Consolidated Statements of Income (unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Apr. 02, 2011	Mar. 31, 2012	Apr. 02, 2011
Revenue:
Product	$ 112,788	$ 97,029	$ 230,239	$ 186,930
Service	16,231	16,032	32,477	32,007
Total revenue	129,019	113,061	262,716	218,937
Cost of sales:
Product	64,648	56,430	131,520	107,329
Service	7,981	7,724	16,093	16,029
Total cost of sales	72,629	64,154	147,613	123,358
Gross profit	56,390	48,907	115,103	95,579
Operating expenses:
Selling and marketing	19,206	17,151	36,215	33,730
General and administrative	13,917	10,329	27,113	18,820
Research and development	6,068	3,558	11,027	6,686
Total operating expenses	39,191	31,038	74,355	59,236
Income from operations	17,199	17,869	40,748	36,343
Interest expense	(296)	(384)	(620)	(854)
Interest income	84	61	202	104
Other (expense) income, net	(399)	60	(422)	117
Income before income taxes	16,588	17,606	39,908	35,710
Provision for income taxes	5,431	5,798	13,212	10,613
Net income	$ 11,157	$ 11,808	$ 26,696	$ 25,097
Basic-
Earnings per share (in dollars per share)	$ 0.70	$ 0.77	$ 1.69	$ 1.63
Weighted average number of common shares outstanding - basic (in shares)	15,906	15,430	15,793	15,367
Diluted-
Earnings per share (in dollars per share)	$ 0.69	$ 0.75	$ 1.67	$ 1.60
Weighted average number of common shares outstanding - diluted (in shares)	16,106	15,838	15,969	15,682
Dividends declared per share (in dollars per share)	$ 0.25	$ 0.20	$ 0.50	$ 0.40