Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2022	Jul. 31, 2021	Apr. 30, 2022
Accounting Policies [Abstract]
Cash equivalents	$ 0		$ 0
Net loss	(319)	$ (172)
Net cash provided by (used in) operating activities	(195)	216
Accumulated deficit	72,301		71,982
Working capital	1,800
Cash and cash equivalents	8,058		9,007
Unrecognized tax benefits	181		$ 181
Income tax penalties and interest expense	0	0
Unrecognized tax benefits anticipated during the next 12 months	0
Provision for income taxes	$ 17	$ 14