Annual report pursuant to Section 13 and 15(d)

Property, Plant and Equipment (Details)

v2.4.1.9
Property, Plant and Equipment (Details) (USD $)
12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2013
Property, Plant and Equipment      
Total property, plant and equipment, gross $ 34,355,000us-gaap_PropertyPlantAndEquipmentGross $ 35,534,000us-gaap_PropertyPlantAndEquipmentGross  
Less accumulated depreciation (30,832,000)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment (32,643,000)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment  
Total property, plant and equipment, net 3,523,000us-gaap_PropertyPlantAndEquipmentNet 2,891,000us-gaap_PropertyPlantAndEquipmentNet  
Depreciation expense 1,200,000us-gaap_Depreciation 1,800,000us-gaap_Depreciation 2,300,000us-gaap_Depreciation
Minimum      
Property, Plant and Equipment      
Estimated Useful Life 2 years    
Maximum      
Property, Plant and Equipment      
Estimated Useful Life 10 years    
Machinery, rental equipment, equipment, automobiles and furniture      
Property, Plant and Equipment      
Total property, plant and equipment, gross 20,873,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpst_MachineryRentalEquipmentEquipmentAutomobileAndFurnitureMember
20,665,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= cpst_MachineryRentalEquipmentEquipmentAutomobileAndFurnitureMember
 
Machinery, rental equipment, equipment, automobiles and furniture | Minimum      
Property, Plant and Equipment      
Estimated Useful Life 2 years    
Machinery, rental equipment, equipment, automobiles and furniture | Maximum      
Property, Plant and Equipment      
Estimated Useful Life 10 years    
Leasehold improvements      
Property, Plant and Equipment      
Total property, plant and equipment, gross 9,760,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LeaseholdImprovementsMember
9,731,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LeaseholdImprovementsMember
 
Estimated Useful Life 10 years    
Molds and tooling      
Property, Plant and Equipment      
Total property, plant and equipment, gross $ 3,722,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ToolsDiesAndMoldsMember
$ 5,138,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ToolsDiesAndMoldsMember
 
Molds and tooling | Minimum      
Property, Plant and Equipment      
Estimated Useful Life 2 years    
Molds and tooling | Maximum      
Property, Plant and Equipment      
Estimated Useful Life 5 years