Summary of Accounting Policies (Details) - Revenue from External Customers by Products and Services - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020
Revenue from External Customer [Line Items]
Revenue	$ 54,254	$ 41,507
Satellite Revenue [Member]
Revenue from External Customer [Line Items]
Revenue	26,980	20,422
Government Non-Space Revenue [Member]
Revenue from External Customer [Line Items]
Revenue	24,775	16,939
Other Commercial & Industrial Revenue [Member]
Revenue from External Customer [Line Items]
Revenue	$ 2,499	$ 4,146

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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+ Details