Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020
Cash flows from operating activities:
Net loss	$ (733)	$ (7,046)
Non-cash charges to earnings	3,411	5,955
Net changes in operating assets and liabilities	6,655	331
Net cash provided by (used in) operating activities	9,333	(760)
Cash flows from investing activities:
Proceeds on redemption of marketable securities	1,998	3,037
Purchase of marketable securities	(1,948)	(4,049)
Purchase of fixed assets and other assets	(971)	(1,641)
Net cash used in investing activities	(921)	(2,653)
Net cash used in financing activities:
Repayment of PPP Loan	(4,965)	0
Proceeds from UBS line of credit	3,000	0
Repayment of UBS line of credit	(3,000)	0
Net cash used in financing activities	(4,965)	0
Net increase (decrease) in cash and cash equivalents	3,447	(3,413)
Cash and cash equivalents at beginning of period	3,808	3,683
Cash and cash equivalents at end of period	7,255	270
Supplemental disclosures of cash flow information:
Interest	102	75
Income Taxes	$ 511	$ 0