Provision for Income Taxes - Components of Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2018	Apr. 30, 2017
Federal Income Tax Expense (Benefit), Continuing Operations [Abstract]
Provision for Income Taxes, Current, Federal	$ 0	$ (14)
Provision for Income Taxes, Total, Federal	0	(14)
State and Local Income Tax Expense (Benefit), Continuing Operations [Abstract]
Provision for Income Taxes, Current, State	3	0
Provision for Income Taxes, Total, State	3	0
Foreign Income Tax Expense (Benefit), Continuing Operations [Abstract]
Provision for Income Taxes, Current, Foreign	30	33
Provision for Income Taxes, Total, Foreign	30	33
Provision for Income Taxes, Current, Total	33	19
Provision for Income Taxes, Total	$ 33	$ 19

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 6.I.7)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
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Amount of current foreign income tax expense (benefit) pertaining to income (loss) from continuing operations.

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Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

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-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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-Publisher FASB
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Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Amount of current and deferred federal income tax expense (benefit) attributable to income (loss) from continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32672-109319

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Amount of current and deferred foreign income tax expense (benefit) attributable to income (loss) from continuing operations.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of state and local current and deferred income tax expense (benefit) attributable to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

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