Summary of Significant Accounting Policies - Additional Information (Details)		3 Months Ended
	Jun. 10, 2022	Jul. 31, 2022 USD ($) $ / shares	Jul. 31, 2021 USD ($)	Jun. 03, 2022 $ / shares	Apr. 30, 2022 USD ($) $ / shares
Summary of Significant Accounting Policies [Line Items]
Useable life of device over years		7 years
Depreciation expense		$ 6,412	$ 6,973
Reverse stock split, conversion ratio	0.0303
Reverse stock split, description		1-for-33 reverse stock split
Revenue		$ 3,200	$ 7,484
Contract assets from contracts with customers		0			$ 0
Contract liabilities from contracts with customers		0			0
Remaining performance obligations		$ 0			$ 0
Common stock, par value | $ / shares		$ 0.001		$ 0.001	$ 0.001
Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated useful lives		3 years
Customers payment terms		30 days
Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful lives		5 years
Lease term		12 months
Customers payment terms		60 days