CONSOLIDATED INCOME STATEMENTS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net sales	$ 562,329us-gaap_SalesRevenueNet	$ 529,354us-gaap_SalesRevenueNet	$ 463,090us-gaap_SalesRevenueNet
Cost of sales	395,429us-gaap_CostOfGoodsAndServicesSold	377,892us-gaap_CostOfGoodsAndServicesSold	329,653us-gaap_CostOfGoodsAndServicesSold
Gross profit	166,900us-gaap_GrossProfit	151,462us-gaap_GrossProfit	133,437us-gaap_GrossProfit
Research and development expenses	16,975us-gaap_ResearchAndDevelopmentExpense	16,447us-gaap_ResearchAndDevelopmentExpense	14,152us-gaap_ResearchAndDevelopmentExpense
Selling, general and administrative expenses	108,645	102,861	93,083
Operating income	41,280us-gaap_OperatingIncomeLoss	32,154us-gaap_OperatingIncomeLoss	26,202us-gaap_OperatingIncomeLoss
Interest income (expense), net	11	51	(151)
Other income (expense), net	(840)us-gaap_OtherNonoperatingIncomeExpense	(3,169)us-gaap_OtherNonoperatingIncomeExpense	(1,413)us-gaap_OtherNonoperatingIncomeExpense
Income before provision for income taxes	40,451	29,036	24,638
Provision for income taxes	7,917us-gaap_IncomeTaxExpenseBenefit	6,073us-gaap_IncomeTaxExpenseBenefit	8,085us-gaap_IncomeTaxExpenseBenefit
Net income	$ 32,534us-gaap_NetIncomeLoss	$ 22,963us-gaap_NetIncomeLoss	$ 16,553us-gaap_NetIncomeLoss
Earnings per share:
Basic (in dollars per share)	$ 2.06us-gaap_EarningsPerShareBasic	$ 1.51us-gaap_EarningsPerShareBasic	$ 1.11us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ 2.01us-gaap_EarningsPerShareDiluted	$ 1.47us-gaap_EarningsPerShareDiluted	$ 1.10us-gaap_EarningsPerShareDiluted
Shares used in computing earnings per share:
Basic (in shares)	15,781	15,248	14,952
Diluted (in shares)	16,152	15,601	15,110

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 2

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.2(a),(d))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688