561	83,814
Gross margin	23,878	35,636	36,423	55,141
Selling, general and administrative	13,084	13,176	25,543	26,797
Research and development	6,861	9,386	14,051	17,522
Income (loss) from operations	3,933	13,074	(3,171)	10,822
Other income (expense):
Interest income	195	162	400	334
Other expense	(2,307)		(5,701)
Income (loss) before income taxes	1,821	13,236	(8,472)	11,156
Provision (benefit) for income taxes	166	4,498	(2,917)	3,804
Net income (loss)	$ 1,655	$ 8,738	$ (5,555)	$ 7,352
Earnings (loss) per share data:
Basic (in dollars per share)	$ 0.07	$ 0.40	$ (0.25)	$ 0.33
Diluted (in dollars per share)	$ 0.07	$ 0.39	$ (0.25)	$ 0.33
Weighted average shares outstanding:
Basic (in shares)	22,273,629	22,030,330	22,256,292	21,980,453
Diluted (in shares)	22,697,590	22,383,791	22,256,292	22,353,434