Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 24, 2017		Jun. 25, 2016
Cash flows from operating activities:
Net income	$ 17,193		$ 771
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Loss on disposal of microwave communications equipment business	278		55
Depreciation and amortization	4,339		5,365
Share-based compensation expense	3,476		3,533
Deferred income taxes	(986)		(740)
Changes in other accrued liabilities	308		271
Changes in other assets	90		(30)
(Gain) loss on disposal of assets	(21)		38
Changes in current assets and liabilities, excluding effects from acquisitions:
Accounts receivable	(23,106)		(2,811)
Inventories	(9,557)		1,045
Accounts payable	7,034		514
Other current assets	(1,773)		(1,362)
Income taxes payable	822		(2,647)
Deferred profit	(610)		3,130
Accrued compensation, warranty and other liabilities	(279)		(1,170)
Net cash provided by (used in) operating activities	(2,792)		5,962
Cash flows from investing activities, excluding effects from acquisitions:
Sales and maturities of short-term investments	30,657		6,991
Purchases of short-term investments	(20,477)		(14,554)
Cash paid for Kita, net of cash received	(11,716)
Purchases of property, plant and equipment	(2,415)		(1,767)
Cash received from sale of fixed assets	109		813
Net cash used in investing activities	(3,842)		(8,517)
Cash flows from financing activities:
Issuance (repurchases) of common stock, net	4,420		(1,560)
Cash dividends paid	(3,221)		(3,148)
Repayments of long-term debt	(840)
Net cash provided by (used in) financing activities	359		(4,708)
Effect of exchange rate changes on cash and cash equivalents	2,702		606
Net decrease in cash and cash equivalents	(3,573)		(6,657)
Cash and cash equivalents at beginning of period	96,045	[1]	115,370
Cash and cash equivalents at end of period	92,472		108,713
Supplemental disclosure of cash flow information:
Cash paid for income taxes	3,761		5,161
Inventory capitalized as property, plant and equipment	122		142
Property, plant and equipment purchases included in accounts payable	348		131
Dividends declared but not yet paid	$ 1,673		$ 1,601

[1] Derived from December 31, 2016 audited financial statements