Stock Compensation Plans - Additional Information (Details) (USD $) In Thousands, except Share data, unless otherwise specified
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12 Months Ended |
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Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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Dec. 31, 2011
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Sep. 30, 2010
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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Issuance of common stock |
$ 3,282us-gaap_ProceedsFromIssuanceOfCommonStock
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$ 1,256us-gaap_ProceedsFromIssuanceOfCommonStock
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$ 795us-gaap_ProceedsFromIssuanceOfCommonStock
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Total compensation cost not yet recognized, stock options |
11,059us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
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Unrecognized compensation cost for stock based compensation, period of recognition |
1 year 9 months 7 days
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Options, exercises in period, total intrinsic value |
4,640us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
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957us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
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1,267us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
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Allocated share-based compensation expense |
10,539us-gaap_AllocatedShareBasedCompensationExpense
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6,766us-gaap_AllocatedShareBasedCompensationExpense
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4,690us-gaap_AllocatedShareBasedCompensationExpense
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Options, outstanding, number |
4,415,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
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4,425,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
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4,475,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
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Qualified Employee Stock Purchase Plan [Member] |
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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Number of shares available for grant |
10,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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Offering date |
5.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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Stock issued during period, gross |
89,581us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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112,646us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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98,513us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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Shares authorized under stock option plans, exercise price range, lower range limit |
$ 2.87us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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$ 1.57us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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$ 1.25us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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Shares authorized under stock option plans, exercise price range, upper range limit |
$ 4.03us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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$ 2.97us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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$ 1.69us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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Issuance of common stock |
291us-gaap_ProceedsFromIssuanceOfCommonStock / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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201us-gaap_ProceedsFromIssuanceOfCommonStock / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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138us-gaap_ProceedsFromIssuanceOfCommonStock / us-gaap_AwardTypeAxis = lts_QualifiedEmployeeStockPurchasePlanMember
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Plan 1999 [Member] |
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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Number of shares available for grant |
1,194,854us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = lts_Plan1999Member
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Granted |
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500,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross / us-gaap_AwardTypeAxis = lts_Plan1999Member
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Options, outstanding, number |
15,786,001us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = lts_Plan1999Member
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16,932,401us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = lts_Plan1999Member
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17,302,468us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = lts_Plan1999Member
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17,765,468us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = lts_Plan1999Member
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Plan 1999 [Member] | Maximum |
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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Granted |
25,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross / us-gaap_AwardTypeAxis = lts_Plan1999Member / us-gaap_RangeAxis = us-gaap_MaximumMember
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Awards with annual limit |
1,500,000lts_AwardsWithAnnualLimit / us-gaap_AwardTypeAxis = lts_Plan1999Member / us-gaap_RangeAxis = us-gaap_MaximumMember
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Plan 2009 [Member] |
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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Number of shares available for grant |
22,929,061us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = lts_Plan2009Member
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Granted |
3,641,212us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross / us-gaap_AwardTypeAxis = lts_Plan2009Member
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2,788,212us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross / us-gaap_AwardTypeAxis = lts_Plan2009Member
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3,725,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross / us-gaap_AwardTypeAxis = lts_Plan2009Member
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Awards with annual limit |
1,500,000,000lts_AwardsWithAnnualLimit / us-gaap_AwardTypeAxis = lts_Plan2009Member
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Combined voting power |
10.00%lts_SharebasedCompensationArrangementbySharebasedPaymentAwardCombinedVotingPower / us-gaap_AwardTypeAxis = lts_Plan2009Member
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Fair market value |
100.00%lts_SharebasedCompensationArrangementbySharebasedPaymentAwardFairMarketValue / us-gaap_AwardTypeAxis = lts_Plan2009Member
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Fair market value for ten percent shareholder |
110.00%lts_SharebasedCompensationArrangementbySharebasedPaymentAwardFairMarketValueforTenPercentShareholder / us-gaap_AwardTypeAxis = lts_Plan2009Member
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Options, outstanding, number |
20,379,199us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = lts_Plan2009Member
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18,145,564us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = lts_Plan2009Member
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15,937,715us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = lts_Plan2009Member
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12,503,994us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = lts_Plan2009Member
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Plan 2009 [Member] | Maximum |
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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Granted |
45,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross / us-gaap_AwardTypeAxis = lts_Plan2009Member / us-gaap_RangeAxis = us-gaap_MaximumMember
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Plan 2009 [Member] | Restricted Stock [Member] |
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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Number of shares available for grant |
14,409us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = lts_Plan2009Member / us-gaap_PlanNameAxis = us-gaap_RestrictedStockMember
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200,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = lts_Plan2009Member / us-gaap_PlanNameAxis = us-gaap_RestrictedStockMember
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Equity instruments other than options, forfeited in period |
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12,500us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod / us-gaap_AwardTypeAxis = lts_Plan2009Member / us-gaap_PlanNameAxis = us-gaap_RestrictedStockMember
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Allocated share-based compensation expense |
$ 2us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = lts_Plan2009Member / us-gaap_PlanNameAxis = us-gaap_RestrictedStockMember
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$ 54us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = lts_Plan2009Member / us-gaap_PlanNameAxis = us-gaap_RestrictedStockMember
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Employees and Director Option [Member] |
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Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
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Options, grants in period, weighted average grant date fair value |
$ 1.85us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = lts_EmployeesAndDirectorOptionMember
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$ 0.74us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = lts_EmployeesAndDirectorOptionMember
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$ 1.13us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = lts_EmployeesAndDirectorOptionMember
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