Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Apr. 30, 2020	May 01, 2019
Accounting Policies [Abstract]
Cash equivalents	$ 0		$ 0
Net income (loss)	75,000	$ (641,000)
Net cash provided by (used in) operating activities	(715,000)	(279,000)
Accumulated deficit	72,598,000		72,673,000
Working capital deficit	1,300,000
Cash and cash equivalents	6,943,000		8,342,000
Unrecognized tax benefits	178,000		178,000
Provision for income taxes	13,000	15,000
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net	$ 5,673,000	$ 3,103,000	$ 2,798,000
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net				$ 3,200,000
Deferred rent				900,000
Operating lease liability				$ 4,100,000