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
Income Statement [Abstract]
Revenue	$ 186,586us-gaap_SalesRevenueNet	$ 193,534us-gaap_SalesRevenueNet	$ 159,258us-gaap_SalesRevenueNet
Cost of revenue	118,146us-gaap_CostOfGoodsAndServicesSold	118,241us-gaap_CostOfGoodsAndServicesSold	94,206us-gaap_CostOfGoodsAndServicesSold
Gross profit	68,440us-gaap_GrossProfit	75,293us-gaap_GrossProfit	65,052us-gaap_GrossProfit
Operating expenses:
Selling, general and administrative	43,857	44,195	33,656
Research and development	26,320us-gaap_ResearchAndDevelopmentExpense	22,542us-gaap_ResearchAndDevelopmentExpense	21,700us-gaap_ResearchAndDevelopmentExpense
Total operating expenses	70,177us-gaap_OperatingExpenses	66,737us-gaap_OperatingExpenses	55,356us-gaap_OperatingExpenses
Income (loss) from operations	(1,737)us-gaap_OperatingIncomeLoss	8,556us-gaap_OperatingIncomeLoss	9,696us-gaap_OperatingIncomeLoss
Interest expense, net	169	4	116
Amortization of debt discount and prepaid debt costs	20	60	57
Income (loss) from operations before income taxes	(1,926)	8,492	9,523
Income tax provision	4,346us-gaap_IncomeTaxExpenseBenefit	2,152us-gaap_IncomeTaxExpenseBenefit	2,349us-gaap_IncomeTaxExpenseBenefit
Net income (loss)	$ (6,272)us-gaap_NetIncomeLoss	$ 6,340us-gaap_NetIncomeLoss	$ 7,174us-gaap_NetIncomeLoss
Net income (loss) per share:
Basic (in dollars per share)	$ (0.21)us-gaap_EarningsPerShareBasic	$ 0.22us-gaap_EarningsPerShareBasic	$ 0.25us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ (0.21)us-gaap_EarningsPerShareDiluted	$ 0.22us-gaap_EarningsPerShareDiluted	$ 0.25us-gaap_EarningsPerShareDiluted
Weighted average common shares outstanding:
Basic (in shares)	29,216	28,869	28,568
Diluted (in shares)	29,216	28,903	28,709

Amount of noncash expense included in interest expense to allocate debt discount and premium, and the costs to issue debt and obtain financing over the related debt instruments. Alternate captions include noncash interest expense.

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