Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Oct. 26, 2013	Apr. 30, 2013
Current assets:
Cash and cash equivalents	$ 66,126	$ 75,332
Short-term investments	77,677	73,241
Accounts receivable, net of allowance for doubtful accounts of $531 at October 26, 2013 and $936 at April 30, 2013	36,238	19,770
Unbilled receivables and retentions	7,256	11,304
Inventories, net	60,629	62,561
Income tax receivable	8,120	11,777
Deferred income taxes	5,400	5,166
Prepaid expenses and other current assets	4,317	4,303
Total current assets	265,763	263,454
Long-term investments	51,707	68,916
Property and equipment, net	26,039	24,429
Deferred income taxes	5,587	5,606
Other assets	1,720	1,060
Total assets	350,816	363,465
Current liabilities:
Accounts payable	11,774	16,144
Wages and related accruals	11,669	12,116
Customer advances	3,605	7,519
Other current liabilities	6,261	6,408
Total current liabilities	33,309	42,187
Deferred rent	614	771
Liability for uncertain tax positions	5,211	5,321
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.0001 par value: Authorized shares - 10,000,000; none issued or outstanding
Common stock, $0.0001 par value: Authorized shares - 100,000,000 Issued and outstanding shares - 22,704,189 at October 26, 2013 and 22,614,315 at April 30, 2013	2	2
Additional paid-in capital	132,549	130,527
Accumulated other comprehensive loss	(676)	(705)
Retained earnings	179,807	185,362
Total stockholders' equity	311,682	315,186
Total liabilities and stockholders' equity	$ 350,816	$ 363,465