Annual report pursuant to Section 13 and 15(d)

Basis of Presentation Basis of Presentation (Details 1)

v2.4.1.9
Basis of Presentation Basis of Presentation (Details 1) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2013
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Revenue                 $ 84,127us-gaap_SalesRevenueNet $ 102,073us-gaap_SalesRevenueNet $ 38,808us-gaap_SalesRevenueNet
Cost of revenue                 57,317us-gaap_CostOfGoodsAndServicesSold 61,612us-gaap_CostOfGoodsAndServicesSold [1],[2] 26,192us-gaap_CostOfGoodsAndServicesSold [1]
Gross profit 4,666us-gaap_GrossProfit 4,395us-gaap_GrossProfit 8,065us-gaap_GrossProfit 9,684us-gaap_GrossProfit 8,090us-gaap_GrossProfit 11,932us-gaap_GrossProfit 12,022us-gaap_GrossProfit 8,417us-gaap_GrossProfit 26,810us-gaap_GrossProfit 40,461us-gaap_GrossProfit [1],[2] 12,616us-gaap_GrossProfit [1]
Gross Margin                 31.90%wstl_GrossMargin 39.60%wstl_GrossMargin 32.50%wstl_GrossMargin
Selling and Marketing Expense                 12,407us-gaap_SellingAndMarketingExpense 13,304us-gaap_SellingAndMarketingExpense [1] 6,783us-gaap_SellingAndMarketingExpense [1]
Intangible amortization                 6,377us-gaap_AmortizationOfIntangibleAssets 4,889us-gaap_AmortizationOfIntangibleAssets [2] 887us-gaap_AmortizationOfIntangibleAssets
Income tax benefit (expense) 31us-gaap_IncomeTaxExpenseBenefit 72us-gaap_IncomeTaxExpenseBenefit 69us-gaap_IncomeTaxExpenseBenefit 29us-gaap_IncomeTaxExpenseBenefit 8,585us-gaap_IncomeTaxExpenseBenefit (38)us-gaap_IncomeTaxExpenseBenefit (68)us-gaap_IncomeTaxExpenseBenefit (19)us-gaap_IncomeTaxExpenseBenefit 201us-gaap_IncomeTaxExpenseBenefit 8,460us-gaap_IncomeTaxExpenseBenefit [2] (29,392)us-gaap_IncomeTaxExpenseBenefit
Net income (loss) (13,000)us-gaap_NetIncomeLoss (27,540)us-gaap_NetIncomeLoss (14,649)us-gaap_NetIncomeLoss (2,818)us-gaap_NetIncomeLoss 4,437us-gaap_NetIncomeLoss 1,925us-gaap_NetIncomeLoss 1,328us-gaap_NetIncomeLoss (2,764)us-gaap_NetIncomeLoss (58,007)us-gaap_NetIncomeLoss 4,926us-gaap_NetIncomeLoss [2] (44,038)us-gaap_NetIncomeLoss
Scenario, Previously Reported [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Revenue                   102,073us-gaap_SalesRevenueNet
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		38,808us-gaap_SalesRevenueNet
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember
Cost of revenue                   60,115us-gaap_CostOfGoodsAndServicesSold
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		25,483us-gaap_CostOfGoodsAndServicesSold
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember
Gross profit                   41,958us-gaap_GrossProfit
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		13,325us-gaap_GrossProfit
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember
Gross Margin                   41.10%wstl_GrossMargin
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		34.30%wstl_GrossMargin
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember
Selling and Marketing Expense                   14,663us-gaap_SellingAndMarketingExpense
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		7,492us-gaap_SellingAndMarketingExpense
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember
Intangible amortization                   4,908us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		887us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember
Income tax benefit (expense)                   8,782us-gaap_IncomeTaxExpenseBenefit
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		(29,392)us-gaap_IncomeTaxExpenseBenefit
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember
Net income (loss)                   5,367us-gaap_NetIncomeLoss
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember 		(44,038)us-gaap_NetIncomeLoss
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioPreviouslyReportedMember
Restatement Adjustment [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Cost of revenue                   1,359us-gaap_CostOfGoodsAndServicesSold
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[3] 709us-gaap_CostOfGoodsAndServicesSold
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[3]
Gross profit                   (1,359)us-gaap_GrossProfit
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[3] (709)us-gaap_GrossProfit
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[3]
Selling and Marketing Expense                   (1,359)us-gaap_SellingAndMarketingExpense
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[3] (709)us-gaap_SellingAndMarketingExpense
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[3]
CSI [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Revenue         3,700us-gaap_SalesRevenueNet
/ us-gaap_BusinessAcquisitionAxis
= wstl_CSIMember 		      29,500us-gaap_SalesRevenueNet
/ us-gaap_BusinessAcquisitionAxis
= wstl_CSIMember 		3,700us-gaap_SalesRevenueNet
/ us-gaap_BusinessAcquisitionAxis
= wstl_CSIMember 		 
CSI [Member] | Restatement Adjustment [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Cost of revenue                   138us-gaap_CostOfGoodsAndServicesSold
/ us-gaap_BusinessAcquisitionAxis
= wstl_CSIMember
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[2]  
Gross profit                   (138)us-gaap_GrossProfit
/ us-gaap_BusinessAcquisitionAxis
= wstl_CSIMember
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[2]  
Intangible amortization                   (19)us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_BusinessAcquisitionAxis
= wstl_CSIMember
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[2]  
Income tax benefit (expense)                   (322)us-gaap_IncomeTaxExpenseBenefit
/ us-gaap_BusinessAcquisitionAxis
= wstl_CSIMember
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[2]  
Net income (loss)                   $ (441)us-gaap_NetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= wstl_CSIMember
/ us-gaap_StatementScenarioAxis
= us-gaap_RestatementAdjustmentMember 		[2]  
[1] Certain amounts have been reclassified to reflect a change in accounting principle (see Note 1).
[2] Certain amounts have been adjusted to reflect measurement period adjustments related to the CSI acquisition (see Note 2).
[3] See Voluntary Change in Accounting Principle above