Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Operating activities
Net (loss) income	$ (4,185,000)	$ 23,345,000	$ 41,070,000
Loss on sale of business, net of tax			265,000
Net (loss) income from continuing operations	(4,185,000)	23,345,000	41,335,000
Adjustments to reconcile net (loss) income to cash (used in) provided by operating activities:
Depreciation and amortization	60,825,000	19,262,000	9,888,000
(Income) loss from equity method investments, net	(5,889,000)	10,481,000	5,487,000
Amortization of debt issuance costs	789,000	145,000
Realized gain from sale of available-for-sale investments		(11,000)	(180,000)
Provision for doubtful accounts	(6,000)	(114,000)	388,000
Other non-cash expense (income)	649,000	(449,000)	(703,000)
Non-cash lease expense	6,814,000	5,150,000	4,574,000
Loss on foreign currency transactions	233,000	1,000	1,000
Deferred income taxes	(7,282,000)	(1,694,000)	3,419,000
Stock-based compensation	5,390,000	6,932,000	6,227,000
Loss (gain) on disposal of property and equipment	8,277,000	123,000	(71,000)
Amortization of debt securities	242,000	309,000	(1,423,000)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	3,084,000	17,177,000	(42,869,000)
Unbilled receivables and retentions	(31,883,000)	8,381,000	(22,790,000)
Inventories	(27,160,000)	(5,179,000)	8,855,000
Income taxes receivable	(442,000)		821,000
Prepaid expenses and other assets	(4,534,000)	(6,104,000)	831,000
Accounts payable	(7,044,000)	2,565,000	3,127,000
Other liabilities	(7,496,000)	6,212,000	8,180,000
Net cash (used in) provided by operating activities	(9,618,000)	86,532,000	25,097,000
Investing activities
Acquisition of property and equipment	(22,289,000)	(11,263,000)	(11,220,000)
Equity method investments	(6,884,000)	(2,675,000)	(14,498,000)
Business acquisitions, net of cash acquired	(46,150,000)	(385,614,000)	(18,641,000)
Proceeds from sale of ownership in equity method investment	6,497,000
Proceeds from loan repayment	4,345,000
Proceeds from sale of property and equipment			81,000
Redemptions of held-to-maturity investments			185,917,000
Purchases of held-to-maturity investments			(176,757,000)
Redemptions of available-for-sale investments	35,851,000	146,425,000	200,892,000
Purchases of available-for-sale investments	(23,882,000)	(125,644,000)	(106,607,000)
Other	224,000
Net cash (used in) provided by investing activities	(52,288,000)	(378,771,000)	59,167,000
Financing activities
Principal payments of term loan	(10,000,000)
Payment of contingent consideration			(868,000)
Tax withholding payment related to net settlement of equity awards	(1,245,000)	(1,992,000)	(1,062,000)
Holdback and retention payments for business acquisition	(7,814,000)	(1,492,000)
Exercise of stock options	2,776,000	1,522,000	100,000
Payment of debt issuance costs	(293,000)	(3,878,000)
Proceeds from long-term debt		200,000,000
Other	(31,000)
Net cash (used in) provided by financing activities	(16,607,000)	194,160,000	(1,830,000)
Effects of currency translation on cash and cash equivalents	(1,319,000)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(79,832,000)	(98,079,000)	82,434,000
Cash, cash equivalents and restricted cash at beginning of period	157,063,000	255,142,000	172,708,000
Cash, cash equivalents and restricted cash at end of period	77,231,000	157,063,000	255,142,000
Cash paid, net during the period for:
Income taxes	1,879,000	2,405,000	532,000
Interest	5,025,000
Non-cash activities
Unrealized (loss) gain on investments, net of deferred tax expense of $8, $1 and $14 for the fiscal years ended 2021, 2020 and 2019, respectively	(43,000)	(60,000)	50,000
Issuance of common stock for business acquisition		72,384,000
Change in foreign currency translation adjustments	(6,814,000)	75,000	276,000
Issuances of inventory to property and equipment, ISR in-service assets	17,481,000	769,000
Acquisitions of property and equipment included in accounts payable	$ 1,117,000	$ 756,000	$ 1,425,000