Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Sales:
Product	$ 81,143us-gaap_SalesRevenueGoodsNet	$ 90,295us-gaap_SalesRevenueGoodsNet	$ 90,677us-gaap_SalesRevenueGoodsNet
Service	91,448us-gaap_SalesRevenueServicesNet	71,993us-gaap_SalesRevenueServicesNet	46,435us-gaap_SalesRevenueServicesNet
Net sales	172,591us-gaap_SalesRevenueNet	162,288us-gaap_SalesRevenueNet	137,112us-gaap_SalesRevenueNet
Costs and expenses:
Costs of product sales	48,843us-gaap_CostOfGoodsSold	51,518us-gaap_CostOfGoodsSold	51,775us-gaap_CostOfGoodsSold
Costs of service sales	50,301us-gaap_CostOfServices	45,058us-gaap_CostOfServices	30,363us-gaap_CostOfServices
Research and development	14,101us-gaap_ResearchAndDevelopmentExpense	12,987us-gaap_ResearchAndDevelopmentExpense	12,147us-gaap_ResearchAndDevelopmentExpense
Sales, marketing and support	32,976us-gaap_SellingAndMarketingExpense	28,792us-gaap_SellingAndMarketingExpense	24,069us-gaap_SellingAndMarketingExpense
General and administrative	24,448us-gaap_GeneralAndAdministrativeExpense	17,764us-gaap_GeneralAndAdministrativeExpense	12,188us-gaap_GeneralAndAdministrativeExpense
Total costs and expenses	170,669us-gaap_CostsAndExpenses	156,119us-gaap_CostsAndExpenses	130,542us-gaap_CostsAndExpenses
Income from operations	1,922us-gaap_OperatingIncomeLoss	6,169us-gaap_OperatingIncomeLoss	6,570us-gaap_OperatingIncomeLoss
Interest income	738us-gaap_InvestmentIncomeInterest	657us-gaap_InvestmentIncomeInterest	510us-gaap_InvestmentIncomeInterest
Interest expense	1,296us-gaap_InterestExpense	637us-gaap_InterestExpense	323us-gaap_InterestExpense
Other (expense) income	(39)us-gaap_OtherNonoperatingIncomeExpense	494us-gaap_OtherNonoperatingIncomeExpense	86us-gaap_OtherNonoperatingIncomeExpense
Income before income tax expense	1,325	6,683	6,843
Income tax expense	1,284us-gaap_IncomeTaxExpenseBenefit	2,150us-gaap_IncomeTaxExpenseBenefit	3,263us-gaap_IncomeTaxExpenseBenefit
Net income	$ 41us-gaap_NetIncomeLoss	$ 4,533us-gaap_NetIncomeLoss	$ 3,580us-gaap_NetIncomeLoss
Per share information:
Net income per share, basic (in dollars per share)	$ 0.00us-gaap_EarningsPerShareBasic	$ 0.30us-gaap_EarningsPerShareBasic	$ 0.24us-gaap_EarningsPerShareBasic
Net income per share, diluted (in dollars per share)	$ 0.00us-gaap_EarningsPerShareDiluted	$ 0.30us-gaap_EarningsPerShareDiluted	$ 0.24us-gaap_EarningsPerShareDiluted
Number of shares used in per share calculation:
Basic (in shares)	15,420	15,144	14,777
Diluted (in shares)	15,605	15,341	15,019

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