CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Oct. 29, 2016	Oct. 31, 2015
Operating activities
Net loss	$ (15,814)	$ (2,562)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	3,401	2,765
Loss from equity method investments	111	122
Impairment of available-for-sale securities		2,186
Provision for doubtful accounts	119	(231)
Losses on foreign currency transactions	269	63
Loss on sale of equity securities		219
Deferred income taxes	(329)	215
Stock-based compensation	1,813	2,082
Tax benefit from exercise of stock options	22	196
Gain on disposition of property and equipment	(7)
Amortization of held-to-maturity investments	1,259	2,146
Changes in operating assets and liabilities:
Accounts receivable	29,562	(8,908)
Unbilled receivables and retentions	2,029	5,558
Inventories	(17,682)	(8,922)
Income tax receivable	(3,957)	(2,887)
Prepaid expenses and other assets	(555)	119
Accounts payable	1,413	(7,653)
Other liabilities	(7,933)	(7,417)
Net cash used in operating activities	(6,279)	(22,909)
Investing activities
Acquisition of property and equipment	(4,514)	(2,804)
Equity method investment		(186)
Redemptions of held-to-maturity investments	53,961	55,847
Purchases of held-to-maturity investments	(79,052)	(43,072)
Proceeds from the sale of property and equipment	7
Sales and redemptions of available-for-sale investments	400	987
Net cash (used in) provided by investing activities	(29,198)	10,772
Financing activities
Purchase and retirement of common stock		(3,756)
Principal payments of capital lease obligations	(192)
Tax withholding payment related to net settlement of equity awards		(29)
Exercise of stock options	258	544
Net cash provided by (used in) financing activities	66	(3,241)
Net decrease in cash and cash equivalents	(35,411)	(15,378)
Cash and cash equivalents at beginning of period	124,287	143,410
Cash and cash equivalents at end of period	88,876	128,032
Cash paid during the period for:
Income taxes	1,786	1,519
Non-cash activities
Unrealized change in fair value of long-term investments recorded in accumulated other comprehensive loss, net of deferred tax expense of $29 and $18, respectively	43	27
Reclassification from share-based liability compensation to equity	307	$ 228
Acquisitions of property and equipment included in accounts payable	$ 704