XML 95 R81.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Mar. 31, 2017 | Mar. 31, 2016 | Mar. 31, 2015
Compensation and Retirement Disclosure [Abstract] |  |  |
Percentage of common stock matched under deferred compensation plan | 50.00% |  |
First certain percentage of eligible contribution under deferred compensation plan | 6.00% |  |
Recorded expense under deferred compensation plan | $ 0.4 | $ 0.4 | $ 0.4

X
- Definition Defined Contribution Plan Company Contribution Percentage Match Common Stock + References No definition available. + Details
Name: | amsc_DefinedContributionPlanCompanyContributionPercentageMatchCommonStock
Namespace Prefix: | amsc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Contribution Plan Percentage Of First Eligible Employee Contribution Matched By Employer + References No definition available. + Details
Name: | amsc_DefinedContributionPlanPercentageOfFirstEligibleEmployeeContributionMatchedByEmployer
Namespace Prefix: | amsc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of the cost recognized during the period for defined contribution plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration