Consolidated Statements of Operations and Comprehensive Loss (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue	$ 147,588us-gaap_SalesRevenueGoodsNet	$ 132,257us-gaap_SalesRevenueGoodsNet	$ 105,946us-gaap_SalesRevenueGoodsNet
Cost of goods sold	41,801us-gaap_CostOfGoodsSold	32,750us-gaap_CostOfGoodsSold	25,282us-gaap_CostOfGoodsSold
Gross profit	105,787us-gaap_GrossProfit	99,507us-gaap_GrossProfit	80,664us-gaap_GrossProfit
Operating expenses:
Research and development	21,616us-gaap_ResearchAndDevelopmentExpense	16,199us-gaap_ResearchAndDevelopmentExpense	16,571us-gaap_ResearchAndDevelopmentExpense
Clinical and regulatory affairs	13,243elgx_ClinicalAndRegulatoryAffairs	8,679elgx_ClinicalAndRegulatoryAffairs	6,343elgx_ClinicalAndRegulatoryAffairs
Marketing and sales	73,411us-gaap_SellingAndMarketingExpense	63,588us-gaap_SellingAndMarketingExpense	53,953us-gaap_SellingAndMarketingExpense
General and administrative	26,663us-gaap_GeneralAndAdministrativeExpense	21,409us-gaap_GeneralAndAdministrativeExpense	20,266us-gaap_GeneralAndAdministrativeExpense
Contract termination and business acquisition expenses	0us-gaap_GainLossOnContractTermination	0us-gaap_GainLossOnContractTermination	422us-gaap_GainLossOnContractTermination
Settlement costs	0us-gaap_LitigationSettlementExpense	0us-gaap_LitigationSettlementExpense	5,000us-gaap_LitigationSettlementExpense
Total operating expenses	134,933us-gaap_OperatingExpenses	109,875us-gaap_OperatingExpenses	102,555us-gaap_OperatingExpenses
Loss from operations	(29,146)us-gaap_OperatingIncomeLoss	(10,368)us-gaap_OperatingIncomeLoss	(21,891)us-gaap_OperatingIncomeLoss
Other income (expense):
Interest income	245us-gaap_InvestmentIncomeInterest	50us-gaap_InvestmentIncomeInterest	30us-gaap_InvestmentIncomeInterest
Interest expense	(5,709)us-gaap_InterestExpense	(321)us-gaap_InterestExpense	(7)us-gaap_InterestExpense
Other income (expense), net	(5,798)us-gaap_OtherNonoperatingIncomeExpense	3,061us-gaap_OtherNonoperatingIncomeExpense	325us-gaap_OtherNonoperatingIncomeExpense
Change in fair value of contingent consideration related to acquisition	7,928	(8,500)	(13,700)
Total other income (expense)	(3,334)elgx_TotalOtherIncomeExpense	(5,710)elgx_TotalOtherIncomeExpense	(13,352)elgx_TotalOtherIncomeExpense
Net income (loss) before income tax	(32,480)	(16,078)	(35,243)
Income tax benefit (expense)	62us-gaap_IncomeTaxExpenseBenefit	10us-gaap_IncomeTaxExpenseBenefit	(531)us-gaap_IncomeTaxExpenseBenefit
Net loss	(32,418)us-gaap_NetIncomeLoss	(16,068)us-gaap_NetIncomeLoss	(35,774)us-gaap_NetIncomeLoss
Other comprehensive income (loss) foreign currency translation	3,369	(845)	(222)
Comprehensive loss	$ (29,049)us-gaap_ComprehensiveIncomeNetOfTax	$ (16,913)us-gaap_ComprehensiveIncomeNetOfTax	$ (35,996)us-gaap_ComprehensiveIncomeNetOfTax
Basic and diluted net loss per share (in USD per share)	$ (0.50)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.26)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.60)us-gaap_EarningsPerShareBasicAndDiluted
Shares used in computing basic and diluted net loss per share	65,225	62,607	59,811

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