Organization and Significant Accounting Policies - Revenue by Category (Details)	3 Months Ended		6 Months Ended
	Oct. 26, 2019 USD ($)	Oct. 27, 2018 USD ($) contract	Oct. 26, 2019 USD ($)	Oct. 27, 2018 USD ($) contract
Disaggregation of revenue
Number of active contracts | contract		1		1
Contract Liability
Disaggregation of revenue
Revenue	$ 828,000	$ 6,000	$ 1,658,000	$ 1,554,000
Domestic
Disaggregation of revenue
Revenue	49,965,000	46,726,000	88,773,000	82,078,000
International
Disaggregation of revenue
Revenue	33,306,000	26,253,000	81,409,000	68,944,000
U.S. government
Disaggregation of revenue
Revenue	50,302,000	46,941,000	99,436,000	82,849,000
Non-U.S. government
Disaggregation of revenue
Revenue	32,969,000	26,038,000	70,746,000	68,173,000
FFP
Disaggregation of revenue
Revenue	60,518,000	50,054,000	128,462,000	108,057,000
CPFF
Disaggregation of revenue
Revenue	21,257,000	22,870,000	39,521,000	42,853,000
T&M
Disaggregation of revenue
Revenue	1,496,000	55,000	2,199,000	112,000
Small UAS
Disaggregation of revenue
Revenue	59,157,000	42,199,000	125,903,000	83,415,000
TMS
Disaggregation of revenue
Revenue	7,924,000	15,019,000	13,511,000	37,785,000
HAPS
Disaggregation of revenue
Revenue	13,393,000	12,832,000	25,728,000	24,395,000
Other
Disaggregation of revenue
Revenue	$ 2,797,000	$ 2,929,000	$ 5,040,000	$ 5,427,000