Quarterly report pursuant to Section 13 or 15(d)

Property, Plant and Equipment (Details)

v2.4.1.9
Property, Plant and Equipment (Details) (USD $)
3 Months Ended 9 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Mar. 31, 2014
Property, Plant and Equipment          
Total property, plant and equipment, gross $ 34,701,000us-gaap_PropertyPlantAndEquipmentGross   $ 34,701,000us-gaap_PropertyPlantAndEquipmentGross   $ 35,534,000us-gaap_PropertyPlantAndEquipmentGross
Less accumulated depreciation (31,539,000)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment   (31,539,000)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment   (32,643,000)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Total property, plant and equipment, net 3,162,000us-gaap_PropertyPlantAndEquipmentNet   3,162,000us-gaap_PropertyPlantAndEquipmentNet   2,891,000us-gaap_PropertyPlantAndEquipmentNet
Depreciation expense 300,000us-gaap_Depreciation 400,000us-gaap_Depreciation 900,000us-gaap_Depreciation 1,400,000us-gaap_Depreciation  
Machinery, rental equipment, equipment, automobiles and furniture          
Property, Plant and Equipment          
Total property, plant and equipment, gross 20,942,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpst_MachineryRentalEquipmentEquipmentAutomobileAndFurnitureMember
  20,942,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpst_MachineryRentalEquipmentEquipmentAutomobileAndFurnitureMember
  20,665,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpst_MachineryRentalEquipmentEquipmentAutomobileAndFurnitureMember
Leasehold improvements          
Property, Plant and Equipment          
Total property, plant and equipment, gross 9,760,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LeaseholdImprovementsMember
  9,760,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LeaseholdImprovementsMember
  9,731,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LeaseholdImprovementsMember
Molds and tooling          
Property, Plant and Equipment          
Total property, plant and equipment, gross $ 3,999,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ToolsDiesAndMoldsMember
  $ 3,999,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ToolsDiesAndMoldsMember
  $ 5,138,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ToolsDiesAndMoldsMember