CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jul. 29, 2017	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2015
Operating activities
Net income		$ 47,419	$ 17,647	$ 13,078	$ 13,078
Gain on sale of business, net of tax		(8,490)
Loss from discontinued operations		2,964	3,887	4,601
Net income from continuing operations		41,893	21,534	17,679
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization		7,669	5,982	5,054
Loss from equity method investments	$ 1,283	3,944	1,283	119
Impairment of long-lived assets		4,398	255	46
Provision for doubtful accounts		(39)	977	48
Impairment of intangible assets and goodwill			1,021
Gains on foreign currency transactions		38	(87)	284
Deferred income taxes		4,792	2,853	309
Gain on business acquisition				(584)
Stock-based compensation		6,985	4,956	3,392
Loss on disposition of property and equipment		76	20	44
Amortization of held-to-maturity investments		(1,506)	1,424	2,382
Changes in operating assets and liabilities:
Accounts receivable		25,821	11,070	(19,720)
Unbilled receivables and retentions		(36,175)	2,253	615
Inventories		(16,631)	1,192	(16,816)
Income tax receivable		(821)
Prepaid expenses and other assets		(2,401)	139	(1,484)
Accounts payable		(7,054)	5,736	545
Other liabilities		(4,043)	9,224	(166)
Net cash provided by (used in) operating activities of continuing operations		26,946	69,832	(8,253)
Investing activities
Acquisition of property and equipment		(8,896)	(9,563)	(9,017)
Equity method investments		(7,598)	(3,267)
Business acquisition, net of cash acquired				(430)
Proceeds from sale of business		31,994
Redemptions of held-to-maturity investments		260,918	227,663	121,522
Purchases of held-to-maturity investments		(267,122)	(221,680)	(148,991)
Redemptions of available-for-sale investments		2,250	450	400
Net cash provided by (used in) investing activities from continuing operations		11,546	(6,397)	(36,516)
Financing activities
Principal payments of capital lease obligations		(161)	(288)	(390)
Tax withholding payment related to net settlement of equity awards		(1,094)	(397)	(5)
Exercise of stock options		71	2,705	3,865
Net cash (used in) provided by financing activities from continuing operations		(1,184)	2,020	3,470
Discontinued operations
Operating activities of discontinued operations		(7,686)	(623)	(2,246)
Investing activities of discontinued operations		(431)	(1,219)	(838)
Net cash used in discontinued operations		(8,117)	(1,842)	(3,084)
Net increase (decrease) in cash and cash equivalents		29,191	63,613	(44,383)
Cash and cash equivalents at beginning of period	$ 79,904	143,517	79,904	124,287
Cash and cash equivalents at ending of period		172,708	143,517	79,904
Cash paid, net during the period for:
Income taxes		6,780	1,813	1,804
Non-cash activities
Unrealized gain on investments, net of deferred tax expense of $51, $25 and $43, respectively		57	70	74
Reclassification from share-based liability compensation to equity			384	307
Change in foreign currency translation adjustments		(34)	36
Acquisitions of property and equipment included in accounts payable		$ 810	$ 379	$ 724