Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Cash flows from operating activities:
Net earnings			$ 2,726	$ 2,911
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	$ 1,514	$ 2,183	3,194	4,428
Stock-based compensation expense	700	500	1,198	946
Net gain on investments			(803)	(356)
Deferred income taxes			(344)	(131)
Changes in operating assets and liabilities:
Purchases of trading securities			(285)	(21,412)
Proceeds from maturities and sales of trading securities			3,119	16,975
Accounts receivable, net			4,009	2,180
Prepaid expenses and other assets			322	(1,160)
Accounts payable and other liabilities			(3,344)	389
Deferred revenue			(3,021)	(720)
Net cash provided by operating activities			6,771	4,050
Cash flows from investing activities:
Capitalized computer software development costs			(371)	(1,890)
Purchases of property and equipment, net of disposals	(45)	(128)	(163)	(238)
Net cash used in investing activities			(534)	(2,128)
Cash flows from financing activities:
Proceeds from exercise of stock options			2,853	6,358
Dividends paid			(7,118)	(6,884)
Net cash used in financing activities			(4,265)	(526)
Net change in cash and cash equivalents			1,972	1,396
Cash and cash equivalents at beginning of period			79,814	61,288
Cash and cash equivalents at end of period	81,786	62,684	81,786	62,684
Cash paid during the period for:
Income taxes, net of refunds			205	260
Supplemental disclosures of noncash operating, investing and financing activities:
Accrual of dividends payable	$ 3,576	$ 3,505	$ 3,576	$ 3,505