Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Cash flows from operating activities:
Net earnings			$ 5,037	$ 6,197
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	$ 1,247	$ 1,882	4,441	6,310
Stock-based compensation expense	700	600	1,901	1,510
Net gain on investments			(1,945)	(1,036)
Deferred income taxes			(325)	(192)
Changes in operating assets and liabilities:
Purchases of trading securities			(779)	(21,934)
Proceeds from maturities and sales of trading securities			3,534	22,687
Accounts receivable, net			5,248	(3,344)
Prepaid expenses and other assets			922	(1,279)
Accounts payable and other liabilities			(1,897)	3,058
Deferred revenue			(2,204)	1,135
Net cash provided by operating activities			13,933	13,112
Cash flows from investing activities:
Capitalized computer software development costs			(604)	(2,697)
Purchases of property and equipment, net of disposals	(298)	(101)	(461)	(339)
Net cash used in investing activities			(1,065)	(3,036)
Cash flows from financing activities:
Proceeds from exercise of stock options			4,735	7,837
Dividends paid			(10,696)	(10,392)
Net cash used in financing activities			(5,961)	(2,555)
Net change in cash and cash equivalents			6,907	7,521
Cash and cash equivalents at beginning of period			79,814	61,288
Cash and cash equivalents at end of period	86,721	68,809	86,721	68,809
Cash paid during the period for:
Income taxes, net of refunds			485	504
Supplemental disclosures of noncash operating, investing and financing activities:
Accrual of dividends payable	$ 3,597	$ 3,523	$ 3,597	$ 3,523