Consolidated Statements of Cash Flows (USD $)	3 Months Ended
	Jul. 26, 2013	Jul. 27, 2012
Cash Flows From Operating Activities:
Net income	$ 8,673,926	$ 8,075,033
Non-cash items included in net income:
Depreciation	1,010,839	924,637
Amortization of intangible assets	346,162	198,471
Stock-based compensation	3,153,499	4,406,533
Deferred income taxes	(483,988)	4,112,304
Deferred license revenue amortization	(1,467,869)	(373,492)
Impairment of investment		4,058,768
Unrealized loss (gain) in foreign currency transactions and other	(13,497)	152,980
Changes in operating assets and liabilities:
Accounts receivable, net	(366,782)	(2,801,911)
Inventories	149,041	(136,270)
Other current assets	376,748	996,345
Other assets	47,705	4,846
Litigation settlement accrual	7,111,090
Accounts payable and accrued liabilities	(9,049,218)	(4,686,429)
Net cash provided by operating activities	9,487,656	14,931,815
Cash Flow From Investing Activities:
(Increase) decrease in restricted cash	(309,740)
Payments for short-term investments	(14,990,389)
Proceeds from Sale, Maturity and Collection of Short-term Investments	5,000,000
Purchases of plant and equipment	(5,533,847)	(1,165,358)
Intangible asset purchases	(1,250,000)	(2,500,000)
Net cash used in investing activities	(17,083,976)	(3,665,358)
Cash Flows From Financing Activities:
Purchase of treasury stock	(12,964,495)	(11,964,983)
Proceeds from exercise of options for common stock	2,613,639	6,179,777
Cash settlement of compensation plan share-based units	(936,115)
Realized excess tax benefits - stock compensation based	4,474,196	400,311
Net cash used in financing activities	(6,812,775)	(5,384,895)
Effect of exchange rate changes on cash and cash equivalents	22,358	(243,814)
Net increase in cash and cash equivalents	(14,386,737)	5,637,748
Cash and cash equivalents at beginning of year	120,708,572	96,654,275
Cash and cash equivalents at end of year	106,321,835	102,292,023
Supplementary Disclosures of Cash Flow Information:
Cash paid for interest		27,495
Cash paid for income taxes	266,322	361,983
Supplementary Disclosures of Non-Cash Investing and Financing Activities:
Purchases of property and equipment through accounts payable and accrued liabilities	$ 290,703	$ (191,180)