Goodwill (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Jan. 31, 2015
Goodwill
Balance as of April 26, 2014	$ 4,558us-gaap_Goodwill
Disposal of automated rigging systems for theatre applications	(22)
Acquisition, net of cash required	1,244us-gaap_GoodwillAcquiredDuringPeriod
Foreign currency translation	(526)us-gaap_GoodwillTranslationAdjustments
Balance as of January 31, 2015	5,254us-gaap_Goodwill
Live Events
Goodwill
Balance as of April 26, 2014	2,381
Disposal of automated rigging systems for theatre applications	(22)
Acquisition, net of cash required	0
Foreign currency translation	(55)
Balance as of January 31, 2015	2,304
Commerical
Goodwill
Balance as of April 26, 2014	723
Disposal of automated rigging systems for theatre applications	0
Acquisition, net of cash required	0
Foreign currency translation	(3)
Balance as of January 31, 2015	720
Transportation
Goodwill
Balance as of April 26, 2014	129
Disposal of automated rigging systems for theatre applications	0
Acquisition, net of cash required	0
Foreign currency translation	(54)
Balance as of January 31, 2015	75
International
Goodwill
Balance as of April 26, 2014	1,325
Disposal of automated rigging systems for theatre applications	0
Acquisition, net of cash required	1,244
Foreign currency translation	(414)
Balance as of January 31, 2015	$ 2,155

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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