CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jan. 28, 2017	Jan. 30, 2016
Operating activities
Net (loss) income	$ (17,997)	$ 3,602
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	5,188	4,547
Loss from equity method investments	119	248
Impairment of available-for-sale securities		2,186
Provision for doubtful accounts	115	(252)
Losses on foreign currency transactions	272	63
Loss on sale of equity securities		219
Deferred income taxes	(698)	18
Stock-based compensation	2,736	3,170
Tax benefit from exercise of stock options	22	302
Loss (gain) on disposition of property and equipment	37	(32)
Amortization of held-to-maturity investments	1,827	3,086
Changes in operating assets and liabilities:
Accounts receivable	32,553	(5,052)
Unbilled receivables and retentions	4,079	6,916
Inventories	(31,320)	(7,020)
Income tax receivable	(2,487)	(3,952)
Prepaid expenses and other assets	(1,190)	455
Accounts payable	(3,170)	(9,457)
Other liabilities	(4,510)	(4,746)
Net cash used in operating activities	(14,424)	(5,699)
Investing activities
Acquisition of property and equipment	(7,586)	(4,259)
Equity method investment		(295)
Redemptions of held-to-maturity investments	93,208	67,402
Purchases of held-to-maturity investments	(122,978)	(75,740)
Proceeds from the sale of property and equipment	7
Sales and redemptions of available-for-sale investments	400	987
Net cash used in investing activities	(36,949)	(11,905)
Financing activities
Purchase and retirement of common stock		(3,756)
Principal payments of capital lease obligations	(291)	(341)
Tax withholding payment related to net settlement of equity awards		(29)
Exercise of stock options	655	1,026
Net cash provided by (used in) financing activities	364	(3,100)
Net decrease in cash and cash equivalents	(51,009)	(20,704)
Cash and cash equivalents at beginning of period	124,287	143,410
Cash and cash equivalents at end of period	73,278	122,706
Cash paid during the period for:
Income taxes	1,786	1,539
Non-cash activities
Unrealized change in fair value of long-term investments recorded in accumulated other comprehensive loss, net of deferred tax expense of $6 and $23, respectively	32	34
Reclassification from share-based liability compensation to equity	307	228
Acquisitions of property and equipment financed with capital lease obligations		$ 694
Acquisitions of property and equipment included in accounts payable	$ 408